from NO compression to LOW compression in one cylinder

[Scott Danforth]

see your local engine builder first

he probably has core motors and about $1500 to rebuild a GM motor

you just need a longblock since you can re-use most of your stuff. I would get new manifolds.

or look at people like Michigan motorz.

working with your local guy, you can probably haul out the boat, pull the drive, pull the existing motor all while the motor is being done, then get the motor on the stand, start transfering your accessories, etc. and get the motor back in the boat within a week. aligned and drive back on. you could be back in boating business within 10 days.

 

[tank1949]

Like I said, when I hold the valve up in the seat, and fill the backside with fluid through the exhaust port, it will hold the fluid until I release it. Nothing wrong with it or the seat.

Yesterday, I filled the entire cylinder with seafoam and let it sit 24 hours, hoping it was just stuck rings. I went back 24 hours later and every drop of that seafoam was gone. It had leaked past the rings. I did another compression test and it was zero. I was like wtf, how did I go from 40 to zero? I thought that when I did the test yesterday, there was a little seafoam in the cylinder and maybe that basically made it a wet test. So I added a little 90w oil and did a wet test today, 15psi. So it is definitely worse than yesterday. How did that happen?

I am not pulling the heads or fixing this engine, as stated. I never intended to keep this engine. I will have to put a new engine in in the off season. My goal is to salvage what I can from this season since I spent 2k on a dock and can't get my money back and can't sell my spot to someone else. I'm not gonna put all kinds of time and money into this block when my plan was always to put a 5.7 in it eventually. But I just want to get something out of it this year.

Just a thought.... Retest your compression tester. Years ago, I almost pulled an engine due to a defective tester. I performed the same compression tests with a second tester and discovered that my first tester's release valve was not functioning correctly. Motor was fine!