Club Triumph

Hi there

Does anybody have access to an SAH parts catalogue by any chance please. I am trying to learn more about the 307 profile camshaft I installed 35 years ago - particularly interested to know if this is a medium or high lift cam (I can't remember!).

Many thanks

Rich

Hi Rich

Unfortunately the one SAH catalogue that I can put my hands on (just a pretty basic price leaflet) does not give any technical specifications.

However checked my 'archive' and found one of Colin Vizard's books published in 1970 from info based on articles he wrote for Car and Car Conversions during the 1960s.  These books are what many of us considered 'tuning bibles' and I have the one for Triumph Engines Over 1300cc  and gives a summary of suitable cams for bigger Triumph engines, both saloons and sports cars, with technical spec and suggestions of suitability for use.

He lists various Piper, Derrington and SAH cams, and while your cam is not actually mentioned one can estimate from the SAH numbering sequence and reference to the other manufactures' cams that this is probably a cam with 30/70 timing.  Lift also looks to be about 0.40 inches.

He suggests (if I interpret his writing correctly) that this is pretty good for reasonably tuned engine giving a good boost of power without getting into the issues of poor drive ability for road use.

It is interesting to compare this with Chris Witor's specifications, both in his technical supplement and the catalogue itself. 

He gives the 308778 cam considered by many to be an ideal 'sports' cam and as fitted to Mk1 and earlier Mk2 PIs as having timing of 25/65 with 0.232" lift. 

The 307689 cam as fitted to the TR5 and early TR6 is given as 35/65 with 0.250 lift giving a factory quoted 150bhp.  This cam was discontinued in the later TR6 and a slightly softer can fitted (as also happened with the saloon) to give 135 bhp.

Note the lower lift to that given earlier in Vizard's book at about 0.4", and even when CW does his uprated 308778 cam he only increases it from 0.23" to 0.25"

Performance from a cam is not just about lift but also the timing.  However the simplest way of getting an estimated check of lift is to whip off your rocker cover, remove plugs to make turning the engine over more easy, mark with a pen or 'Tippex' a datum point on the push and measure the movement of the push rod ....... NOT the end of the rocker at the valve stem end.  Removing the rocker arm to measure the rise and fall of the end of the end of the push is probably more accurate especially of a dial test indicator is used but that is extra faff considering that it seems you only want to get a guide.

MUT

Brilliant, thanks MUT.  Thats more info than I could ever expect.  Really appreciate you taking the time.

I didn't notice any amazing change with the 307 cam except poor tickover - but I probably didn't time it correctly and this was literally the only performance improvement to the engine!

The engine is being reconditioned at the moment & I think I am most likely to sell the 307 (smooth tickover is more important to me these days!) - so if anybody is interested let me know.

Hi Rich

I may be interested but depends upon the price - would go with the engine in AFH which is a very early Mk1 2000 which I started to modify in 1990 using primarily early/mid 1960s stuff acquired from autojumbles.  This included SAH manifolds, rocker cover and other things which I never got round to fitting though was after a genuine SAH manifold to keep within the SAH thingy when finished

A used AFH for about 5 years as a daily driver until some problem cropped up (cannot remember what after nearly 25 years ...... and a 74 year old brain) and started the rebuild ....... and sidetracked on other things so still on going .......!

If you are considering a useful upgrade could I would suggest a 308778 spec. one as a good original Triumph spec. option?

MUT

Quoted from TedTaylor-

Hi Rich

I may be interested but depends upon the price - would go with the engine in AFH which is a very early Mk1 2000 which I started to modify in 1990 using primarily early/mid 1960s stuff acquired from autojumbles.  This included SAH manifolds, rocker cover and other things which I never got round to fitting though was after a genuine SAH manifold to keep within the SAH thingy when finished

A used AFH for about 5 years as a daily driver until some problem cropped up (cannot remember what after nearly 25 years ...... and a 74 year old brain) and started the rebuild ....... and sidetracked on other things so still on going .......!

If you are considering a useful upgrade could I would suggest a 308778 spec. one as a good original Triumph spec. option?

MUT

Thanks MUT.  According to Chris Witor, the 308778 was standard for the GT6 mk2 (like mine) - but it seems to be difficult to come by one. The TR5 cam (307689) seems to be popular (again rare) and the TR6 appears to have the lesser rated 311399 as also fitted to the GT3 Mk3.  This one is readilly available however!

Chris Witor does the 308778 and also a slightly amended version with more lift on the inlets.  Both are excellent all-rounders but the amended version probably won't bring much benefit over the standard one unless the engine has other tuning mods as the cam is not the limiting factor in the standard engine.

Nick

Any cam you may want is available from Newman cams, just tell them what you want.

Havebeen in a TR with a bit more than a standard cam from Newmans, really nice with lots of torque.

Thanks all, much appreciated.