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Aluminium bodied GT4


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Really really good job and a great feature to read.

Cant wait to see it in the flesh.

Aluminium coloured paint would have been the icing on the cake for me with a blank cream racing roundel on the bonnet and doors.

Am sure it will look good in the blue though of course!

Oh - and I'd have had painted wires not chrome - gun metal so darker than body.

 

Am sure your fed up with opinions but hope you take it in good spirit as its got us all talking and is a fantastic project!

 

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Am sure your fed up with opinions but hope you take it in good spirit as its got us all talking and is a fantastic project!

 

 

 

Not at all Duncan. This project has been a make it up as you go along effort right from the start and people expressing their opinions have given me fresh ideas and not a little encouragement. So, please keep them coming. 

 

I've now started the MK2 inner wings. The originals though effective don't in my opinion suit the rest of the car mainly because they are angular and not curved. They are the only straight lines on the whole of the body. The picture shows the buck which is not quite finished and the first piece of formed aluminium. I made this piece using the wheeling machine. Two further pieces are needed which once finished will be welded together to make the panel.med_gallery_67_25_64023.jpg

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  • 2 weeks later...

Ten days since my last post and I've been working on the inner wings every day. Getting the shape right and producing an interface for mounting has been a real challenge. The whole job has turned out to be a lot more difficult than I imagined. It's not just a question of making something that will protect the bonnet from flying stones but also to look reasonable and in keeping with the rest of the car. The left hand one is finished but some way to go for the one on the other side. 

 

One thing I have managed to achieve is to bring the aluminium down sufficiently to protect the sill end from grit straight off the tyre. I did something similar on my GT6 and it worked very well.

 

A couple of pictures followmed_gallery_67_25_72839.jpgmed_gallery_67_25_2090.jpgmed_gallery_67_25_36868.jpg

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  • 2 weeks later...

We competed in the Coupe Florio speed hill climb on Sunday and what a superb climb it is marred only by me catching a dose of food poisoning which prevented me from driving the last timed run. The car exceeded my wildest dreams in the way it handled and the amount of grip from the XASs. I've no idea what the safe rev limit is for a 1500 engine but I saw five six in fourth (90mph) before anchoring up for the first right hander which was actually the first exit at the roundabout. The hill itself, all 1.7 miles was quite bumpy and tighter than it appeared on the videos. It was a huge amount of fun and gave a terrific adrenalin rush. Having re-run my videos I can see how I could have been quite a bit quicker; too early on the brakes and not fully trusting the car where there was no room for getting it wrong. This was the first time I'd put the car under any sort of pressure.To be quick in a low powered car it is particularly important to carry the momentum through the corner and there were instances where I was not brave enough to carry it off. But we did not disgrace ourself and were really pleased that we had been invited to compete in the event.

 

The car itself created a terrific amount of interest and throughout the day whilst parked in the paddock there were groups of people looking at it and paying very complimentary remarks. So all very encouraging.

 

I will try to put one of the climbs on YouTube when we get home. In the meantime a couple of pictures showing the four cars in our little group and my car in the paddock.med_gallery_67_25_71645.jpgmed_gallery_67_25_74346.jpg

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Tomorrow, the car is booked for a short rolling road session just to establish maximum power. This will give a bench mark for comparison once the engine is stripped and built properly. At that stage a pair of new DCOE40s will be fitted. I'm really interested to find out exactly what it is knocking but my guess is that it is not much more than 70bhp at the wheels. I'll report back.

 

Now as far as painting or not to paint it looks like I'm about to execute a U turn on this. I am being seriously swayed by popular opinion to leave it in its raw state. I've still not quite decided but am well on the way. One quite significant factor is having it painted and finished to such a standard that I would be frightened to use the car and leave it in a car park. As it is, there is no paint to scratch and is eminently usable. I don't want to lose that.

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The result of the rolling road session was hugely disappointing but not unexpected. The engine produced 68.50bhp at the wheels at 5000rpm. After that power fell to 61bhp at 5500rpm. But we now have a benchmark for comparison when the engine is rebuilt with a decent cam and a pair of new Webers.

 

But on the positive side equalling my friend's time in his 160bhp Lotus Cortina and beating the likes of an E Type, Mini Marcos, TVR etc with a fraction of the power speaks volumes for the way the car handles and goes round corners. Pure Chapman!

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Hi John

 

I loved the video, and she sounds terrific. As you correctly observe, it is power-to-weight that counts, not raw horsepower, and how you can carry speed through corners.

Leaving her in polished ally would be very Chapmanesque, and in the spirit of the project, although you will probably need to order an industrial quantity of Solvol Autosol metal polish :)

 

Regards

 

Steve

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  • 2 weeks later...

Quite a few people along the way have questioned the wisdom of downsizing the engine from a lusty six to a puny four but do you know, it not only works well but the considerable weight saving has made the car infinitely more pleasurable to drive. The steering is light and sharp and the way the car devours a series of bends puts me in mind of my Caterham, it is that competent. One huge factor in this department  is the amazing grip afforded by the Michelin XAS FF tyres. They were of course specially designed for motor racing and were the control tyre for the Formula France single seater series in the 70s. The car corners on rails and feels totally secure. Not only that, they look right on the car. I see no reason to go wider and load up steering effort when we have the XASs which deliver in every department. I remember that one of the few people to endorse the small engine route was Dave Pearson who said that he had known a few people who had done the same thing and none that he knew of regretted the downsize. I could have course fitted a Zetec and type9 box for a fraction of the cost of a modified 1500 and gained huge power, weight and reliability benefits. It has been done before and I know Clive is delighted with his Spitfire conversion. I was fortunate enough to drive a T6 Le Mans car with a 150bhp Zetec and that experience will stay with me for a long time. But I guess I am just stubborn because I want my car to be totally Triumph and not to be thought of as a Special.

 

So, having done close on three thousand miles in the car after one or two hiccups along the way I'm very happy with the specification which does work very nicely. In case it might be of interest to anyone else here it is;

 

Suspension

Fully polybushed (Blue)

Rotoflex but with CV conversion.

Gaz adjustable dampers all round with adjustable spring seats on the front.

Rear uprated rear spring having all six leaves at a quarter inch thick.

330 pound inch coil springs on the front. 9.5 inches open length.

Thin anti-roll bar 5/8?

 

Tyres

Michelin XAS FF 155R13

 

Engine

1500 specification to be announced

 

Gearbox

Three rail GT6 close ratio box with overdrive.

 

Differential

3.89:1

 

Weight

with half a tank of fuel

Spare wheel and tools

820kg

 

It is sobering to note that each wire wheel and tyre weighs 17.9kg and I have five of them! And that's not counting the weights of the spinners and spline adaptors.

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Thanks. Of great interest. Seems heavier than expected. Iirc my bond gt4 is under 800 kg. with its 1500 and j type. however it handles terribly and needs setting up!

 

The weight is in the wheels I fear; nearly 100kg if you add in the spinners and spline adaptors. But of course the rotoflex wishbones are heavy as well all adding to the unsprung weight. A 13 x 5 aluminium Minilite weighs in at 5.1kg and the Michelin XAS 155R13 at 7kg. So by replacing the wire wheels with Minilites I could save about 40kg. Worth thinking about.

 

I hope you manage to improve the handling on your GT4 and if I can help with any more information on what I've done please drop me an email.

 

regards

 

John

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Thanks. Of great interest. Seems heavier than expected. Iirc my bond gt4 is under 800 kg. with its 1500 and j type. however it handles terribly and needs setting up!

get a bit of string, 2 tape measures, 2 bricks and 2 stright bits of metal about 600mm-1m long. An assistant, and about an hour or so.

It will transform the car.....

 

I guess I ought to stick mine on a weighbridge. Just out of interest. 

And John, not sure if canleys still sell the alloy lower wishbones? I have wondered about a fabricated version too, that would be much lighter.

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get a bit of string, 2 tape measures, 2 bricks and 2 stright bits of metal about 600mm-1m long. An assistant, and about an hour or so.

It will transform the car.....

 

I guess I ought to stick mine on a weighbridge. Just out of interest. 

And John, not sure if canleys still sell the alloy lower wishbones? I have wondered about a fabricated version too, that would be much lighter.

 

There was a chap selling a pair of Canley alloy wishbones on the CT site a couple of months back. Unfortunately, they have been sold so I've missed them. But at the time when they came up I was concerned with the basics like the engine problems and getting the car ready for the trip to France rather than enhancements. But it does look as if Canley still supply them so I may well buy a pair from them at some point.

 

I've just finished the second inner wing and overall I'm happy with the result. They won't work any better than the MK1s but they are curved rather than angular and in my view, suit the car better. I cannot believe how many hours I've spent on them. They are quite a complicated shape, made more difficult by interfacing them with the valences, forward extensions and the bulkhead protectors. But they are done now and something else to tick off the list.

 

med_gallery_67_25_66419.jpgmed_gallery_67_25_917.jpg

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The next little job is to make the bonnet hinges adjustable. This would have been so much easier done when I made the frame before the aluminium skin was fitted. I cannot believe I made the hinges non-adjustable. What was I thinking about?

 

But I have a design in my head which I hope will be fairly easy to make and that will do the job. To achieve a good shut line between the doors and the sills the bonnet needs to be raised a fraction at the front, and moved back by about twelve mms.

 

I'll post some pictures as soon as there is anything to show.

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  • 4 weeks later...

One of the Classic Car magazines is going to run an article on the car and just before we went away on holiday the photographer arranged to come down and take some pictures. Predictably, after two weeks of near perfect weather, the day of the photoshoot was very wet. We sat in his car on Dartmoor for over an hour before the rain abated sufficiently to allow him to get to work . He was very interesting to talk to and the time passed quickly. He had some good kit which lit the car as if it were a sunny day.med_gallery_67_25_8744.jpgmed_gallery_67_25_58184.jpg

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After weeks of anguishing over paint or not to paint, the decision has finally been made. Painting it is and the colour; French Blue. The die was cast when I painted the steel structure in that colour so it would be a bit ofdd if the body were in one colour and the interior and all the bits behind the panels in another. I'm about to start the strip down ready for painting and at the same time, the engine will be stripped down and an assessment made. gallery_67_25_50287.jpg

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I've made the adjustable hinges which, when fitted, should allow a small amount of upward movement and about 20mm fore and aft. The new hinges which are M8 rod ends will fit inboard of the chassis brackets. They will be mounted on a slotted plate welded to the bonnet frame. I've used an M12 screw drilled and tapped internally to M8. The M12 setscrew passes through the slot on the backing plate and underneath is a captive nut which slides back and forward along the narrow slot.This gives longitudinal adjustment. The rodgallery_67_25_20146.jpgmed_gallery_67_25_57489.jpg ends can be screwed in or out to raise or lower the front of the bonnet.The existing fixed hinges will be cut off. The last picture shows a threaded bar going through the old and the new so that in theory once the fixed hinge is removed the new ones will put the bonnet in an identical postion to the fixed hinges and the hinge pins will line up. I'm now plucking up courage to remove the fixed ones.gallery_67_25_61482.jpg

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  • 2 weeks later...

So, I'm now happy with the bonnet to door and sill gaps and finally the car is stripped down ready for painting. It was a funny old feeling to see it leave the workshop after three years residence as it was taken to the bodyshop. I have absolutely no idea when I shall see it back here but so long as it is back on the road by April all will be well.

 

I've just ordered a pair of new DCOE40s and the engine is ready to go to the engine builder for strip down and assessment. 

 

While the car is away I shall use the time to refurbish the window mechanisms and sort out all the stuff that is surplus which I can hopefully sell. And there is plenty of it. It will go on Ebay but I'll give you a heads up when the auction starts.

 

med_gallery_67_25_23184.jpgmed_gallery_67_25_36967.jpg

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John all I can say is ................???

 

 

Happy Christmas

 

 

youve earnt it

 

Pete

Pete, that's really kind of you; thank you. This is a very good opportunity to send my best wishes to you and your family and to thank you for all the unstinting help you give us all on the forum. Without your incredible knowledge and expertise this would be a poorer place.

 

Best regards

 

John

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  • 1 month later...

I have to say how touched I was by the concern that a number of you showed after having seen my car advertised on the Cars and Classics site. I've made some really good friends on this forum and I would like to thank you all for your support.

 

I would also like to reassure you that all is good in the Bonnet household and there have been no dramas necessitating the sale of my pride and joy. I put the car on for a silly price just to test the market and see if I could gauge its value. There was never any intention to sell it. In fact I have planned a full year for the car with highlights being Santa Pod and the Silverstone Classic.

 

While the car is being painted, the engine is being rebuilt to a much higher spec and should be ready by the end of next month. I've placed an order for the polycarbonate windows which should be here in a week or two As the car is not an exclusive racer, in the interests of ventilation, I'm retaining the opening front quarter lights and also the rear D lights.  Still in the interest of lightness, I have a pair of Canley rear wishbones  to go on and will be fitting Minilites in place of the chrome wire wheels. On the debit side I have a Jigsaw roll cage to go in and that isn't light. Cosmetically, I have also ordered everything I need from Park Lane Classics to reupholster the seats in black leather which I hope and believe will finish the car off nicely. If the car were a person it would be very mixed up not knowing it it's a racing car or a road car. It's not radical enough to win anything but as it showed in France it is good enough to give a good account of itself but still practical enough to be used comfortably on the road..And that suits me very nicely.

 

 

I'l keep you posted once things get moving again. 

 

John

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