How to seal an intake? [Archive] - Chevelle Tech

: How to seal an intake?


oregonchevelle
Dec 31st, 04, 7:42 PM
I have taken off my aluminum intake to try and fix a leak near the distributor. I have had people tell me to use the cork gaskets and some tell me not too. What is your guys opinion on the best way to reinstall an aluminum intake onto aluminum heads to keep it from leaking. (especially near the distributor)

d1_bradley
Dec 31st, 04, 8:58 PM
First, GET EVERTHING CLEAN AND DRY. Use brake cleaner to completely degrease the top end. Then use "printo seal" gaskets. Throw away the end seals. Use Hi Tack around the water ports and lay the sides (there is a "correct side up" marker on them. Lay a bead of Black Silicone (I use 598B black) 1/4" or so across both ends and extend it up onto the side gaskets at the corners. Let the silicone sit for about 15 minutes, then drop the manifold straight down onto the engine then install all bolts using a sealer on the threads. You should also use SAE washers on all the bolts to get a proper torque. Torque starting at the center and circle your way out to the ends. Let it sit for 18 to 24 hours before you add water or try to start. After starting and warming engine, recheck torque on all bolts. You will have NO leaks, well at least on the intake. Don't forget to install the new Distributor gasket.

Olle
Jan 1st, 05, 12:26 AM
I have always had good luck with Fel-Pro's rubber end seals, with an added dab of silicone at the ends. But doing it like Dave described will result in a custom made silicone seal that fits your engine and intake perfectly, and pretty much never leaks. Only reason I don't do it like that is that I'm such a worry-wart, and would rather risk a small oil leak, rather than a big blob of silicone falling down in my engine if I screw up when mounting the intake. I know that chances of that happening are slim to none if you just let it dry, but still... smile.gif

Brob
Jan 1st, 05, 5:03 PM
Looking at my the ends of my ZZ4 intake it looks like GM has laid a bead of silcone down.

598 Ultra Black by Loctite "guaranteed not to leak". It is a true OEM hi-temp silcone, meets GM Spec. Much better than the gold/copper silcone

I use this on my coppergaskets for my headers. They have never leaked.

1970SS396&1967
Jan 2nd, 05, 7:10 PM
Just a bead of black silicone has always woked for me.
Gerry....

turbo
Jan 3rd, 05, 9:37 AM
when I put my afr heads on I had a problem sealing the back of the intake. I always have just used rtv on the ends but this one had a pretty big gap and on the third attempt to seal it I ended up using a bead of rtv, then the cork end gasket, then another bead of rtv on top and that finaly sealed it. Also I found out from afr
that they make spacers for the ends if you have a large gap on the ends.
which was going to be my next step but I didn't need them after I did the rtv,cork,rtv sandwich

Hi-po SS 454
Jan 4th, 05, 2:50 AM
Follow d1_bradley's instructions, except I use a high temp. aluminum color silicone sealer which matches the color of an aluminum manifold, for got the name of it, but it works for me.

forcd ind
Jan 6th, 05, 12:34 PM
follow what the others have said, but i have gone 1 step further and turned the intake over, and roughed up the seal area(100 grit) on the ends to give the sealer something to grip on-i have had the oil slip between the sealer and manifold in some rare cases

Keith Tedford
Jan 6th, 05, 5:16 PM
PST by Loctite is a very good thread sealant. Judging by the number of broken intakes and carb bases that I have seen, it is a good idea to use a torque wrench and do everything to spec. This will pretty well guarantee no broken parts.

oregonchevelle
Jan 7th, 05, 1:47 AM
Thanks for the help guys. I ended up putting the black 598 silicone on the ends up onto the ends of the gaskets too. Seems to be working but will not be able to tell for sure until I can take it out and drive it some. Redoing the front end so will be a few more days. Just let it idle for 5 min. or so so far.

webfoot
Jan 7th, 05, 6:22 PM
Originally posted by oregonchevelle:
will not be able to tell for sure until I can take it out and drive it some. Looks like its gonna rain from now till June, you already missed your chance! ;)