Here's the scenerio. You travel to buy a low mileage engine that is reportedly in very good condition. The engine is sitting indoors on a pallet. Usually a compression test is done to check engine condition but these tests are only done on a hot engine. Anyone devise a method for checking an engines condition while cold? I believe that with oil in the cylinders you might get some reading but a low reading that doesn't tell very much. . Best that I can figure is that if all cylinders read the same low compression number the engine might or might not be good. I always look inside each plug hole with an inspection camera but this can only detect piston top condition, metal chips or excessive carbon in the cylinders.
Does anyone know of any method that can be used to check the condition of an engine out of the car and on a pallet?

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, ZZP Intercooler, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

You could try a compressed air leakdown test if you are so equipped. See if they all bleed down about the same.

Wet compression test with equal and non-low results is a good method.

If possible, you could also get it on a hoist or stand, pull the pan, and check the bearings. Pulling the pan off can also let you get a good look in the cylinders from the bottom, to check for extraneous wear on cylinder walls.

I guess it also depends on what you're buying (short block, long block, whole dropout), and what you intend to do with it. Even if these basic things check out, there are lots of things you could end up finding later on, that can be pretty bad as well. Which is also why I like to employ the rule of thumb of "if it's used, redbuild it first."

Yes, I would go with a leak down test after putting a little oil in each cylinder and turning it over a couple of times. May be better to spray some from a can if you can find something a little thicker than WD-40. At the TDC, look at the leak down gauge and then you can rock the crank back and forth a few degrees around TDC to get the rings to seat right. This is how an annual inspection is done on an aircraft engine, cold. Depending on the leak down gauge you have, you may have to hold the crank at TDC so the pressure doesn't blow the piston down. Larry

quote If possible, you could also get it on a hoist or stand, pull the pan, and check the bearings. Pulling the pan off can also let you get a good look in the cylinders from the bottom, to check for extraneous wear on cylinder walls.

Good point. We have to drop the pan anyway to install a new gasket when we put it on an engine stand that will be the next check. Engine only has 70K miles but the car was sitting idle for a while.

quote Originally posted by trotterlg: Yes, I would go with a leak down test after putting a little oil in each cylinder and turning it over a couple of times. May be better to spray some from a can if you can find something a little thicker than WD-40. At the TDC, look at the leak down gauge and then you can rock the crank back and forth a few degrees around TDC to get the rings to seat right. This is how an annual inspection is done on an aircraft engine, cold. Depending on the leak down gauge you have, you may have to hold the crank at TDC so the pressure doesn't blow the piston down. Larry

I am heading in this direction. Cylinders have already been both fogged , some 10W30 oil squirted in there and th engine cranked. We do have a leakdown tester here but it is usually used on hot engines. Its a simple two gauge unit. Never did one cold, but there is always a first time. I'll try your method.
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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, ZZP Intercooler, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 10-22-2011).]

it has been my experience, that, when buying a "used engine", ( doesn't matter how low the miles are supposed to be), ALWAYS concider it to be a "CORE" ! Then when you get it home, tear it down & inspect it. In the end , you will save yourself "ALOT of grief". Used, or previously rebuilt engines are very seldom "what they are represented to be".