Engine compression vs leak down test expert needed

[Rage]

Originally Posted by jeffswav

Do you have a flat tappet cam or roller. I had a flat tappet cam go down before and caused lower readings. If you have a roller it would be unlikely. I have been their before. My engine has been out 3 times. I pull my own engines and do my own assembly work. Machine work is still expensive and not having a running boat sucks. l would keep investigating and would not wait until spring when you could be boating. you can learn a lot just by pulling the intake and valve covers. Good luck!!

No it is a roller cam and rockers. Your experience with the compression going down because of the cam lobe going away adds more good information on possibility of a loosening rocker possibility being the cause which I intend to follow up.

No way I am not going to sort this out before spring.

Thanks

[jeffswav]

Originally Posted by Rage

No it is a roller cam and rockers. Your experience with the compression going down because of the cam lobe going away adds more good information on possibility of a loosening rocker possibility being the cause which I intend to follow up.

No way I am not going to sort this out before spring.

Thanks

I guess your boat is in storage. I paid for storage for years and now I finally have a building to store everything in. Your rockers would have to be pretty loose to loose compression. It would probably be making a lot of noise. Good luck with everything and let us Know in the spring what you decide to do.

[Rage]

Originally Posted by jeffswav

I guess your boat is in storage. I paid for storage for years and now I finally have a building to store everything in. Your rockers would have to be pretty loose to loose compression. It would probably be making a lot of noise. Good luck with everything and let us Know in the spring what you decide to do.

My boat is on a covered poly lift on the lake. I work on the boat year around as weather permits so I'll be back at it in about a month. The exhaust/engine is loud enough that a rocker came totally loose a while back and I never knew it until went looking for the reason for WOT rpm drop. Also wishfull thinking.

Thanks for the well wishes. I'll take all the luck I can get.

[jeffswav]

I have Comp Cams Rollers with "Polly Locks?" If you set them correctly they should not loosen up. You adjust the nut then tighten down the allen head. Do you have studs with adjustable rockers? If that is not set correctly they may loosen up.

[Rage]

Originally Posted by jeffswav

I have Comp Cams Rollers with "Polly Locks?" If you set them correctly they should not loosen up. You adjust the nut then tighten down the allen head. Do you have studs with adjustable rockers? If that is not set correctly they may loosen up.

The Crane rockers have the same locking system but had to cut down the length of the intake adjustment/locking nut to clear valve cover. So not quite as robust but 99.9% likely installer error if that is what is going on. Thanks.

[Rage]

I retested the compression, this time with a fully warmed engine. The compression on all cylinders was good.