Sounds like a burnt valve. The squirt of oil should have slowed the
blowby of the piston. The next step is to do a leak down test. Crank
the engine to the point the suspect cylinder should fire, remove the
plug (if you haven't already to crank it into position) and hook an
air hose chuck to the plug hole. Pressurize the cylinder and listen
for where the air is escaping. Probably a burnt valve, where the air
would be heard in the exhaust manifold. But could be the head gasket
also. Either way, the head's got to come off.
the other Richard Jackson
NOT of fantasy flame fame
72 MK IV
______________________________ Reply Separator _________________________________
Subject: Compression, TR6
Author: MORROW@udavxb.oca.udayton.edu at Internet-Mail
Date: 8/24/95 3:41 PM
Hello all. I got tired of scraping the carbon off of #6 plug and decided to
run a compression check on the beast. Cylinders #1-#5 were all between
130-135 psi, but #6 was only 70! A squirt of oil into #6 hole and a recheck
gave only 80 psi. What is the most likely problem here? Broken ring? Worn
ring? Valves/valve guides? The car runs fine, but is very smoky at initial
startup (black smoke, not grey), little or no smoke after driving a while.
#6 plug gets completely covered over with carbon after about 500 miles and
won't fire. Any suggestions would be appreciated. Thanks.
Gary Morrow, 72 TR6
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