[BryanT2016]

Well tearing down for DOD issues and did a compression test just to see where its at. #1 is at 215 psi, the rest are at about 220. I thought that was pretty good (have build gen 1 engines) for the mileage. But now see on here most people seem to get about 260 to 270 or so. Searched the internet and didnt find much, maybe looking in the wrong place. 90k on the motor, but ran great before the lifter issue. So am i looking at a bottom end in your guys opinion?
If so going to put 6.6 rotating assembly in it for a few more cubes. Might as well.

[bishopts]

Compression test is pretty good for finding valve closing issues but it's not the best at finding valve opening issues. That little of a difference i would look somewhere besides lifters for whatever you're problem is

[KingLT1]

5psi is within spec. Most of the time when doing a CLT you look for a drastic variation in PSI across all the cylinders. I would chalk up the overall lower numbers being error of the testing method or equipment. You likely just need to check the heads and upgrade the valve train.

[SomeGeoffGuy]

That's fine. It is only a bad result if there is one WAY different from the others.

-Geoff

[KirillWA]

Originally Posted by KingLT1

5psi is within spec. Most of the time when doing a CLT you look for a drastic variation in PSI across all the cylinders. I would chalk up the overall lower numbers being error of the testing method or equipment. You likely just need to check the heads and upgrade the valve train.

+1 to this. 5psi difference in one is OK, and difference is more important then absolute numbers due to differences is measuring accuracy.

[BryanT2016]

guess i was wondering more about the PSI, if im getting only 220 and others getting 270+, do i need a to do a leackdown on the cylinders.

[bishopts]

You could have fuel washed rings. Or a compression gauge that isnt that accurate. Or both

[bishopts]

I had a car with low compression the other day and it was the seals on one of the injectors.

[h018871]

You stated it ran great before the lifter issue. Soooo, if you’re looking for an excuse to upgrade this is it and have the money, go for it. Otherwise valve job on the removed head(s) and button it up.

[Boost Creep]

5psi difference is nothing to really worry about. All cylinders should be within 15% of each other was the standard at one time.

If you think the psi seems low, try a different gauge. Yours might read low while the others you saw might read a little high.

Just do the DOD delete with new lifters, have the heads cleaned up, valve job and mild porting maybe. Inspect the cylinder bores while it's apart, if all good send it.

Then save up for a nice 427 short block swap later.

[BryanT2016]

Thanks all for the input, cylinders still have some light hone marks so im going to check the bearings and press on. Going ss3 cam so will have to pull to do the converter anyway.

[BryanT2016]

(((UPDATE) Well found some of the problem, The valves seem to be fine not stuck, will check when i pull all the way down, that cylinder had good compression, not the one 5 psi low. #7 of coarse. Cylinder walls look great for 90k.




if you cant see or i did incorrectly, its a bent push rod and still has hone marks in cylinder