Best cam for Triumph 2.5

Best cam for Triumph 2.5

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Discussion

Stevo302

Original Poster:

395 posts

145 months

Friday 18th January 2013
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Ive been told by a good friend that the cam out of a TR5 would be the one to go for. What are other peoples thoughts?

Twin SU's, stage 2 head, 6 branch s/s manifold.

Cheers.

rallyspit

55 posts

170 months

Friday 18th January 2013
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It very much depends what car the engine is in and what you want to use it for.

I ran a 2500S estate primarily as a service barge for historic rallying. I wanted to have some fun with it but it also needed to be tractable as it often towed a loaded car trailer. The TR6 cam, richer needles and a head skim sufficed to give me what I wanted (plus overdrive on 2, 3, and 4).

However if you are building a 2.5 GT6 (for example) and want the power band moving higher, personally I'd contact Newman Cams. They made a superb job for a fast road cam for my spitfire.

I'm not aware of any differences between the TR5 and TR6 cam, but doubtless someone will be along soon to correct me. I would be careful of getting a cam from an export engine, the TR250 was a USA emissions detuned version of the TR5, and there are a few around in the UK. It's also worth getting the crank and flywheel and clutch balanced together.

caziques

2,651 posts

175 months

Sunday 27th January 2013
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I reckon the 25-65-65-25 profile fitted to Spitfire II/III, GT6 II, Vitesse II, early 2.5 PI is hard to beat with carbs.

We found a TR5 profile (35-65-65-35) went well but was thirsty with too much overlap, and needed PI to tame it.

Later cars from 73 on all used an 18-58-58-18 cam, same timing as some earlier ones but with more lift. For reasons unknown these tend to suffer badly from wear on the lobes.

Stevo302

Original Poster:

395 posts

145 months

Sunday 27th January 2013
quotequote all
Good advice. Thank you.