auto vs marine intake manifold gaskets

[nateo]

Can auto intake gaskets be used on 86 merc 305? Not a single boat store open on sunday around me.

 

[Bt Doctur]

yes, no issues

 

[nateo]

I used a felpro from autozone (ment for a 5.0 camaro from same year) a couple of weeks ago (also on a sunday with boat store not open). It appeared to match it pretty closely, although it matched the holes in the head it didn't seem to match the intake itself. It kinda had some raised areas on the gasket itself that didn't match. I've been having a devil of a time getting the boat to run correctly and I'm now thinking it may be due to vacuum leak via the intake.

Perhaps the camaro had a different intake/carb.

 

[nateo]

No Title

:facepalm:

 

[Eric 3.7LX Alpha 1]

Back when I use to race cars, we'd scrap the front and back gasket and use a nice bead of red or orange Permatex silicone instead. Think I remember Bondo saying the same in another thread.

http://www.hotrodders.com/forum/sbc...ng-styles-gaskets-vs-bead-sealant-172986.html

 

[duped]

Yup, throw the rubbers away. I have always used Ultra Grey on the ends. You can get intake gaskets off the shelf at Auto Zone or wherever without having them look up a specific car. They have them sitting in the "performance parts" and chrome dress up crap aisle.

86 Camaro is fuel injected, so yeah...gaskets are not the same. Order for an older truck, or just get the ones off the shelf I mentioned above.

 

[flipbro]

Gaskets are the same. Fuel injected or not. Nateo you need to do a vacuum test or at the very least spray some carb cleaner around the base of the carb and intake and observe your rpms. If the go up you have a vacuum leak. But a vacuum gage is your best bet. Stop just assuming its this and that do the test and get it fixed.

 

[nateo]

No Title

Gaskets are the same. Fuel injected or not. Nateo you need to do a vacuum test or at the very least spray some carb cleaner around the base of the carb and intake and observe your rpms. If the go up you have a vacuum leak. But a vacuum gage is your best bet. Stop just assuming its this and that do the test and get it fixed.

I would have hooked up the vac gauge this morning but truck is in shop until sometime this week and boat is in dry storage with no water access. meanwhile summer is wasting away and I have an available sunday to work on it. they did seem pretty close other then that hole in the middle and those squares that are raised. I'm either going to fix or sink it before the summer is over, thats my plan

 

[nateo]

Just found a thread that indicated marine gaskets use stainless steel vs auto are just regular steel. Makes me a little worried as I also used the auto gasket on the head I took off! ahh!! lol. wonder how long it'll last....

 

[flipbro]

No worries if you boat freash water. Don't over think things. Lol The center hole is just a heat riser crossover for the ckock on carb the raised portions of gasket is just to help seal they should have been facing.up towards the intake side. Stick to the trouble shooting and you will get it all figured out.

 

[tonka329]

I'm the Commercial Side Mgr for the local Oreilly's and I just look up a '92 Chevy with the 350. Same year and the same size that's in my boat. The only problem is my water pump pulley bolt holes won't line up with the new pump... I'm new to the Mercruiser world

 

[bruceb58]

Just found a thread that indicated marine gaskets use stainless steel vs auto are just regular steel. Makes me a little worried as I also used the auto gasket on the head I took off! ahh!! lol. wonder how long it'll last....

That would be for head gaskets. Never seen an intake manifold gasket that metal on it.

 

[nateo]

on the auto gasket it has those little raised squares that are a steel core I believe. My suspicion is that it raised just enough to prevent intake from sealing properly. going to slap the merc part in there and see what happens.

 

[81 Checkmate]

Depending on the year/ type of manifold you have - tells you to use the little block off plates or not. Most likely you should have notice when you took it apart if they were installed on the motor or not. I have had AUTO FEL-PRO INTAKE GASKETS on my freash water boat for last 2 years and have not had a single problem.

Good Luck!

 

[nateo]

Back when I use to race cars, we'd scrap the front and back gasket and use a nice bead of red or orange Permatex silicone instead. Think I remember Bondo saying the same in another thread.

http://www.hotrodders.com/forum/sbc...ng-styles-gaskets-vs-bead-sealant-172986.html

I reinstalled the intake last night. wishing I would have taken this advice. It's difficult to be certain the little rubbers didn't move when reinstalling. Hopefully I didn't hose it. will find out as soon as truck gets out of shop.

 

[Bt Doctur]

Should you need to reinstall another one do it this way for a leak proof fit.
Clean the surfaces to alcohol/brake-kleen, etc. apply a 1/4 inch thick bead of RTV Black. Install manifold and start manifold bolts.
Now STOP and come back tomorrow
Now torque manifolds bolts down,This will leave a cured bead of RTV to seal everything and not just get squished out.