<VV> Engine Problem....What to do?

[Mikeamauro@aol.com]

"Today, I bought a compression tester.  Here are the results on a cold
engine.
>
> # 1        150
> # 2        160
> # 3        150
> # 4          60
> # 5        160
> # 6        150
>
> Obviously, #4 is not good.  This is what JR thought after my posts stating
> that my brother and his friend thought the bad cylinder was #6.
>
> So, what do I do?  Does this indicate that the valve seat is thinking
about"

Before simply pulling the head- based on an assumption that the valves are 
the only issue, I'd go a bit further...position valves closed in #4, then, using 
an air hose fitting-to-spark plug thread adapter, pressurize the cylinder 
with shop air to approximately 100 psi.  If you hear air coming out of the 
carburetor, the problem is an intake valve, from exhaust..it's an exhaust valve, 
from the crankcase oil fill, well, in that case, don't bother with just the head- 
drop the engine: the problem is not (only) valve or head gasket related.  The 
danger in assuming the heads/valves are (only) at fault is that, even after 
getting the heads "just right", you could still have problems with worn or 
broken piston rings.  In as much as the other five cylinders crank test equally, 
using the air test--while comparing the results to the other "good" 
cylinders--should narrow things down nicely.  Doing an actual cylinder-to cylinder leak 
down test (using a calibrated test instrument) would be best, but, in your 
case, with one cylinder so low, a straight air test should point you in the 
correct direction.  Good luck.
Mike Mauro