P6 cam valve lash specification

I would assume that if they are factory cams, they would use the same clearance, but I honestly don't know, and I am wondering why I never asked before either. My P6 cams were running 8 and 10 as well, but I couldnt tell you if the previous people even knew if it had those cams. But as the valve buckets and shims, as well as the base circle of the cam are identicle, I would still bet its the same clearance. 8 and 10 are stock clearances for stock motors, so its obviously not to tight on those engines.
I do know that sometimes guys will tighten up clearance for a bit more performance, and equally, some, and I fall into this end, like to run a bit loose. I dont know how much noise you are talking about, and what you consider excessive. If it was quiet at 10, and its not acceptable at 12, maybe split the difference and try 11?

 

I set up my 77 to stock OM requirements . Inlets .008 - .010 (set mine at .010) and exhaust .012 - .014 (set mine at .014) and don't have any excessive noise. But then again I've had a lot of cars with solid lifters and didn't mind the noise then. I'll always set the exhaust a little loose to slow down the typical valve pound in.

 

Steve, you running P6 cams?

 

BTW: Value clearance affects valve timing also.

So running them looser means the cams will be opening a little later than the designer intended. Personally I believe in listening to the people that make things myself ... why would we know more about these cams than the company that made them?

BTW: The old Jaguar 6 cylinder twin cam engine inlet clearances (from memory) are only 0.002" ...

Pete

 

The valve clearance relates to valve expansion, it has nothing to do with the cam profile you have.

If you have excessive noise and it is a clearance, it must have some kind of problem.

I've seen QV shims fitted to 2V engines before, that rattle around and cause a tap noise, or some other problem.

Usually, valve noise is not excessive until clearance gets over 0.020"

Maybe you have an exhaust manifold crack/tick, or sticky exhaust valve...or even a tight clerance holding the valve slightly open when hot, but if your clearances really are as you say, then the noise is not from that.

 

I talked to Bill Pound about this a couple of years ago. On his advice, we set lash on my P6 to stock spec to give the ex valve a bit more seat time (cooling).

They don't make the noise you describe.
Philip