Valve Clearances

[Straightsix]

How crucial do you think it is to set valve clearances HOT?

I’m wanting to check mine, the cam is a Fast road 83 with .022” inlet .024” exh. and states HOT. 
 

By the time I get down to checking/adjusting them on an unfamiliar engine the engine will  be bloody cold again!.

At the moment the tappets sound fairly quiet, my concern is have they been set to the std .010” ??

I would imagine they’d sound like a singer sewing machine given 22/24 clearances.

If not I can imagine they will do  ! 🫤

TIA

 

 

[Nigel Clark]

With Triumph factory camshafts, I've only ever set the valve clearances when cold.

I would only suggest adjusting hot if an aftermarket cam supplier specifically recommends doing so.

Nigel

[Pete Lewis]

the only reason i see for having double the normal tappet gap is to stop the springs bottoming out 

the Triumph spec is done on a cold engine if your cam manufacturer states  "hot"  then hot it should be  

might be wrong but whats the point of having a higher lift if you have to reduce the valve opening by increasing the the tappet gap 

seems just a must have you dont need the headache jobby that goes with it ????

Pete

[JohnD]

2 hours ago, Straightsix said:

How crucial do you think it is to set valve clearances HOT?

I’m wanting to check mine, the cam is a Fast road 83 with .022” inlet .024” exh. and states HOT. 
 

By the time I get down to checking/adjusting them on an unfamiliar engine the engine will  be bloody cold again!.

 

SS,

As said above, if the cam grinder says "Hot", then Hot they should be.

And you over-estimate the rate of cooling of an engine, while underestimating your own ability to check the clearances!   

An overheated engine should  be left for a least 30 minutes before popping the rad cap, but it will reman hot for two or more hours.   Setting might take longer than half an hour, but a check run through them can be done in under 15.

John

[Straightsix]

JD That’s useful to know, according to this chart, double valve springs should have been fitted too.

I’m expecting I may have to readjust them if I find them overly noisy - following my first attempt. 🤞

Hot it is then, many thanks.

[Iain T]

My Newman cam is 14 & 16 thou clearance cold. Your spec of 22 & 24 thou hot will certainly clatter when cold. At least adjusting hot will keep you warm in winter! 

Iain