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TR6 camshaft question


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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

 

 

F171904A-9BCF-44AF-AB26-F39321BA7190.jpeg

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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

 

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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. 

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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.

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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.

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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 by timpress
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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.

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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.

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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.

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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

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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.

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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

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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

 

79AE8F9D-E642-41A4-A714-20F9A83DA400.jpeg

E2BFFADA-4CA1-4692-B6F9-C300C73F3E8D.jpeg

Keith, No Problems.

Dave

 

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