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Discussion Starter #1
HI forum, I have a slight leak from my valley pan (1972 455 HO stock engine) that drips down the back of the block and over the bell housing creating a nuisance (one or two drops on floor after driving. Any recommendations for a good seal kit as I don't relish the idea of removing the carburetor and manifold again once I get it sorted out.
I do know understand that the car is nearly 50 years old, but I still think I can have her drip free!
Thanks,
Tim
 

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Howdy! Don't fret too much about removing the carb and manifold, that's one of the easier jobs to do on a Pontiac. A few tips: If you haven't separated the coolant crossover from the rest of the intake, then make sure you drain enough coolant from the system to keep it from pouring out of the fronts of the heads when you pull the intake. Test fit everything. Make sure the curved shapes on the cover match up with the curves on the front and rear of the block, especially at the corners. Massage the arcs if you need to. I like to "attach" the pan seal to the pan itself with silicone sealant and let it sit for at least an hour to partially cure up before I install it. I leave the other surface dry. On that valley cover seal surface on the block and heads, put a small dab of silicone in each of the 4 "corners" where the block and heads meet. Don't go crazy - you're just trying to create a seal at these points. You don't want globs of sealant coming loose and floating around in your engine, potentially clogging your oil filter pick-up. Watch the long edges of the valley seal and don't over-tighten. It'll have a tendency to push out below the intake ports if you do. Don't forget about that small bolt that pulls the intake forward into the back of the timing cover. Make sure you get the all the sealing surfaces nice and clean on the rear of the timing cover and on the intake, then reinstall the rubber seal with a *LIGHT THIN* coat of good silicone sealant on both sides. Install the intake and tighten that small bolt just enough to make the surfaces touch, then let it sit for an hour before tightening that bolt. When you're going back together, install the intake with all the bolts started and maybe barely finger tight, but not tightened, then tighten that small bolt first before torquing down the rest of the intake bolts. Use quality gaskets. I like the Felpro's that have the sealing rings around the ports. I install my intake gaskets dry on both sides because I like to be able to remove the intake manifold several times without having to replace the gaskets. I've also separated the front coolant crossover from the intake which provides me with two benefits: I can pull the intake without having to open up the cooling system, and tightening that small crossover to timing cover bolt does not mess up the alignment between the intake manifold and the intake ports in the heads.

Don't get in a hurry when working with silicone sealant. Before applying final torque to the bolts, you want to hit the "sweet spot" where it has cured up enough to have adhered itself to the mating surfaces really well, but has not yet gotten so firm that it can't "squish around" some when things are tightened down. Once you've got everything torqued, leave it alone and let it final cure before you start it and heat things up. I like to allow at least 12 hours regardless of what the information on the tube says.

Getting these engines sealed is more about how much care you take in fitting and assembly than it is about the specific seals/gaskets you use.

Bear
 

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Don't sweat a few drips, Show me and old car that doesn't mark it's turf ;) , and I'll show a car that doesn't get driven.
When Mr knows everything points out a drip or two under my '66 after a good hard drive, I just say Good then I know it still has oil :D
 

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Howdy! Don't fret too much about removing the carb and manifold, that's one of the easier jobs to do on a Pontiac. A few tips: If you haven't separated the coolant crossover from the rest of the intake, then make sure you drain enough coolant from the system to keep it from pouring out of the fronts of the heads when you pull the intake. Test fit everything. Make sure the curved shapes on the cover match up with the curves on the front and rear of the block, especially at the corners. Massage the arcs if you need to. I like to "attach" the pan seal to the pan itself with silicone sealant and let it sit for at least an hour to partially cure up before I install it. I leave the other surface dry. On that valley cover seal surface on the block and heads, put a small dab of silicone in each of the 4 "corners" where the block and heads meet. Don't go crazy - you're just trying to create a seal at these points. You don't want globs of sealant coming loose and floating around in your engine, potentially clogging your oil filter pick-up. Watch the long edges of the valley seal and don't over-tighten. It'll have a tendency to push out below the intake ports if you do. Don't forget about that small bolt that pulls the intake forward into the back of the timing cover. Make sure you get the all the sealing surfaces nice and clean on the rear of the timing cover and on the intake, then reinstall the rubber seal with a *LIGHT THIN* coat of good silicone sealant on both sides. Install the intake and tighten that small bolt just enough to make the surfaces touch, then let it sit for an hour before tightening that bolt. When you're going back together, install the intake with all the bolts started and maybe barely finger tight, but not tightened, then tighten that small bolt first before torquing down the rest of the intake bolts. Use quality gaskets. I like the Felpro's that have the sealing rings around the ports. I install my intake gaskets dry on both sides because I like to be able to remove the intake manifold several times without having to replace the gaskets. I've also separated the front coolant crossover from the intake which provides me with two benefits: I can pull the intake without having to open up the cooling system, and tightening that small crossover to timing cover bolt does not mess up the alignment between the intake manifold and the intake ports in the heads.

Don't get in a hurry when working with silicone sealant. Before applying final torque to the bolts, you want to hit the "sweet spot" where it has cured up enough to have adhered itself to the mating surfaces really well, but has not yet gotten so firm that it can't "squish around" some when things are tightened down. Once you've got everything torqued, leave it alone and let it final cure before you start it and heat things up. I like to allow at least 12 hours regardless of what the information on the tube says.

Getting these engines sealed is more about how much care you take in fitting and assembly than it is about the specific seals/gaskets you use.

Bear
THIS^^^^. Excellent instructions, follow them to a 'T'. I pulled the engine out of my '67 back in 2011 (I rebuilt it in 1988) to do a total reseal, as it was a leaker. I did the rear main and all the gaskets, taking my time to make sure all the surfaces were clean and straight, and nothing was over tightened. 7 years later, and many thousands of miles, my car honestly does not leak a drop of oil. Each year, I drive it 255 miles to a friend's house up in Nevada City and park it in his driveway. Not a drop on the ground. None in my garage, either. Very strange, after driving the car for decades prior and having it mark its territory all over the place. While the engine was out, I rebuilt the trans, resealed it, and rebuilt the power steering pump that was also leaking as well. Totally dry 51 year old car. It IS possible...just takes attention to the details. The 389 in my '65 (I rebuilt it waaay back in 1981) is still drip free, but has oil seepage build-up all over the place, due to hardening of the cork gaskets. The only oil it leaves on the ground is a drop or two from the countershaft of the Muncie, which I neglected to seal up when I installed the clutch in 1984.....
 
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