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77 Oil Leaking

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Old Feb 4, 2012 | 11:50 AM
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Default 77 Oil Leaking

Need some ideas as to oil leak. New rebuild 350 to 383 stroker and have oil leak from intake manifold and heads. I have been told not to use rubber gaskets, that came with it, while others said use blue permatex. As always thank you for the help! Rich
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Old Feb 4, 2012 | 01:54 PM
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Hey Acesone:

If all the manifold bolts are tight then it looks like it's time remove the manifold and replace the gaskets. Once removed, understand that the head surfaces, the manifold surfaces and the block surfaces where the gaskets/seals interface have got to be SQUEAKY clean. After removing all the old gasket material WITHOUT gouging up the mating surfaces, I use a FLAT aluminum bar with 600 grit wet/dry sandpaper wrapped aound it and some trans fluid to ensure that the surfaces are squeaky clean and FLAT. Any problem areas will show themselves quickly when working out the areas with the surfacing bar. (P.S. keep grit and debris out of the intake ports & bolt holes). You indicated that this was a 383 rebuild, so I am assuming that the manifold bolt holes are clear. If you are unsure, run a tap down the threads to ensure this. Similarly, check the manifold bolts for any problems or excessive length, and be careful that the bolts are not bottoming out when installed on your manifold.

Once you have everything cleaned up and checked for flatness, take the manifold and set it on the block with no gaskets. Make sure everything lines up properly... It'll probably be OK but you'd be surprised what might show up. Check that the joint between the head surfaces and the manifold surfaces are parallel. If not, see your local machinist... or have a heart to heart with your engine builder.

Once everything is checked out, I do the good Fel-Pro gaskets AND i use the rubber seals with a dab of RTV around the seals in the corner joints ONLY. Install all the gaskets DRY. Don't cover everything with goop. Make sure all the corner joints are set together properly with a dab of RTV and then set the manifold CAREFULLY on the block in a straight down fashion. Try to get it just right the first time so you don't have to slide it around to get it all aligned. Use THREAD sealant on the manifold bolt threads and then start them into the heads. Once they are ALL started by hand, tighten down lightly, starting with the bolts at the center of the manifold going side-to-side to the ends and then torque them down in the same fashion.

Thats how I would do it...

Installing the manifold without the rubber seals using a bead of RTV is fine too. I just have found that the rubber ones work OK if done correctly.

Good luck
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Old Feb 4, 2012 | 02:11 PM
  #3  
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From: BC
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Originally Posted by rainmaninwa
Hey Acesone:

If all the manifold bolts are tight then it looks like it's time remove the manifold and replace the gaskets. Once removed, understand that the head surfaces, the manifold surfaces and the block surfaces where the gaskets/seals interface have got to be SQUEAKY clean. After removing all the old gasket material WITHOUT gouging up the mating surfaces, I use a FLAT aluminum bar with 600 grit wet/dry sandpaper wrapped aound it and some trans fluid to ensure that the surfaces are squeaky clean and FLAT. Any problem areas will show themselves quickly when working out the areas with the surfacing bar. (P.S. keep grit and debris out of the intake ports & bolt holes). You indicated that this was a 383 rebuild, so I am assuming that the manifold bolt holes are clear. If you are unsure, run a tap down the threads to ensure this. Similarly, check the manifold bolts for any problems or excessive length, and be careful that the bolts are not bottoming out when installed on your manifold.

Once you have everything cleaned up and checked for flatness, take the manifold and set it on the block with no gaskets. Make sure everything lines up properly... It'll probably be OK but you'd be surprised what might show up. Check that the joint between the head surfaces and the manifold surfaces are parallel. If not, see your local machinist... or have a heart to heart with your engine builder.

Once everything is checked out, I do the good Fel-Pro gaskets AND i use the rubber seals with a dab of RTV around the seals in the corner joints ONLY. Install all the gaskets DRY. Don't cover everything with goop. Make sure all the corner joints are set together properly with a dab of RTV and then set the manifold CAREFULLY on the block in a straight down fashion. Try to get it just right the first time so you don't have to slide it around to get it all aligned. Use THREAD sealant on the manifold bolt threads and then start them into the heads. Once they are ALL started by hand, tighten down lightly, starting with the bolts at the center of the manifold going side-to-side to the ends and then torque them down in the same fashion.

Thats how I would do it...

Installing the manifold without the rubber seals using a bead of RTV is fine too. I just have found that the rubber ones work OK if done correctly.

Good luck
One small addition to this excellent advice. When I'm finished cleaning I degrease the surface with aerosol brake cleaner, preferring the CR brand Brak Kleen. Then keep oily fingers off the surfaces and gaskets.

Ensure you have adequate crankcase ventilation.

Steve g
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