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Old 02-22-2017, 10:18 PM
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PMD1969 PMD1969 is offline
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Default Exhaust and other gasket(s) refresh

I have been creating a list of items that I will need to complete the project of pulling the intake/exhaust manifolds to replace leaking gaskets.

Does anyone know what the size of the GM exhaust clamp is at the bottom of the "Y" pipe collector? Any specs for it and where I can find them would be a great help.

I definitely have all of the gaskets I need and even have the extra thick gasket to try as well. Not sure if I will need that as I have the stock thin metal ones which should work but we'll see.

Anyone know where I can find the spring and housing for the exhaust valve? I have been wanting to simply close that system off since it is prone to failure and it won't be used anymore. Anyone remember what the material was that people used to fill the inside of the exhaust manifold to close it off?

Last thing I need is the thread pitch and size of the exhaust studs and nuts that I will need after they shear off and break.

If you thin of anything else let me know.

I might keep posting back with pictures to help others as I go along.

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Old 02-23-2017, 11:36 AM
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TheSilverBuick TheSilverBuick is offline
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After a bunch of research on it, I came to the conclusion it probably isn't worth filling the exhaust manifold to separate it. It takes a few quarts of fairly expensive ceramic filler, or you could use aluminum if you have a good source of aluminum stock and can pour it. For what it takes, look for some headers. The exhaust flapper can either be wire tied open or I removed it and tapped the rod holes and put bolts in them.

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Last edited by TheSilverBuick; 02-23-2017 at 11:42 AM.
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Old 02-23-2017, 09:12 PM
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PMD1969 PMD1969 is offline
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Quote:
Originally Posted by TheSilverBuick View Post
After a bunch of research on it, I came to the conclusion it probably isn't worth filling the exhaust manifold to separate it. It takes a few quarts of fairly expensive ceramic filler, or you could use aluminum if you have a good source of aluminum stock and can pour it. For what it takes, look for some headers. The exhaust flapper can either be wire tied open or I removed it and tapped the rod holes and put bolts in them.
Many many moons ago there was a thread about this very thing on the OHC Forums. The guy had a pinkish colored material that looked and acted a lot like Bondo. He filled the exhaust ports that feed the system and then showed pictures of how well it had worked. Not sure if it is still working since the guy disappeared.

Yes aluminum would be great to use but I don't have the resources to do that. Where to get the material and how to keep it molten for the pour seems like it might be a bit expensive.

My goal would be to keep the exhaust manifold as factory as possible.

More importantly do you know where I might find the thread pitch and size of the exhaust studs at?

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69 OHC ZH Sprint Hurst 3 Speed 3:55 (1 of 213)
99 Valkyrie 1520cc Flat 6 108hp/110tq - For Sale
http://sohcsix.yuku.com/forums/1/OHC-lounge
Wanted: 1969 OHC "H" Camshaft
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Old 02-23-2017, 10:31 PM
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TheSilverBuick TheSilverBuick is offline
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I believe it is 3/8-16. I have hardware store bolts in mine.

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1969 Firebird with a turbo'd Pontiac L6 controlled by a MegaSquirt 3 and backed with a microsquirt controlled 4L60e and 4.56 gears! (Drag Week 2018!)
  #5  
Old 02-24-2017, 06:44 AM
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Jeff Hamlin Jeff Hamlin is offline
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The Parts Place offers a functional replacemnet for the Thremo Spring;
http://www.ebay.com/itm/331073664648...%3AMEBIDX%3AIT

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Last edited by Jeff Hamlin; 11-18-2018 at 08:22 AM.
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