Intake manifold install question
02-03-2009, 07:48 PM
#1
Drifting
Thread Starter
Intake manifold install question
I am reinstalling my intake manifold
. With the gasket set came two manifold gaskets and two rubber end gaskets...plus a round gasket that goes I don't know where. I am trying to keep engine NCRS as possible so am using the rubber engine gaskets (against almost all advice). So...1. any idea what the round gasket is and where it goes, and 2. which goes on first, the intake gaskets or the end gaskets and do the ends overlap or meet just right? Thanks...
. With the gasket set came two manifold gaskets and two rubber end gaskets...plus a round gasket that goes I don't know where. I am trying to keep engine NCRS as possible so am using the rubber engine gaskets (against almost all advice). So...1. any idea what the round gasket is and where it goes, and 2. which goes on first, the intake gaskets or the end gaskets and do the ends overlap or meet just right? Thanks...
02-03-2009, 08:07 PM
#4
Drifting
The round gasket goes between the distributor and the manifold. The intake gaskets lie flat against the heads, and the end rubber seals overlap them. Use gasket sealer around the water passages and something like Gasgacinch around the intake ports. Use a sealer on the threads of the mounting bolts so they don't wick oil up the threads and onto the manifold.
02-03-2009, 08:53 PM
#6
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Make sure your surfaces are clean enought to eat off of, no joke. Otherwise oil or contaminates will cause the gasket sealer/gaskets to slip. Take a center punch and dimple the front and back block surface every inch to three quarter inch. When you put your end gaskets down first, this helps them to get a bight and stay put. Put a dab of sealer at the corner of each front and rear gasket as it meets the intake gaskets, just enough to form a union between the two. Make sure to put the correct bolts in the the correct holes, since it's possible to pinch a push rod with a long bolt. Before you put on the manifold look to see which bolts go closest to the pushrods. I can't remember which location it is, but look for the shorter bolts to make sure. Use a machine tap to chase all the threads, (cover the lifter valley to catch debris) thereby making sure you get the correct torque (30 ft. lbs.) on the bolts. Use the correct sealer for the bolt threads. Follow the manual sequence for tightening the bolts in two stages. I would let everything set for a day before putting in fluids. After you have cycled the engine a couple of time check all your bolts. Don't forget a new thermostat. 
Dennis
Dennis
02-03-2009, 09:46 PM
#7
Drifting
With ALL that Dennis states, but especially these......well stated.
02-03-2009, 10:28 PM
#8
Racer
Has there been any machining done to the block deck surface? If so, the heads will sit lower, allowing the intake to sit lower also, the shops never remove any material from the end rails.
So, depending on how much decking was done, there may not be room for those end gaskets anymore and if you attempt to use them they will just get squeezed out when you tighten up all the bolts.
To be safe, just use a good sized bead of Permatex ultra blue RTV (NOT silicone as it does not hold up) and install without the seals, as already posted previously be sure all surfaces are cleaned well with solvent so the RTV adheres well. Its been done this way for years, works fine, just trim any excess RTV off after its cured. Lots and lots of builders use this methos exclusively wheter any machine work has been done or not.
Good Luck!
So, depending on how much decking was done, there may not be room for those end gaskets anymore and if you attempt to use them they will just get squeezed out when you tighten up all the bolts.
To be safe, just use a good sized bead of Permatex ultra blue RTV (NOT silicone as it does not hold up) and install without the seals, as already posted previously be sure all surfaces are cleaned well with solvent so the RTV adheres well. Its been done this way for years, works fine, just trim any excess RTV off after its cured. Lots and lots of builders use this methos exclusively wheter any machine work has been done or not.
Good Luck!
02-04-2009, 11:39 AM
#9
Drifting
Thread Starter
Uncle427, no machining done to the block deck surface. Only reason I am using the seals instead of RTV, is to try and keep it as original as possible (original matching numbers L79block). Might have to pull everything off again and do it the "right" way, with Feltpro and RTV some day soon, but until then, I want to try it with original parts and see how that works. I might have been the first person to ever pull this intake (and valve covers) off this engine as the gasket material was pretty well gone. Car was supposed to have 50k "original miles" so maybe that wasn't just a sales pitch.
02-04-2009, 12:54 PM
#11
02-04-2009, 02:25 PM
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02-04-2009, 07:57 PM
#13
Drifting
Thread Starter
They were definitely rubber not neoprene or cork...like I said, might have been first time the intake might have ever been off. JohnZ...did each protruding tab have the GM logo molded on it, or just one tab...and if these don't, is that NCRS points off? Thanks...
02-06-2009, 12:55 PM
#14
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