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Hi everyone! Just curious as whether or not to use the thick exhaust manifold gaskets thst came in my fel-pro full engine gasket kit? And if so, should any type of sealer accompany them? Its going on my 72 Olds 350.
Thanks!
Chris
Any time an Olds V8 powered car came in with an exhaust leak to the shop I worked at years ago, we would track it down. Usually either the donut or the manifold to head leaking. An exhaust gasket fixed it every time. The gasket is your choice, I would use anti seize on the bolts, good if you ever need to remove them.
Last edited by olds 307 and 403; July 25th, 2016 at 05:33 PM.
Ok. That makes sense. Before i dissabembled back in 2012, i did have a leak but i think that was more due to the sloppy dual exhaust conversion that the shop had done. Thanks!
Chris
So I have noticed that the area of the heads where the exhaust manifolds hook up is a Little rough as I m cleaning it up. I know that they didn't come from the factory with the gasket but you guys think that night help prevent leaks with the rough areas?
Thanks.
Chris
Location: I moved to pittsburgh so I can be near Primantis
Posts: 405
its a tough call, manifolds tend to warp outwards at the edges. if you had work done to them did they surface the exhaust port side? if so, have them scrape a few thou off the manifolds as well. first heat up the metal clads, rusts, seals just like the factory.
On a 40 year old engine, the heads and the manifolds warp. To say the manifolds will seal without a gasket would require both surfaces to be (properly) machined flat. Having recently had the manifolds off my engine, I can tell you they are not only warped, they are twisted. It took .020" to get the driver's side straight, because where it was leaking, it eroded. I still chose to use a metal gasket after the machine work. Yes, cheap gaskets don't last long and none of them will seal for long if the surfaces are warped.
I'd recommend holding the manifolds up against the heads.
If there is any significant gap anywhere, then one or both needs to be resurfaced (confirm with a straightedge).
If there is just the tiniest gap, then using a gasket will probably take care of it.
On my own car, I used the gaskets, along with a generous amount of Nevr-Seize, and used stainless steel screws, and over the first few hundred miles I retightened it a few times, and I have had no problems (yet...).
If there is just the tiniest gap, then using a gasket will probably take care of it.
I've never had a problem with stock Olds manifolds without gaskets, but if the mating surfaces are pitted, you might have an issue. I had a problem on the exhaust system of my truck, where there is a flange between pipe sections. The flange was warped an pitted and wouldn't seal, even with the gasket. I used Walker Acousti/Seal, and this stuff is magic. NAPA sells it. I highly recommend it for problem exhaust systems.
I suspect this will work at pitted flanges on the output side of a manifold as well? Or is there too much exhaust pressure at such a thin contact line where the flared pipe meets the manifold?
I suspect this will work at pitted flanges on the output side of a manifold as well? Or is there too much exhaust pressure at such a thin contact line where the flared pipe meets the manifold?
If surfaces are poor, etc. and you feel the need for a gasket, I recommend Summit 111440 copper gaskets. Fiber type gaskets blow out from the heat, etc. and need to be re-torqued occasionally.
Fel-Pro are metal sheathed with more compressability (is that a word?) so they fill a bigger gap with less chance of leaking. Copper may or may not be annealed soft enough to seal an uneven surface. Its a fine balancing point between durability and sealing.
[QUOTE=joe_padavano;944160]I've never had a problem with stock Olds manifolds without gaskets, but if the mating surfaces are pitted, you might have an issue. I had a problem on the exhaust system of my truck, where there is a flange between pipe sections. The flange was warped an pitted and wouldn't seal, even with the gasket. I used Walker Acousti/Seal, and this stuff is magic. NAPA sells it. I highly recommend it for problem exhaust systems.
Interesting. I'm going to save that for the future.
One of my many teenage jobs was working at Midas, hey I needed to do some exhaust and suspension work on my car. They gave an employee discount, had a lift, and fire wrenches. Anyway they had cases of a similar product that we used everywhere there was a leak, stuff was fantastic.
I've heard of guys using roofing tar as well in the Midas shops here. Just goop it on flame harden the top a little to stop it from running off, then slap em' together.
If the leak is caused by pitting or parts that don't quite fit together correctly, it should help a lot.
As it turns out i couldn't find acousti seal, nobody in this area carries it.
I tried another product but that didn't seem to work. The issue is that the flare outs on the crossover pipe seem to be bent, i can't get it to fit dead center on the manifolds. The exhaust leak happened when somebody was driving the car hard, spinning the tires etc, to "blow it out"...he blew it out alright. Really dont' want to go the dual exhaust route and other than trying to find a new crossover not sure what to do at this point..
As it turns out i couldn't find acousti seal, nobody in this area carries it.
I tried another product but that didn't seem to work. The issue is that the flare outs on the crossover pipe seem to be bent, i can't get it to fit dead center on the manifolds. The exhaust leak happened when somebody was driving the car hard, spinning the tires etc, to "blow it out"...he blew it out alright. Really dont' want to go the dual exhaust route and other than trying to find a new crossover not sure what to do at this point..
I've never had a problem with stock Olds manifolds without gaskets, but if the mating surfaces are pitted, you might have an issue. I had a problem on the exhaust system of my truck, where there is a flange between pipe sections. The flange was warped an pitted and wouldn't seal, even with the gasket. I used Walker Acousti/Seal, and this stuff is magic. NAPA sells it. I highly recommend it for problem exhaust systems.
Joe
Just got a tube of this for fixing a couple of leaks on my motorcycle (another one of my completed restoration projects). It is not cheap, $19.00 a tube now at NAPA. But it does do magic and fixed my leaks. Thanks!!!
July 25th, 2016, 04:12 PM
These gaskets kind of remind me of the puffy stickers from the 1980's...
