silver_evo

03 Evo 8 with 83K miles with Kelford 272's.

Engine at operating temp with throttle 100% open

Dry : 110-115-90-115
Wet : 190-190-160-255

I was highly confused about the 255, but saddened by the 160 wet test.
I plan to do a rebuild at 120K. I think the years to tuning with running 1-3 counts of knock has caused damage to the #3 piston rings.

No noticable buring of oil or any symptoms of a HG failure.

The numbers are low, but I blame the cams for the low overall pressure.
Let me make sure I got this right before I do the next step.

A cylinder leak down test consists of removing the #3 plug with #3 cylinder at TDC, using a fitting/adapter and pressurize the cylinder with shop air (100#)

Air escaping from the TB is intake valve seal.
Air escaping from exhaust is exhaust valve seal.
Air escaping from oil cap is piston ring blow by.

Thanks for the look and advice.

mithrandir7533

iTrader: (1)

If those numbers are accurate, I don't think you will make it to 120k miles before your rebuild. You want the numbers to all be within 10% of each other. I would be worried about the 255. I'm not experienced enough though to comment on what the problem could be. I would double check your numbers!

mt057

iTrader: (6)

Get a leakdown tester. I don't really even bother with the compression test anymore. The leak down will let you know what you need to know and takes about the same amount of time. I bought my tester for about $100 if I remember.

silver_evo

Yeah, I was looking at the leak down testers, they have a pressure gauge and a % leak gauge. I'm going to see if I can rent/check one out from my local parts store.

silver_evo

As for the mileage, 120K was an estimate on rebuild because I would be due for a timing belt again. I mainly drive my motorcycle around to save gas. I maybe drive 100 miles a month on the Evo, I want to wait until I'm back on the mainland before I tear it apart again (3 years). Lack of machine shops and expensive shipping makes a rebuild in Hawaii a bad idea.

Anarchy99

iTrader: (196)

Not possible to have 255 psi pressure in cylinder 4

silver_evo

Yeah, I thought it was weird too. I did the test twice. I may have put too much oil in the cylinder, it was maybe 1 oz. which would've reduced the volume resulting in higher pressure, but I doubt 1 oz would make that much a volume difference.

I did that cylinder twice to make sure, then I did the 160 again to make sure the gauge didn't break. It was accurate.

killercd4G63

iTrader: (4)

agreed
how

mcm308

iTrader: (13)

Im no pro by any means but I could see excessively high psi with too much fluid in the combustion chamber with an interference engine like these. Try again with 1/2 ounce fluid in all cylinders and compare numbers.