Triumph GT6 project

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Introducing our Triumph GT6 project


After a long search we have finally found a suitable car for our next project. We have trawled the internet for months and we found our Triumph GT6 in just about the furthest place from our Cheshire base as is possible. Very early one April morning we set out to Cornwall to pick up the car, purchased over the phone with only the sellers description to go on! All we can say is be very wary buying cars this way!

To recap a little, we have been looking to expand our interest in Historic Motorsport. Up to now we have concentrated on single seaters with the odd foray into long distance sports car racing. We decided to see how easy it could be to take a standard road car and turn it into a respectable racing machine. We are going to share our experience with you and we will update the build on our website whenever we complete a significant part of the project. We aim to take you through the selection, puchase, build, race and development of the car over the next few months. 

Selection Why a Triumph GT6? One of the reasons for doing this project was our desire to create a racing car using our skill and ingenuity and not our credit cards! We could have just broken the bank, bought a Lotus Elan and gone racing but thinking outside the box slightly, we wanted the base car to be relatively inexpensive and also interesting. The Triumph offers an easy to work on car with a good spares network. The specification is also good, it has a 6cyl. engine, independant suspension all round, it is small and light and it is a good looking GT car! It may not be the most obvious choice (one of our reasons for choosing it) but back in the day this was a very successful model in US racing. Group44 won a couple of Championships with the GT6 mk2 in fairly standard form, still using the std. Stromberg Carbs.

Purchase This proved to be very interesting and an abject lesson in buying cars off the internet sight unseen! It was lucky that the seller (we will call him Ernie) ended up selling the car to us as we intended to take it apart again. Ernie was very encouraging over the phone, clearly impressed by his restoration efforts! "It only needs the loom connecting up and an MOT" the electrics were beyond him so he had decided to sell his project. On first glance it appeared to be complete and ready to go, it started and ran in a fashion and had lots of new parts including a new wiring loom. One thing he did say was that the car was totally rust free, on this point he was true to his word. Ignoring the shoddy workmanship of the "restoration" the fact that this was totally rust free made it a very good purchase for us. We did not want to spend months cutting out rusty metal and welding in a new floor pan, in this case we have been very lucky. The car did come with a van full of "spares" time will tell if any are any good!

Build The start of the re-build has been delayed slightly as we decided to move our workshop. We are now moved in and the build up has begun. The ultimate spec. has still to be decided on. Our intention is to keep it as standard as possible to start with, just carrying out modifications that will enhance it as a road car and be of benefit on the track. Once we have track tested it we can take things from there. There are quite a few racing options for us to choose from we are looking at the HSCC as a starting point as the regulations limit the amount of modifications that can be carried out.

So where to start! We removed all of Ernies new carpet and marvelled at the way he had burnt out a section of the new wiring loom! Good job it was the interior lights section, a repair to the earth connections should see the rest of the loom useable. We were able to get the engine running very smoothly. The Stromberg carbs have rubber diaphragms and to the amature car restorer look very easy to replace. There is a correct way to fit these, needless to say they had been fitted incorrectly preventing the carbs from working properly. So far so good, the engine sounded fine now it was running! We managed to get the car running around our car park enough to hear the wailing from the gearbox bearings, our next job then!

Removal of the engine and gearbox from the GT6 (or Spitfire) is very sraight foreward once the bonnet has been removed. Once the gearbox was stripped we found the main shaft damaged beyond repair and the bearings shot. We have decided to remove the overdrive unit. Some say that more time is gained by removing this heavy item than from the extra gearing it allows, we will find out in due course. In order to remove the O/D unit you need to replace the tail housing, as these are no longer available a suitable second hand gearbox was won on ebay, one trip to Oxford later and we had our part. The gearbox rebuild completed so lets see what the engine is like.

While the engine was out a couple of easy modifications were decided upon. We would baffle the sump pan and fit some ARP conrod bolts. Both of these mods offer benefits to fast road and track use in the form of improved reliability. With sump off we checked on the engine condition and could not quite believe what we found. It would appear that the engine has been completly rebuilt wth new shells, thrust bearings and new pistons. Everything is clean the engine has obviously not been run since it has been rebuilt. A lucky find for us and as the seller was not sure about the condition of the engine we are comforted by the knowledge that he has not let his restoration skills loose inside the engine! With these mods. complete the engine and gearbox are now ready for re-assembly. Almost forgot, when you remove the O/D you need another propshaft, a couple of inches longer! In the interest of reliabilty we bought a new one.


The wiring loom has been modified and repaired. The repairs were many and varied as more and more evidence of amateur involvement became known. From basics such as connectors falling off the end of wires to the main starter solenoid being loosely atached by a couple of wood screws! Modifications carried out are related to future Motor sport applications and include removal of the standard ignition switch, now separate ignition switch, starter button with battery cut out's and fitting electric fuel pump and electronic ignition. All of these modifications are easily carried out and are suitable for road use, the check and overhaul of the wiring will also have a positive effect on future reliability.

Up on its stands in the workshop we started to strip down the suspension assy's. One of the front uprights had a bent trunion scroll and one of the rear lower arms was found to be out of shape, both of these items have been replaced. During dismantling we found out how poor the new "copper" brake pipes when one of the flared ends fell off the end of the pipe!! We are staggered that
this car could have been put on the road by an unknowing purchaser. All brake pipes have now been replaced with cunifer tube combined with Aeroquip braded hoses all made up to our own high standard. The original rubber suspension bushes have now all been replaced with new stiffer poly bushes. This will enhance suspension control to the benefit of road and track use.

On removal of the rear suspension we discovered that the differential had started to leak heavily from all of the seals. At this point the decision was made to invest in a Limited Slip Differential bearing in mind the competition future of the car. We selected a Gripper Differential over the more populer torque bias differential as we felt this would perform better in competion events, torque bias diff's would be suitable for road use though. Another change will be yo the drive shafts. We have been dissapointed with the quality of various components available. the Rotaflex couplings being an example. We are changing to C.V.joints instead of Rotaflex for a number of reasons. One is reliability due to poor quality parts. Another is removing the Rotaflex couplings allows us to mount the rear shock absorber directly to the chassis removing some stress from the bodyshell. We will also modify the lower arm pick up point to further improve wheel control. Needless to say we wont be using any off the shelf kits for the conversion prefering to devise our own design. We have assembled all the parts required and as soon as some small maching work has been completed we will then fit to the car and describe the comversion in the next installment.


After a slight delay in proceedings, machining of the uprights taken longer than expected to complete, we are now into the final phase of the GT6 build. We were hoping to be out on circuit by the end of April lets see if we can make it before June! Over the last couple of months we have put together the C.V. joint conversion using the stronger Lotus Elise wheel bearing assy. mated to C.V. joint drive shaft. This conversion will add to the cars reliability both for road use and competition requirements. In conjunction with this mod we have fitted a spacer to the rear spring to lower the ride height and we are modifying the lower suspension mounting to optimise the rear roll centre and improve wheel camber control.

We have finalised the fitting of the foam filled alloy fuel tank we won on ebay! As the GT6 has an open cockpit we need to seal the tank from the interior. This is a mandatory requirement for motorsport use. Some pics of this will appear shortly.

We have also managed to fit one of our spare motor sport silencers last used on our March F2 car, it looks very purposeful and we cant wait to hear how it sounds, the Triumph Straight 6 may not be the most powerful of engines but it does make a good noise!   




Here are some pics of the fuel tank installation. We are using a foam filled 6 gallon tank for now, the sealed mounting box has been designed to take a larger tank once we are happy with the final vehicle specification.

Modified lower suspension arm mountings
Trying to recreate an evening padock scene!

We have finished the fuel tank this week. The fuel pump has now been installed and the whole assembly is now securely located just behind the rear axle line. We have some finishing off to do with the various pipes from the tank, the overflow needs locating and the vent valve/roll over valve needs to be installed. The pictures show the completed tank assembly prior to fitting and one with the tank installed.

The drive shafts will be fitted next week then we just need to finalise our choice of dampers. We were thinking GAZ or AVO depending on who does the best deal. Once these are on we can then start road testing the car then book a track day for the end of June.   



Rear suspension now coming together
O/S/R Suspension

A busy few days on the GT6. We have now fitted the suspension and exhaust system, the distributor has been fitted with an electronic module, new off ebay for £35! At 11.30 last night the engine bellowed into life, sounds very nice with the large bore racing silencer fitted.

 We decided to use AVO dampers as we have heard good comments on these units, the price was also competitive (thank you AVO) Another tweak we have decided on is to fit height adjustable coil overs all round. This will enable the suspension to be further fine tuned with control over the corner weights. To start with we are using 600lb springs on the front and 200lb coils on the rear. This is extreme for road use but should be a good starting point for track use. The pictures show the detail of the new set up and you can also see the CV jointed drive shaft in place.

 Another day's fettling should see the car on its wheels and off down to the MOT garage. The next update hopefully will see the car being put through some serious road tests. We are under pressure now with a dead line as we have entered the 360 Motor Racing Club event at Snetterton in August. A 6 hour race for a freshly compeleted car. All we need to do now is organise a roll cage....



N/S/R Suspension
O/S/F Suspension
Shiny new oil catch tank

With the MOT passed (failed on handbrake at first attempt) and some initial engine running faults rectified, we have begun putting some mileage on the GT6. First indications appear to be quite good. The car is very quick and will redline in all gears but for serious track use we will need a 5th gear. It sounds very nice and does look the part on the road but we have decided to pull out of the 360 event. There is still much to do to make it race ready as well as fitting the roll cage. It will be on track in the next couple of weeks to start fine tuning the running gear though and we are hoping to race it before the year is out. Check out our facebook page to here the GT6! Link on front page.


Due to our other commitments, work on the GT6 has slowed a little recently. After the track test it became apparent that we need a fifth gear. The popular Ford Type 9 gearbox being the obvious choice (there are plenty of alternative ratios and upgrades for this option) finding one proved harder than anticipated! We eventually obtained one from a V6 engine model with the longer input shaft. To save some time we purchased an adaptor plate from Canley then "won" the other bits required from Ebay! new clutch, gearbox mount and a quick change gear lever.

The installation has proved to be very straight forward indeed, some minor drilling to the bell housing, cutting off some corners on the gearbox case. drilling new holes for the mounting and a slight re-shaping of the chassis rails. The whole job being completed within the day. Another modification we have done while the engine was out is to replace the steering rack with a faster rack. 

New rack fitted, awaiting engine and new gearbox
Ford Type 9 gearbox ready for fitting
Quick shift gear lever and modified gearbox cover

Other modifications we have made since the track test are:

Thicker front anti-roll bar

Oil cooler fitted to final drive, to improve cooling and increase oil capacity in diff.

The rear transverse leaf spring has been modified to be simply a top link so now does not provide any spring assistance to the rear suspension.

In progress at the moment, we are replacing side glass and tailgate with Lexan and awaiting the arrival of a set of triple weber carburettors. A lighter radiator is being investigated and we also have a 2.5 litre engine to play with, though we intend to have the car out this year using the present 2.0 litre engine. 

Testing at Oulton Park

Le Mans works spitfires

Group44 GT6
Group44 170bhp using Strombergs!
GT6 circa 1970 Misano Italy

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