snomobeelr Posted May 31, 2018 Share Posted May 31, 2018 I found I have an oil leak it is coming from the Intake. After further inspection some coolant seepage also on the front intake bolt. I've ordered a new gasket set and going to reinstall the intake. There are so many posts out there regarding what sealant to use on the intake bolts and on the "China Walls" front and back of the engine. Looking for advise on what people have used and not having an issue with. Thank You BBC - 454 Airgap - RPM Intake Aluminum Heads Quote Link to comment Share on other sites More sharing options...
1970mcss Posted May 31, 2018 Share Posted May 31, 2018 I used Gray RTV from GM and thread sealer also from Chevrolet. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted May 31, 2018 Share Posted May 31, 2018 X2- silicone, either black or clear on the intake ends and liquid thread sealer on the bolts. The bolts not sealed can cause the dreaded oil through the bolt leak and I have found a few having a vacuum leak through bolts that were not sealed. Quote Link to comment Share on other sites More sharing options...
snomobeelr Posted June 5, 2018 Author Share Posted June 5, 2018 Thanks Guys. I ended up using Permatex Ultra Black. I always assumed I had a Vacuum leak but could never find it. After pulling the Intake and seeing the gasket I was in shock. It has been like this for four years since the engine was professionally built and assembled. From the looks of it they must have overloaded the sealer on the intake to disfigure the gasket the way you see it. After replacing the intake gasket replacement my vacuum went from 8 to 9 lbs to 19 lbs!!. Pictures below if your interested Quote Link to comment Share on other sites More sharing options...
amsterdam84 Posted June 5, 2018 Share Posted June 5, 2018 This all makes sense now. I have had coolant seeping on top of my intake ever since installing it as well as some oil. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted June 5, 2018 Share Posted June 5, 2018 Glad you found it! I bet it runs alot better now and stops better too! Nice job!! Quote Link to comment Share on other sites More sharing options...
overdrive Posted June 6, 2018 Share Posted June 6, 2018 That's a great increase in the vacuum. Nice job on the fix. Dan Quote Link to comment Share on other sites More sharing options...
rsorg Posted June 6, 2018 Share Posted June 6, 2018 hi snomobeelr ,how did you check and where for a vacuum test, thanks roger Quote Link to comment Share on other sites More sharing options...
snomobeelr Posted June 6, 2018 Author Share Posted June 6, 2018 Thanks Guys I hope this helps you out Mike and other people with the same trouble. The engine build I did was supposed to have good vaccum for the Brakes. Always suspected there was a Vacuum leak but couldn' t find it. I guess I should have realized with the other issues I had and before I spent the money on the hydroboost brake systems To check the Vaccum - I have a vacuum gauge and used a Hose T on it. One hose to the gauge.Then placed the T between the hose to the the Distributor and Carburetor. Quote Link to comment Share on other sites More sharing options...
John S Posted June 6, 2018 Share Posted June 6, 2018 Thanks Guys I hope this helps you out Mike and other people with the same trouble. The engine build I did was supposed to have good vaccum for the Brakes. Always suspected there was a Vacuum leak but couldn' t find it. I guess I should have realized with the other issues I had and before I spent the money on the hydroboost brake systems To check the Vaccum - I have a vacuum gauge and used a Hose T on it. One hose to the gauge.Then placed the T between the hose to the the Distributor and Carburetor. With that type of gasket is it put on dry or with sealant. I assume the blue lines are the sealing points that do not require sealant but let me know as I am planning on replacing mine also. The problem with sealant is many believe that if enough is good more is better and too much is just right. John S Quote Link to comment Share on other sites More sharing options...
snomobeelr Posted June 6, 2018 Author Share Posted June 6, 2018 Less is more in this situation. They were Fel-Pro gaskets Very light layer of RTV around only the water jackets on the top of the side of the gaskets that face the Intake. Thats why you don't see the blue around the water jacket ports in the picture. The ends (China Walls ) is different story. The Edelbrock instructions say not to use gaskets on the walls just use the RTV. I was shocked so I called Edelbrock and they said that is correct , not to use the gaskets on the front and back - (China Walls and to use Permetex Ultra black. That is thick , once area cleaned do a test fit to gauge how much of a bead you need to lay across to seal it and you go up on the head about a 1/2 inch on each side . Also layed a heavy bead of RTV on each bolt on the bottom threads to seal them. To hold the gaskets in place I uses a little of this on gasket facing the Head : AVIATION FORM-A-GASKET #3 SEALANT 16 I let it cure for about 36 hours before I added antifreeze and started car back up. Quote Link to comment Share on other sites More sharing options...
John S Posted June 7, 2018 Share Posted June 7, 2018 Less is more in this situation. They were Fel-Pro gaskets Very light layer of RTV around only the water jackets on the top of the side of the gaskets that face the Intake. Thats why you don't see the blue around the water jacket ports in the picture. The ends (China Walls ) is different story. The Edelbrock instructions say not to use gaskets on the walls just use the RTV. I was shocked so I called Edelbrock and they said that is correct , not to use the gaskets on the front and back - (China Walls and to use Permetex Ultra black. That is thick , once area cleaned do a test fit to gauge how much of a bead you need to lay across to seal it and you go up on the head about a 1/2 inch on each side . Also layed a heavy bead of RTV on each bolt on the bottom threads to seal them. To hold the gaskets in place I uses a little of this on gasket facing the Head : AVIATION FORM-A-GASKET #3 SEALANT 16 I let it cure for about 36 hours before I added antifreeze and started car back up. Thank you Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.