Posted By: dodger1
383 Exhuast leak problem - 12/31/08 04:40 PM
My Dad has a problem with his roadrunner burning out the gasket between the exhuast manifold and pipe flange, 3 times he,s replaced the gasket any ideas? Thanks
383 Exhuast leak problem
Posted By: NTOLERANCE
Re: 383 Exhuast leak problem - 12/31/08 05:16 PM
I would check to see if either of the two surfaces are warped. Expecially the pipe. Or the pipe isnt coming up to the manifold "true" meaning there is lateral tension on the pipe. This would cause the pipe surface and manifold surface to not mate up evenly.
Tried double gaskets?
Tried double gaskets?
Posted By: CR8CRSHR
Re: 383 Exhuast leak problem - 12/31/08 07:21 PM
If you are using the stock exhaust manifolds, then no gasket is required. All Mopars with stock exhaust manifolds were put on with out gaskets and thus were only metal to metal. Check the surface facing on the manifolds and the heads and if need be a slight swipe of the surfaces will true them up. But get rid of the gaskets as they are not needed.... 
Posted By: ZIPPY
Re: 383 Exhuast leak problem - 12/31/08 07:28 PM
He isn't talking about the gasket between the manifold and the head.
One thing I've noticed is that most muffler shops will make you an exhaust and will use a 3/8 bolt, which is a no-no because the hole in the manifold is something bigger (I think 7/16 but it's been awhile, I no longer run stock manifolds). The small bolt in a big hole allows everything to move around too much which causes gasket failure. But now that I typed all that, it will probably end up being something else.
One thing I've noticed is that most muffler shops will make you an exhaust and will use a 3/8 bolt, which is a no-no because the hole in the manifold is something bigger (I think 7/16 but it's been awhile, I no longer run stock manifolds). The small bolt in a big hole allows everything to move around too much which causes gasket failure. But now that I typed all that, it will probably end up being something else.
Posted By: 1_WILD_RT
Re: 383 Exhuast leak problem - 12/31/08 07:31 PM
Quote:
If you are using the stock exhaust manifolds, then no gasket is required. All Mopars with stock exhaust manifolds were put on with out gaskets and thus were only metal to metal. Check the surface facing on the manifolds and the heads and if need be a slight swipe of the surfaces will true them up. But get rid of the gaskets as they are not needed....
He said manifold to pipe flange not manifold to head... I fought a head pipe leak on my Challenger for years finally I bought a set of replacment flanges from Accurate LTD & rater then try cutting the original off & weld the new one on I sandwiched the new one between the original & the manifold then welded around the outside of both flanges...Haven't had a problem since...
Posted By: bboogieart
Re: 383 Exhuast leak problem - 12/31/08 07:40 PM
Quote:
He isn't talking about the gasket between the manifold and the head.
One thing I've noticed is that most muffler shops will make you an exhaust and will use a 3/8 bolt, which is a no-no because the hole in the manifold is something bigger (I think 7/16 but it's been awhile, I no longer run stock manifolds). The small bolt in a big hole allows everything to move around too much which causes gasket failure. But now that I typed all that, it will probably end up being something else.
Originally there was no gasket on the pipe, or head, side of the manifold. The gaskets are to take up slack ( So to speak) The mating surfaces have to be flat and even with each other. As the system heats up the seal should get tighter. If not the system will continue to leak as soon as the gasket gets burned out. I never had an luck stacking gaskets, ( 2 or more) but you just never know.
Posted By: 70RR383
Re: 383 Exhuast leak problem - 12/31/08 09:42 PM
One word,REMFLEX!!!.Best gaskets made. remflex.com
Posted By: bboogieart
Re: 383 Exhuast leak problem - 12/31/08 09:46 PM
Quote:
One word,REMFLEX!!!.Best gaskets made. remflex.com
These motors do not need exhaust gaskets unless something is wrong.
Posted By: 70RR383
Re: 383 Exhuast leak problem - 12/31/08 09:57 PM
Thats very easy for you to say.Have you ever had a exhaust leak???It drives you crazy.If you want to be that way and assemble and reassenble your manifolds and exhaust,go ahead,for me I put gaskets(remflex and forget about it.Also he is talking about the manifold to EXHAUST,not head.
Posted By: pro451bee
Re: 383 Exhuast leak problem - 12/31/08 10:06 PM
Thats why I now have headers
Posted By: bboogieart
Re: 383 Exhuast leak problem - 12/31/08 10:14 PM
Quote:
Thats very easy for you to say.Have you ever had a exhaust leak???It drives you crazy.If you want to be that way and assemble and reassenble your manifolds and exhaust,go ahead,for me I put gaskets(remflex and forget about it.Also he is talking about the manifold to EXHAUST,not head.
I make sure all mating surfaces are flat and no leaks. No gaskets on either mating surfage as I stated befor.
Posted By: 1_WILD_RT
Re: 383 Exhuast leak problem - 12/31/08 10:34 PM
Quote:Quote:
One word,REMFLEX!!!.Best gaskets made. remflex.com
These motors do not need exhaust gaskets unless something is wrong.
Really?
Posted By: bboogieart
Re: 383 Exhuast leak problem - 12/31/08 10:49 PM
Yep
just cuz someone makes something doesn't mean you need it. The factory might even have used them,(?)
but I never took one off a factory set up.
My cars are all older then that page (70&up).
I've been doing this since these cars were only 5 to 10 years old.
You my need them, all I am saying is I never have.
Get them on straight and they don't leak.
I have seen alot heat risers leak and folks thought it was at the pipe.
just cuz someone makes something doesn't mean you need it. The factory might even have used them,(?)
but I never took one off a factory set up.
My cars are all older then that page (70&up).
I've been doing this since these cars were only 5 to 10 years old.
You my need them, all I am saying is I never have.
Get them on straight and they don't leak.
I have seen alot heat risers leak and folks thought it was at the pipe.
Posted By: 1_WILD_RT
Re: 383 Exhuast leak problem - 12/31/08 11:02 PM
Quote:
My cars are all older then that page (70&up).
Posted By: stumpy
Re: 383 Exhuast leak problem - 12/31/08 11:03 PM
There has always been a gasket between the flat pipe and manifold. It is necessary and I have been working on these cars since the early 60s as a dealer tech.
Posted By: 68HemiB
Re: 383 Exhuast leak problem - 12/31/08 11:10 PM
Quote:
Yep
just cuz someone makes something doesn't mean you need it. The factory might even have used them,(?)
but I never took one off a factory set up.
My cars are all older then that page (70&up).
I've been doing this since these cars were only 5 to 10 years old.
You my need them, all I am saying is I never have.
Get them on straight and they don't leak.
I have seen alot heat risers leak and folks thought it was at the pipe.
I am sure that we all are impressed by your ability to take used, mass-produced parts and align/true them up so as to not need a gasket, even in places that were originally assembled using a gasket.
The Original Poster, however, is not in your shoes, and is not helped by your claims.
Posted By: bboogieart
Re: 383 Exhuast leak problem - 12/31/08 11:27 PM
I don't want to anger you experts,
I am just saying what I know.
(Claims) Please.
I am just saying what I know.
(Claims) Please.
Posted By: 1_WILD_RT
Re: 383 Exhuast leak problem - 01/01/09 12:03 AM
According the the manuals & my experiance (I've worked on these cars since 72) 318 & 426 which both have cone type connections didn't use gaskets, big block does...
BTW I typed this earlier & got interupted so it's posted 45 minutes late...
BTW I typed this earlier & got interupted so it's posted 45 minutes late...
Posted By: sthemi
Re: 383 Exhuast leak problem - 01/01/09 12:11 AM
I had the same problem with them a couple of years ago,
I tried new gaskets from a couple of places, new correct size 7/16ths bolts, but the real problem was a mis alignment between the pipe and engine. The pipe hit the engine or torsion bar and would not allow the gasket to do it's job.
I had new head pipes made and installed at a local muffler shop and it was problem solved.
I tried new gaskets from a couple of places, new correct size 7/16ths bolts, but the real problem was a mis alignment between the pipe and engine. The pipe hit the engine or torsion bar and would not allow the gasket to do it's job.
I had new head pipes made and installed at a local muffler shop and it was problem solved.
Posted By: 75RoadRunner
Re: 383 Exhuast leak problem - 01/01/09 02:14 PM
Make sure you are using the correct size bolts, and the gaskets with the metal crush ring. If they are still blowing out, you have an alignment problem. Just my
Posted By: floyd
Re: 383 Exhuast leak problem - 01/01/09 02:23 PM
I'll second the recommendation for remflex. I had the same problem with my 340 driver. The remflex gasket was an easy fix. Just be careful not to over tighten (DAMHIK).
http://catalog.remflex.com/
http://catalog.remflex.com/
Posted By: 62maxwgn
Re: 383 Exhuast leak problem - 01/01/09 02:29 PM
Quote:
I don't want to anger you experts,
I am just saying what I know.
(Claims) Please.
If it is a flat exhaust flange it had a gasket.I don't get into debates much but I'll argue with you till the sun sets on this one.The second car I ever took the exhaust pipes off was a 54 Dodge Royal Pace Car convert with a 241 Hemi.It had gaskets fifty four years ago and so did the 50 Plymouth flathead six which was before that.And,if you want to see a parts page as above from a 1957 parts book showing gaskets,let me know.
Posted By: MO_PA
Re: 383 Exhuast leak problem - 01/01/09 03:35 PM
Quote:
If it is a flat exhaust flange it had a gasket.I don't get into debates much but I'll argue with you till the sun sets on this one.The second car I ever took the exhaust pipes off was a 54 Dodge Royal Pace Car convert with a 241 Hemi.It had gaskets fifty four years ago and so did the 50 Plymouth flathead six which was before that.And,if you want to see a parts page as above from a 1957 parts book showing gaskets,let me know.
I agree!!!!!!!!
Posted By: dodger1
Re: 383 Exhuast leak problem - 01/01/09 06:40 PM
Thanks for all the great info ,I know for sure theres 3/8 bolts in it and Well make sure the mating surfaces are flush,
Posted By: kenworth_goose
Re: 383 Exhuast leak problem - 01/01/09 07:12 PM
I had the same problem on my 77 bigblock truck. Kept burning the gaskets out. It was way to lean. Swapped out the carb for a fatter one and no more burned gaskets.
Posted By: NTOLERANCE
Re: 383 Exhuast leak problem - 01/01/09 07:17 PM
One thing you can try to help out, once youve got it bolted up, take a torch and heat the pipe near the manifold. There is usually a bend hear the flange, try and heat at that bend. (assuming you have acess to a torch)
If there is some sort of stress in the pipe, the heating will take the stress out. youll actually see small parts of the pipe metal flake off as the pipe "un-stressess" Many times while working at a Car-X we would heat certain new pipes to relieve stress. Aftermarket pipes dont always fit correctly. Some would be stressed so much, they would crack off in a few thousand miles.
If there is some sort of stress in the pipe, the heating will take the stress out. youll actually see small parts of the pipe metal flake off as the pipe "un-stressess" Many times while working at a Car-X we would heat certain new pipes to relieve stress. Aftermarket pipes dont always fit correctly. Some would be stressed so much, they would crack off in a few thousand miles.
Posted By: NTOLERANCE
Re: 383 Exhuast leak problem - 01/01/09 07:18 PM
I didnt see if you posted which side was blowing out, but I will guess its the drivers side. 