• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)

GT6 GT 6 questions

Share this page

brgrmyster

brgrmyster

Senior Member
Offline
Gentlemen: To the GT6 subject matter experts, may I impose on you for some guidance? I recently bought a 1968 GT6 Mk 1, KC 12938 L, which my research suggests is a late 1968 close to the end of Mk 1 production (KC 13752). The motor number, however, is KD 51386 E, which my research would suggest is an early motor for the GT6+ (in the U.S.), with GT6+ commission numbers beginning at KC 50001 (presumably the engine numbers were fairly close).

So, am I looking at a late GT6 Mk 1 in which the factory installed an early GT6+ engine? Or, did a PO install the later engine?

Secondarily, am I correct in determining the GT6+ engine (KD series) had a Delco D204 dizzy, a Lucas 15 ACR alternator, a mechanical fuel pump with a metal top (not the earlier glass bowl fuel pump), and Stromberg 150CDS carbs (not the earlier CDs or the later CDSE)?

I would be most appreciative for your help. My intent is to restore the car to as close as stock as possible.

Thanks,
Jeff
 
More likely is that a PO installed a later engine. The details you describe of the GT6+ engine sound about right (ISTR, for example, that most if not all "Mk1" GT6s had a Lucas C40L generator), although I'd have to go home and look at my 1970 GT6+ to be absolutely sure.
 
I have to agree with Andy. The engine was swapped out at some point.

As for the distributor I can't say but the pump is mechanical and all metal.
The carbs are the 150cds if I remember correctly.

They have the white plastic piece on the side.

Here is a good site for reference of many of the parts and changes
https://www.triumphspitfire.com/Ref.html
But I am sure you have found this already but I will post it anyways.

I guess I will need to look when I get home as well.

One thing I have never gotten a good handle on is the different distributors so any links or help from others would be great to tell the differences and what are interchangeable.
 
Can do some more searching, but the fuel pump should have the metal top. Glass tops ended around engine 5000.

Welcome to the GT6 world - totally awesome little cars. It is my absolute smile car, even more than my 1980 Porsche 911SC. My 68 was completed just before yours (I have 11039) and also have the original engine still in the car (#9989).

My little car has the 150CD carbs.

You may also wish to track the gearbox and rearend numbers to see how they compare to the MK I range.

Have found that this particular forum is not the best for the GT6 cars. Better sources of info I would check the Triumph Experience and the Club Triumph forums.

An engine photo is attached (side valance and oil filter housing removed) and can always supply more.

If you're totally curious about your car order a certificate from the British Motor Heritage Trust.

jb
 

Attachments

  • 25756.jpg
    25756.jpg
    94.8 KB · Views: 424
To all - many thanks. I dug through some original paperwork with the car, and found the original Triumph Servicing Schedule Manual in which the selling dealer on 8/3/68 (date of sale) recorded the engine number - KD 12402 E. Makes sense, close to the commission number. So, it originally had an early GT6+ U.S. emmissions engine. At some point a PO (could have been the restorer who rebuilt the engine) swapped it out for a later KD engine. I think another giveaway is a photo by the restorer of the rolling frame - the engine has a silver valve cover, which would indicate a later GT6+ engine. I understand when they went to the Mk 2 and GT6+ they moved away from a chrome cover to the silver cover.

These pictures are a great help. If anyone has a late 68 or early 69 GT6 with the U.S. emmissions motor (as original), I'd be very interested in any photos, both sides of the engine. I'm especially interested in the vacuum lines, advance and retard, from the dizzy, running to the Stromberg 150CDS carbs. I think I'm missing a vacuum valve on the carb throttle linkage to which both lines ran. From the vacuum valve, it was split to the two carbs (?). Very confusing.

I appreciate everyone's help!

Jeff
 
Jeff, the "KD" prefix in the original engine number likely refers to a "US specification" engine rather than the home market "KC" engine, especially seeing as the numerical sequence is in line with the commission number as you note. A "MkII" or GT6+ engine would've started numerically in the 50001 range and, of course, would've also had the "full-width" head (no exposed pushrod tubes).

Hopefully someone with a stock '69 can help with photos; I don't know offhand if my 1970 is exactly the same or not.
 
Thanks Andrew. So I'm correct that this is from a GT6+, likely a early or mid-1969? It does have the full-width head with no exposed pushrod tubes at KD 51386E. Still struggling with the ZS 150CDs carbs - trying to determine proper vacuum routing (rigid lines?), plus find a vacuum valve that is missing.

Many thanks Andrew.

Jeff
 
Vacuum wise it just goes from the distributor to one of the carbs. At least that is all there is on my 70 GT6.
 
These are photos of my '68 GT6 KC13000L. It's engine # is KD12463E. I was told the valve (in my hand) was used to close the throttles faster on off throttle deceleration. I've owned the car since 1983 and it was disconnected (but still in place) then. The hard and soft vacuum lines are routed as original. That "retard" vacuum line from the distributor I have plugged and is non-functioning. Hope this helps some.

IMAG0138.jpg


IMAG0058-1.jpg


IMAG0133.jpg


IMAG0134.jpg
 
Wow! Magnificent. These photos are very helpful, and that is the very vacuum valve I have missing. If you're interested in parting with it, please advise. I'll provide a cell phone number. I notice you're in PA. I'm down here in the southeast - Media, PA.

Many thanks,

Jeff
 
Jeff - It doesn't function.....And I'm told when they did, all one had was a very poorly running GT6.
 
Mine had the same setup. That valve openned at idle to bring vacuum to the retard side of the vacuum advance. It would bring the timing down to 4 degrees ATDC at idle for improved emission readings. Mine was also not in use.
 
Being that you have a GT6+ block the question is what else is GT6+. Do you treat it like a + or a mk1.
 
Thanks men. More research convinces me this is a straight GT6 Mk 2 engine, with ZS 150CDS carbs (not the CDSE). It was the GT6+ U.S. engine that had the vacuum control valve. None apparently on this accelerator linkage. And, the vacuum lines appear much simplified, at least according to Canley Classics for a MkII (Plarte AB). No rigid piping - two simple lines.

So, if anyone out there has good photos of a GT6 Mk II engine, especially so the carb and vacuum setups, I'd be very appreciative.

This is maddening! The TR6 was so much simpler.

Thanks,
Jeff
 
Back
Top