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Is it possible to machine HP manifold gasket surface?

Posted By: NAS Backyard

Is it possible to machine HP manifold gasket surface? - 10/09/10 07:07 PM

I've had a litttle tic tic tic leak forever on my RR . I replaced the exhaust flanges, half the exhaust and numerous gaskets with no luck. I was thinking they might be leaking at the manifold gasket surface. It has the stock waffled tin gaskets. I also need to reseal the manifold stud treads since they leak a little. Whats a good sealer to use on the studs. My plan was to remove the manifolds, sandblast, Por 15 manifold grey paint, have them resurfaced, new Mr Gasket hi temp gaskets and reseal the stud threads. Am I missing anything.? Thanks

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Posted By: superbyrd

Re: Is it possible to machine HP manifold gasket surface? - 10/09/10 07:24 PM

i have always used hi-temp black permatex on the stud threads,never had a problem. as for the manifolds,i just use a good straight edge and a 90 degree air grinder with a 36 grit sanding pad. then i install them with good fel-pro exhaust manifold gaskets. have never had any leaks or issues with them.
Posted By: stubbs300

Re: Is it possible to machine HP manifold gasket surface? - 10/09/10 07:25 PM

Cr8crshr bought a used set for his Satellite project and had them surfaced to CYA and when he went to torque them it broke one of the eyelets. He used Remflex gaskets. Soooooooo he got the repops from Yr. 1 and comparing the 2 surfaces, he found the old ones where alot thinner, so maybe the old ones had been surfaced a time or two. Just something to think about that they might not be able to handle it. Good luck though with whatever you decide.
Posted By: drew72

Re: Is it possible to machine HP manifold gasket surface? - 10/09/10 07:36 PM

I'm guessing the the eye hole broke because the manifold wasn't actually flat to begin with. These manifolds are difficult to set up on a mill or grinder, but it can be done.
Posted By: Twostick

Re: Is it possible to machine HP manifold gasket surface? - 10/09/10 07:52 PM

Try some hi-temp rtv silicone on both sides of the gasket and see if that cures it. A little crude but it is the easiest solution if it is leaking at the gasket flange and not too badly warped.

Kevin
Posted By: Rick_Ehrenberg

Re: Is it possible to machine HP manifold gasket surface? - 10/09/10 08:24 PM

Sure, they warp all the time, any machine shop can clean 'em up (mill or surface grind).

OEM there were no gaskets and none were needed. Warped, though, thick gaskets are helpful, but if they blow out, you have an even bigger leak.

Rick
Posted By: Neil

Re: Is it possible to machine HP manifold gasket surface? - 10/09/10 10:07 PM

Copper high temp rtv (no gasket needed) will seal stock cast iron exhaust manifolds.
Posted By: dOc !

Re: Is it possible to machine HP manifold gasket surface? - 10/09/10 10:14 PM

i have heard that the most leak-free combo is some soft copper gaskets that seal-well and also allow the exh-man heat to weap-off into the cyl head.
Posted By: JohnRR

Re: Is it possible to machine HP manifold gasket surface? - 10/10/10 03:12 AM

I have every used one I get resurfaced because they are not flat after 30 plus years , any good machine shop can do it .
Posted By: Twostick

Re: Is it possible to machine HP manifold gasket surface? - 10/10/10 05:26 AM

The trick is how to find a "GOOD" machine shop.

Kevin
Posted By: NAS Backyard

Re: Is it possible to machine HP manifold gasket surface? - 10/10/10 06:43 AM

I have a great machine shop. Looks like I had a small leak. I can't believe I drove this this 12K miles like this! FYI machine your manifolds during rebuild!

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Posted By: NAS Backyard

Re: Is it possible to machine HP manifold gasket surface? - 10/10/10 06:52 AM

The centers are in by 1/32-1/16th! Sand blast, magnaflux, machine, POR 15 manifold gray. Lots of leaks on the studs. That was caused by using never seize instead of thread sealer, Duh! My Bad! Anybody know where I can get a reasonably priced heat flapper thingamajigg (heat riser?) May as well fix that too.

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Posted By: JohnRR

Re: Is it possible to machine HP manifold gasket surface? - 10/10/10 02:20 PM

Quote:

Anybody know where I can get a reasonably priced heat flapper thingamajigg (heat riser?) May as well fix that too.



What type of choke set up are you using on your carb ?
Posted By: CR8CRSHR

Re: Is it possible to machine HP manifold gasket surface? - 10/10/10 04:17 PM

Quote:

Cr8crshr bought a used set for his Satellite project and had them surfaced to CYA and when he went to torque them it broke one of the eyelets. He used Remflex gaskets. Soooooooo he got the repops from Yr. 1 and comparing the 2 surfaces, he found the old ones where alot thinner, so maybe the old ones had been surfaced a time or two. Just something to think about that they might not be able to handle it. Good luck though with whatever you decide.



Yep they broke due to stress cracks from years of use. Hot then Cold will do that to cast materials. Even if they appear to be in good shape, the interior metallurgy can have flaws that will be brought out after lengthy use. Any way...with the new Y1 manifolds and using the Remflex Gaskets, I feel I have a good seal. EBoogher is right that from the factory they didn't use any gaskets. I did this time just because and after my initial break in run on the new motor I will re-torque the manifold bolts. NAS Backyard...today I will be out in my shop organizing stuff and I have a complete Heat Riser Kit..if I can find it , you can have it. I will PM with details later....cr8crshr/Bill
Posted By: NAS Backyard

Re: Is it possible to machine HP manifold gasket surface? - 10/10/10 06:30 PM

Manual choke. Thanks Bill! I'm running an 800cfm Edelbrock but will be trying a little "experiment" with a cough!spit! choke! gm qjet.
Posted By: NAS Backyard

Re: Is it possible to machine HP manifold gasket surface? - 10/10/10 10:00 PM

Sandblasted...

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Posted By: NAS Backyard

Re: Is it possible to machine HP manifold gasket surface? - 10/10/10 10:04 PM

POR 15 Manifold Gray, ready for machine shop, I'll put another coat on when there done.

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Posted By: JohnRR

Re: Is it possible to machine HP manifold gasket surface? - 10/10/10 10:11 PM

Quote:

Manual choke. Thanks Bill! I'm running an 800cfm Edelbrock but will be trying a little "experiment" with a cough!spit! choke! gm qjet.



With a manual choke you don't need the flapper , I'd just remove it completely and block the holes .
Posted By: CR8CRSHR

Re: Is it possible to machine HP manifold gasket surface? - 10/11/10 03:08 PM

Quote:

Quote:

Manual choke. Thanks Bill! I'm running an 800cfm Edelbrock but will be trying a little "experiment" with a cough!spit! choke! gm qjet.



With a manual choke you don't need the flapper , I'd just remove it completely and block the holes .



That is correct also. If you are still interested though I do have one. Still looking for it as I spend today in the shop....
Posted By: NAS Backyard

Re: Is it possible to machine HP manifold gasket surface? - 10/11/10 06:32 PM

Quote:

Quote:

Quote:

Manual choke. Thanks Bill! I'm running an 800cfm Edelbrock but will be trying a little "experiment" with a cough!spit! choke! gm qjet.



With a manual choke you don't need the flapper , I'd just remove it completely and block the holes .



That is correct also. If you are still interested though I do have one. Still looking for it as I spend today in the shop....


Thanks for the offer Bill, I'm going to leave the holes plugged up for now. Who knows , there may be a set of TTI's in the future!
Posted By: NAS Backyard

RESULTS after machining HP manifold gasket surface - 10/25/10 06:43 AM

Got the manifolds resurfaced for 60.00 and after some very mild port matching, I installed them with Mr. Gasket 5936 header gaskets. Do to core shift in the original manifold castings it still leaked on the pass side where the gasket didn't quite cover the edge of the manifold. So refering to the fact they came from the factory with no gaskets, I removed the pass side gasket, cleaned both surfaces and reinstalled. Suprise! NO LEAKS! So the lesson learned and to pass on is: Resurface your old manifolds before installing and don't waste your money on gaskets.
Posted By: Challenger 1

Re: RESULTS after machining HP manifold gasket surface - 10/25/10 11:52 AM

Quote:

Got the manifolds resurfaced for 60.00 and after some very mild port matching, I installed them with Mr. Gasket 5936 header gaskets. Do to core shift in the original manifold castings it still leaked on the pass side where the gasket didn't quite cover the edge of the manifold. So refering to the fact they came from the factory with no gaskets, I removed the pass side gasket, cleaned both surfaces and reinstalled. Suprise! NO LEAKS! So the lesson learned and to pass on is: Resurface your old manifolds before installing and don't waste your money on gaskets.




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