Sprint valve clearances.

[sprintchris]

Hi,

I shall be reassembling my Sprint engine soon, I have a new Kent fast road cam to go in, I'm wondering if the valve clearances should be set to that of a standard cam or if it's different.

Some advice would be gratefully appreciated.

Thanks in advance,

Chris.

[Jon Tilson]

On a Kent fast road its similar to an STR91. What is the timing? Do you know the number of the cam ?

If its 106 ATDC then its 8 inlet and 9 exhaust....like mine.

Jonners

[soe8m]

0,15 in 0,20 ex. gives a nice quiet engine. There's a direct valve operation and no pushrods involved so it can be adjusted much narrower than the data from "the books".

Jeroen

[Triumph1300]

Do you mean mm Jeroen? 15, and 20 thou if an inch seems a bit wide?

[tony g]

Yes he means mm .15 being 6 thou and .2 being 8 thou, but you knew that Bruce

Tony

[trackerjack]

Yes he does mean .015" and .020" because I recall running it past Jeroen before I set the engine valve clearances on the various engines I have built recently after noting that Sprints tap like Fred Astaire and other cars like Hillman Imps and Ford twinkies that use the same method have much tighter clearances than Triumph recommend. The bonus is quieter engine and slightly more power.

[dursley92]

Sorry but I'm confused now folks. There appears to be two contradictory recommendations here.

What is the suggestion for a standard Sprint?

Is it 0.015" and 0.020" in old money because I was working from the factory manual which specifies 0.018" for both?

[Carledo]

Sorry Russ, Jeroen, being of the Dutch persuasion, thinks in Metric and any figures you get from him are in mm, NOT thou!

I believe his experience suggests you can get away with 6 thou (0.15 mm) inlet clearance and 8 thou (0.20 mm) exhaust, even with a standard engine.

Like me, Jon is getting confused in his old age!

Steve

[soe8m]

Mm.

Jeroen

[Carledo]

Mm.

Jeroen

See, he's thinking again ^^^^^^^^^!!!!!! Some say that............................

[trackerjack]

Well I am an old man now and of course suffered a brain injury last year.
However I hang my head in shame because its .15mm in and .2mm ex.
I just wrote quickly without too much thought
No one would believe I am a toolmaker and am measuring stuff all day

[dursley92]

Well I am an old man now and of course suffered a brain injury last year.
However I hang my head in shame because its .15mm in and .2mm ex.
I just wrote quickly without too much thought
No one would believe I am a toolmaker and am measuring stuff all day

OK thanks for explaining so I can safely reduce those settings way down 0.15mm (0.006") inlet and 0.2mm (0.008") exhaust then?

You realise I will have to re-do all those b****y shims again!

[soe8m]

Yes and the engine becomes less noisy.

Jeroen

[tony g]

Yes and then run out of thicker ones at No 8


OK thanks for explaining so I can safely reduce those settings way down 0.15mm (0.006") inlet and 0.2mm (0.008") exhaust then?

You realise I will have to re-do all those b****y shims again![/quote]

[trackerjack]

I feel your pain as I have just done an engine for someone and ALL the shims had to be bought as non that I had were suitable which is amazing considering I had a pot full of the pesky things.
I found Robsport were very helpful with what I needed.