97oldscutlas Posted August 3, 2013 Report Share Posted August 3, 2013 anybody go the compression specs? I did some searching without much luck. I"ve got 2 cylinders way off left is front of engine 4 5 6 1 2 3 1 - 160, 103, 135, 142, 140 2 - 190, 200, 200 3 - 181, 156, 156 4 - 172, 171, 173 5 - 200, 181, 189 6 - 112, 125, 120 tested each three times didn't do the oil test, prob should've got coolent leaking out the front of cylinder 4 was just gonna through it back together with new gaskets cause owner wanted it running. didn't run all that bad before suprisingly. Now she wants it running right, so prob gonna do a compressed air test see if i can hear where she's leaking Not that serious cause with it torn down she thinks she wants a valve job and new piston rings anyways. anybody got good links for the specs or should i just join alldata? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted August 4, 2013 Report Share Posted August 4, 2013 alldata says no cylinder under 100PSI, no more than 30% variance between highest and lowest cylinder, engine at operating temp, all plugs removed and throttle wide open. Quote Link to comment Share on other sites More sharing options...
Schurkey Posted August 4, 2013 Report Share Posted August 4, 2013 (edited) Be sure to inspect for head/block cracks and/or warpage that could cause the coolant loss into the cylinder. Best case = gasket failure, but that's not guaranteed. If you're going to replace the rings, you'd better inspect EVERYTHING along the way--timing chain, bearings, pistons (collapsed, worn skirts) etc. Might as well tell her "complete overhaul" than to quote for rings and valve job. Edited August 4, 2013 by Schurkey Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted August 4, 2013 Report Share Posted August 4, 2013 Shurkey's got good advice...best scenario for what you're describing is a headgasket for the coolant leak, and burned valves dropping the compression. I'd check carefully...rings might prove to be unnecessary, if this is the case. Quote Link to comment Share on other sites More sharing options...
97oldscutlas Posted August 5, 2013 Author Report Share Posted August 5, 2013 Agreed.. Always appreciate the experienced advise on this forum. Took the weekend to discuss with the owner the intricacies of a bottom end rebuild, the risks of tearing it down, parts being too worn or out of spec, and how in most cases its best to let a worn in engine alone unless you plan for a complete rebuild and spec it back out. So, I’m gonna take an evening and bolt back together so I can let it warm up and do a legit compression test to be sure and how bad the rings are if at all. Hopefully the compression won’t change much and we can just plan on a head check and valve job Quote Link to comment Share on other sites More sharing options...
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