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Discussion Starter · #1 ·
OK...to many here more experienced than I this might sound like a silly topic. I realize the basic concept of removing/replacing the intake but I've never done it before and I wanted to get some input on the basics (step by step) so that I don't make any beginner mistakes!
*Are there things I should make note of before I remove it? I realize that I will want to make specific note of the dist. position before pulling it so that I get it back the same way (or close enough to fire up and then set initial).

*I have read posts of others getting leaks in the corners where the block and heads meet because of something they forgot or didn't quite address properly. What's the best approach to avoid this? How long do you allow RTV to set up before assembling and is there such a thing as too long?

*I have read that you want to use a gasket adhesive to apply the gasket to the heads and allow that to set up before assembly...correct?

*I have an older ('92 vintage) Holley aluminum intake and don't know the torque spec on the bolts...would a newer Edelbrock intake (25 ft-lbs) be comparable?

Anything I forgot?

I apologize for the length and appreciate any feedback...as always!:)
 

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The Chevrolet engine architecture is something of a pain in the tuckus; both the distributor and the coolant passages go through the intake manifold--so--R 'n' R of the manifold means you have to re-time the engine, AND you're gonna get wet.

Other GM engine families put the distributor directly into the block (Pontiac and Olds) or into the front timing chain area (Buick and Cadillac) so you don't have to dick with the distributor to change the intake manifold. Smart idea...

A common trick for Pontiac engines is to saw off the water crossover portion of the manifold; then the air/fuel passages can be removed without draining the coolant. Can't do it on a Chevy because there aren't enough bolts to prevent leakage once you cut the manifold.

So, sorry, for those of us with Chevies, we have to be careful to align the distributor after installing the manifold; AND we get to burp the cooling system (at least once) after installation, too.

Have some extra coolant on hand; and if there's anything else you need to do with the cooling system--now's the time to prepare for that, too. How's your thermostat, water pump, radiator and all the cooling system hoses?
 

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Be sure to mark the position of the rotor as well as the distributor housing. Both are important.

As for the corners where the gaskets meet, make sure the surfaces are clean and then use a dab of sealer at each corner.

The torque should be the same for any aluminum manifold.

Be sure to drain as much antifreeze from the radiator as you can before you loosen any bolts.

I always stuff paper towels down each port to keep dirt and gasket material out. Once I'm ready to put it all back together, I use a shop vac to get any loose pieces and then remove the paper towels. Lay a rag in the lifter valley to catch any loose particles and be sure to take it out before you place the manifold in place.

Don't get in a hurry and double check everything.
 

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Discussion Starter · #5 ·
Be sure to mark the position of the rotor as well as the distributor housing. Both are important.

As for the corners where the gaskets meet, make sure the surfaces are clean and then use a dab of sealer at each corner.

The torque should be the same for any aluminum manifold.

Be sure to drain as much antifreeze from the radiator as you can before you loosen any bolts.

I always stuff paper towels down each port to keep dirt and gasket material out. Once I'm ready to put it all back together, I use a shop vac to get any loose pieces and then remove the paper towels. Lay a rag in the lifter valley to catch any loose particles and be sure to take it out before you place the manifold in place.

Don't get in a hurry and double check everything.
Thanks, Robert, for the step-by-step suggestions. One question...you said "use a dab of sealer in each corner", but I'm a little confused. For reference I looked at the instructions for installinng a new Edelbrock RPM. They recommend running a 1/4" bead of silicone all across the front and back edges and overlapping up onto the gasket in each corner. Is this pretty much what you're suggesting?
 

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For any "newbie" doing a manifold swap (or just good practice):

- Before loosening any bolts, get the engine on TDC/#1 cylinder.
- Pull the dist. cap & make a mental note of the rotor position.
- Drain cooling system.
- Pull dist., & strip off any brackets, doo-dads, etc. on the old manifold that connects to the "car" or other parts of the engine (you want a nice, clear open shot working space).
- Remove old manifold.
- Stuff rags/toweling into all ports, and lay a towel in lifter valley.
- Scrape off all remnants of old gasket material (shop vac is a great idea).
- Wipe down all mating surfaces with acetone or lacquer thinner (removing all oil, etc.).
- Dry fit all gaskets! Make sure they line up correctly, and make note of how the end "tab A into slot B" fit together. Pay attention to any notations of "this side out", or "this side to head".

On assembly, don't rush. I like to use a little Permatex "Hi-Tack" on the intake port gaskets so they'll stick in place, and a thin bead of RTV along the front & rear lifter valley rails, with a pea-sized blob at the valley rail to head joint. Set the gaskets in place and let the sealants set up a bit.

Apply another thin bead of RTV on the valley rail gasket tops, another pea-sized blob on the joints. Wait about 15 minutes, letting the RTV "skin over" a bit. Now carefully set the intake in place, trying to get it down & in on the 1st go. The idea is to have a thin bead of "squeeze out" along the valley rails and the valley to head joints.

Torque the manifold to specs, following the correct pattern.

Reverse the 1st few steps and get it running.
 

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Discussion Starter · #7 ·
For any "newbie" doing a manifold swap (or just good practice):


Apply another thin bead of RTV on the valley rail gasket tops, another pea-sized blob on the joints.
Cool, John...just as I was hoping for. Can you explain this part a little more...what are you referring to as the "valley rail gasket tops"? Is this a bead all along the top edge of the manifold-to-head gasket from front to back of the engine? If I interpret correctly, you're looking to see a little RTV squeezing out of the entire perimeter of the manifold, not just along the front and back edges, right?
 

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Cool, John...just as I was hoping for. Can you explain this part a little more...what are you referring to as the "valley rail gasket tops"? Is this a bead all along the top edge of the manifold-to-head gasket from front to back of the engine? If I interpret correctly, you're looking to see a little RTV squeezing out of the entire perimeter of the manifold, not just along the front and back edges, right?
Not sure but I hope that's not what he is saying. I think means the front and rear rails of the block that run across from head to head. Take the rubber or cork seals that came with intake gasket set and place them in the closest trash can. Spray the head side of the intake gaskets with copper sealant. Once they're tacky place them on the heads, aligning the intake ports and bolt holes in the head. Then run a bead of ultra grey or black RTV across the 2 rails from gasket to gasket. Make sure it overlaps the gasket a bit. Let the RTV tack over then carefully lower the intake into place.
 

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I think means the front and rear rails of the block that run across from head to head.
Yes, this is correct... the thin "rail" of engine block between the heads.

I dunno, it seems to be personal preference but I've always used the "rail" gaskets (either cork or rubber). As I said earlier I just put a thin smear of RTV on the surface, and a little blob at the corner joints.... never had a leak yet.

There is no place for RTV to be on the long manifold/head surfaces - except for maybe a thin smear around the water passage openings.
 

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Discussion Starter · #10 ·
Cool! Thanks again to all for the input!
 

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I dunno, it seems to be personal preference but I've always used the "rail" gaskets (either cork or rubber). As I said earlier I just put a thin smear of RTV on the surface, and a little blob at the corner joints.... never had a leak yet.
Some guys use them and have good luck, others won't even consider using them. Me, I've had better luck with just a bead of RTV.
 
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