loose_electron
Donation Time
Ah yes, the never ending saga....
OK, got a 2.8L V6 that was rebuilt, ported, with 2.9 valves, a Jose grind cam and many other goodies about 800 to 2000 miles of driving back. (guessing on the mileage, mostly a prior owner)
From what I can tell, engine was bored out .020" at that point in time with suitable pistons and rings done.
Coming up to the here and now, compression on 5 cylinders is over 120psi. One cylinder shows compression of about 90psi.
Cylinder with low compression is #4, front of engine, US drivers side.
Looking at the engine, there is also a slight leakage of coolant between block and head near that cylinder. Leakage is on the bottom edge of the head/block connection point.
Running a pressure test on the cylinder (valves closed, pressurize the cylinder via the spark plug opening) shows leakage of air by the cylinder and no leakage thru the carb (bad intake valve) and no leakage out the exhaust(bad exhaust valve)
Right now my guess is that the piston rings or cylinder wall is the problem, but wanted to throw it out there for other opinions. The coolant leakage in the same area might mean something else, they could be related or two seperate things.
Advice, ideas or comments?
Thanks,
Jerry
OK, got a 2.8L V6 that was rebuilt, ported, with 2.9 valves, a Jose grind cam and many other goodies about 800 to 2000 miles of driving back. (guessing on the mileage, mostly a prior owner)
From what I can tell, engine was bored out .020" at that point in time with suitable pistons and rings done.
Coming up to the here and now, compression on 5 cylinders is over 120psi. One cylinder shows compression of about 90psi.
Cylinder with low compression is #4, front of engine, US drivers side.
Looking at the engine, there is also a slight leakage of coolant between block and head near that cylinder. Leakage is on the bottom edge of the head/block connection point.
Running a pressure test on the cylinder (valves closed, pressurize the cylinder via the spark plug opening) shows leakage of air by the cylinder and no leakage thru the carb (bad intake valve) and no leakage out the exhaust(bad exhaust valve)
Right now my guess is that the piston rings or cylinder wall is the problem, but wanted to throw it out there for other opinions. The coolant leakage in the same area might mean something else, they could be related or two seperate things.
Advice, ideas or comments?
Thanks,
Jerry