dyno

well It looks as if my engine was taking on water through the first two intake bolts on both sides of my 7.4's I'm using merlin heads and thought they were blind holes but there not!!!!!washed out my mains.....what should I put on the bolts on re-assembly? Rvt?should I use stainless bolts? one of the ones I took out was about half gone.....Help!!!

traviss

we use tubes of GM teflon sealer..

excaleagle42

stainless bolts from your local hardware store are fine. i used permatex liquid brush on high pressure thread sealant with good results. 25 ft. lb. torque. they don't get too hot because they are in the water so don't worry about galling.

Tinkerer

With the gaskets properly seated the water should not have been able to get into the engine. It should have come out around the bolt head and onto the top of the intake. Not into the engine. Have your heads been cut? Before you put the intake back on clean all the gasket areas and set the intake back on and see if it sits level and if you push it over against one of the heads (keeping the bottom still sitting on the block) does it hit the head tight at both the front and the back at the same time? ( is the angle of the head the same as the intake ) The intake must not rock when sitting on the block and ALL the surfaces MUST be parallel. Then try the other side. Next set the intake to head gaskets on and set the intake in place-- is there still about an 1/8 inch gap between the bottom of the intake and the block? If you don't have at least 1/8 inch the intake might be bottoming out before the side gaskets are properly pinched. DON'T USE THE CORK GASKETS use RTV blue and let it tack up for about 10 minutes before you install the intake. OH and yes I do use thread sealer.

dyno

the heads and the intake are stock never cut on Steve....

Tinkerer

Check the fit of the intake. Did you use the cork gasket?

dyno

no steve the gaskets are not cork....

Tinkerer

I'm only talking about the bottom gasket between the intake and the block--- not the ones that go between the intake and the heads. DON"T use any gasket on the bottom use RTV silicone.

It sounds to me like the gasket wasn't pinched properly and didn't seat.

formula31

And check to make sure that the bosses for the 4 widest bolts (I dont remember the bolt #'s) are not hitting the valve cover ridge on the heads. I have had to do some grinding on some intakes when using GM heads. Not sure on the Merlins. Ive never used thread sealer on my intake bolts but I do goop up the area around the water jackets with ultra black.