In a message dated 4/12/99 7:25:26 PM Eastern Daylight Time,
ckotting@iwaynet.net writes:
> 1: 153 (or thereabouts, my tester's only marked in 5lb increments)
> 2: 130
> 3: 135
> 4: 155
>> SNIP
> I ran a pseudo leakdown test by hooking up the compression tester and
> cranking the engine 4-5 revs, left the tester hooked up and noted how much
> the pressure dropped off from the max reading in 20 minutes. I only
> checked the best and worst cylinders (#4 and #2) as it was getting late,
> but they each only bled down about 3 lbs in 20 minutes.
A compression tester cannot double as a leakdown since it has a oneway
valve in it, plus it would be almost impossible to get the piston to stop in
just the right spot with the valves closed.
As far as the compression test it looks like you did it correctly. Try adding
a tablespoon of oil down each spark plug hole and redoing the compression
test. This is called a wet reading. If the compression improves significantly
it means that the rings/bores are worn, In your case since two adjacent
pistons are low it could be a head gasket. Other possibilities are worn
valves or maybe a broken ring. A leak down test would tell you where the
problem lies. If under pressure you hear air coming out of the exhaust its
the exhaust valve, out the intake it's the intake valve, out the valve cover
its a ring, out the adjacent cylinder a head gasket.
Hope this helps.
Regards,
Peter S.
Charlotte NC
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