Hey guys I got some weird compression numbers on a motor I bought off Craigslist.i had 60 on 2 holes on the passenger side and 90 on 1 hole in the driver side.I totally ignored this and put the motor in my truck(project truck)and the truck runs good but lacks power big time.No check engine light or misfire and so far I put 2000 miles on the engine so far and I'm gonna check the low holes tomorrow.I was told that the engine only had 70k on it and it sat in this guys garage for 5 years!It only gave me a 15.7 in a short bed with long tubes and a tune witch is **** in a 2wd swb.With 3 low numbers do you think this would be valve related or ring related?thanks in advance for any past experience or info

 

Rings could be stuck or a valve could be hung open.

My money is that motor is hurt.

 

it was a roll over motor and yea your probably right man that sucks.5 years is a long time to sit and the story gets stretched more and more.guess I'll do a wet compression test and see what happens.I got a lq9 otw but I can't honestly sell this 5.3 to somebody knowing it's issue and that sucks lol

 

Boat anchor it and get another shortblock

 

well that sucks lol plenty of motors out there

 

When you say valves could be stuck open u mean like it sat acertain way for a long time and now it's used to being pushed down and the valves not making a tight deal?

 

Meaning,

A valve from each cylinder is stuck in the guide, thus, holding it open or preventing it from sealing all the way.

Happened to me on an old SBC. It doesn't happen so much on the LS platform but it's still a possibility. Only way to tell is to pull the heads.

 

Could be corrosion on the valve seat as well, causing the valve not to sit flush all the way.

I'd pull the motor, dingle ball hone the cylinders, lap the valves and let it eat.

 

Alright guys here's the numbers after2042.8 miles of road time the hole that was 90 is now 145And the hole on driver side that was 65 is now 115And the hole in the back on passenger side is now 1302 of those numbers aren't great but there above 100 hmm maybe there was calcium build up on the heads u should seen the waster pump **** was nasty

 

thanks for breaking that down for me buddy