Valve clearence error

[overdrivegear]

I checked the clearances on my valves (warning: English units ahead) and they were as follows:

Intake:  .006(1) .014(2) .016(3) .011(4) (spec is .008-.012")
Exhaust:  .010(1) .010(2) .012(3) .012(4) (spec is .016-.020")

I then did a cold compression tests and the *worst cylinder* retained 95% compression with very little leaking around the rings and virtually none around the valves.  I was expecting some serious leaking issues from the valves.  Do these clearances really indicate valves way out of adjustment or is there some acceptable error even outside the specified range?  There is some mechanical noise coming from my engine, probably the valve train, that could be related to this issue.

[Vincent Waldon]

The fact that you're talking about percentages and have identified at least generally what kind of leakage you have and where suggests that you did a "leakdown" test rather than a "compression" test ?

A compression test involves attaching a latching gauge to each cylinder and cranking the engine over, recording the highest pressure reached. Generally the numbers are in the 300-400 psi range and you look for the absolute values as well as differences between cylinders.  Because you are cranking the engine over valve clearances play a role.

A leakdown test involves attaching a set of gauges to each cylinder and using compressed air to pressurize the cylinder to a known value.. often 100 psi.  A second gauge tells you how much is leaking, in percent... 95% generally is considered to be a good-to-great reading.  Because you are not cranking the engine over valve clearances do *not* play a role (unless you have 0 or negative clearance, causing a valve to stay jammed open!).

Which of the two scenarios matches yours ?

[Gearhead]

Either way, If you're an honest guy, I have an almost complete shim set and tools in Suwanee, if you want to borrow them to correct the clearances.  I'll only charge you the cost to replace the shims that you use.