Intake Manifold Gasket replacement

[nba1341]

Hello folks took my car to the shop for the brake problem and got it fixed under warranty and they also identified my oil leak as the intake manifold gasket which I have been searching for They wanted 300 to fix it so I said no and ill do it myself Now here is the question of which gasket to use and also I hear to use a think coat of black rtv on the top of the gasket? and by that do they mean silicone sealant or rtv gasket maker? Also I have read good and bad about fel pro 1250 set so anyone using this and any leaks? My leak was coming from the rear btw seaping down until the oil pan and blowing onto my exhaust Any links to installs and what not would be helpful.... Also if you could provide torque specs for the intake manifold My setup goes as follows: 302 block Edelbrock F4B manifold Stock E6 Heads (blehhh)

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[kalli]

it's leaking probably because on the last install the cork gaskets were used ...
big no no. whatever you heard about the black RTV is correct

you'll need a good small torque spanner that would read at least between 20 and 30 foot pounds

drain the water. you can leave the oil in engine for this. Remove carb, then the intaike

clean all surfaces (mechanical get rid of all gaskets and chemical wipe down with alcohol or something like that which gets grease/oil off)
get the felpro 1250 (they're good)
in the packet you'll find cork gaskets (throw them away)
as well you will find little squres to block the middle of the intake gasket (exhaus crossover). If you have an aluminum head, use them

if the waterports are manky (there's no proper edge on the head, kinda eaten up), then put a very small amount of the black rtv around that as well where needed.

when you place the gaskets they will slot into the headgaskets (there's gasketmaterial for that). the better option is to get four old intake bolts (or evne longer ones), cut the top off and cut a slot for screwdriver in there. those you can use as a guide for dropping the intake. It's def a nice to have, but I found I need this only on cast iron intakes which are heavy. matter of preference. once you have the bolts you will always use them.

before you drop the intake make a thick bead of the RTVat front and back. make them wider than they need to be (when looking at front of engine). I mean overlap the gaskets. as in start the bead one inch earlier and stop one inch later then you'd think you should.... hard to explain

then drop the intake on it.

put the bolts back in (make sure to oil them, which gives better torque reading)
tighten them in the order specified and to the torque specified.
Don't use a ratchet for bolting it down, it's likely to exceed the torque while doing that.
Just use the socket and extension and your fingers. and when they are all finger tight do it with the torque spanner.

once finished with torque spanner, go through it again and again and again until no bolt moves anymore when you apply the correct torque. (can take up to 5 times as the intake settles while you do that. the V-shape of the intake causes this)

enjoy ... it's enjoyable work and with the money saved you can buyt a nice little torque spanner for that, the black rtv, new set of bolts if you want and still go to the pub a few times ...




Kalli

[pass1over]

black rtv? I thought you used grey rtv to install manifolds, at least thats what we've always used. And check with the manufacturer of your manifold for proper torque and torque sequence for your manifold. Most Edelbrock manifold instructions have torque value between 15-20 ft/lbs.

[kalli]

i ahev used blue and black so far without trouble

[rtintwo]

This is off of edelbrock's website and they are talking about aluminum intakes.

"We recommend Fel-Pro Printoseal gaskets.
The use of Permatorque gaskets can lead to improper sealing
due to the hardness of the gasket. Don’t USEPermatorque
gaskets."

Also take a look at the links on edelbrocks website

http://www.edelbrock.com/automotive_...all/misc.shtml

Now for what i do. A thin and smooth coat of RTV or gasket glue to hold the gasket inplace on the head. Just enough to hold the gasket inplace and nothing more. As long as you have clean and smooth surfaces the gasket will seal. A filling bead of sealant where the end seals meet the gaskets. A bead of sealant around the water ports.

I dont use a thick coat of RTV because this will cause uneven torquing of the manifold because a thick coat is never an even coat. Also a thick coat will squeeze out into the air passages and partially block them, possibly rip off while the engine is running and go into a cylinder.

As for torque setting and pattern. Google 302 intake torque pattern and you will bring up alot of diagrams that explain it better than i can write it.

[kalli]

yah the felpro 1250s are printoseal
i have the RTV thin as well, but it needs to be thick at the front and back (away from the head, so you can be sure it's gonna be a proper seal). has to be at least the thickness of the cork gaskets. i usually go for around half inch ..

[chris66dad]

The tip Kalli mentioned about guide pins is really helpful to align everything
Get some long 4" 5/16 bolts (you need 4) and cut the heads off. Run those down a bit in the center four holes. Use them to align and center your gasket on the heads. Use the headless bolts as guide pins - they will help you land the intake straight down to not displace the gaskets or the bead of RTV on the front and back ridge. Start the other bolts and get them finger tight then remove the guide pins and add the center bolts.

Good Luck and Be safe
Ron

[1965screamer]

Ive always used the cork gaskets but I glue them to the block first with some 3m weatherstrip adhesive so they dont move. Then I just put a thin layer of silicone on top, never had any leak

[coda618]

The issue with the cork endseals is that they can slide when torquing the manifold down and squeeze out of place. However, if you take your time and use 3m weatherstrip adhesive exactly as directed to glue to the block they will not move (you have to put a thin film on the block surface and the gasket, let them tack up then stick down). I also do it on the gasket to manifold side as well. Block gasket surface must be super clean-I use brake klean. I have used this method many times and have not had a problem. Also, as mentioned, use a little RTV at the joints where the end gaskets meet the gaskets on the head. Also, get the correct Torque sequence, it matters. Get teh studs as well, makes it so much easier. The problems come when you drop the manifold on and its not lined up and you start trying to shift things around. Good luck.

[kalli]

the fear of having scrape all that crap off would already put me off using 3m weatherstrip and cork gaskets :-)