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Exhaust Manifold Gasket Replacement [message #162795] Mon, 12 March 2012 20:51 Go to next message
Who_dun_it is currently offline  Who_dun_it   
Messages: 148
Registered: April 2007
Location: Thousand Oaks, CA
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Senior Member
I am replacing the exhaust manifold gaskets and would like to info from other folks that have performed that task. I expect to buy the copper coated gaskets from Jim K.
1. One of the manifolds is cracked. Fortunately I have another pair. Are these repairable?
2. The exhaust system did not have manifold to header pipe springs. Does someone here have them to sell or do I buy elsewhere? They seem to be readily available.
3. Is there any advantage to use socket head bolts instead of the regular ones?
4. Other than making sure that the mating surfaces are clean, are there other tips I should be aware of?

Thanks
Les
Thousand Oaks CA
Re: [GMCnet] Exhaust Manifold Gasket Replacement [message #162799 is a reply to message #162795] Mon, 12 March 2012 21:07 Go to previous messageGo to next message
ljdavick is currently offline  ljdavick   
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Registered: March 2007
Location: Fremont, CA
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Senior Member
I used the Remflex gaskets from Jim K and would recommend them to anyone. Big squishy wonderful gaskets that sealed up all my leaks.

I used grade 8 bolts and anti-seize. I now know that the grade 8's might not have been the best choice. I'll find that out if I ever have to remove the things.

Larry Davick

On Mar 12, 2012, at 6:51 PM, Les Leach <les-DOT-leach-AT-yahoo-DOT-com> wrote:

>
>
> I am replacing the exhaust manifold gaskets and would like to info from other folks that have performed that task. I expect to buy the copper coated gaskets from Jim K.
> 1. One of the manifolds is cracked. Fortunately I have another pair. Are these repairable?
> 2. The exhaust system did not have manifold to header pipe springs. Does someone here have them to sell or do I buy elsewhere? They seem to be readily available.
> 3. Is there any advantage to use socket head bolts instead of the regular ones?
> 4. Other than making sure that the mating surfaces are clean, are there other tips I should be aware of?
>
> Thanks
> Les
> Thousand Oaks
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
Re: Exhaust Manifold Gasket Replacement [message #162800 is a reply to message #162795] Mon, 12 March 2012 21:11 Go to previous messageGo to next message
armandminnie is currently offline  armandminnie   
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I would also recommend the Remflex gaskets from JimK instead of the copper. Also use the tin bolt locks that JimK sells and anti-sieze. Torque to 14 to 18 lbs, lock them and forget them.

Armand Minnie
Marana, AZ
'76 Eleganza II TZE166V103202
visit my gmc blog
click here to visit gmcws.org
Re: Exhaust Manifold Gasket Replacement [message #162805 is a reply to message #162795] Mon, 12 March 2012 21:29 Go to previous messageGo to next message
Carl S. is currently offline  Carl S.   
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Registered: January 2009
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Who_dun_it wrote on Mon, 12 March 2012 18:51

I am replacing the exhaust manifold gaskets and would like to info from other folks that have performed that task. I expect to buy the copper coated gaskets from Jim K.
1. One of the manifolds is cracked. Fortunately I have another pair. Are these repairable?
2. The exhaust system did not have manifold to header pipe springs. Does someone here have them to sell or do I buy elsewhere? They seem to be readily available.
3. Is there any advantage to use socket head bolts instead of the regular ones?
4. Other than making sure that the mating surfaces are clean, are there other tips I should be aware of?

Thanks
Les
Thousand Oaks CA



Les,

One of the first things I did (had to do) to our coach when I first got it, was to replace the exhaust manifold gaskets. I got them from Dave Lenzi and Dave included instructions and Thick flat washers. I assume Jim K provides the same items. Dave is very specific about how to torque the bolts and how and when to re-torque them.

I got the spring/shoulder bolt kits locally, but found them hard to use. The new bolts were not quite as long as the old ones and they were hard to get started. I ended up re-using most of the old ones. I also sourced the donuts locally.

Dave told me to not let the machine shop resurface the manifolds on a belt sander, but the machinist said he had no other way to do it. It worked out fine.

There is a recommendation here to use low grade bolts, but I didn't know any better and used grade 8s. They worked out fine and I didn't have any problem with them when I had to remove one of the manifolds in order to make the installation of the 3.70 final drive easier. I replaced the gasket on the left side at that time with a new one.

I have put about 13,000 miles on the coach since doing this job, without any sort of a problem.

Good luck. It is an easy job, especially if you remove the fender liners and do the work through the fenders.


Carl Stouffer '75 ex Palm Beach Tucson, AZ. Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member

[Updated on: Mon, 12 March 2012 21:33]

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Re: [GMCnet] Exhaust Manifold Gasket Replacement [message #162806 is a reply to message #162800] Mon, 12 March 2012 21:25 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   
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Registered: March 2004
Location: Americus, GA
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Senior Member
I, too, recommend the Remflex gaskets. But be VERY careful with them.
DO NOT bend them; they WILL break easily. And tighten them only as
their instructions specify; don't get carried away.

I have them on the Cad 500 and didn't follow the latter suggestion
very well, so had to replace them after 4-5K miles. Before tearing
the engine down this time, I spray washed it, with the heads and
manifolds still installed. The spray demolished the exposed portions
of the Remflexes! Left an awful looking ragged mess. I cut away the
worst of the debris around the manifold; I'm confident that the seals
were not disturbed -- hopefully I'll know that for sure tomorrow. I
have spares, just in case.

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com



On Mon, Mar 12, 2012 at 10:11 PM, Armand Minnie wrote:
>
>
> I would also recommend the Remflex gaskets from JimK instead of the copper.  Also use the tin bolt locks that JimK sells and anti-sieze.  Torque to 14 to 18 lbs, lock them and forget them.
> --
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] Exhaust Manifold Gasket Replacement [message #162818 is a reply to message #162799] Mon, 12 March 2012 22:19 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   
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Senior Member
ljdavick wrote on Mon, 12 March 2012 22:07

I used the Remflex gaskets from Jim K and would recommend them to anyone. Big squishy wonderful gaskets that sealed up all my leaks.

I used grade 8 bolts and anti-seize. I now know that the grade 8's might not have been the best choice. I'll find that out if I ever have to remove the things.

Larry Davick

Larry,

Grade 8 bolts is not a bad choice, but when you use them in a high temperature application, be aware that they will stress relieve. While a Gr. 8 is necessarily a better alloy, it gets a good portion of its strength from the heat treatment. That just goes away. The best move is use Gr. 8 tensioned to no more than Gr. 3 load, lots of anti seize (high alloy is more prone to seize) and some sort or retention (a keeper or safety wire).

You do do learn some useful things when you live in Dyno-land.

Matt


Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
Re: [GMCnet] Exhaust Manifold Gasket Replacement [message #162851 is a reply to message #162795] Tue, 13 March 2012 08:15 Go to previous message
Mr ERFisher is currently offline  Mr ERFisher
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Registered: August 2005
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here go
http://gmcmotorhome.info/engine.html#manifold

time to move up?
gene

1. One of the manifolds is cracked. Fortunately I have another pair. Are
> these repairable?
> 2. The exhaust system did not have manifold to header pipe springs. Does
> someone here have them to sell or do I buy elsewhere? They seem to be
> readily available.
> 3. Is there any advantage to use socket head bolts instead of the regular
> ones?
> 4. Other than making sure that the mating surfaces are clean, are there
> other tips I should be aware of?
>
> Thanks
> Les
> Thousand Oaks CA
> _______________________________________________
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> Unsubscribe or Change List Options:
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>



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http://gmcmotorhome.info/APC.html
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