timpress Posted March 20, 2022 Report Share Posted March 20, 2022 Hi all, I’m needing to order a new camshaft for my engine rebuild but I just want confirm this is the later one as I don’t have an engine number on engine. I believe it’s a later engine with 2journal but wanted expert advise.. picture attached to help thanks Quote Link to post Share on other sites
john.r.davies Posted March 20, 2022 Report Share Posted March 20, 2022 According to my TriumphTune manual/catalogue, that is a a camshaft from a 2.5L saloon, with a broad groove on the front boss. TR5-6 had two narrow grooves and from '72 they were all the same with 3 narrow rings. John Quote Link to post Share on other sites
timpress Posted March 20, 2022 Author Report Share Posted March 20, 2022 6 minutes ago, john.r.davies said: According to my TriumphTune manual/catalogue, that is a a camshaft from a 2.5L saloon, with a broad groove on the front boss. TR5-6 had two narrow grooves and from '72 they were all the same with 3 narrow rings. John Interesting. I have posted on this forum before that there is no engine number so its definitely got originality issues. I assume if I get a later TR6 camshaft that it will be interchangeable. The head is from a later engine as the number matches a later car. Quote Link to post Share on other sites
john.r.davies Posted March 20, 2022 Report Share Posted March 20, 2022 After fifty plus years, it's a rare Triumph that isn't a 'bitsa' by now! Nothing wrong with that! No engine number could mean that it's been 'decked' by skimming the block. Quote Link to post Share on other sites
astontr6 Posted March 20, 2022 Report Share Posted March 20, 2022 3 hours ago, timpress said: Interesting. I have posted on this forum before that there is no engine number so its definitely got originality issues. I assume if I get a later TR6 camshaft that it will be interchangeable. The head is from a later engine as the number matches a later car. Based upon the camshaft saga about camshaft failures that went on this Forum for years, I would only fit a Newman camshaft which has been made from a new blank and their PH2 which is the same as BL's old S2 which was never sold here in the UK. This camshaft is a better cam than what was fitted to the CP engine. It works well with 10:1 compression, as fitted to my car. Pulls from 1500 RPM. Bruce. Quote Link to post Share on other sites
DaveR Posted March 21, 2022 Report Share Posted March 21, 2022 This cam was used in the 2.5 PI saloon to late 1972, Mk2 GT6 and Vitesse. It's part number is 308778. In PI (2.5 Litre) terms it is the 132BHP cam. Dave Quote Link to post Share on other sites
timpress Posted March 21, 2022 Author Report Share Posted March 21, 2022 (edited) 17 minutes ago, DaveR said: This cam was used in the 2.5 PI saloon to late 1972, Mk2 GT6 and Vitesse. It's part number is 308778. In PI (2.5 Litre) terms it is the 132BHP cam. Dave So much knowledge on this forum!. I have ordered a standard 125bhp cam as the block has been decked and recesses removed and the head is good, flat but of unknown thickness and I didnt want any valve and piston collisions. I wonder if the bottom end came from a 2.5 saloon. Any way to tell? Edited March 21, 2022 by timpress Quote Link to post Share on other sites
charlie74 Posted March 21, 2022 Report Share Posted March 21, 2022 You can get an idea of compression ratio based on head thickness from here: https://www.goodparts.com/tr6-compression-ratio/ Quote Link to post Share on other sites
Keith Warren Posted March 21, 2022 Report Share Posted March 21, 2022 (edited) Hi Timepress A few years ago Dave Rumens put very good article in the Courier so hope he does not mind me copying it. Keith Edited March 21, 2022 by Keith Warren Quote Link to post Share on other sites
astontr6 Posted March 21, 2022 Report Share Posted March 21, 2022 6 hours ago, timpress said: So much knowledge on this forum!. I have ordered a standard 125bhp cam as the block has been decked and recesses removed and the head is good, flat but of unknown thickness and I didnt want any valve and piston collisions. I wonder if the bottom end came from a 2.5 saloon. Any way to tell? The removal of the recesses or counter bores is not a good idea as they were put their to improve the sealing and use the later modified head gasket with F1 type fire rings. Has your block got the strengthen web running along the bottom of the block?? This block also had a modified cylinder head to go with it. All this was done to improve head gasket sealing and to cut down on exhaust valve seat distortion and loss of compression on PI engines and warranty claims. Bruce. Ex Coopers who made all BL's head gaskets. Quote Link to post Share on other sites
Andy Moltu Posted March 21, 2022 Report Share Posted March 21, 2022 9 hours ago, timpress said: So much knowledge on this forum!. I have ordered a standard 125bhp cam as the block has been decked and recesses removed and the head is good, flat but of unknown thickness and I didnt want any valve and piston collisions. I wonder if the bottom end came from a 2.5 saloon. Any way to tell? I shouldn't worry overly about vale/piston collisions - the 6 pot is essentially a non-interference engine where the valves don't normally protrude far enough to meet the pistons. Quote Link to post Share on other sites
ntc Posted March 21, 2022 Report Share Posted March 21, 2022 20 minutes ago, Andy Moltu said: I shouldn't worry overly about vale/piston collisions - the 6 pot is essentially a non-interference engine where the valves don't normally protrude far enough to meet the pistons. I would like to see you put that to the test. Quote Link to post Share on other sites
john.r.davies Posted March 21, 2022 Report Share Posted March 21, 2022 NTC, Do you know anything about Triumph engines? They are, essentially, non-interference engines by reason of the 'bathtub' combustion chamber, and valve that don't rise up out it. The pistons stay in the block, well out of the way. Conceivably, a high-lift cam, some block decking to produce 'pop-up' pistons and an unfeasably high compression could contradict that, but which idiot is going to do it? John Quote Link to post Share on other sites
Andy Moltu Posted March 21, 2022 Report Share Posted March 21, 2022 Simple enough to put to the test when assembling engine or changing a timing chain. Put crank with any of the pistons at the and rotate the cam. It will miss. If you believe me rotate the cam so a valve is fully open an then spin the engine over. If you hear a catastrophic clatter feel free to say "I told you so". The for Essex V6 3.0 are similar which is just as well given their propensity for stripping timing gears. Quote Link to post Share on other sites
ntc Posted March 21, 2022 Report Share Posted March 21, 2022 In std you are right however many have been skimmed and many have modified cams I have seen contact made but not my work Quote Link to post Share on other sites
andyhall Posted March 21, 2022 Report Share Posted March 21, 2022 21 minutes ago, ntc said: In std you are right however many have been skimmed and many have modified cams I have seen contact made but not my work I can vouch for this, when I stripped my race engine after it's 3rd failure you could see slight marking on 2 of the pistons Quote Link to post Share on other sites
DaveR Posted March 22, 2022 Report Share Posted March 22, 2022 17 hours ago, Keith Warren said: Hi Timepress A few years ago Dave Rumens put very good article in the Courier so hope he does not mind me copying it. Keith Keith, No Problems. Dave Quote Link to post Share on other sites
ntc Posted March 22, 2022 Report Share Posted March 22, 2022 17 hours ago, andyhall said: I can vouch for this, when I stripped my race engine after it's 3rd failure you could see slight marking on 2 of the pistons Cheer’s Andy they have gone quite now says it all Quote Link to post Share on other sites
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