intake manifold gasket replace


Old 03-22-05, 06:34 PM
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Question intake manifold gasket replace

Hi: I have a 5.7 omc 350, I need to replace the intake manifold gasket . I have the omc repair manual, but It's the first time for me and I am worried that I can do some thing wrong.Do you have any suggestion?

Thank you.
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Old 03-22-05, 09:05 PM
Join Date: Nov 2004
Posts: 74
Intake manifold gasket replacement

Follow the manual carefully. Torque to specification and sequence is imperitive, as is cleaning of surfaces. Prone to air leaks, use a red silicone gasket sealant (or as recommended in the manual), on both sides of the gasket. Air leak can cause overheating in a cylinder adjacent to a leak, resulting in premature failure of intake valve due to overheating (stretched stem) or burning of a corner of a (aluminum) piston. Big problems (I've had both), but not since using RED (high Temp) silicone. Be patient in re-assembly!
Old 03-23-05, 06:41 PM
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gasket replace

Thanks old Joe, and how do you recommend to clean the surface ; with a special cleaner or just a fine sand paper?

Thanks again.
Old 03-25-05, 10:31 AM
Join Date: Nov 2004
Posts: 74
Replace intake manifold gaskets

Cannot use abrasives on engines! Can contaminate wearing surface, namely the cylinder walls.

I use a putty knife as a scraper (will not gouge or scratch), then a wire brush. Chase all holes with a tap if necessary, but ensure you blow them out so any dirt is removed. Same for bolts - brush off and wash in varsol. Bolts and holes clean to ensure accurate torque readings. Spray the bolt threads with light lubricant (WD40) before assembly.

A related problem is the front and rear (cork) gaskets situated between the intake manifold and the engine block. To keep these from squirming or slipping out of position when placing the intake manifold on them, I glue them into their correct positions. I use red silicone as the glue, pressing them firmly onto the engine block, and letting dry overnight.

At assembly time I spread silicone on the intake gaskets as prviously described, them on the top surfaces of the cork gaskets, then I squeeze a bead of silicone into the four corners to ensure no gap will occur there. Then lower the manifold into place and tighten in prescribed sequence.

It is a good idea to check the exhaust manifolds for flatness so no exhaust leaks occur there. If you are not satisfied with the exhaust manifolds they can be planed flat at a machine shop. The alternative is to find a good used replacement. In any event apply red silcone to both sides of the exhaust manifold gasket at assmbly.

All fasteners and bolts must be cleaned and lubricated.

Always use a torque wrench for these fasteners.

Safe boating...
Old 04-19-05, 10:45 AM
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Unhappy clunch noise in reverse

Hi I put back in the water my bayliner this weekend, everything was working fine until I reach my sleep, than I put in reverse to enter in my sleep when I heard I clunch noise, which was not constant. I grease the gimbali when I winterized it in NOvember. IT is a OMC cobra 5.7. Somebody knows what can be wrong?



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