Triumph GT6 MK3 vintage race car part 1

A tour of the GT6 race car engine bay , part 1. Visit thevintageline.com for the copper nickel brake line kits that I mentioned in the video. I will be adding part 2 of this video next week.
My friend and I built this vintage race car over the course of several years. It may have been raced in Canada when it was new, but I have very little information about it's history.
The engine was built to be reliable so that we could sort out the car on track. It could certainly make more power by increasing the compression ratio and doing a few other things. It has been very reliable so far. I drive a street GT6 and I can tell you that there is no comparison between the stock engine and this one. This engine revs very freely and is still making power up to the rev limiter (7000 RPM). This is due to all of the work done on the head, the exhaust header and the weber carb setup.

[@tomm9178]

Hell of a job, very nice. Well done. I had a '56 GT6+ back in '70 when I was 20 and just loved it. It was so much fun to drive on country roads. The gearing in 1st & 2nd was just awesome on its 5 speed. 1st would take you to near 30 MPH and 2nd into the low 50s. What a great little car it was!

[@printer1105]

I had one of these in the mid 80s I used to outrun all the imports with it back then. The synchro-mesh transmission was sweet. Also the rear end made cornering a blast. I loved that maroon ground hugger.

[@lordleonusa]

I do like the boxing in work on the lower A-arms of the front suspension

[@Voodooand]

Really awesome modification.

[@lordleonusa]

I also like the tube strengthening the front suspension towers

[@kevink2315]

Excellent video, great documentation. I did something similar to my 68 GT-6, and won 2 of 3 seasons in Auto-X, and had many summers of HPDEs. I used the British Leyland competition guides to prep for SCCA D-Production racing, as well a phone calls to their mechanics Brian and Lacky?, who were available at certain times for consultation. Engine: Mega-Porting, Polishing, balancing, CC'g, S2 cam and Comp Dep't valve springs, retainers, and tubular alum push rods, Cannon header, stock radiator! Milled 1/8" off head for 10.25 CR. Trip webers. Susp'n & Brakes: Comp Dep't 550 lb fr springs, RR "swing spring" with longer half-shafts, I" fr bar & Alum pivot bush, 9/16" custom rr bar 5 pos'n, Koni Shocks, TR-7 5-1/2" rims, larger rear drums & cylinders. Custom shift linkage with U-joint, upgraded laygear bearings. All Dialed In. Shocked a lot of people at Summit Point Raceway. Engine designed for broad torque curve ... with 3:27 rear, went from a stop to 80 mph in 2nd gear!

[@sblackwell8150]

KevinK2

[@racketman2u]

nice, the GT6 is a sweet little car! You surely beefed up the diff though; I never hotted mine up for fear the stub axles would snap like carrots, they were well known for that. One thing about those weber-type side-drafts over the Strombergs; the throttle response would be much better.

[@jamespeterburch]

Nice car mate, looks very quick!

[@tw3lv3oclokc]

why is this so entertaining?

[@Porsche9elfer]

@godspeakfire Before you rebuild it check if you have the USA spec anti smog motor. It has noticeably less horsepower as they lowered the compression ratio and messed with the cam specifications.

[@Porsche9elfer]

@JSB87 The fuel pressure is about 2-3 psi

[@godspeakfire]

I have a 1972 Triumph GT6 MK3, it has the stock engine, I can't wait to restore mine. I like what you did, but I want to redo it, not mod it.

[@RocketRaven]

@Porsche9elfer are you using a bypass filter?

[@joealters1700]

What fuel pressure are you running to the webers?

[@muschialli]

Triumph Tune not the best cast missing the n but are awesome got them on both our 2.5 vitesse convertibles

[@bernardwarr4187]

Fantastic video and information. One more question, I noticed you moved the engine back half and inch. Other than re drilling the rear mounting any difficulty’s?

[@Porsche9elfer]

As I recall it was more than 1/2 inch, you can move the engine mount and spacer to the rear side of the bracket on the chassis. Of course this will effect other components that rely on the position of the engine, such as the exhaust. I no longer own the car so I can not look to see what was done. cheers and good luck!

[@bernardwarr4187]

@@Porsche9elfer many thanks. I am thinking about moving the engine mount behind the bracket that it’s currently in front off. Particularly as installing new custom exhaust to at this point. Any movement rearwards sure will help! Best wishes

[@Porsche9elfer]

@@bernardwarr4187 I always wondered why Triumph purposefully mounted the engine further forward. Possibly to maintain the position of the shift lever the same as the Spitfire. I can not think of any other good reason.

[@lordleonusa]

'sturdy braided fuel 'line' needs to be 30R9 or higher hose to avoid deterioration by the ethanol in modern fuels.

[@Porsche9elfer]

race fuel does not have ethanol!

[@kevinpayne8648]

Hi. I have a gt 6 and looked at the exhaust manifolds going from square to round. Are you confident you can grind out the head to suit the round exhaust ports. ..? Kevin

[@Porsche9elfer]

Yes. In fact we did exactly that. It is a lot of work but the engine revs very well.

[@Porsche9elfer]

yes , I did it and works great.

[@onepersoncanequalmanyvoice3184]

What company built this engine? I really like the suits and your narrating.

[@Porsche9elfer]

Thank you. I built the engine and a few others for this car.

[@XSidVicious509X]

What's the fastest you went in it?

[@tomashton1781]

I used to mess with those car,s and Fiats back in the late 60,s, there were no cams, ignitions, etc available, a three ring forged piston and the stuff you have should be good for 180 plus, (im essing)

[@Smalltechguy]

I don't know how often you check your page, but I am trying to help a retired Veteran get this 1972 model GT6 going. I've never messed with dual carb set up, but what has me baffled right now is the rotor in the ignition comes off very easy unlike others that I had dealt with. Will this not cause damage to the cap??? This car needs lots of TLC, but I need to know if it will crank. It does have the Stromberg carbs. I'm replacing the vapor hoses since they were melted and the existing fuel lines are clogged with the old rubber hoses that melted also from the fuel. I see one vacuum line that seems to go no place toward the front of the motor. It is held in by a grommet of some sort.

[@Porsche9elfer]

A better place to ask questions would be one of the British car forums. You will receive a lot more quality replys than on KZbin , which has become a very confusing venue for communication : ( The rotor does come right off with little or no effort. What holds it down is the cap itself. There should be a spring on top of the rotor which contacts the carbon of the cap. Good luck! They are fun little cars.

[@Smalltechguy]

Hey thanks for getting back with me...really shows good people..I did as you stated about finding a forum and joined and thought I had saved it to my favorites. This car will be fun to work on. I froze your photo of your rotor cap and wires. Is this your firing order 1-5-3-6-1-4???

[@bernardwarr4187]

Some great mods there. Which one make the biggest difference to lap time?

[@Porsche9elfer]

The driver!

[@bernardwarr4187]

@@Porsche9elfer I think your chassis bars are great. Sure it’s a lot more positive?

[@Deet3450]

I would like to ask you about Mikuni Carbs vs Webers or SUs for the GT6. I am looking into purchasing a GT6 restorted by Chris of PRI/ Moto Chancelli. I would appreciate your opinion. I do not know what is the best way to get in contact with you. I will also place this on your Porche video. Your help and opinion would be greatly appreciated. I do not want to make the wrong purchase. Thanks Lonnie

[@Deet3450]

+Porsche9elfer Thanks for the quick reply. I would prefer The SUs but the Jap Carbs are what Chris used on his stage 2 engine for the GT 6 restoration that he did. Additionally, there are many more mods that he did to the GT6 during the restoration. Is there a way that we can communicate a more privately for further discussions on the car?

[@mickydeloach7807]

Deet3450 my gt6 has stromberg carbs

[@Porsche9elfer]

When you decide to go racing the price of the car is usually just the first step. A full season of (amateur) racing would easily eclipse the market value of this car.

[@onepersoncanequalmanyvoice3184]

Do you by any chance build GT6 engines for people?

[@Porsche9elfer]

Sorry, I do not.

[@Xfgbeasfcvggsf]

Do you still own it?

[@Porsche9elfer]

No. Just trying to help out other builders.

[@stevek3036]

Putting those carbs' on a non cross flow OHV engine is somewhat of a sledge hammer approach to extracting more BHP. You can't get any significant increase in power if the inherent design doesn't allow for it. Its called the law of physics. I would imagine that the jetting on those carbs would have to be somewhat throttled otherwise the exhaust would be flowing with neat petrol.

[@Porsche9elfer]

Compared to which other carburetor setup that might be somehow better in your opinion? We have not randomly thrown a huge carb setup on an otherwise stock engine. That certainly would be folly, and as you suggest, might indeed break the "law of physics". Perhaps you are not aware this is vintage racing, there are rules and classes based on the induction system used. Even then I would be hard pressed to want to fit an alternate system. This engine runs at WOT most of the time. Please either apologize for your insult at our lack of knowledge or suggest an alternative carb setup that would be superior.

[@racketman2u]

@Steve blahblah so side draft webers won't work on a non-crossflow, huh? what rubbish. My 240Z gained 30% with minor mods; although the mods do all have to "work" together; I found that increasing the compression ratio to around 10:1 really made the carbs sing. as for that nonsense about "throttled" jets; you do know you can get different sizes, right? thats called "tuning".

[@kevink2315]

See my reply for my engine details. You are generally correct, if referring to a stock engine. I 1st put my trip webers on my stock, 8.5 CR '68 (US) when the original Strombergs were stolen, and there was no significant power improvement , as the cam, ports, crude combustion chambers, and spindly push rods that elastically buckled (bend) at about 4500 rpm, all limited power, no matter what carb improvement was made. Only when I did the SCCA D- Production engine mods did they prove their worth. Note with a single carb barrel per cyl (no plenum) the Webers work by pulsing the flow, and need to be oversized, compared to carb(s) on an oem type plenum manifold.

[@kevink2315]

As a practitioner, I can say the laws of physics are not any limiting factor here. Cross flow heads are better based on heat transfer and port size, but siamesed ports still benefit from head prep and carb improvements, and other mods.

[@matthewjenkins1161]

ROFL at that. If the inlet and exhaust ports have appropriate valves at the end and are optimised for flow and velocity, the fact the are on the same side of the head is of minor consequense. Granted a crossflow design would keep the intakes cooler, gaining a few bhp from denser intake. Even a normally aspirated 5 port BMC A-Series can achieve over 100bhp per litre, though defiantly not on the original single SU carb.