Exhaust manifold

R

ray

New member
Jul 26, 1998
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We have just had our right side exhaust manifold surfaced and are ready
to re-install. Originally manifold was installed without gasket so this
is the way I intended to go using anti-seize. I have heard opinions on
different ways to go: two different types of Fel-pro gaskets, two
different types of copper gaskets. Not yet convinced of any of the
above. Would like to hear a convincing opinion.
Ray and Elisa 1973 Painted Desert ?
 
Ray; for a fact I must or should be considered an expert in this area. In
the past year I've replaced gaskets around six times. Finally I installed
Mr. Gasket for Pep boys. To add merrit or put icing on the cake; I welded
the left side and ground it with a disk grinder to eye ball good. Installed
gaskets (no lubricant) using grade 8 bolts, lock washer and extra heavy
flats. Drove 100 miles re-tightened, another 100 miles and tightened as
tight as possible, another 100 miles - you guessed it and now this last time
(today) pulled the bolts again. Was able to move a few of them slightly; if
I pulled harder I'd break the bolts. IT'S QUITE AS A MOUSE. Sometimes wonder
if the enginer is running. I was determined for it to be quite and it is.
Before with the other gaskets ( I used the only ones I could get and even
made some from industrial material) I went to almost this extreme and even
used high temp RTV and did everything I could to no avail. This did the
trick. It's all in the gasket material and tighten all you can after
thermals. Get all elastic out.
- -----Original Message-----
From: Ray
To: gmcmotorhome
Date: Tuesday, September 01, 1998 12:25 AM
Subject: GMC: Exhaust manifold

>We have just had our right side exhaust manifold surfaced and are ready
>to re-install. Originally manifold was installed without gasket so this
>is the way I intended to go using anti-seize. I have heard opinions on
>different ways to go: two different types of Fel-pro gaskets, two
>different types of copper gaskets. Not yet convinced of any of the
>above. Would like to hear a convincing opinion.
> Ray and Elisa 1973 Painted Desert ?
>
>
 
Ray I went through the felpro gaskets, didn't last. Te last one recommended
by Cinnabar was the worse. Went tot parts America and bought a cheap Mr.
gasket set ($8.35) and installed them with Permatex copper high temp silicon
(700 degrees) on both sides of the gasket, and let me tell you that stuff
works. ONe of my manifolds was warped too! Very quiet and doesn't leak a
drop yet. I highly recommend it.

>We have just had our right side exhaust manifold surfaced and are ready
>to re-install. Originally manifold was installed without gasket so this
>is the way I intended to go using anti-seize. I have heard opinions on
>different ways to go: two different types of Fel-pro gaskets, two
>different types of copper gaskets. Not yet convinced of any of the
>above. Would like to hear a convincing opinion.
> Ray and Elisa 1973 Painted Desert ?
>
>
>
 
Boy Mr. Pickens, in my opinion you are a lucky fellow. With my luck I would
have cracked the cylinder head bosses for sure. When tightening those bolts
good rule of thumb is to use a torque wrench and be very careful. If the
surfaces are flat it does not take much torque to seal them. If you ever
either crack one or twist off the bolt, you will need lots of aspirin. A
simple job just became tougher.

>Ray; for a fact I must or should be considered an expert in this area. In
>the past year I've replaced gaskets around six times. Finally I installed
>Mr. Gasket for Pep boys. To add merrit or put icing on the cake; I welded
>the left side and ground it with a disk grinder to eye ball good. Installed
>gaskets (no lubricant) using grade 8 bolts, lock washer and extra heavy
>flats. Drove 100 miles re-tightened, another 100 miles and tightened as
>tight as possible, another 100 miles - you guessed it and now this last time
>(today) pulled the bolts again. Was able to move a few of them slightly; if
>I pulled harder I'd break the bolts. IT'S QUITE AS A MOUSE. Sometimes wonder
>if the enginer is running. I was determined for it to be quite and it is.
>Before with the other gaskets ( I used the only ones I could get and even
>made some from industrial material) I went to almost this extreme and even
>used high temp RTV and did everything I could to no avail. This did the
>trick. It's all in the gasket material and tighten all you can after
>thermals. Get all elastic out.
>-----Original Message-----
>From: Ray
>To: gmcmotorhome
>Date: Tuesday, September 01, 1998 12:25 AM
>Subject: GMC: Exhaust manifold
>
>
>>We have just had our right side exhaust manifold surfaced and are ready
>>to re-install. Originally manifold was installed without gasket so this
>>is the way I intended to go using anti-seize. I have heard opinions on
>>different ways to go: two different types of Fel-pro gaskets, two
>>different types of copper gaskets. Not yet convinced of any of the
>>above. Would like to hear a convincing opinion.
>> Ray and Elisa 1973 Painted Desert ?
>>
>>
>
>
>
 
Sam:

I couldn't agree more with Thoms' observation.

As an engineer, why would you not be knowledgeable of and concerned with
torque limitations? All materials have limits, no?

Paul Bartz

From: Thomas G. Warner [mailto:warner]
Sent: Tuesday, September 01, 1998 4:41 PM
To: gmcmotorhome
Subject: Re: GMC: Exhaust manifold

Boy Mr. Pickens, in my opinion you are a lucky fellow. With my luck I
would have cracked the cylinder head bosses for sure. When tightening
those bolts good rule of thumb is to use a torque wrench and be very
careful. If the surfaces are flat it does not take much torque to seal
them. If you ever either crack one or twist off the bolt, you will need
lots of aspirin. A simple job just became tougher.

Ray; for a fact I must or should be considered an expert in this area.
In the past year I've replaced gaskets around six times. Finally I
installed Mr. Gasket for Pep boys. To add merrit or put icing on the
cake; I welded the left side and ground it with a disk grinder to eye
ball good. Installed gaskets (no lubricant) using grade 8 bolts, lock
washer and extra heavy flats. Drove 100 miles re-tightened, another 100
miles and tightened as tight as possible, another 100 miles - you
guessed it and now this last time (today) pulled the bolts again. Was
able to move a few of them slightly; if I pulled harder I'd break the
bolts. IT'S QUITE AS A MOUSE. Sometimes wonder if the engineer is
running. I was determined for it to be quite and it is.

Before with the other gaskets ( I used the only ones I could get and
even made some from industrial material) I went to almost this extreme
and even used high temp RTV and did everything I could to no avail.
This did the trick. It's all in the gasket material and tighten all you
can after thermals. Get all elastic out.

From: Ray
Date: Tuesday, September 01, 1998 12:25 AM
Subject: GMC: Exhaust manifold

We have just had our right side exhaust manifold surfaced and are ready
to re-install. Originally manifold was installed without gasket so this
is the way I intended to go using anti-seize. I have heard opinions on
different ways to go: two different types of Fel-pro gaskets, two
different types of copper gaskets. Not yet convinced of any of the
above. Would like to hear a convincing opinion.
Ray and Elisa 1973 Painted Desert ?
 
Dear Thomas; been doing this for over thirty years. Walked into a shop one
day (Kodak, TN) and the guys were pullin a sight glass via torque wrench and
for a week had been replacing and breaking said glasses many of which were
broken in the shop via torque wrench - when I laughed they handed me the
wrench. Since the assembly went on a boiler and was 300# fittings I used a
short handled wrench and pulled it tight by feel. Once did the job; no
leaks: been there done that, rest my case. But then again, I can't paint
worth a ____!
- -----Original Message-----
From: Thomas G. Warner
To: gmcmotorhome
Date: Tuesday, September 01, 1998 4:41 PM
Subject: Re: GMC: Exhaust manifold

>Boy Mr. Pickens, in my opinion you are a lucky fellow. With my luck I
would
>have cracked the cylinder head bosses for sure. When tightening those
bolts
>good rule of thumb is to use a torque wrench and be very careful. If the
>surfaces are flat it does not take much torque to seal them. If you ever
>either crack one or twist off the bolt, you will need lots of aspirin. A
>simple job just became tougher.
>
>
>
>
>
>

>>Ray; for a fact I must or should be considered an expert in this area. In
>>the past year I've replaced gaskets around six times. Finally I installed
>>Mr. Gasket for Pep boys. To add merrit or put icing on the cake; I welded
>>the left side and ground it with a disk grinder to eye ball good.
Installed
>>gaskets (no lubricant) using grade 8 bolts, lock washer and extra heavy
>>flats. Drove 100 miles re-tightened, another 100 miles and tightened as
>>tight as possible, another 100 miles - you guessed it and now this last
time
>>(today) pulled the bolts again. Was able to move a few of them slightly;
if
>>I pulled harder I'd break the bolts. IT'S QUITE AS A MOUSE. Sometimes
wonder
>>if the enginer is running. I was determined for it to be quite and it is.
>>Before with the other gaskets ( I used the only ones I could get and even
>>made some from industrial material) I went to almost this extreme and even
>>used high temp RTV and did everything I could to no avail. This did the
>>trick. It's all in the gasket material and tighten all you can after
>>thermals. Get all elastic out.
>>-----Original Message-----
>>From: Ray
>>To: gmcmotorhome
>>Date: Tuesday, September 01, 1998 12:25 AM
>>Subject: GMC: Exhaust manifold
>>
>>
>>>We have just had our right side exhaust manifold surfaced and are ready
>>>to re-install. Originally manifold was installed without gasket so this
>>>is the way I intended to go using anti-seize. I have heard opinions on
>>>different ways to go: two different types of Fel-pro gaskets, two
>>>different types of copper gaskets. Not yet convinced of any of the
>>>above. Would like to hear a convincing opinion.
>>> Ray and Elisa 1973 Painted Desert ?
>>>
>>>
>>
>>
>>
>
>
 
Ray check the surface on your head. If there is erosion the manifold
surfacing alone won't help. I changed exhaust gaskets many times until I
did a valve job on the heads and found out the surfaces on the heads were
eroded causing the problem. I still used gaskets and continued to torque
the manifold bolts until the gaskets seated. Haven't had any problem since.

Bob 77 PB

>We have just had our right side exhaust manifold surfaced and are ready
>to re-install. Originally manifold was installed without gasket so this
>is the way I intended to go using anti-seize. I have heard opinions on
>different ways to go: two different types of Fel-pro gaskets, two
>different types of copper gaskets. Not yet convinced of any of the
>above. Would like to hear a convincing opinion.
> Ray and Elisa 1973 Painted Desert ?
>
>
>
 
Ray,

I just went thru this also. I've put on about 3500 miles now without a
problem.

I put new gaskets in last year with out going to the expense of having the
headers milled. I judged the heads to be too rough to seal without a gasket
so I used a metallic gasket from NAPA and they were leaking again after a
few hundred miles. This was probably due to the headers not being flat.

This year I had the heads milled flat then used a gasket recommended by our
local speed shop. He sez its the type the racers use. It's by Mr Gasket and
cost about $16 for the set. I believe I saw the same gasket at Auto zone
also. It's made of a grey rubbery material which is thicker and much more
pliable than the metallic type was. I used ultra copper sealant and anti sieze.

This seems to have solved my problems OK and I'd do it the same way again.

Hope it helps

Dick

>We have just had our right side exhaust manifold surfaced and are ready
>to re-install. Originally manifold was installed without gasket so this
>is the way I intended to go using anti-seize. I have heard opinions on
>different ways to go: two different types of Fel-pro gaskets, two
>different types of copper gaskets. Not yet convinced of any of the
>above. Would like to hear a convincing opinion.
> Ray and Elisa 1973 Painted Desert ?
>
>
>
 
I am convinced that the biggest problem in sealing the manifolds is that to
much gasket material is used. The better the thermal connection between the
exhaust manifolds and the cylinder head, the less chance you have of warping
them. The idea is to dissipate the heat through the cylinder head to the
water jackets. With that said if the cylinder head and exhaust manifold are
flat and no erosion is present due to blow by of the gases, than the best
connection is obtained with a solid copper gasket and very little anti
seize. The cylinder heads than act as a heat sink for the manifolds and go
a long way in reducing the warpage. I believe that is why GM originally
installed the exhaust manifolds without gaskets.If you have some warpage
than in my opinion the best compromise and the thing that has worked for me
is a Mr. Gasket exhaust manifold gasket and permatex ultra copper high temp
silicon. Whisper quiet so far.

>Ray,
>
>I just went thru this also. I've put on about 3500 miles now without a
>problem.
>
>I put new gaskets in last year with out going to the expense of having the
>headers milled. I judged the heads to be too rough to seal without a gasket
>so I used a metallic gasket from NAPA and they were leaking again after a
>few hundred miles. This was probably due to the headers not being flat.
>
>This year I had the heads milled flat then used a gasket recommended by our
>local speed shop. He sez its the type the racers use. It's by Mr Gasket and
>cost about $16 for the set. I believe I saw the same gasket at Auto zone
>also. It's made of a grey rubbery material which is thicker and much more
>pliable than the metallic type was. I used ultra copper sealant and anti sieze.
>
>This seems to have solved my problems OK and I'd do it the same way again.
>
>Hope it helps
>
>Dick
>

>>We have just had our right side exhaust manifold surfaced and are ready
>>to re-install. Originally manifold was installed without gasket so this
>>is the way I intended to go using anti-seize. I have heard opinions on
>>different ways to go: two different types of Fel-pro gaskets, two
>>different types of copper gaskets. Not yet convinced of any of the
>>above. Would like to hear a convincing opinion.
>> Ray and Elisa 1973 Painted Desert ?
>>
>>
>>
>
>
>
 
Hey; I'll endorse the Mr. Gasket Exhaust manifold set. But I went through
Auto Zone NAPA all the metals I could find. The only I didn't do was;
fabricate pure sheet copper and heat to cherry and drop in alchol - that'll
turn like rubber.
- -----Original Message-----
From: Dick Kennedy
To: gmcmotorhome
Date: Wednesday, September 02, 1998 10:39 PM
Subject: Re: GMC: Exhaust manifold

>Ray,
>
>I just went thru this also. I've put on about 3500 miles now without a
>problem.
>
>I put new gaskets in last year with out going to the expense of having the
>headers milled. I judged the heads to be too rough to seal without a gasket
>so I used a metallic gasket from NAPA and they were leaking again after a
>few hundred miles. This was probably due to the headers not being flat.
>
>This year I had the heads milled flat then used a gasket recommended by our
>local speed shop. He sez its the type the racers use. It's by Mr Gasket and
>cost about $16 for the set. I believe I saw the same gasket at Auto zone
>also. It's made of a grey rubbery material which is thicker and much more
>pliable than the metallic type was. I used ultra copper sealant and anti
sieze.
>
>This seems to have solved my problems OK and I'd do it the same way again.
>
>Hope it helps
>
>Dick
>

>>We have just had our right side exhaust manifold surfaced and are ready
>>to re-install. Originally manifold was installed without gasket so this
>>is the way I intended to go using anti-seize. I have heard opinions on
>>different ways to go: two different types of Fel-pro gaskets, two
>>different types of copper gaskets. Not yet convinced of any of the
>>above. Would like to hear a convincing opinion.
>> Ray and Elisa 1973 Painted Desert ?
>>
>>
>>
>
 
I just put in a y and a 3" pipe from the connection of the two mufflers. If
chaning out the Midas (which were put in before I bought the coach) would help,
I would like to consider just that portion of the muffler changes.

Al Chernoff

> Ray; for a fact I must or should be considered an expert in this area. In
> the past year I've replaced gaskets around six times. Finally I installed
> Mr. Gasket for Pep boys. To add merrit or put icing on the cake; I welded
> the left side and ground it with a disk grinder to eye ball good. Installed
> gaskets (no lubricant) using grade 8 bolts, lock washer and extra heavy
> flats. Drove 100 miles re-tightened, another 100 miles and tightened as
> tight as possible, another 100 miles - you guessed it and now this last time
> (today) pulled the bolts again. Was able to move a few of them slightly; if
> I pulled harder I'd break the bolts. IT'S QUITE AS A MOUSE. Sometimes wonder
> if the enginer is running. I was determined for it to be quite and it is.
> Before with the other gaskets ( I used the only ones I could get and even
> made some from industrial material) I went to almost this extreme and even
> used high temp RTV and did everything I could to no avail. This did the
> trick. It's all in the gasket material and tighten all you can after
> thermals. Get all elastic out.
> -----Original Message-----
> From: Ray
> To: gmcmotorhome
> Date: Tuesday, September 01, 1998 12:25 AM
> Subject: GMC: Exhaust manifold
>
> >We have just had our right side exhaust manifold surfaced and are ready
> >to re-install. Originally manifold was installed without gasket so this
> >is the way I intended to go using anti-seize. I have heard opinions on
> >different ways to go: two different types of Fel-pro gaskets, two
> >different types of copper gaskets. Not yet convinced of any of the
> >above. Would like to hear a convincing opinion.
> > Ray and Elisa 1973 Painted Desert ?
> >
> >
 
Surprisingly I think we more or less have agreement here. The original
installation without a gasket requires perfect mating surfaces which we no
longer have on the old machines so gaskets are needed. I'm sure everyone is
also aware that there is another school which believes headers are the way
to go.

Mine are installed with class 8 bolts like the speed shop recommended. My
thinking was more along the line of using the soft stuff so they could be
drilled out when necessary. I've got mixed feelings on this one and am not
sure which is right. It could be that the smart thing to do is loosen and
retorque them once a year so they don't sieze. What is every ones thoughts
along this line?

The one common thread is that we all seem to suffer from warped manifolds
eventually. I thought about ceramic coating to minimize this when I did mine
but didn't pursue it. Has any one else done anything along this line? I
know that some of the header crowd use ceramic but I haven't heard it
mentioned by any of the cast iron fans.

Dick

>FWIW, when I bought my '75 Eleganza in spring '96, it had one broken and one
>eroded exhaust manifold. One of my first projects was to replace both
>manifolds with brand new ones from Cinnabar. One side, the exhaust port
>sealing surface was in relatively good shape, so I installed the new manifold
>with no gasjet, just some Ultra Copper from Permatex. The other head was
>obviously eroded, so I used the gasket supplied by Cinnabar (Fel-Pro, IIRC).
>Both sides were carefully cleaned, broken bolts drilled out and retapped
>(aaargh!!!!), and tightened with a torque wrench. Neither was retorqued.
> The test was last summer when we did a 5,000- mile run to New England and
>back. (We did not spare the horses on that trip.) A couple of local trips,
>and I rechecked things this summer. The side with the Fel-Pro (a respected
>name in gaskets BTW) was intact. The side sans gasket was leaking badly.
> I stilll think one should do as the factory did and use no gaskets, but
>ONLY if all surfaces are PERFECT. Myself, I pulled the leaking left manifold,
>cleaned everything up, and reinstalled it with Mr. Gasket's solid copper
>gasket. Only a few hundred miles, but so far so goood. I'll let y'all know
>how it holds up.
>
>Rick Staples
>
>
>
 
The other possible preventive measure would be to have the manifolds ceramic
coated. This would lower their temperature dramatically. The cost should be
on par with the header setup and it would still be stock.

Has anyone in the group done this?

Dick

>One aspect of the leaking exhaust manifolds that I haven't seen discussed is
>prevention. I, too, changed gaskets & manifolds over 6-8 years and 75K miles,
>searching for the right combination, when a trucker provided a bit of wisdom
>that I think actually helps. I was told to let the engine idle for 5-10
>minutes before shutting down to give the exhaust manifolds a chance to cool
>from their normal cherry red temperature condition. This was especially
>important when rolling into the gas station following an expressway cruise.
>Now I just pull in and let it idle while I check trans fluid, tires, etc.
>before shutting down. It's been 3 years and almost 25K miles leakfree on the
>original un-ground manifolds with Mr. Gasket metal/fiber gaskets. Dave Evans
>'73 Canyon Lands
>
>
 
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