Tryin' to be the man, my dog think's I am. marine diesel service owner
Don't know the spec's,
All engine bolt's "should" be torqued. In the case of manifold's, the even torque spread's out the surface bearing area , allowing for a consistant sealing pressure. If you over torque (one side tighter than the other) you have just effectively ruined your sealing surface. Yes gasket's are used, but they are "spec'ed" with the intention of use in an evenly torqued application. I'm sure Jaw's or one of the "gas guy's" can help you out. You may have to PM them, this new forum, for me anyway makes it hard to see if a new topic (or question) comes up. Frank
Ray what do you have engine wise. Also are the manifolds/risers stock or do you have have something funky like aluminum or stainless, inquiring minds need to know.
Duck,
I believe the risers and manifolds are stock-like if not stock. The motors are 99 350 chev's. I think they were re-done in 2004. We just recently got the boat. Nuthin fancy here, only, hopefully, serviceable, functional equipment.
Also, to update, we removed the head from the port side of the problem motor. A compression test showed very low compression (30) and slightly low (150) in the middle two cylinders. We're having a valve job done. We think the riser/manifold gasket failed slightly and allowed a little water into the heads corroding the valve to the point of non-seal. Also, the spark plug in that cylinder had rust on it.
It's due to be completed today so we should have it back on soon.
Also also...Does anybody know the torque value and torque pattern for the heads on this motor?
Torque all the riser bolts in a cross pattern to 15lb then do it again to 25lb then finally to 40lb. Check the torque after running for 30 minutes then again after running 20 hours.
The heads are first torqued to 45 then 85. Start with the middle 2 band work your way out in an X pattern first all the bolts to 45 the do it all again at 85.
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