Valve adjustment question

[5Tractorguy]

I'm going to check the valve clearances on the '61 this spring. Shop manual says to get the engine up to temp, pull valve cover and adjust valves. How easy is this to do with the engine idling? Or am I better off getting up to temp and shutting down to adjust?

[Ed Snyder]

Originally Posted by 5Tractorguy

I'm going to check the valve clearances on the '61 this spring. Shop manual says to get the engine up to temp, pull valve cover and adjust valves. How easy is this to do with the engine idling? Or am I better off getting up to temp and shutting down to adjust?

You can do it either way. I've always done it with the engine running. You'll get the job done a lot faster that way.

[Jim A]

I'd say shut it down.
It might be quicker if you work fast to avoid oil splatter and getting whacked by the fan, but I can't see an advantage to let it run.

[LEWISMATKIN]

hello 5tractorguy, this is Lewis Matkin. The factory manual says that the valves were to be set hot at idle. Specifications are 0.012"H for the intake, and 0.018" for the exhaust. I have also set the valves cold(for obvious reasons--OUCH!) by adding 0.002" to each measurement. This method has worked well for me in the past. I hope this is of some assistance.

Cordially,
Lewis Ellis Matkin, Jr.
Ridge Manor, Fla.
1965 1002 305E-V6

[TJ's GMC]

Originally Posted by Ed Snyder

You can do it either way. I've always done it with the engine running. You'll get the job done a lot faster that way.

I agree....faster and easier. Oil pressure drops down enough to keep the oil splatter to a minimum as well.

[5Tractorguy]

Thanks guys! I'll give it a whirl at an idle and if all else fails, I can always shut down and adjust quick.

I know the fist time I did this wasn't quite accurate so I'd like to get them back to where they should be.

[Ed Snyder]

Originally Posted by 5Tractorguy

Thanks guys! I'll give it a whirl at an idle and if all else fails, I can always shut down and adjust quick.

I know the fist time I did this wasn't quite accurate so I'd like to get them back to where they should be.

Just don't try using a box end wrench on the adjusting nut while it's going up and down. A breaker bar with a socket works much better.

[Jim A]

I am afraid I have never understood the purpose and process of adjusting valve lash (clearance) while an engine is running.
First, I think damage to the gauge is possible through hammering.
Second, with the gap opening and closing around 300 times a minute at idle, how do you "feel" the exact resistance you are looking for?
Third, it is often hard to tighten the locknut without changing the gap when the rocker is still and not bouncing up and down those 300 times.

To overcome these difficulties, some real advantage must be gained by the running vs, not difference.

I should say that I have adjusted the valves of probably over 100 engines of over twenty makes over a period of 60 years.