Hey all, Compression tests questions/comments. Poured ATF on top of all 8 pistons last weekend. After starter repair, did comp test today. Was pleased with passenger side, 135-140 all. Driver's side was another story, 115,155,180, didn't fight #8. Comments? I assume (if accurate) the large variance indicates time for a rebuild. My question, I assume we can still try to start/run it to check the transmission some? The 185 seems over the top (wet vs dry ??)?? Chris
Unless you know the complete history of the engine and know for fact the oil never got changed/run low and/or was overheated and/or severely abused?.. these little shorter stroke shortblocks can last a good long while compared to many other engine designs. 90% of the time it's the valves that are leaking the worst. I would also guess you have some carbon buildup on that higher numbered cylinder. Before assuming the worst I would use the trans fluid to clean off the carbon deposits, which may or may not be affecting valve seal, and then follow that up with some water poured down the carb while revving it a bit. If no help there then I would guess a burned valve and/or pounded out/pitted valve seats. Factory valve guides and seals don't last too long in these motors either which causes oil usage. Bigger problem with freshening heads only is that a marginally acceptable shortblock condition gets taxed much harder when you correct the valve leakage and start driving it harder. I've killed a few that way through the years but some can last a long time even with a few more occasional beatings. PS. those are old mechanics tricks and there are some side affects that should be considered with the methodology. If you need more detail on the procedure I can post it later on if need be.
