Intake Manifold prep for gaskets and silicone

[GUITAR1989]

Hey guys I have a vacuum leak in my in my manifold so Im replacing the gaskets. I pulled the manifold and got all the lose debris off then I used some cleaner to get off the oil and remaining stuff. Where the old gaskets were sitting its discolored. Almost like a shadow where the gaskets use to be on the block. It isnt coming off so I was wondering if thats normal. It isnt a thick layer or anything its almost like its stained onto there but it doesnt whipe off. I just wanted to see what you guys have to say about it What do you guys do when cleaning your manifolds and blocks for gasket installs?

[DustyRusty]

Use one of those Scotch-Brite pads.  I've mostly used the green or red ones because that's what I had available.  There may be a more proper one but the red/green worked for me.

Rusty

[Blazin]

I use the little scotch pads that go on a whizzer tool. Bout 2" in diameter. Fine sand paper would work too. I also don't use the end gaskets. Just a nice thick bead of high quality silicone. I buy it in half tubes from Ford. You can also get it from International truck dealers too. Same stuff but Ford puts there name on it. It was originally designed for the DT 466, and 7.3 oil pans as they are not even close to fitting good! Since the first time I used it, I have never used any other silicone.

[GUITAR1989]

Ill go get some of those pads you guys mentioned i think theyll do the trick
Heres the stuff i was talking about


also theres rust in the back passenger side take a look...not sure if this opening is for coolant or what but take a look and tell me how bad this is. It sure doesnt look good

[Irish_Alley]

it is a water outlet. the heads on our trucks can be swapped that port matches the one on the front side of the driver’s side block the water doesn’t move much back there like up front it usually looks worse than the front. now about the stains don’t worry about that spray some parts cleaner on a rag and wipe it down make sure to remove all the old gasket maker first. i wouldn’t use the rubber pieces that come with the gaskets. use some rtv "the orange stuff" and put a bead on both sides of the block smear some around the water jackets and a dab or two where you can. let it get tacky and put it all back together. let it sit for a day.

[GUITAR1989]

cool Thanks for the help guys.

[Irish_Alley]

change your oil also lol

[1979C20]

Here is how I did my intake, granted I didnt have to clean the mating surface since they were fresh heads, but Ive done this in the past as well with NO leaks. You can find my engine build here http://forum.73-87chevytrucks.com/smforum/index.php?topic=20691.30

I put the 2 black S shaped gaskets on the front and back and put a bead of black RTV in the pockets on each end. then I put a thick bead of Black RTV around the water jackets on the side gaskets, on both sides of the gasket to keep it nice and sealed up.

The pockets with silicone are the red circles
The water jackets with silicone on BOTH sides are the green squares.

[Blazin]

I tried using the end rubbers back when I first started out working on motors. They never worked. I never use them now. Over the years have made friends with a couple guys that build engines, and they don't either.
I just redid an intake gasket on a 350 at work, the previous mechanic had used the end gaskets, and red silicone. It leaked oil like the Valdez!
Also do youself a favor and get a tube of the gray silicone I mentioned from your local Ford dealer. You will not be disappointed. Comes in a caulking style tube, but half as long as your typical caulk tube. The stuff is awesome!

[thirsty]

It leaked oil like the Valdez!

Automatic undercoating system.

[Irish_Alley]

I'm with blaze that's the same reason I never use them. The first time was all it took

[Dr_Snooz]

I use grey RTV for water applications, black for oil and haven't ever used red. I surrounded the water holes with gray and put dabs of black in the corners where the rubber strip goes. So far, it's sealed up real nice with no leaks.