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Triumph TR6 - I think I need my head examined...

No sooner have I finished this winter's projects than the plans start for next winter... I think the next thing to look at is the head. I say thins because during the carb tuning I have been doing I have found some things which seem like problems to me. Specifically, I think that there is a problem with the valves for No.1 cylinder. The symptoms are:

* Using a Gunson's Colourtune shows sparks in No.1, but no flame
* After switching the engine off, I see exhaust-type smoke slowly drifting out of the vent at the lower right of the carb flange (for the temp. compensator)

Oddly, the engine runs quite well, and even sounds fairly smooth, even with (apparently) only 5 cylinders, so I plan to drive through the summer and sort it out when the weather turns. I suspect that th problem is down to the absence of the plug at the end of the rocker shaft (and the screw by No.5 was missing), which probably starved the front of the head of oil. When I adjusted the gaps last year the ones at the front were way off (around 0.1 inches, at a guess, maybe more). Maybe I should check those gaps again.

Assuming I do need to rebuild the head, the question has to be what would you recommend I do? I don't know if the head has even been skimmed - how would I know? I suspect that if I am going to remove the head and put in new guides etc. I "might as well" (where have I heard that phrase before...) try to improve the performance a bit - I have a '75, so lowest compression stock. Would just a skim do anything? What else would I need? New camshaft? Is the head something I can do myself? I know I would need a machine shop to do the skimming, but what about valve guides? Hardened seats for unleaded fuel?

As ever any and all thoughts, experience and advice would be appreciated.



Increasing the CR (compression ratio) is one of the least expensive and most effective performance improvements. The difficulty is knowing when to stop (i.e. CR too high for octane of gasoline available)! Others on the BBS might be able to provide information on what CR they are running.

There are various web sites (Good Parts?) where you can get information on how thick the stock head is, and therefore whether it has been skimmed.

For the Toronto Triumph Club "Ragtrop" magazine I did a couple of articles on running various TR6 engine modifications through a software simulation program (Dyno 2000). Those articles are on the CD that Rick et all, have distributed.

You might find that information useful.

Leonard G Middleton

Alister, You have mail.
Doug Baker

Thanks guys

I sent an e-mail off to Richard Good, so I will see if he can offer some guidance. It will be a while before I start this job (I hope) but I would like to start preparing now - I have to find a machine shop, I guess. Any comments on what the cost would be to have a head skimmed? How about the valve seats/seals? Is that a machine shop job, or something I can do?

Thanks as usual

This thread was discussed on 07/05/2007

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