Replacing intake manifold gaskets
Posted: Sat Aug 08, 2009 9:31 pm
En route to Carlise 2009, I sprayed those behind me with antifreeze leaking from my recently repaired intake manifold. I had it repaired, because it was leaking... (*sigh*) I'm resigned to the fact that sometimes, if you want something done right, you have to do it yourself. So after consulting with Ed Eckerson, I bought a set of NOS Offenhauser intake manifold gaskets from Gary Pavlovich:
Ed since learned that they are available new from Phethean Racing Products, P/N 5433 for $11.50:
http://www.offyparts.com/
[This link appears to now be busted; and a Google search does not yield a result... (*sigh*.) Best to check with Gary Pavlovich. -Dan]
These are "composite" gaskets, not metal (as are the FelPro kits available from NAPA) -- and are more forgiving of minor fluctuations in the intake mating surface. The important difference, however, is that they must be retorqued -- not only after installation, but after burn-in.
Here's the 318 before I started:
Stripped of parts and manifold bolts, the manifold is ready to remove:
I work a thin-blade screwdriver through the sealer at the front end, and the manifold pops loose. Yow! That sucker is heavy! I end up lifting it off at an angle, and setting it on the floor. Then I peer at the block...
Oh no! There's antifreeze sitting in pools, next to the lifters! How did this happen? I check the dipstick...
There's no water in the oil. Whew! A quick phone call to Ed; this happened when I removed the intake manifold, likely from a pool of antifreeze within the manifold. Sure enough, where I set the manifold on the floor, there's a little pool of antifreeze. I mop it all up, and per Ed's advice, I "chase" it with oil poured liberally over the cam and ports; I'll drain the pan and refill before I crank it up, and there should be no harm done.
Next, I clean the block and head surfaces, blocking all bolt holes and ports, scraping off all sealer and other deposits, and cleaning with alcohol...
The FelPro kit I had also bought -- and ended up not using -- has front and rear "spongy" gaskets, that dovetail into the left and right gaskets:
Ed has a great suggestion: Lock down the left/right gaskets to the head with short cap bolts, and glue down the spongy gaskets in position, knowing their exact placement with the left/right gaskets -- let them set up, so that they don't squiggle around when the manifold is reset:
Enough for tonight -- tomorrow, I'll reset the manifold, do the first round of torqueing, and let it sit again. Ed discovered that, within a couple hours, the bolt torque with the composite gaskets dropped -- even without firing up! Whatever it takes, to get this finally right.
Here's a pic of the intake manifold, all cleaned up:
To be continued...
Dan
Ed since learned that they are available new from Phethean Racing Products, P/N 5433 for $11.50:
http://www.offyparts.com/
[This link appears to now be busted; and a Google search does not yield a result... (*sigh*.) Best to check with Gary Pavlovich. -Dan]
These are "composite" gaskets, not metal (as are the FelPro kits available from NAPA) -- and are more forgiving of minor fluctuations in the intake mating surface. The important difference, however, is that they must be retorqued -- not only after installation, but after burn-in.
Here's the 318 before I started:
Stripped of parts and manifold bolts, the manifold is ready to remove:
I work a thin-blade screwdriver through the sealer at the front end, and the manifold pops loose. Yow! That sucker is heavy! I end up lifting it off at an angle, and setting it on the floor. Then I peer at the block...
Oh no! There's antifreeze sitting in pools, next to the lifters! How did this happen? I check the dipstick...
There's no water in the oil. Whew! A quick phone call to Ed; this happened when I removed the intake manifold, likely from a pool of antifreeze within the manifold. Sure enough, where I set the manifold on the floor, there's a little pool of antifreeze. I mop it all up, and per Ed's advice, I "chase" it with oil poured liberally over the cam and ports; I'll drain the pan and refill before I crank it up, and there should be no harm done.
Next, I clean the block and head surfaces, blocking all bolt holes and ports, scraping off all sealer and other deposits, and cleaning with alcohol...
The FelPro kit I had also bought -- and ended up not using -- has front and rear "spongy" gaskets, that dovetail into the left and right gaskets:
Ed has a great suggestion: Lock down the left/right gaskets to the head with short cap bolts, and glue down the spongy gaskets in position, knowing their exact placement with the left/right gaskets -- let them set up, so that they don't squiggle around when the manifold is reset:
Enough for tonight -- tomorrow, I'll reset the manifold, do the first round of torqueing, and let it sit again. Ed discovered that, within a couple hours, the bolt torque with the composite gaskets dropped -- even without firing up! Whatever it takes, to get this finally right.
Here's a pic of the intake manifold, all cleaned up:
To be continued...
Dan