Author Topic: Exhaust gasket  (Read 218 times)

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Offline Tim Hensley

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Exhaust gasket
« on: November 28 2019, 11:01:23 PM »
Took the car out for a Sunday drive on a Thursday. Got a exhaust leak on driver side,TA stock replacement header so itís got to be my FelPro exhaust gasket. On the car about 2 years.
Replace with FelPro a set of Cometic or Fullthrottle wisbang gasket?
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Offline Scoobum

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Re: Exhaust gasket
« Reply #1 on: November 28 2019, 11:49:19 PM »
I used the cheapass Felpros with the slots in them...for easy re and re.
109 235 Cubic Inch Stock Stroke Balanced Rotating Assembly
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Offline 1KWIKSIX

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Re: Exhaust gasket
« Reply #2 on: November 29 2019, 07:15:28 AM »
X2
I'm with Scoobum!
Felpro 1400's here, with T/A Race Headers &  no issues

Offline Steve Wood

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Re: Exhaust gasket
« Reply #3 on: November 29 2019, 10:22:42 AM »
paper thin coat of high temp orange rtv on both sides of the gasket if you use a gasket
Steve Wood

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A lot of broken parts does not make you a racer; it makes you a slow learner.

Offline Tim Hensley

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Re: Exhaust gasket
« Reply #4 on: November 30 2019, 03:47:37 AM »
FelPro on there way No one on the island have a set
Price we pay for 85 degree winter
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Offline earlbrown

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Re: Exhaust gasket
« Reply #5 on: November 30 2019, 12:25:31 PM »
I like RTV on both surfaces, let them skin over then bolt them up.


The good thing about running without a gasket, is if you have a leak...  it's a SMALL leak.

With a gasket, you got a 1/16" slot that vents pressure like crazy.
'87 GN - 4.2L SFI Turbocharged innercooled V6 - Chrome valve covers - supra pump - 14" K&N - 52mm throttlebody - rocker shaft supports -  1/2 intake spacer - TB coolant bypass - 3" ATR exhaust tip - Alum intake pipe - NOS timing cover - chip - relocated charcoal canister - CR42's - stock

Offline Tim Hensley

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Re: Exhaust gasket
« Reply #6 on: December 11 2019, 03:06:35 AM »
Ok a thin like .010 smear on both sides or .030 X .030 bead on both sides ?
Arizona GN109 forged rotating assembly
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Offline Steve Wood

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Re: Exhaust gasket
« Reply #7 on: December 11 2019, 10:09:25 AM »
Thin! we are using it more like glue to prevent tiny leaks.  A thick bead will (or can) blow out.
Steve Wood

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Offline SuperSix

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Re: Exhaust gasket
« Reply #8 on: December 11 2019, 11:28:01 AM »
Yep - you just want to seal tiny imperfections, the larger the film, the more chance there is it will blow out.
'87 GN, 60lb, TA49, THDP, FTP cam, T+ lots o' shit - in process... Close.. SOOOOOO CLOSE!!
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Offline bullnerd

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Re: Exhaust gasket
« Reply #9 on: December 11 2019, 05:47:39 PM »
Is it me or are Steve and Earl saying two different things?

Steve - thin coating on both sides of a gasket ?

Earl - no gasket, thin coating on both mating surfaces? 

Offline Steve Wood

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Re: Exhaust gasket
« Reply #10 on: December 11 2019, 06:07:05 PM »
I seldom have a serious difference of opinion with Earl and this is not one of those rare times-if ever.

The cars came from the factory with no gasket.  Just the metal to metal seal was the way it was.  Over the years, I never used one...I just checked the header with a straight edge and if it had no warp, I put a paper thin smear of high temp around the ports and torqued them down evenly.  Never had a leak.

On the other hand, I have seen some badly warped headers after someone did a half azzed welding repair.  In this case, I always tried to get them to take them to a machine shop and at least dress them down on a belt sander.  Then I applied the high temp and never had a problem.

In recent years, everyone insists you have to have a gasket.  As I am not getting paid for advice and I damn sure have enuf of my own cars to wrench on, I just gave up and stopped arguing :D

In this case, he said he had a gasket and I figured he was going to use it so I suggested a paper thin coat on either side to seal off any minor erosion or pitting.

Either way should work fine.
Steve Wood

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Offline bullnerd

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Re: Exhaust gasket
« Reply #11 on: December 11 2019, 07:33:48 PM »
Thanks for clearing that up Steve.

When I was in hs in the 80s my friends uncle said never use a gasket! lol! But that was SBC / BBC stuff. 

Offline earlbrown

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Re: Exhaust gasket
« Reply #12 on: December 11 2019, 10:11:40 PM »
Even with gaskets you should put a thin film of both sides (and let it skin over) after you soak them in water first.
  It won't work as well as metal-to-metal.  But anytime I'm faced with a decision between 'it won't hurt', and 'it might help'. I choose the latter.

But the best way to seal headers is a thin film of RTV on the CLEAN head and the CLEAN header ports.   Let it skin over, then install the parts together.    Give them a few minutes to get to know each other, then torque them down using anti-seeze as a lube.  Then do the same thing on the crossover.  With that method, if there's ever a leak, it's time to weld up the DS header again.

Doing that will seal them fully. AND if a leak happens to develop, worst case it will be a SMALL leak.     In comparison, blowing the side out of an 1/16" gasket will make a big ass hole that just gets bigger as the gasket erodes from both burnt ends.



....and this is coming from a guy that sells exhaust gaskets on eBay....     So don't buy those gaskets, just use the RTV. :D
'87 GN - 4.2L SFI Turbocharged innercooled V6 - Chrome valve covers - supra pump - 14" K&N - 52mm throttlebody - rocker shaft supports -  1/2 intake spacer - TB coolant bypass - 3" ATR exhaust tip - Alum intake pipe - NOS timing cover - chip - relocated charcoal canister - CR42's - stock

Offline earlbrown

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Re: Exhaust gasket
« Reply #13 on: December 11 2019, 10:24:47 PM »
And my spacial perception has always took issue with the ''you have to use a gasket on warped flanges'' theory.   Even with only 16 threads per inch, I know I can deflect the hell out of a header flange. The head isn't going to give.
  Starting with a warped flange, I just can't see a header port being able to rock up enough to fully unload the seal.  It just doesn't have that much 'resistance to being straightened back'.  Especially when you throw on the heat.   ....which is compounded when the flange isn't fully thermally coupled to the nice cold head (in comparison).  I just can't see how one couldn't 'unwarp' with a few heat cycles under torque.

   Now I kinda believe the 'theory' on the PS headers outlet flange.  Once the ears get curled up (usually from using a thick gasket in the first place), the nuts just don't have the leverage to fully pull down the sealing ring area of the turbo. The ears get torqued while the center is dropped down a little.  Since about 70% of the bore is unsupported, it's a leak waiting to happen.
  But instead of a gasket band-aid that costs money and time to get, a few well placed adjustments with an Estwing hammer will put hose ears below flush.  Then you've got three spring loaded helper tabs to add to the clamping load.

  But what do I know?  I'm a guy that sells exhaust gaskets on eBay and beats the shit out of my GN with a framing hammer when it needs it. :D   (note: I don't recommend the gaskets, they're just there to save people money that would buy them anyway)

   That being said, years ago, TB3 send me a warped up DS header to experiment on and I stuck it in the surfacing machine.    And I will NEVER TRY that again.   I got it shaved after probably two hours. The finish looked like shit, I beat the everyloving crap out of the CBN cutter, and the amount of noise that came off that workpiece was astounding.   It just did not want to be machined.

  Now it functions as a wall hanger and a model for my SS exhaust bolt kits.  Most likely never see boost again.
'87 GN - 4.2L SFI Turbocharged innercooled V6 - Chrome valve covers - supra pump - 14" K&N - 52mm throttlebody - rocker shaft supports -  1/2 intake spacer - TB coolant bypass - 3" ATR exhaust tip - Alum intake pipe - NOS timing cover - chip - relocated charcoal canister - CR42's - stock

Offline Tim Hensley

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Re: Exhaust gasket
« Reply #14 on: Today at 02:09:02 AM »
Steve I did order Two sets of gasket, long sleepless nights has convince me I have went and blown $30 more bucks needlessly. I almost feel back to gaskets seeing Earl sells them on Ebay even after his post on just RTV.LOL Earl almost got me. Iím looking for the RTV of choice.
Just hate how the ricers exhaust looks with all the RTV all over the place. Iíll be cleaning the extra gooey stuff off




Arizona GN109 forged rotating assembly
DLS 210-210
Champion irons
Extreme Auto stage II trans and converter