Foreword:-
Some might say a two seater sportscar isn’t a sportscar unless it’s a soft top? That’s a
fair comment I suppose, after all how many two seater
sportscars can you think of that have been produced don’t come in cabriolet
form? Off the top of my head I cant think of a single one to be honest, apart from the MK1 MR2.
Yes it came as a factory T-bar and
indeed Toyota tendered out 15 MK1s to a cabriolet conversion firm in the States
back in the early days but sadly they never made a production run of the soft
top MK1, and I think that was a great shame, how popular would this car have been
if it ticked this last neglected box?
Unfortunately only 3 or so of these ultra rare 15 original Toyota conversions exist today - they were
certainly a stunning variant of the MK1, who knows why
they didn’t put them into production? Today the MK3 Roadster is the embodiment
of this idea, you couldn’t imagine the MK3 as a tin top or t-bar only.
If only the MK1 roadster had become a production model too.
One of the surviving cars is owned by Bob Freitas who lives in Ontario, Canada I believe.
As you can see it’s a stunning conversion. There are more details on this conversion on the
Worlds Largest Supercharger Website.
The idea to reproduce this soft top has niggled
at me for years, those who know me or know of my MK1 exploits will tell you I'm
certainly brave enough or daft enough to try to convert a MK1, indeed I keep
getting asked by people “how long before we see a MK1 cabriolet then Paul?”. Its
not so much about having the guts to cut the roof off, as with anything that’s modified on these cars it needs
meticulous research and forward planning before even thinking about picking a
grinder up.
There have been many poor attempts at converting a MK1, most of which look like a weekends
madness with a saw, I've yet to see anyone do their own conversion and it look
factory. Below are a few that I've found on the net of various hacked off MK1s as
I call them.
Roll bars and removable cover. Just a roll bar behind the seats.
Roof chopped, that’s it.
Roof chopped and small roll hoops.
Roof and screen chopped!!! No comment!
I used to have a dog that liked doing this.
These cars have simply had the tops removed and roll bars added, the green car top left has
a leather hood cover that just stretches over the roll cage and press studs onto
the body, a simple idea but too basic, definitely not one for this country’s weather!
Build plan:-
With the utmost respect for their builders I really don’t want my car to end up like
these, it just isn’t an option. In fact I won't be happy
until it looks exactly right.
Anyone can remove the roof from a MK1 and achieve
any of the above, but I'm going to try to build a conversion that’s as close to
the factory 15 as possible, if not better!
So the plan is to build a professional looking conversion that doesn’t leak,
very little wind noise and with no annoyances about it at
all. I also wondered is the factory soft top roof still available somewhere?
Which car can be converted? What strength will be lost taking the roof off? How
much reinforcing will need to be added? Will it still
look like a MK1 when finished?
Many questions needed answering before I could go any further.
The answers took longer to find than I thought, the factory soft top hood was no longer
available, even after countless emails and enquiries it appears the original firm
that carried out the 15 conversions couldn’t supply the hood. So If this was to
become a reality I would need to either make my own hood from scratch or find
one on another car that would transfer over without too much trouble. The problem
with that however is that you need to find a donor hood that copies the MK1 roof
shape - a MK1 with a round VW beetle roof just wouldn’t look right at all!!
Then which car can be converted? A few years ago I had a totally scrap MK1 coupe shell at
my garage, so I decided to whip the roof off with a Stihl saw before the scrap
man took it away, purely in the name of research of course!
I found that the coupe had a very stiff roof with extra skin sections inside it and cross
braces everywhere. The screen pillars were very flimsy and when the roof was off
I could move the screen by hand - not good at all!
I more or less resigned myself to the fact that that was that and there was no way
forward, not without completely re-engineering a MK1 shell from scratch. Two years
later and I found myself wondering if the T-bar shells had any secret inbuilt
strength that Toyota might have engineered in. Was it possible that a T-bar has
a stiffer chassis? After removing the headlining on my T-bar it surprised me to
find none of the extra strength in the roof that the coupe had, the roof was single skin on the rear angled rakes too! So
clearly they must have made the T-bars stronger in the chassis and screen
pillars, the T-bar section just being more cosmetic, the
project was back on!
In January 2005 I started to look around at other soft top cars to see if anything out
there even vaguely resembled a MK1 roof shape. More importantly than that was the
need for the roof to match the door glass angle and the seal needed to be
perfect, after all what’s the point in a soft top that
rains in for 10 months of the year?
Every single hood frame I looked at was either too round or just all wrong, some I considered
were the MGF hood - too round around the door glass, MX5 - wrong around the door
glass and just all wrong in general, Mercedes of various sorts and a few
others, all a million miles away from working without complete alteration. Shortly
after I was driving into town on my way to work one day when a car pulled up
alongside me at the lights, my attention was immediately drawn to its roof - the
first thing that struck me was the fit of the roof around the door glass, it had
a perfect 90 degree angle around the corner of the window, just like a MK1 has! I
even missed the lights turning green I was studying the roof so much! The car in
question was an Alfa Romeo Spyder.
Ignore the rear window angle, its just the door glass fit that’s
important here. I only want this frame as a good starting point so that I can
modify it so that it’s the same shape as a MK1 roof.
As you can see the angle at the top corner of the door glass is perfect, but there are far
more factors to this than just this angle. The angle the glass sits at relative
to the hood frame is also very crucial but I wouldn’t know that until I got my hands on an Alfa
hood. I also noticed the rear plastic window was very similar in shape to a MK1
window, but I didn’t want this hood to sit as it does on the Alfa, the idea was
to replicate the MK1 roof shape so I was pretty sure I could alter this area of
the hood to copy a MK1 roof. The width of the hood was also in question, what if
it wasn’t wide enough to fit? Or too wide? A million
questions and problems all occurred at the same time.
Although it looked like I'd found an ideal hood candidate, I found
the amount of unanswered questions frustrating, there was nothing else for it, I would either have to bite the bullet
and buy an Alfa hood or abandon the project entirely.
Last month, as luck would have it, an Alfa hood came up on good old ebay, so I took a gamble and
bought it, unbelievably I got it for £23 plus £25 postage, it was worth taking a
gamble at that price. I don’t want to even think how much one of these are from
Alfa Romeo new!
One week later and the hood arrived safe and sound, in rather fetching cream if a little
shabby. This wasn’t bought for the hood though as no doubt that would need
re-covering anyway with the planned frame modifications. I was dying to get my
hands on the framework to see if I could make this work!
Later that day I'd taken the headlining out and removed the hood from the frame.
Things were starting to look a lot clearer now. I immediately got my notebook out and tape
measure and began measuring as many dimensions as I could, I checked these
against my t-bar. To my amazement there was about 10mm difference in the hood
width, this is uncanny, it could have been anywhere! 10mm is nothing and I also
found out that the spars that run across the top of the frame have slotted holes
for adjusting the width, that means it was a perfect donor!
Trying not to get too excited I turned my attention to the project car. As some of you may or may
not know this car is undergoing massive alterations. Late last year I shoehorned
a 3 litre V6 Camry engine into it - See www.mr2mk1club.com/V6MR2.html it also has a complete custom suspension set up, massive brake conversion and
earlier this year it became the first MK1 in the world to have its steering
converted to MK2 MR2 power steering - so this car is no stranger to
modification. What the hell I thought, it might as well get its roof chopped as
well as all of the other extreme things I've done to it!
The car is a very long way from completion so the idea was to remove the roof now before I've
gone too far on the rest of the car, the thinking behind
this is if I chopped the roof on a car I'd poured hundreds of man hours into and
ruined it it would be ten times worse than if I did it now and made a
mess.
The Big Chop!:
So the day had arrived when I wasn’t going to get any further with the project unless I
actually went for it and removed the roof. I started by completely gutting the
interior and roof of all fixtures, fittings and trim. After a few hours it left me with this.
Only the dash remains, I also did a screen top panel repair some
months ago as it was rusted badly so the screen needed to come out for
that.
In preparation for the roof coming off I removed both sills from the car and
renewed them with much stronger sections. These were seam welded top and bottom
to give the floor as much strength as possible, this only has to suffice while
the car is stationary, more floor strengthening is going to be added as the
project continues.
So this was it, all of the years of dreaming and planning came down
to one moment - me, the car and a 4½ inch angle grinder.
Bravery is not a strong enough word to describe what it took to make the first cut, I had a
cup of tea, thought about what I was doing, had another cup of tea, generally did
anything except make that cut - I knew if I did there was no turning back.
So I took a deep breath and went for it. The first cut was across the t-bar brace.
This is the moment 10 seconds before I made the first cut, after this one it was like a huge
weight had been lifted and I didn’t have to worry about what I was doing, the rest of the cuts were easy!
The second cut was along the B post pillar.
I deliberately made this cut high so I could trim it down later. If you are
wondering what the yellow primered area is on the right that’s a left side
engine bay vent conversion the same as the drivers side has got, the engines air
filter resides in there.
The third cut was to the rear roof rakes, these needed the exterior section removing first so
that I could get to the inner section. It all looks a bit too brutal but it
didn’t need to be anything more than just getting the roof off at this stage.
The squeamish should look away at this point - I opened the rear pillars up like a sardine tin
to get access to the inside skin. With this done both sides there was nothing
holding the roof onto the car, so off it came!
Quite disturbing looking at your pride and joy in such a state!
This flimsy T-bar roof is nowhere near as strong as the coupe roof. I'm suggesting this is
merely a cosmetic roof on t-bar models.
Oh my God, what have I done!?!? Alarm bells start ringing at this point, have I gone a step too far? Wrecked my car in 30 minutes?
Its not a feeling I would wish on anyone that’s for sure, but you have to look past the carnage and raw look of it to
imagine the final project, that was what I kept telling myself anyway!
So with no way back it was time to refit my doors and get that hood frame into place to see
how things look at this early stage.
So I crudely plonked the frame on top of the car just to get an overview of whether its going
to work or not. Note the Aston Martin style fuel filler relocation on the top
deck, a side effect of putting a vent in the left side of the car. The hood frame
was a surprisingly good fit width wise, as you can see it lines up fairly
well. The length of it is too long though and I need to lose some length at the
header rail where it fits the screen, but seeing as I have to make my own header
rail this doesn’t matter anyway.
You can also see than I can drop the plastic rear window straight down from the rearmost rail
onto where the bottom of the screen used to sit, this will exactly copy the MK1 rear window position.
After more trimming and fitting around the B post top I managed to get the frame sitting
half sensible, but remember its all well and good bolting a frame to a car but if
it won't fit nicely around the door glass it might as well have no hood, I want and indeed insist that this conversion looks factory
like the Toyota version, I don’t want it to look DIY in any way.
From another view you can see the hood is too long and sits about 20mm too high,
at this stage I was just hoping the door glass to roof seals would be close.
The beauty of using a t-bar shell is that it already has a good windscreen top panel to form a
good seal onto a soft top hood, indeed the t-bar seal will be used here to fit my
custom header rail, it will just need altering where I've cut the t-bar brace out
in the middle.
Next job was to make heavy duty sections at the B-posts to mount the frame onto,
this will give structural support to the B-post while giving
the frame a perfect mount. This section that I added is actually part of the Alfa
frame that came attached that I wasn’t going to use. The Alfa hood has a gas ram
damper on both sides of the hood to help it up, there will be no need for any of
this on a MK1.
With the doors refitted and the frame bolted to the mounts I made it was time to check
the door glass fit, something I've been very concerned about.
I also removed the Alfa header rail so that I could check the fit around the glass, my
worries were needless, unbelievably the glass fits at
the perfect angle to the hood frame. You just couldn’t hope for a better fit than
this, its almost like the Alfa hood frame is custom made for the MK1, suddenly its
all looking a lot happier!
This is becoming more of a reality as time goes on, this might just be the best thing I've
ever done to my car. The fit of the frame around the doors is astounding, in fact
it seems to fit better than the t-bar panels did!
Tell me that frame doesn’t look like its meant to be on there? This
fits so well and without too much modification that I'm thinking about offering
this as a conversion to my customers one day - t-bars only remember.
After studying the hood for several minutes and looking at the roof I'd just removed I
took some profile shapes in cardboard and transferred them to the metal roof for
comparison, believe it or not the soft top frame has the
same shape to its roof as the MK1 does, that’s just pure luck.
I then began to wonder how far I can go to get this soft top looking exactly like a tin top
roof, and it came to me that I could re-attach the old
MK1 perspex visor to the last rail on the hood frame, this can then collapse on a
hinge when the hood is stowed, here is the Perspex fitted onto the rear hood
rail, does this all look too familiar?
Not even the Toyota convertibles have the Perspex on. The plan is to run two
collapsable
bars, one each side running from the corner of the
Perspex down to where the roof rakes disappear into the quarter panel. The hood
fabric can then be stitched over the top of this bar so that the roof rakes are
duplicated perfectly. If I can't make collapsable bars then plastic coated wire
will do, this will tension when the roof is up.
A quick diagram showing what I mean is below.
The yellow lines show the planned collapsable bars or just wires, the new hood will go over this to copy the rear roof
rakes. The red dots on top of the passenger rear quarter show where it will be
press studded along the bottom. There won’t be rear quarter light windows on my
hood like a MK1 has. I could possibly include them but the factory 15 didn’t have
them so neither will mine.
The next thing to do however was make the hood attach to the windscreen top panel at the
front. Luckily the MK1 t-bar panel has a bracket on each end of the panel that
the t-bar glass locks into, its these brackets that I
will also use to locate the roof into so that it locates into the same position
every time it comes down.
This is what the roof currently looks like when folded down.
Its maybe not as discreet as it could have been, I'd love to have the space to engineer some
sort of Thunderbirds mechanism were a lid opens up behind the seats and the
frame folds down into it only to be covered up again by the lid, but sadly I've
got a 3 litre V6 taking up all the space under that engine lid so its
impossible. No I'm quite happy with this and by the time I've made a leather roof
cover to go over the top of this when its stowed I'm sure it will look grand. One
thing I'm going to have to do is make some aluminium heat ducts on my MK2 turbo
engine vents that have been grafted into my rear lid, last thing I want is engine
heat melting my roof! I'm sure I can get round that without too much trouble. I've
got very adequate cooling to this engine bay (one vent per side) so I'm sure it
won't be an issue. I could make the hood stow further forward than it does but I
would then start to worry about it clearing the seat head rests, no I think this is ok for now.
I started to think about getting this new hood to match the old roof shape as close as
possible, I needed to duplicate the rear roof raked back sections that run from
the rear Perspex down to the rear wings, I don’t know the real name for these so
from now on I will call them the roof rakes.
I ended up making a separate collapsable frame on each side that folds away by releasing it
from the inside. These will hold the hood fabric up at the back end of the car to
copy the roof rakes.
These rear frames took a lot of thought and playing about with hinges, all of the hinges and brackets have come from the original
Alfa hood and I've yet to add steel of my own up to now.
By the time the hood folds over this and press studs along the bottom it should look quite
close to the original shape. I've made the top end of this frame clip into the
Perspex so that this will support that too.
I made two hinges for the Perspex as well so that it too collapses out of the way when
folding it down.
This is the Perspex folding down, this will be done first when
folding the hood, it actually stows really well and folds right into the
framework.
Now with that folded and the rear arms dropped down the whole roof folds back on itself.
You can see the Perspex sits in a channel between the engine vents and cabin, I didn’t design it that way, it just happened -
a stroke of luck!
Other work included making the screen top seal complete, I've had to
piece a section of t-bar seal into the middle of the roof, it's not perfect but by
the time I've finished it should be pretty good and form a water tight seal onto
the header rail of the hood.
Perhaps one of the most complicated jobs on this project is still to come, actually making
the header rail. I've made the frame fit the car and fold away quite well, it
locates into the peg holes in the screen well, so the biggest challenge now is to
make the header rail work.
It needs to fit perfectly onto the screen seal and it also needs to incorporate the locking
mechanism. I'm hoping to use the latches from the Alfa Romeo header rail as they
look really good.
Some shots below of the project as it looks now.
Plenty to do but the basic soft top mechanism works.
I recently ran a poll on http://www.twobrutal.co.uk/ ( a site
dedicated to extreme modifications to MK1 MR2s/engine swaps etc.) to decide what
this car should be badged as or officially known as. After all if I end up doing
this as a conversion for customers its going to need a name!
The shortlist was:
MK1 Cabriolet
MK1 Roadster
MK1 Spyder
The winner was MK1 Spyder as its closest relative the MK2 came in Spyder form and the roof
I've used is from an Alfa Spyder - so I think a nice chrome Spyder badge for the
boot lid is in order!
PAUL WOODS
