I checked my compression this weekend and this is what I got:

dry- all were between 205 and 210 lbs

With oil in cylinders- between 265 and 275

I though these were high numbers, so I checked it with another tester and I got the same results.

The head has been decked a couple of times--would that make this much of a difference?

In the manual it says unusually high compression can come from carbon buildup in the head. I've ran 2 bottles of techron through the engine in the last 6 weeks (it was running rich because of bad o2 sensor). But I haven't had any problems with overheating or detonation.

The motor seems to run fine--is this high compression a problem.

I know I have weak rings because of the difference in the wet test, but since the dry test is still above spec is that OK?

Thanks in advance

Those #'s seem way to high ud have lots of carbon buildup to hit that

I will gladdly trade ya...
The 84 has about 55 psi - on the high one...
If it was running rich (extra fuel) it could have lead to carbon buildup on the pistons. But if it runs good, why bother with it. My guess would to be run some more techron.
A difference between dry and wet #'s is normal.

Yeah, those numbers just seem really high to me... do you really trust those gauges? You didn't buy them at WalMart, did ya? :D

If you suspect a lot of carbon buildup, one way to get rid of it is to inject a small amount of water into the intake. Key word here is SMALL amount. Find a vacuum line that you can pull off that pulls vacuum as close to the head as possible. Take a cup of water, and GENLTY take sips of water into the hose with the engine revved up some. You'll be amazed at the amount of crap that will come flying out the exhaust. You might want to put a piece of cardboard on the ground unde the exhaust, otherwise it makes a nasty stain on your driveway.

And if you hydro-lock the engine, you didn't hear about this trick from me. :D :D

I've heard about that technique before, but using ATF instead of water. I'd think the ATF would be safer.

Seriously those numbers are more then likely wrong, Around 200 psi I beleive is above 10:1 compression and with your numbers I would imagine it would be 11:1 or 12:1 which would cause detonation problems.

Originally posted by KLF
Yeah, those numbers just seem really high to me... do you really trust those gauges? You didn't buy them at WalMart, did ya? :D

If you suspect a lot of carbon buildup, one way to get rid of it is to inject a small amount of water into the intake. Key word here is SMALL amount. Find a vacuum line that you can pull off that pulls vacuum as close to the head as possible. Take a cup of water, and GENLTY take sips of water into the hose with the engine revved up some. You'll be amazed at the amount of crap that will come flying out the exhaust. You might want to put a piece of cardboard on the ground unde the exhaust, otherwise it makes a nasty stain on your driveway.

And if you hydro-lock the engine, you didn't hear about this trick from me. :D :D Also a good way to clog the CAT!!!