Ran a test on an Evo 8 with GSC cams + bolt ons with 65k miles. 5 cranks to be fair across cylinders. Test was ran cold as well.

Seeing below I noticed around a 20% variance

135-135-130-105

I suspect rings however didn't get to add oil to test. This is a car I'm considering buying. I took $1500 off my offer because of the results. Figure I can pull the engine myself when it gets worse and have it refreshed.

Any opinions on that trade off or results? I value all opinions

 

The manual states the following prior to running a compression check: Ref: 11A-10

• Engine coolant temperature: 80 − 95° C (176 − 203°F)
• The values noted are 145 max / 92 min

The oil add is noted as well on a weak number.

Keep us posted on what you decide & if you buy

 

Yea the test should be done on a hot engine and oil added to the weak cylinder to see if it improves compression.

Also do a leak down test to see how that is.

 

Not sure why you would do a comp test on a cold motor. However the one lower compression means eventually you'll be pulling the motor. So if you're going to pull it you'll need to fully replace all the parts, rods pistons, bearings, oil and water pump, you might as well do valve guides, studs tensioners, belts, other like cam replacement , clutch etc etc etc so you're budgeting for $1500?

 

It can show variances because of tolerance on a loosely built engine

Factory shortblock is $2800 - me selling mine puts me around there

 

Engine needs to be warmed up. If it was ran for 15-20 seconds to pull it into a bay to be worked on, a slightly dripping injector can make one cylinder run rich on cold start, wash it down a bit, and give you a low reading. The car should be driven for ~15 minutes before a compression test.