I'm a fan of Uncle Tony's Garage you tube channel, and I caught an episode wherein he discussed exhaust manifold gaskets. Tony basically said the typical replacement stamped metal with a gray paper like coating gasket material is merely a band aid, and they always fail within 10k miles or so. Tony recommends whatever material came from the factory- because the manifolds expand and contract at a different rate than the heads, so the gasket is engineered to be compatible based on the material of both parts.

Okay- so I have one cylinder (#8) that constantly blows out the manifold gasket. I've cleaned both surfaces, inspected both for flaws, but it seems to only hold up very few miles before it burns a small hole through and I hear that "phat phat phat" noise again. I'm guessing the manifold is slightly warped so that back cylinder doesn't seal the way it should- but that's just a guess. I can remove the manifold and have it planed, but to my "shop tools" (visual inspection and a precision ground straight edge) it's straight, flat and smooth.

Back to UTG advice, the factory gasket is simply a sealer according to the manual- no actual gasket, so what gasket material is best for a replacement exhaust manifold gasket? Is copper better? Is MLS different than the part I get from Best gaskets- and does it even matter if that's the only type of gasket available? Apply more Permatex?

 

First of all, I'm sure that whatever you are watching on the interwebs is talking about a Chebby motor. Olds motors (at least 1964-up) came from the factory without gaskets on the exhaust manifolds. Second, I have yet to find a sealer that works at the temps you will see at the outlet of the exhaust port. Third, the absolute best exhaust gasket I've found is Remflex. Just be sure to follow the instructions when torquing. If you overtorque and crush these gaskets, you ruin them.

 

I use the FelPro MS90078 gaskets for both the headers and the exhaust mainfolds that were on my 71 98. I don't use any Permatex on the gasket.

I tried "performance gaskets" from Summit and Jegs, but they didn't last any longer than the FelPro gaskets.

 

UTG is a Dodge guy. He had the nerve to say Olds V8's blew head gaskets back in the day and that is part of the reason they didn't become popular. Supposedly he did a whole bunch. He sure loves the SB Dodge, a huge head gasket blower, much worse than any Olds V8. I have never had issues with Olds manifolds leaking. Even the shop I apprenticed at, an Olds V8 would come in with a leak, as Joe said, metal on metal. We would clean it up and install a gasket, good to go. Sounds like your manifold is warped, these things happen on 50 year old vehicles.

 

Actually Joe, Uncle Tony is a Mopar guy.

 

When I purchased my W, the exhaust on it was terrible. I replaced it all short of the W-Z's. I had them resurfaced and used remflex gaskets
and so far so good.

 

I run headers and found it was all too easy to overcrush the Remflex and bend the header flange. I use the Summit 111440 embossed copper gaskets.

 

It?s been my experience the prep is far more important than the type of gasket used. As long as the surface is clean, relatively flat, and properly torqued they don?t leak.

 

Grateful for all the input. I pulled the manifold and my "guy" Steve is going to resurface the manifold for me. It only took maybe an hour to get this off the engine, because It's been on and off three or more times in the last 2 years.


this is where it has been burning through.

Upon close inspection, it's really not a clean and flat surface.

Steve Dutcher from Greenfield did the crank on my 394 rebuild, and he's the real deal. He's also semi-retired. Another good machine shop aging out.
Scary- where are we going to find this kind of expertise in another 10 years?

 

the worst thing you can do is listen to Uncle Tony. He?s a hack and a Luddite .
some of the stuff he does is so whacked..like the time he helped that guy rebuild his small block Mopar. when it went to the dyno it had no oil pressure because they put the wrong size bearings in it and had massive clearance

or the latest dumb thing where he chastised Nocks garage for not adding the heat tubes to the cross ram on a 413?.he said it wasn?t making the expected HP because they were running the manifold to cold
so Nick added the heat tubes and it immediately killed the the HP and TQ.

now Tony rarely shows himself actually working on anything,, he does that off camera, then talks about the procedure or process after the fact.

that?s because he?s a clutz,, watching him fumble with stuff was embarrassing for him. he said that himself, he fumbles and drops stuff when he videos himself, so rarely does it anymore

 

I got to find that no oil pressure SB Dodge build from the "great" Uncle Tony. Jamie, an actual Tech from Dead Dodge Garage is much better to watch than UTG. He has a whole bunch of engine assembly videos. Nick lost power, a lot with those heat tubes that were supposedly magic. Honestly the first version Nick did with the long ram was best, 300+ HP and 500 ft-lbs down low. Pretty sure Chrysler just made up hopeful numbers, kind of like their advertised compression ratio, usually nowhere close. Nick made factory numbers with a W31, almost like Oldsmobile delivered what they advertised.

 

His biggest line of bs was him working at a GM dealership doing only Olds head gaskets everyday.

 

I think he's got some really good advice for the practical, every day type stuff but I think it's becoming more and more obvious that he's 85% talk. When it comes down to it, he's just a blowhard that thinks he knows everything. He certainly talks a good game but I think that's all he is.....game.

I used to enjoy him anyway but since the Canada **** talking, I won't entertain him anymore.

 

Back to the original topic. Could some of the issue be too much back pressure in the exhaust system? Maybe a better flowing muffler would help. Not an engineer but this issue seems to affect some cars more than others.

 

Really pissed me off, saying that with a straight face while praising the head gasket blowing SBD.

 

Really, shitting on Canada now, I like him even less now, F him.

 

Maybe he worked during the Olds 350 diesel days....