I don't have a leak-down tester. What I've done is get a plastic
(nylon?) hose barb to pipe thread adapter-fitting. Attach a short
length of air hose with a quick connect at the other end of short air
hose. Then position the cylinder in question at TDC with valves closed
and screw in the plastic pipe thread end into the spark plug hole *by
hand*. The threads are not the same but close enough to get a few
turns and the plastic fitting will not harm the threads in the head.
Then I apply air pressure ~ 60-80 psi. **Be careful as the motor could
turn, especially if it is not at exactly TDC.** Listen for air
escaping through the intake, exhaust, cooling system, crankcase and
around the edges of the head. Also listen for air escaping at adjacent
cylinder's spark plug holes (plugs out...) if you suspect the gasket
has blown between cylinders.
Some slight hissing past the rings is normal. But if you compare a
known good to a suspected bad you'll get an idea of what to expect
there.
It doesn't give you a definitive reading like a real leak-down tester.
But mine only costs a dollar or so...
Re: freon in the A/C, if it is still present, it is advised to have a
shop evacuate the system. Irks me that they charge so much for that.
Eric Russell
STOC #2860
Mebane, NC
http://home.mebtel.net/~ejrussell
----- Original Message -----
From: "Steve Shipley"
> Can someone explain the procedure for diagnosing what I'm assuming
> is going to be low compression on two or more cylinders? I'm going
> to
> have to buy a compression tester. Mine is ancient. Or do I get
> better
> information by doing a "leak down" test?
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