Mercruiser 5.7 1(m) - Intake Manifold Install

In this video I install a Vortec intake manifold on a 5.7 Mercruiser V8 engine. There is a tightening sequence as well as a bolt pattern to follow in order to equally compress the manifold on the gaskets on all corners. The silicone sealant used is Permatex Ultra Gray. The thickness of the bead I placed at each end is about 3/16”-1/4”. The gaskets came out of a standard automotive engine rebuild gasket set. I normally wouldn’t use plastic intake manifold gaskets but since there is no Dexcool used in the boat’s cooling system plastic gaskets are acceptable in open cooling marine engines.

[@jeremiahmejias6719]

That you. Great video and the tip with the studs made it so buttery smooth. Thanks again

[@mardymcdonald2334]

Excellent detail 👍👍

[@moccasinmarine]

Thanks

[@setthehook4me]

What's your take if my starboard side manifold and risers, runs hotter than port side? I have a '01 MCM 5.7L with extended risers. I don't have an overheating alarm, but to the touch it comes out hotter. Thanks for your great videos too.

[@moccasinmarine]

IT’s either corroded and partially blocked exhaust manifolds or the flapper in the exhaust has broken loose and is blocking exhaust from getting out. One trick is to get clear plastic hose so you can see how much water is flowing to each side of the engine.

[@setthehook4me]

@Moccasin Marine LLC Great idea thank you

[@bnelson1980]

Great videos! I have a Vortec engine and just purchased a JEGS 555-513002 intake manifold. Just curious what goes into what ports. Do any need plugs? Thanks for any help.

[@moccasinmarine]

Not sure what you mean by ports? If you are referring to vacuum ports you should seal them all with threaded and sealed plugs. In a marine bilge a backfire would blow rubber plugs and seals off the intake leading to a fire or explosion. That’s why you won’t find vacuum ports on a marine intake or carburetor.

[@josuerivera2527]

I had that problem with the intake I had the old version engine now I got that engine and I need to get intake manifold from which car I can get it

[@moccasinmarine]

No cars or trucks with Vortec heads had carburetor intakes. You have to buy a marine cast iron intake or edelbrock aluminum intake if you have closed system cooling.

[@ericeddy7280]

What sealant you use. ?

[@moccasinmarine]

Depends on what gasket I’m sealing but 90% of the gaskets I do I use Permatex ultra gray.

[@ericeddy7280]

@@moccasinmarine thank you. Im doing the intake on my 5.7 volvo penta.

[@badertaj2211]

Did you put sealant on the top and bottom of the gasket?

[@moccasinmarine]

Yes but only on the water ports