By Adam Hutchinson
This 4age engine had notched up 130,000 miles and was then replaced with an import engine, poor
thing!… it had been sitting in a garden under a tarpaulin for nearly a year.
When a mechanic told me that my current engine was on the way out, I decided I
would rescue this ‘garden ornament’ 4age and inject a new lease of life into it.
I will use common techniques and materials available from the average car or diy
store, and a ‘Haynes’ MK1 MR2 manual bought from this site at £14.95!
Some work will be sent out to an engine shop (a very minimal amount) and I will also complete some
of the technical machining work myself to help save some of the regular expense
from a commercial re-build.
A new engine block and head from Toyota (short block) was £1722 + vat (around £2k), that’s without
all the expensive ancillaries, and just one more thing - they don’t make them
anymore! So lets see what costs we can save and what kind of build can be
achieved - and with some good work and a lot of love, I’ll have a superb example
restored and replenished and ready to run another hundred thousand miles in the
way only the AW11 can…..
01 cam side view
02 gearbox side view
03 under air intake manifold
04 rocker cover
05 under air intake right
06 inlet valves
07 inlet manifold
08 inlet manifold top
It is most probably in average shape for its year and mileage, The standard bhp is 122.
with a few nips and tweaks, and some ‘extra costs’ I hope to achieve just over
the 130bhp mark - at the very least, I will have a new condition engine to run
on. I’ll submit the rolling road readings when its finished!
As you can see, the engine looks like it could be doing a whole lot better from the outside
views.... I have no idea what lays within as yet, first things first.. some
notable amount of work must be put into the ancillaries that are attached with
rust or screws??……we are about to find out…..
The first part of this engine I will refinish are the bits that are first to come off!, they are
the inlet manifold and the throttle body, so with a set of spanners in hand, I
set off...
The mechanics of the throttle body seemed fine, springs and such like were pretty strong. I
didn't sand blast the bore like I did the outside as it needs to be a smooth
surface to stop build up of crap from the air, It seemed to have a black film in
the bore particularly on and around the brass flip gate. I cleaned this with
paraffin and a soft brush and buffed it up with scotch brite cloth.
09 throttle body blasted and bore buffed
The inlet manifold
had seen sunnier days too, not really a whole lot of work here, just general
cleaning / degreasing and bringing the finish back up. I sand blasted the
outside, then treated the gasket seating faces with various abrasive mediums.
Firstly I filed the gasket seating face as flat as possible, I was careful not
to take too much off, I then used some emery cloth followed by scotch brite for
finishing, the difference you can see in the shadows is very small probably less
than a thou .001" or .0394mm, this will be compensated by the gasket. I could
have took too much off which would have left dips in the face which wouldn't
form a good seal. Better to leave it on than go too far.
10 inlet manifold blasted
Reference them with how they looked on the weekend with the first lot of pics. Sandblasting is
a God send, also I put them through a degreasing machine to clean the build ups
of dirt from the inside of the castings.
Next come the injectors. I cleaned the injectors thoroughly in paraffin and blew the gauzes
out with compressed air to remove any dirt trapped in the internal filters. They
look in good shape, the bush seals are fine on the injectors, the little gauzes
inside the injectors are nice and clean now. The jet holes in the tip are in
good shape too, under an eye glass the holes have nice square shape edges where
they break through, so no signs of bellmouthing or wear. Generally in good
condition. I will replace the o-rings though as they look a bit out of shape and
round after 130,000 miles of vulcanization - (toughened up from the elements) I
wonder if the bore size of the jet holes is stated in Haynes? I can check these
hole sizes with pin gauges, but honestly they look in very good shape.
The water pipes you saw before were in pretty bad shape, so firstly I sandblasted them to remove
the red rust, being careful not to remove the zinc plating at either ends of the
pipes and also the plating on any smaller pipes attached. The zinc plating will
only rust after years of weather erosion so mine was still pretty good upon
inspection, you can see it in the untreated pipes pic, to the right of both
pipes at the end, I taped them up before sand blasting. The pipes were then degreased.
Because these pipes are for the flow of water (made out of steel too) and had some
considerable erosion before blasting. I asked around for the best said treatment
and came up with 'Smoothrite' which is 'Hammerite’s' little brother and is
available in a spray can application, so makes for easy work, it cost me £6.99 a
tin. I bought the silver colour, which gives a smooth matt finish. 3-4 coats, 15
mins in between coats. That will keep my pipes shining for years to come ……
11 Water pipes painted with Smoothrite silver
The throttle body was in sound mechanical condition as per checks and refinishing before. Before
painting it was sand blasted and degreased. The finish I wanted for this was
metallic, I chose a metallic silver spray made by Tetrosyl this cost £4.99 for a
spray application. Tetrosyl also manufacture a lacquer specially formulated to
coat their metallic and pearlescent series of paints available at around £4/5.99
for a spray on application. So after giving the throttle body 3-4 coats of
metallic silver paint, I then gave it 3-4 coats of lacquer which gives a hard
transparent coating to the metallic coat - great! The finish is excellent will
show up great in the engine and will last a good few years to stop oxidisation
of the bare aluminium cast parts, (and easy to wipe off crud too).
12 Throttle body painted and lacquered
The exhaust manifold bracket was rife with red rust too, so again, sand blasted and
degreased, and then I gave it a good coating of silver Smoothrite for a great
finish to keep the rust well away. I will say here that I have chosen not to put
Smoothrite on the various aluminium ancillaries of the engine, purely for the
fact that Smoothrite is a rust preventing paint, and aluminium does not rust -
it only oxidises. So, Smoothrite for all the steel parts, the cast iron engine
block and the oil sump, and a metallic 'fleck' paint with a hard lacquer coating
or just a coat of clear lacquer for the aluminium parts.
13 Exhaust manifold bracket
Here are the two main castings of the air control valve. they were thoroughly cleaned with
paraffin and a soft brush first off, this helps to clean the carbon deposits out
of the bores and cleans most oil and dirt off the components. Once cleaned, I
inspected the spring mechanisms and tooling, they seemed pretty taught and the
tooling was in good order, (see Haynes for a vacuum check to check the whole
component) there was no visible damage or un-treatable deformities of any kind
on either of the castings. I buffed the faces with emery paper to remove the
traces of the old gaskets, followed by running a Swiss file across the faces
flatly and very softly to remove any gouging or possible nicks (there were none
anyway but just to be sure) as the gasket needs a flat face to seat proper, you
will find most tolerances in the Haynes manual, most gasket faces have a limit
of 0.05 mm out of flat. Mine was fine, I could tell, I'm a toolmaker! - but you
might want to put a straight edge across the faces, hold up to the light to
check for any light gaps, and put a shim where the gaps are to check the
tolerance is good. Once the faces were certified good, I buffed them with a
smooth Scotch Brite pad to be doubly sure (I'm a perfectionist!) - not mirror
finish though, that's too smooth, you want a tiny key for the gasket material,
but still smooth!...get me??...see pics.
14 AIR CONTROL VALVE CASTING
The bores of the castings need to be shiny and smooth as this helps retard the deposit of carbon
and dirt in operation. If there are any scratches or pits or nicks of any kind,
you must buff these out with a smooth Scotch Brite cloth till they are nice and
shiny. The brass stops in the bores I buffed up with a wire brush tool on a
portable die grinder (electric Dremel will do fine) Be careful not to scratch
the bores! - and if you do just buff them again with Scotch Brite. The outside
faces (sides) of the castings were pretty dull and pitted and slightly eroded,
so...as with most other outside faces on the ancillaries, I sand blasted them to
take any deposits off and bring them up to original condition. When
sandblasting, tape over the whole gasket face with brown tape and cut round the
edges of the castings to protect the 'now' shiny bores of the castings, you
definitely don't want a sand blasted finish in your bores.
That really goes for any bores or 'inside' pipe work in the engine, they want to be smooth and as
shiny as you can get them. Once sand blasted, I dipped the two castings into a
bucket of paraffin and gave them a good wash, followed by a degrease in a
machine. If you only had paraffin this would suffice.
For painting I taped up the gasket faces and left the edge of the castings naked, after all,
the side faces are the only ones exposed so they need protection from the dirty
air and weather flying around under your boot lid. It's aluminium, so I only
lacquered these parts, a good 3-4 coats. A small issue with the lacquer has
popped up, I'm not sure how it will react to heat from the head, the air control
valve is bolted straight onto the head so undoubtedly heat will transfer into
it. Just how much I am not entirely sure, I'm quietly confident that it will be
ok, at worst the lacquer will turn brown with heat, for sure, I will only be
able to tell when the engine has run hot - a way off yet! And if that does
happen I will get an infra red beam thermometer, direct it at the brown spot
when the engine is running and survey the reading, I then should be able to
approach the paint shop with a figure for some appropriate lacquer, is there
such a thing?
...here are all of the parts of the air control valve cleaned, sand blasted, buffed, lacquered and
Hammerited as necessary. The control valve actuator (bottom right in pic) needs
a vacuum test (see Haynes) and the VSV valve needs a test including a 12v
battery supply (Haynes) The vsv also has an o-ring in it and a tiny spring
(don't lose it!) I replaced the o-ring lightly lubing it with molybdenum grease
to give a good lasting non solid seal. A wipe with oil will do fine, and this
goes for all of the seals and o-rings in the engine, change them while you have
the chance. In general every part was meticulously cleaned, inspected and
treated / changed where necessary, I've been building machines for 7 years! I
have a solid aptitude for mechanical mechanisms and materials, if you are
unsure, see a parts specialist or a good mechanic should do.
15 Air control valve exploded
....here is the air control valve re-assembled. There are two small seals on each casting, they
seal the rotating pin which goes through the bores on which the stops are fixed
to. I put a tiny amount of grease on the outside face of the seal, it should
prevent dirt getting into the bores from the outside. It's not full proof but a
fair precautionary measure. I also greased the pin on which the control valve
actuator pivots on to operate the open/close action of the valves. Any joint
that moves or any metal to metal mechanism should be greased / oiled.
I have just noticed that I put the vacuum tank on the wrong way, will reference it and right
it! with the picture I took. Always a good idea when taking a complex piece apart.
17 Long manifold bracket untreated...
18 ...and cleaned
Here are the spray paints I have been using so far, firstly the metallic fleck paint, it has a
small brush in the lid, excellent for detail work if you get that far. The
lacquer in this series is specially formulated to coat the base colours and
effects. The base paints will adhere to most surfaces including steel, aluminium
and other irrelevant stuff like wallpaper and cardboard. Use with a good coating
of the hard lacquer for good results. And to the right, the Hammerite smooth
paint, a Godsend when re-furbishing steel with the view for a 5 year protective
rust preventative coating. It will adhere to aluminium and zinc only with a
special undercoat also available in the Hammerite range. These paints will form
the bulk of the protection for the small ancillaries of my engine. Later I will
introduce some more paints, i.e. heat resistant for the exhaust manifold and
block and sump.
19 Adams little helpers
20 new water pump £40 from Fensport
21 head gasket and manifold seal / semi hardening general gasket seal £3.99ea
22 head gasket set, £80 from Fensport. no question, buy it if considering a rebuild, need new seals.
I will have all the ancillaries off and treated by the end of this week, there is not much left!
One of the last ancillaries is the water pump and housing, as I said earlier I
bought a new water pump, so it was only a matter of re-furbing the water pump
housing bracket itself. The inside chamber of the bracket was pretty well kept
(due to being washed with coolant when running) the outside was the usual dull
dirty, gritty pitted appearance and in need of some love. I cleaned with
paraffin, removed the old gasket deposits and the o-ring, buffed up the gasket
faces, and then taped the faces up ready for sand blasting. After sand blasting
the exterior I removed the tape, degreased the housing and blew off thoroughly
with an air line (use if you have the facility). The o-ring was a flat solid
rubber type, I will replace it with a standard hollow rubber o-ring this is good
enough for a water pipe.
Once cleaned I taped the faces up again and proceeded to apply 3-4 coats of metallic spray
paint, followed by a hard lacquer coating. This photo does not bring the finish
of the paint up to well, it must be seen in the flesh to be appreciated, it is
like the glitter that women wear on their face and body sometimes, superb
finish!.
Just for the record, I was unsure as I said earlier about the effects of the dissipating
engine heat through out the lacquered and painted ancillaries. I did a little
experiment, took a square block of ally about 2-3 " square and sprayed it with
the clear lacquer I'm using. I then put it into an oven (home oven will do with
no flames, and mind the fumes!) plenty of ventilation, and then let the
aluminium soak up heat for 45 minutes a time at different rising temperatures to
study any discolouration or any effects that heat might have on the lacquer.
Here are the results:
50 deg C for 45 mins ...no change So, concluding I think it will be fine on the engine ancillaries, I cant see my engine (the
outside ancillaries) getting up to 180 deg C not sure what the actual figures
are for running temperature - estimate anything from 20 on start up to maybe
90-120 at fast road pace - average 45-85 running. If the Haynes manual has any
figures I will put them up tomorrow.
23 Here is the engine mount in the cam side of the engine, it was rife with red rust.
24 Sandblasted, degreased and then given a good coating of silver Hammerite smooth.
The cam belt jockey pulley is basically a bearing, it seemed in good shape, I checked the
bearing for play, not much there, and I removed the surface rust (very little)
by putting the bearing up in a lathe chuck and applying emery cloth and Scotch
Brite. The plate that is attached to the bearing got a good coating of lacquer,
but not the diameter and running face of the pulley/bearing itself, you don't
want to lacquer that as it will rub off on the cam belt. The fan belt idler
pulley was in fine shape, I buffed the pin with Scotch Brite in a lathe. The
large piece you can see is the plate that goes in between the flywheel and the
block. I cleaned this with paraffin as I did with most other parts and then gave
it a good coating of Hammerite smooth black.
25 At the same time I gave the spark plug cover the same treatment.
Here is the exhaust manifold - I had a few minor problems with this taking the heat shields
off. When I first took it off the engine a few of the bolts sheared off in the
manifold and left a portion of the stud intact, so I drilled them out carefully,
best way to approach this is to get the manifold positioned in such a way that
the hole is perpendicular(90 degrees) to the horizontal. I then used a centre
punch to punch a dot in the exact middle of the screw thread that's left in the
manifold. If you don't get the centre when drilling you will wipe the threads
out of the hole as well as the stud in there. So I first used a smaller drill
which would follow the centre of the thread easier. Most of the heat shield
fixing screws are M6 x 1.25 The core diameter of this is around 5mm. So put a
smaller drill through first, i.e. 4mm. then open the hole out to its minor
diameter or "core size" for M6 threads it is 5mm. So with putting the 5mm drill
through, it took all the screw out and a few loose threads. I then ran a tap
down to make sure the holes were clean.
I also noted that the larger tapped holes on the manifold were M10 x 1.25, this isn't a standard
metric thread, so if you get a screw stuck in them you will either have to open
the holes out to the next size up - M12 or get a fine thread tap from a machine
shop or maybe a mechanic will have one. The next problem I had was the seating
face of the manifold onto the block, it was appalling! - The limit for flatness
on the face was 0.05 mm. and my seating face if you could imagine was let's say
level in the middle and dipped nearly a mm at either end (.039") it was well
warped! This is due to the heat that goes through the manifold. It releases all
the stresses in the manifold over time and also the manifold absorbs carbon from
the exhaust gases and it distorts somewhat. To remedy this I put the manifold up
in a vice, and hit the face with a bastard file, be careful! It took some time
to get it flat again, and once flat enough (check with a long straight edge)
across all the face, I buffed it with emery cloth and Scoth Brite to ensure a
nice smooth flat finish on the face. There! All better again.
For those of you who don't know, the cracks in the manifold come from the iron absorbing carbon
over its running life, the skin soaks up the carbon and cracks, there isn't much
you can do about it, just make sure you get hold of a manifold that doesn't look
to ropey and cracked. Mine had a few surface cracks and flat lumps of it had
fallen off, but they were trivial and there is still plenty of life left in it.
After re-finishing the gasket faces and extracting the sheared screws, I sandblasted the manifold
and degreased it. The paint I used for the manifold was a high temperature
paint, bought from Halfords or most car stores for about £4.99 a tin, it's not
going to stop the cracks and hardening, but it will stop rust and you can paint
it on anything upto temperatures of 500 deg C. It looks great, applied in
aluminium silver colour, I will use this high temperature paint on the head,
block and sump.
That's the last of the engine ancillaries, tomorrow night off comes the rocker covers and I can
start the work on the head.
26 Treated manifold
It has been a very busy week at home and work for me, here are the details of this weeks engine work...
27 Here is the engine stripped of its immediate ancillaries. You will notice it is
standing on two metal blocks, I had to take the sump off to get a good level
seat on the sump face.
28 Another picture of the stripped engine, the air intake side.
29 A view from the top of the engine.
I had to remove the sump and oil strainer in order to sit the engine square, the sump has been
degreased and painted in 'black' Hammerite smooth, and the oil sump strainer has
been thoroughly cleaned and sandblasted but not painted as it is inside the
sump, we don't want the paint flaking off and running around the engine into the
filters.
The next step was to take the rocker covers off and inspect the camshafts. Surprisingly, I found
them in superb condition (the cam lobes) there was no obvious damage or visible
wear to the lobe faces, they were still like mirrors after 130,000 miles, well
done Mr. Toyota. I believe the shafts are forged from a molybdenum/vanadium
family material. Any typical damage that I might have come across would have
most probably arisen from the cams not being oiled properly. Seems these are in
great shape and the engine has been looked after.
Notice the 'shellac' coating which is going to prove hard to remove! The inside of the
rockers covers were also coated in shellac. Treatment - for the rocker covers
themselves, I merely degreased, scrubbed with a soft/stiff brush and paraffin,
and sand blasted to clean the shellac coating off the covers. Once again
degreased the covers and painted them with high temperature paint in aluminium
colour, ONLY THE OUTSIDE of the covers though, as again I didn't really want any
loose paint falling into any working part of the engine. The oil pumping round
would most probably wash the paint off after time and cause small problems with
the engine.
31 Here are the rocker covers after painting, notice the inside of the cover is
duller due to not having any paint coating.
32 The top side of both covers, don't they look great after treatment.
After the paint on the covers dried a few days later, I bought some metallic blue Enamel poster
paint type thing from a car shop, it was only £2.99 and a brush £1.99. The
details of the covers are now picked out in a lovely metallic blue, will make
for a nice finishing touch to the top of the engine.
33 Another view of the finished covers.
Having visually seen the condition of the cam shaft, it looked good, but to be sure and really
it's a necessity if your thinking of a re-build, I checked the necessary
specifications for cam shaft thrust clearance (end play in the shafts) Left to
right etc. The standard limit in the HAYNES manual asks for play between .08 mm
and .019mm that's .0031" to .0075" The maximum thrust clearance allowable is
.025mm or .010" The method for checking this is to put a dial indicator on the
end face of the cam shaft and insert a pry bar or large screwdriver in between a
journal case and a cam lobe and very gently pry the cam either way to measure
the total clearance of the cam shaft thrust. There are a great number of checks for the head and the valves, for a good reference, you should
without doubt consult a HAYNES manual on the MR2, I wouldn't expect the average
mechanic to know the clearances and limits, there are literally hundreds of
tolerances. Only a specialist MR2 mechanic or a engine re-conditioning shop
would appreciate and play by the limits. Buy a Haynes book from this web site,
recommended!.
Valve Clearance:
Before I go on to remove the camshafts it is a good idea to check the valve clearances. This is
basically the gap between the smallest radius (or largest theoretical clearance
of) the cam lobe and the shim on the 'lifter' or 'bucket' as its known. To check
this clearance I used feeler gauges as recommended by Haynes. Checking 8 of the
valves at a time and working from the cam pulley side (front of engine) to start
with and then progressively away from it (a total of 8 measures per cam of
course <16 valves>) Here are the results I obtained: 34 A close up of the camshafts - GEE look at them shine!
Now the camshafts and lobes are clean and as new in finish. I measured the cam lobes and the
journals to check the limits, as before the log was taken starting from the cam
pulley side of the cams and successive measurements were taken away from it
until I got to the other end. That makes a total of 16 cam lobes to measure,
numbered 1 to 8 on each side and a total of 8 journals to measure. Obviously the
log will show the cam lobes and the corresponding journals numbered both 1 to 4
on each cam.
CAM SHAFT LOBES
AND JOURNALS LOG Right. The standard heights for the lobes are from: 35.555 to 35.565mm that's the standard
height's, the minimum limit allowed (or so said) is: 35.155mm Just for the record. MINES PRETTY GOOD!!
I'm quite
astonished that after 130,000 miles the camshafts can be in the good condition
that they indeed are. See.......
130,000 miles covered at an average of 3000 rpm at 60 mph = 3000rpm x 60 minutes = 180,000
revolutions of the engine per hour, distance of 60 miles is covered in an hour,
therefore: 130,000 miles divided by 60 mph = an average of 2166.67 hours driving
for 130,000 miles covered, multiply the hours driven by the revolutions of the
engine per hour and you get the total number of revolutions for 130,000 miles
covered = 2166.67 x 180,000 = 390,000,600 revolutions The camshaft pulleys are in standard form, not too much deterioration of any kind. I
degreased these and then lightly sandblasted them to take any tiny pits out of
the surface, I think they are Nitrided, which is a chemical or gas surface
hardening process. The skin will be very hard!. I then painted them with heat
resistant silver spray paint, being careful not to spray the teeth of the pulley,
only the faces. For what its worth it wouldn't really harm anything if I did
spray the teeth of the pulleys, but I don't really want any paint flaking off
onto the cam belt as it could very marginally cause a problem but most probably
not. So I just masked the teeth and hit the rest with the spray.
35 Cam shaft pulleys treated.
Now the camshafts are off, and I have checked all the necessary limits required, I can take the
head off of the block and begin the real work! Here is a picture of what I found inside my block cylinders after removing the head. Not a pretty
sight!. This is basically carbon that likes to stick to the combustion chamber
and piston faces, it will be removed later unless I renew the pistons in which
case I'll just chuck these ones out with their carbon deposits intact and let
the trash man deal with them.
36 Cylinder view with coked up pistons
Here is a side on view of the cylinder bores, you see the black lip at the top, that is where the
piston rings stop traveling up the cylinder, and the carbon will black up the
top of the cylinder here where it is not 'wiped' by the piston rings. Also to be
noted here, the pistons and rings wear over time and also wear the cylinder
bore, this black mark will have a lip at the bottom of it, this is a visual and
only a visual GUIDE as to the condition of your pistons, rings and cylinders.
This lip and black mark - it actually looks a lot worse than it may be, without
measuring precisely just yet, I ran my finger over the lip, it felt pretty
minimal maybe a thou or two (.001" to .002") It could mean that I maybe will not
have to re-bore the cylinders, I could maybe get away with a just a hone and
some new rings, it all depends on the measured size of the cylinder bores and
the overall diameter of the pistons. I'll keep you up to date when I start work
on the block.
37 Wear lip on bores view
Here is the head - the valve side of course as the cam side is stripped. Again, totally clad in
lovely carbon, this will probably be the state of combustion chambers with this
many miles.
38 Coked up valve view of head
39 Close up of valve faces coked up
I can see by looking at my valves that they are seated ok, this tells me straight
up that there are no valves that are bent enough to cause a problem, probably
so, not bent at all, I couldn't say right now but it looks good. 41 Here is the head with the valve spring compressor in use on a valve spring
assembly.
I had to make a simple tool which would compress the top of the valve spring and still let me
reach the 'retainers' that are inside and hold the spring cover in place. I made
it from ¾ steel tube 60mm long and chopped 120 degrees out of it right through.
Once the head was half clean I could now progress onto cleaning and polishing the inlet and outlet
ports as best I could. I found the ports were pretty well designed with regards
to air flow, so as for porting and polishing, I wouldn't suggest a whole lot
here. Other than fettling any imperfections out of the ports. I actually fettled
for a good 6 hours on all the 8 main ports and 16 valve entrances!.
I used a high rpm hand grinder (Dremel will do) with an emery cloth wheel on it! I wouldn't advise
a regular abrasive wheel as the head is aluminium and the regular aluminium
oxide wheels would gauge the ports quite bad. After the emery wheel, I then
rubbed all the ports and valve entrances by hand (or should I say finger) with
emery cloth again, so my finger would follow the contour of the irregular bores.
Next step was to wrap a slightly coarse Scotch Brite pad round the spindle of
the hand grinder and polish the all the bores with that. Then I used a finer
Scotch Brite pad and spun it again at 33,000rpm! Gives a nice smooth finish
relatively polished on the bore surface.
The final step on the inlet and outlet bores etc, was to wrap some cloth round my grinding tool
and use a diamond lapping paste in the bores, again at 33,000 rpm gives a great
finish. I first used a 45-micron compound then went round again with a 3-micron
compound. My outlet ports are now nice and smooth and shiny, with little chance
for carbon to pick up and this process should help the vacuum flow of the
exhaust gases out of the head. I would estimate after 6 hours of fettling and
polishing with FINE abrasives, I may have taken off around 3-4 thou (about .1mm)
of material throughout the ports. 6 hours may sound a long time, and you may
think there would be nothing left of my head. The fact is I used fine abrasives
and also there are 16 valve entrances and 8 main inlet / outlet ports, they are
awkwardly shaped and that what takes the time up, and the skin off your fingers.
I don't have any pictures of the disassembled valves, only when they were assembled in the head
and clad in carbon. Although here is a picture after I finished cleaning them
up, note the mirror finish on the faces, this will aid combustion greatly and
will not attract the carbon to it, therefore they should stay in good shape for
a while yet, and shoot my pistons down like a shotgun. I used a diamond lapping
compound (4 grades actually) and spun them at around 3000rpm on a polishing
machine, took me around 5 hours solid to bring all 16 valves up to this
condition. Before polishing I also surface ground the faces square to the stems,
mainly just to give me a good base to polish from, I only took a few thou of
each (.002"-.005") keeping a close eye on the margin width of the valve which
Haynes calls out to be .5mm or .020" taking a few thou off will not matter so
long as the valves are in good shape to start with, here are the inlet valve
faces....
42 Inlet valve faces polished
The exhaust valve faces:
These were in worse shape than the inlet. they are subject to much higher temperatures and it
was a labour intensive careful job to get them back and furthermore to the way I
wanted them. Also to be noted here - they were Rock hard! I mean I could
estimate a surface hardness of something like 64-67 H.R.C. and they DID NOT like
being ground. The first valve I offered up to the surface grinder in a six jaw
chuck was ok for about 50% of the surface area. then when it was cleaning up
more so it started to 'ring' and I reckon the head was about to jump off, I was
lucky. Even with only 15mm sticking out the 6 jaw I reinforced the the gap
between the seating face and the face of the chuck with plasticine. (common
practice in a tool shop) this reduces the nymonics (sound vibration) and stops
the valve wanting to ping off its stem when I take a cut! - could have been
messy!! But with some careful machining here they are.
43 Exhaust valve faces polished
Now the faces were dealt with, it was time to deal with seating faces which are underneath the
valve heads. This is the face which you can see with the GREEN arrow pointing
at, at the top/middle of the face i.e. towards the seated end of the valve, this
portion of face is the only bit of the face that should sit on the valve to
start with when a valve job is done. There is a specific size called out in
Haynes for this portion of the face. It is between 1-1.4mm or ..039"-.055" We
will not worry about this just now (the size of contacting width) more
importantly I have to make sure the faces are not pitted, cracked, or burnt so
that they will form a good seal on the valve inserts in the head. I found quite
a few to be pitted and burnt, none cracked. So I decided I would re-grind all
the valve seating faces.
I was lucky to have access to a cutter grinding machine which is very accurate and I could
grind them quite easy on it. It took me around 2 hours for all 16 to be
precision ground at 44.5°. I took off the minimum material required to clean the
seating faces up true and totally. anything from .001" to .004" was removed. I
was careful not to take too much of the faces and again keeping a close eye on
the margin width. They turned out fine, and with that process, the valves
themselves were now in great shape, ready for lapping into the valve seats in
the head when the head portion of the work is also complete.
Here are the exhaust valve seating faces re-ground, the arrow on this picture is more
pointing towards the measured portion of the face that should not make contact
with the valve seats in the head itself, it should actually be clear from
contact as you will see later when they are lapped in.
Right, now the valves have been re-finished very suitably, I will show you a log of the valve
stem diameters. I actually made a log earlier (sensible move) before I started
any work on the valves. This log is the diameter of each valve stem, I measured
each stem in 3 places from top to bottom of the stem, on the portion that runs
in the guide bushes (easily seen between the light marks at the top and bottom
of the valve stems in the pics. I used a high quality micrometer, which I only
bring out for work like this, a regular micrometer would be ok if it was in good
shape and calibrated! 45 Set of 4-age oem valve springs
The stem seals came in the head gasket set which I already have. I will re-assemble the valves
once any necessary work on the head has been done i.e. re-bushing and re-cutting
of the valve seats.
Right, now the valves /cam shafts/ valve springs / are dealt with, the only other components
left to clean and possibly replenish were the cam shaft half bearings, these
were in fine shape, all I did was to tape up the bearing surface and lightly
sand blast the exterior very carefully, just to remove the shellac. Once blasted
I removed the thick tape from the bearing surfaces, cleaned them in paraffin and
very lightly lapped the seat faces on a lapping stone, I might have taken a few
microns.. (.002mm) this was just to ensure a good seat when they are put back on
the head, I was very careful not to take any more than that the arrow in the pic
points to the lapped finish, as flat as they will ever be.
46 Cam shaft caps
The guide bushes in the head I checked with pin gauges of various diameters. I had a: the 6.010 went in all, 6.020 went in all and a little bit tighter in the inlet valves than the
outlet, the 6.030 was very tight in the inlet, and only a fair drag was felt on
the outlet. The 6.050 only entered at the very top of all the bushes for about
1-5mm. The 6.050 was only to tell me that the valves are not bell mouthed or
excessively oversized, the 6.000 is to tell me that none were undersize, and the
6.000 went in all, so all was well with the guide bushes, no need to re-bush the valves.
Last but not least I checked the lifter diameters and the lifter diameters respective in the head
casting. I used a telescopic gauge for this and a mic. They were all in limits
very nicely, and the clearance of lifter to head was very consistent throughout
and within the tolerance of .015 to .046mm I went for a head skim too, nothing major, just a clean up of the gasket face, which turned out to
be .002' (.05mm) and another .004” (.1mm) to give a tiny nip to the compression
ratio and ensure a good flat seat on the block. So the total taken with the skim
was .006” (.15mm)
The skim is fine, I am happy with that, but the valve cutting wasn’t exactly what I was expecting.
I noticed that of the three valve face angles 30,45 and 60 degrees, they only
cut the 45 degree face, this isn’t good enough, as when they lapped the valves
in they lapped in full face, and Haynes manual clearly states a contacting width
of 1 to 1.4mm. Where I had more like 3mm of lapped ring on the contacting face.
The reason the limit is controlled to a small width of 1 to 1.4mm is to keep ‘valve bounce’ out
of the picture.. if the width is too large, you will get valve bounce and they
wont seat properly when shooting up and down at a great rate of speed. So…..
this must be sorted out properly and the correct widths must be followed.
I went back in to the engine shop and asked the guy why he didn’t cut all 3 angles…(this would
limit the contacting width on the stems when lapped in if they were cut
properly) and he told me that he didn’t have the correct tools to cut the valve
seats, instead he only had means to re-cut the main seat angle, that’s the 45
degree facet.
With that and the fact it was bank holiday weekend, I decided to knock up a tool to cut the valves
which would give me the correct clearance of contact on the 30 degree and 60
degree angles. Here is an exploded picture of the valve cutting tool I made.. it
has a stainless body, turned and knurled, with a 5/16” reamed bore, a constant
velocity (cv) joint on the chucking end to take up any untrue influenced angle
when cutting in a hand drill!!!. I ground a 5/16 drill blank down to 6.01mm for
a length of 50mm and luckily… had a set of 30/45 and 60 degree arbor milling
cutters with a 5/16” bore! So I milled some lugs on to the stainless shaft, put
my drill blank up the bore, chucked the whole tool in a hand drill, and slid the
arbor mill over the 5/16” diameter drill blank. Please don’t try this at home!!
I am an experienced toolmaker / machinist / engineer, it was a gamble for me,
but I know my limits and machining, and as planned the valve cutting tool worked
a treat, saved me from paying any extra expense when the cowboy in the engine
shop tried to fob me off as Joe Public. So if you have your valves re-cut.. make
sure that they cut the faces necessary to give you the correct seat on the
valves of 1 to 1.4mm here are the tools I used to cut and lap my valves…the
sucker stick! and lapping paste, was a total of 4.25 from a car store.
48 Valve cutting tool exploded
49 Valve cutting tool assembled
50 Lapping stick and pastes
Note the green arrow in this pic pointing to the lapped portion of the valve seat (the 45
degree face) if you look above and below the arrow, you can see the 30 degree
and 60 degree faces that should be cut to give a smaller 45 degree face. These
were the faces I had to re-cut after the engine shop ‘missed’ them. So long as
the lapped ‘ring’ on your valve stem seat faces is 1 to 1.4mm everything is
fine. Note the lovely grey ring of correct size!….
51 valve seats after re-cut and re-lap
52 valve stem seats after ‘correct’ valve cutting and after lapping
Ok, the head work is complete, it can now be re-assembled and the final op on the head can be
completed, that is once all re-assembled, the valve clearances will have changed
due to the work that has been done on the valves, so… simply, I will either move
the shims about to give correct valve clearances, and also may surface grind
sizes etc or buy new shims. These can be brought from Toyota or an engine shop.
Re-assembly of the head:
When re-assembling
the head, the first thing to go back into it was the valve stem seals that came
in the head gasket set. To put these in place, I put a very small wipe of oil up
the bore of the seal and just pushed them home on the valve guides. Be careful
not to push to hard onto the seals otherwise the coil spring that holds the seal
on to the valve stem will pop off!. It took about 5 minutes to put the seals on,
so really an easy job. I then put all 16 valves back into the correct ports. As
before any during all assembly, I wiped oil over the components. I used a
mixture of sae 90w transmission gear oil and regular engine oil(75/25 mix), the
gear oil is thick and just helps to stick to the parts. Its vital to have a fair
coat on the part, as when the engine starts for the first time the oil wont
reach all the bearing surfaces for a short period, this is where the assembly
lube comes into play by protecting the parts until the pump has primed the
engine for the first time
I then put all the new valve springs and related components into place. Next step was to use the
valve spring compressor and compress each spring so I could put the ‘keepers’
back in place and then release the compressor. I used cloth on the valve face
side of the compressor to save damage of my lovely polished valves! and then
continued round till all 16 were in place again. That was a very fiddly
laborious task!, took me 2 hours to complete all 16 valves. But once done, I
felt the first part of my engine had come back together, quite exciting, but
still a way to go yet.
Next step was to put the lifters and shims back in and then the camshafts, followed by the
bearing caps, torqued up to the correct torque! (13nm or 9ftlb), all with a wipe
of oil etc.
Once re-assembled I had to check the valve clearances again, these turned out to be around .008”
(.2mm) small on the specified limits for both exhaust and inlet. Naturally the
limits would be undersize and not oversize as I took material off of the valve
stem seating faces, and the valve seats were re-cut. This made the valve
clearance values small… No problem, as to rectify all I did was take the valve
shims out, and surface grind them to the needed thickness, which was less around
.008” (.2mm) for each. Some needed more than others etc. I sized the shims with
a view to sitting near bottom limit of the tolerance, so I would get a longer
working life out of the clearance value before it needed re-grinding again.
If you log the amount of material needed to be ground of each valve shim, it should take a
machine or engine shop around 30 minutes to grind all 16, I wouldn’t expect to
be charged more than £15 commercial price.
Once all ground, I put them back in the lifter buckets and bolted the cam shafts back on, checked a
final time, the valve clearance values were close to bottom limits. As a final
precaution, I undid the bearing cap bolts and put a about a drip of Loctite
thread retainer (240) on each bolt, just to ensure they wouldn’t work there way
out or loose in the near or distant future. Torqued the caps up again, put the
cam-shaft seals on etc. The head is now re-assembled …..phew!
53 Head Re-assembled
Now The head is as good as finished, its time to start work on the block, basically, it consists of
4 main assembly’s, these are the crankshaft, the con rods, the pistons and the
cylinders.
The block
Before I stripped the block, I needed to check a few specifications for crankshaft end play, and
the con rod play. These were within limits of the Haynes manual. That basically
told me that the thrust bearings in the crankshaft didn’t need replacing and
that the general condition of the main bearings and gudgeon pins, and con rods
were ok . It’s not to say they are perfect… as the engine has 130,000 miles on
the clock!.. so the bearings and such like will most probably need replacing,
but the checks have just told me that there is nothing major, wrong with the
block, so that’s a good start.
The pistons and con-rods:
I removed the lip off of the top of the cylinder bores with a cylinder hone (not the right tool!)
but it would suffice for lightly removing the coke lip on the bores. Once that
had gone, I undid the con rod caps and pushed he pistons out of the bore. I
checked the diameters of the pistons, N.B the pistons are actually oval, so when
checking the diameters, mic across the skirt, which is at 90 degrees to the
crankshaft. This is the major diameter (largest) of the piston .. I checked the
diameter in three places from the bottom of the skirt up to just underneath the
oil seal ring groove, and took an average of the readings for each piston. This
would give me a good idea of my major diameter. Here are the results I obtained…
Piston from cylinder 1. 80.928mm Ok so the pistons are all in limit, gladly nearer or just above top limit too. This is good!. I
checked the pistons for any major damage, like scuffing, or any wear below or on
the ring portion of the piston. Mine seemed fine with no abrasion to the
pistons. A good indication of no wear is that the turned finish on the piston
diameter was present from top to bottom. By holding the conrods and twisting the
pistons against the conrods I could see (feel!) there was no play between the
gudgeon pins in the rods and the piston itself, in fact, 3 out of 4 pistons
still had an interference fit on the gudgeon pin, and the fourth was still an
extremely close fit, but just a little looser than the others. These are all
fine, and the gudgeon pins will not need replacing.
The top of the pistons how ever are a different matter! Firstly, I removed the old rings and
cleaned the grooves with a portion of broken piston ring. I then started work on
the profiled faces… these were absolutely caked in carbon from the combustion
process. To remove the carbon residue, Haynes recommends a soft brush and some
alcohol type cleaner or de-greaser. I tried this, it didn’t really work, so I
taped up the diameter of the pistons, and blasted the carbon off with a
sandblaster. Once blasted, I dipped the whole piston/rod assembly in a citric
cleaning solution (this works really well with aluminium, but is not
re-commended for use on aluminium!! as some types react to the citric content of
the solution, and maybe if I left it in over night, it would have eaten some of
the piston surface away!. So I cautiously kept a good eye on the pistons in the
60 minutes that they were soaking up in the citric bath, I then brushed them
with a soft brush. They came out fine with no erosion, and absolutely gleaming.
As a finishing touch, after sand blasting and cleaning the pistons, I buffed the
faces up with the use of a scotch brite pad tool in a pillar drill..
here are the pistons after some basic treatment…..
54 Pistons and con rods cleaned and buffed
The bearings in the con-rods on close inspection were worn in the middle, this was only very
marginal, like a shadow that spanned the center section of the bearing, but if
that shadow had reached the outer edges of the bearing halves, then they would
have degraded and shot quickly. These will need replacing. I bought patterned
con-rod bearings for £44.05. original Toyota big ends are £14.02 + vat each, so
I went for the cheaper. The guy in the engine shop said they would last fine
with regards to replacing oem bearings. I also bought patterned crankshaft
bearings at the same time for £33. Original Toyota mains are £10.27 + vat each
so again with the advice from the engine shop I went for the patterned parts.
Patterned mains and big ends: £44.05 mains £33 big ends Total of £77.05 inc vat I actually
received a discount on these parts of 25% because of the earlier
misunderstanding with my valve cutting. So the total bill came to £57.78.
55 Patterned mains and big end bearings
Note the 4a-gze marking on the box!.. basically the con-rod journal diameters on the crankshaft
are the same in the Later modified 4-age (42mm) as the 4a-gze
(supercharger) so they will do me fine! Just for the record, the earlier 4-age
engines (first stage) con-rod journal diameters are 40mm.
The piston rings will also be replaced, it is a must when re-building etc, as with most probably
the bearings dependant on the state of your engine. I managed to source a set of
original equipment Toyota rings for a discounted price!.. the parts had been
sitting on a shelf in a Toyota dealers for some years, so they gave me a 20%
discount on these, which worked out to the same price I would have paid for a
patterned ring set. The oem Toyota are £76.74 + vat less 20 % !.. £72.13
56 o.e.m piston ring set
When assembling the rings on to the piston, I wiped the piston with oil and also the rings,
there is a ring expander tool especially for putting the rings onto pistons, but
if your very careful in only opening the rings just enough to slip onto the
piston and down into the grooves, you might not snap them! I managed to assemble
them all ok with no breakage.
The crankshaft…..
OK, this is basically the heart of the engine. What I did to clean the crank shaft up ready
for closer inspection was to bath it in the citric cleaning solution. I left it
in over night, and come the morning, with a little use from a soft brush it was
gleaming once again. What I did notice that on both ends of the crankshaft where
the front and rear oil seals ‘sit’ there were grooves worn into the diameters of
the shaft. Also a thin ring of material was swaged ‘up’ from the shaft. These
wear grooves have come from the oils seals themselves, as they are constantly
pressing onto the shaft. I will deal with these shortly, firstly, now clean, I
checked the diameters of the crankshaft main journals and rod journals, they
were very consistent throughout and also in very good condition, with no visibly
taper or scuffs or scratches/gouges etc. The diameters were as follows:
57 Crankshaft cleaned
Main journals: 41.985mm
Rod journals: 48mm
The limits for these diameters are 41.985 to 42mm and from 47.985 to xxxxxx
These are now
checked, to remedy the marks where the oil seals sat, I polished them with
diamond polish.
Right, now the crankshaft is looking good once again, all that is left of the engine block is
the block itself!.. The cylinders are in pretty good shape visually, I can still
see the cross hatching of the hone on the cylinder walls, so I'm not expecting
any major wear of the bore diameters upon inspection. To gauge the bores, I used
a telescopic gauge and a 3-4” mic as you would. Here are the results I
obtained…..
Cylinder 1 81.019mm, Cylinder 2 81.023mm, Cylinder 3 81.009mm, Cylinder 4 81.015mm.
Haynes calls for a size of 81.00mm to 81.03mm with a .2mm limit undersize. We can see these are
fine, but what will need to be done is to ‘bust the glaze’ of the bores.
Basically, the piston rings wear the faces of the cylinder very smooth after
time, and the oil flow up the cylinder walls is suppressed some what, both
degrading the cylinder wall and ring over time and hampering the performance and
‘correct’ running of the cylinder. So.. we bust this glazed surface with a
honing operation, once honed properly, the oil will flow up the 30 degree
witnesses left in the cylinders and will lubricate adequately. You can buy a
tool to hone the cylinders, but if your not experienced I seriously wouldn’t
recommend messing about with one of these tools and a hand drill, it’s typical
diy bodge! I'd take the sensible option of sending your block out to be honed at
an engine shop or machine shop. You know that way that you wont have any serious
bellmouthing, and a nice uniform parrallel hone will be achieved throughout.
It’s a cheap operation too, with the engine shop I am going to use they charge
3.50 per cylinder to bust the glaze and re-hone. I wouldn’t expect them to take
more than .0005” to achieve a nice finish again. If they took .001” as a maximum
I would be happy with that as there’s still plenty room before the sizes hit
bottom limit…but still… no more than necessary.
Before the block goes out for honing I will clean it up! Firstly, I cleaned any excess grease off
of the block with paraffin, once cleaned, I taped up only the cylinder bores and
the bearing cap faces, but they were taped very thoroughly. Im going to sand
blast block exterior, I wouldn’t advise sand blasting if you don’t have a means
to clean the oil galleys and water jacket out properly after sand blasting, and
don’t sand blast the cylinder bores or bearing journals!. I will use a high
pressure washer, and make sure all the grit comes out out of the various
crevices and the water runs clear. It actually took me 2 hrs hard labour! to
remove all of the loose red rust and shellac off the exterior faces. I then
rinsed through the galleys and various crevices for a good 15 minutes until
totally clear and the water was running clear too. I must have gone round each
crevice a good 10 times.
The block was then dried very thoroughly under air pressure. I noticed the block turned orange
instantly after applying cold air at high pressure to it. Don’t worry about this
orange appearance, but clean it quick.. I used a soft brush and some thinners
which evaporate quick. The block was then taped up (all gasket faces and seating
faces and cylinder bores/bearing caps). Obviously I have no intentions to paint
the bores or bearing journals, or anything actually inside of the engine when
re-assembled. I used a high temperature paint on the block, brought from
Halfords, the same stuff I used on the head, but this time it was matt black
paint. It is not totally necessary to use heat proof paint on the block, it does
not really get hot at all. I'm just a bit fickle like that! I used a whole can
of spray on the block, again not necessary, but will give a nice thick coat that
may not be so easily chipped and dented by wandering spanners. And just for
reference, the paint does not actually cure until the engine is up to
temperature a few times, but it will be touch dry until then.
65 Block after treatment
The block has gone out for honing now, when it comes back, the engine will be re-assembled at last!
Here are some pictures of all of the parts that have been treated so far - how
are they looking??
66 Part layout 1
67 Part layout 2
68 Part layout 3
And here's the block after honing, as I said, they took less then a thou (.001”) out of the
bores to bring them up again.
69 Block after honing
Now the block is
finished. The head is finished, The necessary parts have been applied, and I
have all the other parts needed, I can put the engine back together. For this I
used the necessary gaskets, the gasket sealing compounds (hard and soft setting)
a torque wrench, all the cleaned bolts and nuts, and some assembly lube. Here
are some pictures at a few different stages of assembly.
70 New shells in journals
71 Crankshaft and oil pump in
72 Rods and pistons in
73 Sealing the head for assembly
74 Head and camshafts on
And here is the finished product
75 Engine assembled view 1
76 Engine assembled view 2
77 Engine assembled view 3
78 Engine assembled view 4
79 Engine assembled view 5
A fine example of the AW11 engine:
80 Engine assembled view 6
The total costing for mandatory components and labour was as follows:
COSTING LOG:
Part or process:
CYLINDER HEAD CYLINDER BLOCK: CRANKSHAFT
ANCILARIES AND MISCELLANEOUS PERFORMANCE ENHANCING ANCILLARIES Discounting the
performance enhancing extras that are not totally necessary, the build including
the discounts I received from Barnet Toyota and Fensport Cambridge came to a
total of £839.19 inc vat
To be noted here
are the foc costs (free of charge) of which I completed the machining work
myself, to give you a rough idea of what these charges may be, should you not be
able to complete the technical machining in your own time, here is a rough guide
…. OK, there we have
it the actual figure for purchasing necessary parts and a small amount of engine
shop work was £839.19 + a Haynes manual from this site! At £14.95 = £854.14
I think that’s a
very small amount to pay for a new thoroughly over hauled engine. Assuming the
re-furbishment work is undertaken by yourself.
The total cost for
my project including the performance enhancing parts is £839.19 + £14.95 +
£632.91= £1487.05
I would like to thank:
Fensport Cambridge, for their 10% discount
on bulk purchasing of parts.
Peter at Currie Motors Barnet
(Toyota dealership) for various discounts and a great service.
My boss David
Dawson of Dawson Shanahan Ltd
(specialized sub-con production engineers) For letting me build the engine in my
spare time at work! And using our machining facilities....(thanks boss!)
Richard Morgan the editor of this site, for some resource on the re-build and allowing me to
display my efforts on the site. For the benefit of the MR2 MK1 Club.
81 Engine assembly view 7
Thank you all….
Vroom!!………………
The engine is
being fitted in 2 days time, I’ll post up some pictures of it fitted, and soon
to come will be the rolling road results (dyno).
Thanks, Adam As I said earlier - ready for another 100,000 in AW11 style
The club would like to express its thanks to Adam for his superbly documented 4AGE engine overhaul - Richard Morgan, webmaster.
120 deg C for 45 mins ...no change
160 deg C for 45
mins ...very slight yellow tinge (still transparent)
200 deg C for 60 mins
...yellow tinge more apparent, rather like a tobacco stained ceiling, my camera
would not pick up the change, but it is there.
valve
clearance log:
dimensions in MM
INTAKE CAM SHAFT
Inlet valve No.
1 0.3
2 0.24
3 0.27
4 0.21
5 0.22
6 0.21
7 0.17
8
0.17
Haynes clearance value limits for intake: .15 to .25mm
EXHAUST CAM
SHAFT
Outlet valve No. 1 0.265
2 0.31
3 0.235
4 0.32
5 0.34
6 0.37
7 0.39
8 0.33
Haynes clearance value limits for exhaust:
.20 to .30mm
As you can see the values obtained are not bad for an engine
with 130,000 on the clock, not to say they are in limit totally as some of the
limits are just out. For instance looking at the intake valves - valve no 3 is
out of limit by .02mm that is a tiny amount, but really we want it to be
perfect, I'll deal with that later.
The exhaust cam on the other hand is
slightly more out of limit, valve's 2,4,5,6,7 and 8 are out of limit, .01mm
being the smallest value and .09mm being the largest value. Still in engineering
terms this isn't a great amount of clearance, but the never the less, it should
be in limits, and I will correct these clearances later. This is just a log so I
can refer to it once the head has been totally stripped and rebuilt, with any
necessary machining and valves cut and lapped etc. With that possible work these
clearances will change and to correct these clearances we usually replace the
shims with the adequate size shims required.
Right - Now the camshaft /
valve clearances have been checked I can remove the camshafts. You can see by
the previous photos that the camshafts were covered in film of shellac (oil
residue that sticks to your cams and such like!) To remove this I first brushed
the camshafts in paraffin and then lightly rubbed the lobes and journals with a
fine Scotch Brite pad, this removed all of the shellac and left my lobes and
journals fully shiny once more. I then polished the cam shafts with a diamond
lapping paste and a soft cloth, I first used a 45 micron compound then a 3
micron compound (.003mm) this is the size of the grit. Remember I'm just
polishing the camshafts I don't want to remove any material so I didn't polish
for long and very lightly too, but enough to buff it up almost mirror like. Here
is a pic of the finished camshafts:
INTAKE CAM SHAFT dimensions in MM
Cam lobe No. 1
35.45
2 35.46
3 35.45
4 35.43
5 35.45
6 35.44
7 35.46
8 35.47
Journal No. 1 26.95
2 26.95
3 26.96
4 26.95
EXHAUST CAM SHAFT
Cam lobe No.1 35.45
2 35.45
3 35.43
4
35.43
5 35.45
6 35.46
7 35.45
8 35.46
Journal No. 1 26.95
2 26.95
3 26.96
4 26.96
The journal
diameter should be between 26.95 and 26.97mm That's the limit and there's only
.02 discrepancy allowed, any more and your camshaft journals will start eating
away slowly but surely at the head journal seats. This is accumulative according
to the amount of wear in the respective parts.
I think the camshafts
rotate half a turn for every revolution of the crankshaft. Therefore divide that
last figure by two and it gives the total revolutions of the camshaft for
130,000 miles. 390,000,600 divided by two = 195,000,300 revolutions!!
WOW! -
the cams have done that many revolutions after that many miles, and in the
condition they are in now. Quite an astounding result. Well done Mr. Toyota for
a fine choice of camshaft and shim material!
The head came off easily
enough, be sure to use a 12 sided socket! The special type for the head bolts,
and make sure its in good condition, if you chew them bolt heads up you're in
trouble!. Mine were pretty stubborn, but with some sensible down force on the
bolt they shifted ok
It's time
for the valves to come out, to achieve this I used a valve spring compressor.
Once all the valves and the valve seals were removed and bagged individually
I thoroughly cleaned the head with a low temperature pressure washer to remove
most of the shellac and oil and grime. Be careful not to wash it too hot as it
could distort the head, I'd suggest a low temperature like 40-60 degrees with a
high pressure, if you are going to take these steps.
Once all the ports were cleaned, fettled (ported if you like) and polished,
I can now examine the valves themselves, and the valve seats in the head and the
valve guide diameters etc etc.
Before examining the valves, they were
cleaned and de-carboned! I brushed them in paraffin and spun them in a lathe
with a very light abrasive cloth to clean off the carbon deposits from under the
heads and the valve front faces etc. being VERY very careful not to take any
material off the seats, the margins or anywhere, my only aim was to clean so I
could inspect. If I had taken a small amount off the valve stems, maybe around
.01 to .02 mm it could make the oil seals fail , and the stem would have to be
replaced. They are not cheap either! - around £40 each from Toyota for the
exhaust valves which get subject to high temperatures, and £19 each for the
inlet valve stems. So be careful!!!
Here are the results I obtained.
VALVE STEM
DIAMETER LOG
INLET VALVES Dimensions in MM
No : 1 5.979
2
5.977
3 5.978
4 5.977
5 5.980
6 5.976
7 5.978
8 5.978
Haynes limits 5.970 to 5.985 (0.2350" to 0.2356")
EXHAUST VALVES
No : 1 5.972
2 5.972
3 5.971
4 5.978
5 5.972
6 5.971
7 5.972
8 5.969
Haynes limits 5.965 to 5.980 (0.2348" to o.2354")
You can see by this log that the results were very good, for the inlet
valves, I expect the stem diameter has hardly decreased from its original value.
And having said that the values or 'limits' are just below top limit of '5.985mm
so they are in great shape. The exhaust valves are of slightly lower limits with
respect to the inlet. They are still very consistent and I would accept these as
suitable and ok.
NOTE: When I come to checking the guide bush diameters for
the stems in the head, I can re-bush these guides to give me the correct
clearances from the valve stems as per Haynes manual.
And also NOTE! Exhaust
valve no.4 is close to top limit, I will have to be careful with this as if I
replaced it with standard clearance in the guide bush, the limit might be a
little close, and I don't want that as when running hot (fast road pace maybe)
the valve just might seize up as they expand in size very marginally when hot. I
think the co-efficient of linear expansion for steel is around six millionths of
a mm per degree Celsius of temperature. (that's where the clearance comes in! -
not forgetting any carbon residue that may be sticking to your valve stem, you
should definitely play by the limits unless you have a professional experience
of valves and know what you are doing!).
That is the valves themselves dealt
with, quite a job, I totaled around 9 hours of tool making time on these. If you
don't have the facilities for re-grinding and such like, you must send them to a
machine shop or an engine re-build specialists.
I have ordered a new set of
valve springs for the head which totaled £101.28 from Toyota, I had to wait two
weeks for them to come in from Toyota in Belgium as there were no oem valve
springs in England, can you believe it??
6.000
pin, 6.010, 6.020, 6.030, 6.050
Haynes limits 6.01mm to 6.03mm
The valve seats on the head were
pitted and burnt and some were ok, I decided to get them all re-cut, the cost in
the engine shop was only 2 pounds per seat, so £32 for all 16 it’s a good idea
to get them all cut. Lapping the valves in also cost me £17.50.
Piston diameter log…..
Piston 2 80.928mm
Piston 3 80.916mm
Piston 4
80.924mm
Haynes limits for the piston diameter is 80.89 to 80.92mm (3.1846”
to 3.1858”)
Sand blasting £30
Valve seats cut x 16 £32
New oem valve
spring x 16 £86.64
Inlet and outlet ports fettled and polished foc
Valve
stem seat faces re-ground foc
Valve faces ground and mirror polished foc
Valve's lapped in £17.50
Rocker cover crush washers x 8 £7.06
Throttle body gaskets x 2 £2.47
Head skim of .006” £27
Sand blasting foc
Honed 4 cylinders £14
New main bearings
inc 25% discount £33
New con-rod bearings inc 25% discount £44.05
Pistons polished foc
New oem piston rings inc 20% discount £61.39
Crankshaft oil seal diameters re-machined f.o.c
oem crankshaft rear oil
seal £19.58
oem crankshaft rear seal gasket £1.47
Crankshaft timing
pulley and keyway (only as I broke original on diss-assembly) £15.19
New oem oil pump £74.24
New Fensport water pump £39.95
Fensport head gasket set £79.95
Fensport cambelt £14.50
Fensport
fanbelt £9.95
Fensport oil filter £4.95
Fensport fuel filter £16.95
Crush washers for oil cooler hose on sump (oem) x 10 £6.84
oem
thermostat £9.95
Toyota 'red' for life coolant (5 litres) £11.70
Halfords (10-40w) just for run in of engine then will change to Castrol GTX
Magnatec after 2/3 weeks £15
25 hours of sandbasting/ and cleaning the
various engine parts foc
Hammerite spray paint in alluminium and black
finish x 5 £25
Tetrosyl clear lacquer spray x 2 £5
Tetrosyl metallic
effect silver spray x 1 £5
Halfords red gasket sealent x 1 £3.95
Halfords blue gasket sealent x 1 £3.95
Magnex stainless steel exhaust system £275
Magnecor 'blue' high suppression ht lead set £49.95
NGK platinum plugs
£23.80
Ram-air induction filter system £79.95
New Fensport 212mm
standard clutch (not totally necessary) £109.95
all less 10 % discount
courtesy of Fensport Cambridge.
Re-machining the crankshaft £50 (1.5 hours specialized)
Grinding the
valve seating faces £40 (2 hour job specialized)
Fettling and polishing the
head £120 (5-8 hour job if done correct)
Mirror finishing the valves £70 (3
hour job specialized)
Sand blasting and cleaning and painting of the various
engine parts, this figure would be very high, as the labour is intensive, dirty,
and very tedious! I would estimate it to be around £500! So don’t even consider
sending the work out for all the separate pieces, like the air intake, sump,
block, head, throttle body, pipes, bits and bobs. Do it yourself!
