20v st compression leak

[20vceli]

Ever since I have had my 20v it has always ran rich with no engine codes, and there seems to be a misfire while idling ontop of that it idles at a minimum of 1500rpm anyways I did a compression test on it the other day and I got
Cyl 1-150
Cyl 2-180
Cyl 3-180
Cyl 4-180
So I'm thinking its either the head gasket itself or a leaking valve. My question is do replace all the valves if they are some seating improperly in cylinder 1 or could I just regrind the valves. I did check the valve clearence and the max the they were out was a thou of an inch.

[yoshimitsuspeed]

You should really do a leakdown. Low compression could be valves, HG, or rings.
You want to know witch before you tear into it.

[20vceli]

I have done a wet compression test but the results stayed the same. So that's eliminating rings and valve seals.

[jondee86]

My question is do replace all the valves if they are some seating improperly in
cylinder 1 or could I just regrind the valves. I did check the valve clearence and
the max the they were out was a thou of an inch.

If you are going to pull the head, to fix one leaking valve, you might as well
take all the valves out so you can check/clean the valves. and check the condition
of the seats. If the mating surfaces are in good condition, you can clean them up
with some grinding paste and a hand tool. But if there is damage (pitting, burning
etc) the only way to clean them up is to have a machine shop recut the seats and
reface the valves. Then you will need to do the shims or have the machine shop
set the clearances by grinding the valve stems.

Kind of depends on what you want the engine to do, and how much you want to
spend. Race engine with metal head gasket; rebuild the head and reface it. Daily
hack with OEM gasket that you just want to last another year or two; clean it
and do the minimum required to keep it running

Cheers... jondee86