truckerlary

Did I read on a previous thread that when installing the intake on a 350 that to replace the rubber end gaskets with a bead of silicone. I am in the process of putting my 350 together and am needing to know if this is so. Thanks Larry

oldcutlass

I've done it with and without the end seals, personal preference. So yes you read right.

coppercutlass

yes no rubber seals just a big bead of black rtv. Also you gotta let it ooze out when you out the intake oun dont try to smear it smooth .

truckerlary

You say black but will clear work also as that is what I have

coppercutlass

I use the black because its the strongest or so im told . I have never used clear . I have used the blue with no issues in the past.

redoldsman

Check the temperature range on the clear and if it is compatible with oil. I think the black has a higher temp range. For a few bucks I would not chance it.

cjsdad

Maybe I'm just old fashioned, but I have never used RTV for sealing the ends of an intake. I have always used the gaskets and never had issues. I used them just a couple weeks ago when I put the top end of my 330 back together. Cleanliness is next to godliness when it comes to assembling engines so when it comes time to put the intake on, clean the block rails with sandpaper until it is bright. Use a towel to keep debris out of the engine and then vacuum the valley out afterwards to make sure all of those little abrasive particles are not left inside the engine. Then use brake cleaner on a towel to clean the lifter valley, the block, and intake mating surfaces. When you are ready to place the intake, Put a dab of RTV in the corners where the gasket fits between the block and head. Make sure the gasket fits into the crevice without twisting or curling. Set the intake in place and tighten. Just the way I do things.

Nice and clean!

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Installed! No leaks yet.

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IMG_20150615_190111123_HDR_zpsnkv1fann.jpg

steverw

cjsdad may have a point. The dry rubber may hold better than trying the slippery silicone under it. I used silicone and the rubber gaskets when I installed my intake. The gaskets kept squeezing out, nothing i did would keep them in place. Finally I decided to use some of the urethane windshield adhesive I had, and it seems to have worked great. A urethane rubber gasket in a tube. Time will tell when I actually get the motor running. I dont really like RTV, as oil seems to eventually break it down. Back in the early 70's we didnt have RTV. The guys who taught me, told me to use 3M trim adhesive, on ALL gaskets. I guess it worked ok, LOL I cant really remember. Not sure if the intake gaskets squeezed out on that motor, 67 E block, but then I dont think I ever checked or thought about that. It was my first engine build, so I was learning..... It ran great when i finished, leaks? who knows.

oldcutlass

I put a light coat weather strip adhesive on the engine side and the bottom of the rubber end seals, let it skim over and then stick them on. The weather strip cement is a contact type of adhesive and will hold them in place. I also do the same with valve cover gaskets by gluing them to the valve cover.

Warhead

Ditto, I use rubber seals with "Indian head", NEVER EVER EVER had a leak, never squeezed out, and it doesn't look like a rebuilt SBC front cover with the ooze.

olds 307 and 403

Use the Ultra Black, Grey or Right Stuff. Make sure you build the bead up high on the end rails and do around the water ports, both sides of the gasket.

droldsmorland

The Right Stuff. Let it cure and trim it then. I dont know why the gasket companies even waste their time and resources manufacturing the rubber deck seals. They aren't engineered properly and never, NEVER work. They are too thick.

Fun71

You found out exactly why silicone sealer should be used in the corners only when installing the rubber end seals.