Home » Public Forums » GMCnet » Header Gasket (I need to replace my passenger side header gasket)
| Header Gasket [message #329279] |
Mon, 19 February 2018 10:16  |
Russell K.
Messages: 178
Registered: October 2016
Location: Dunedin, Florida
Karma: 4
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On a recent trip, our GMC ('78 403) developed an exhaust noise. On Saturday I found the exhaust leak at the number 8 cylinder where it looks like a small piece of the header gasket broke and blew out. I ordered the Mr. Gasket 7170 copper gasket to put in. I have older Thorley headers (date unknown). My questions are: 1) Do I need to remove the AC bracket to remove the passenger side header? 2) Which RTV gasket sealer should I use, if any? 3) Should I replace the donut gasket at the same time? 4) Can I replace the gasket with just top and bottom access (jacked up), or do I need to remove the fender well liner?
Any tips or tricks are greatly appreciated. Thanks.
1978 Eleganza II, Dunedin, Florida
[Updated on: Thu, 22 February 2018 04:39] Report message to a moderator |
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| Re: [GMCnet] Header Gasket [message #329280 is a reply to message #329279] |
Mon, 19 February 2018 10:32  |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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> On Feb 19, 2018, at 9:16 AM, Russell Keith wrote:
>
> On a recent trip, our GMC ('78 403) developed an exhaust noise. On Saturday I found the exhaust leak at the number 8 cylinder where it looks like a
> small piece of the header gasket broke and blew out. I ordered the Mr. Gasket 7170 copper gasket to put in. I have older Thorley headers (date
> unknown). My questions are: 1) Do I need to remove the AC bracket to removed the passenger side header?
1. No it is not necessary to remove the A/C bracket.
> 2) Which RTV gasket sealer should I use, if
> any?
I used a thin coating of Permatex Ultra Copper on both sides of the copper gasket.
> 3) Should I replace the donut gasket at the same time?
Only if it’s leaking.
> 4) Can I replace the gasket with just top and bottom access (jacked up), or do I need to
> remove the fender well liner?
>
No need to jack it up or take out the liner. You can do it all from the top. Only remove the bolts which go through holes in the copper gasket. Where there are slots loosen the bolts but leave the header attacked but hang ing loose. Slip the gasket down behind the header, hanging it on the bolts, and replace the removed bolts and tighten all bolts.
> Any tips or tricks are greatly appreciated. Thanks.
Note— after a few years the copper gaskets burned out and I replaced them with the composite Remflex gaskets the Applied GMC sells. They have lasted fine for the last 10,000 miles.
Emery Stora
> --
> Russell Keith,
> 1978 Eleganza II "Harry" 403, Danny Dunn Tranny (w/shift kit, 3.50 sprockets, Allison), Thorley, Stock Brakes w/Remote Vacuum Brake Booster, Mico
> Electric Actuated brake lock, Dakota Digital Dash, 6.5kW Onan,
> Dunedin, Florida
>
> _______________________________________________
> GMCnet mailing list
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| Re: [GMCnet] Header Gasket [message #329303 is a reply to message #329298] |
Mon, 19 February 2018 16:51 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Copper gaskets are good, however a header is partially hand crafted so the
ports do not always match up to the gaskets and will end up leaking.
There is also a way to tighten the headers to avoid leaking.
On Mon, Feb 19, 2018 at 12:50 PM, Russell Keith
wrote:
> Thank you Justin and J.R.
> --
> Russell Keith,
> 1978 Eleganza II "Harry" 403, Danny Dunn Tranny (w/shift kit, 3.50
> sprockets, Allison), Thorley, Stock Brakes w/Remote Vacuum Brake Booster,
> Mico
> Electric Actuated brake lock, Dakota Digital Dash, 6.5kW Onan,
> Dunedin, Florida
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Header Gasket [message #329311 is a reply to message #329302] |
Mon, 19 February 2018 19:13 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Bryon,
Never tighten the CENTER TOP bolt.
Just tighten the 4 inline ones and after 200 miles retorque it.
On Mon, Feb 19, 2018 at 2:54 PM, Bryan Hayes wrote:
> One thing that I ran into is not having the surfaces completely clean when
> installing the new gaskets. When I replaced my header gaskets the first
> time, I had some old gasket material stuck on one of the the header
> surfaces that eventually caused another leak. The second time around, I was
> in a
> hurry to replace the gaskets before hitting the road, and didn't
> completely clean the surfaces again. This, of course, led to even more
> leaks.
> Hopefully I learned my lesson the third time around. :)
> --
> Bryan Hayes
> '76 Eleganza II
> Salt Lake City, Utah
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Header Gasket [message #329322 is a reply to message #329311] |
Tue, 20 February 2018 08:44 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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These headers are crap IMHO, too big primaries and that stupid 'o-ring' flange. Good headers have thick flat flanges.
But there is no other choice except build your own. I aint got time for that.
________________________________
From: Gmclist on behalf of Jim Kanomata
Sent: Monday, February 19, 2018 7:13 PM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Header Gasket
Bryon,
Never tighten the CENTER TOP bolt.
Just tighten the 4 inline ones and after 200 miles retorque it.
On Mon, Feb 19, 2018 at 2:54 PM, Bryan Hayes wrote:
> One thing that I ran into is not having the surfaces completely clean when
> installing the new gaskets. When I replaced my header gaskets the first
> time, I had some old gasket material stuck on one of the the header
> surfaces that eventually caused another leak. The second time around, I was
> in a
> hurry to replace the gaskets before hitting the road, and didn't
> completely clean the surfaces again. This, of course, led to even more
> leaks.
> Hopefully I learned my lesson the third time around. :)
> --
> Bryan Hayes
> '76 Eleganza II
> Salt Lake City, Utah
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] Header Gasket - Update [message #329506 is a reply to message #329280] |
Mon, 26 February 2018 05:18 |
Russell K.
Messages: 178
Registered: October 2016
Location: Dunedin, Florida
Karma: 4
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Senior Member |
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Header gasket update; mission accomplished!! I used Emery's method, with one addition. After loosening all five bolts, I temporarily put in longer bolts in the outer two holes, where the gasket is slotted, so that I could move the header enough to clean it and the head, while it was supported by the longer bolts. Reassembly went well too, I put the new gasket in and started the two middle bolts, and then replaced the long end bolts with the proper bolts. Its nice when repairs go according to the plan. Thank you Emery!! By the way, I found two gaskets in there to remove. Wow. The exhaust noise is now gone. It sounds soooooo much better quiet. I'm a happy camper. 
http://www.gmcmhphotos.com/photos/g7144-header-gasket.html
1978 Eleganza II, Dunedin, Florida
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| Re: [GMCnet] Header Gasket - Update [message #329514 is a reply to message #329506] |
Mon, 26 February 2018 08:51 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Be sure to re torque them as you'll be leaking soon
Sent from my iPhone
> On Feb 26, 2018, at 3:18 AM, Russell Keith wrote:
>
> Header gasket update; mission accomplished!! I used Emery's method, with one addition. After loosening all five bolts, I temporarily put in longer
> bolts in the outer two holes, where the gasket is slotted, so that I could move the header enough to clean it and the head, while it was supported by
> the longer bolts. Reassembly went well too, I put the new gasket in and started the two middle bolts, and then replaced the long end bolts with the
> proper bolts. Its nice when repairs go according to the plan. Thank you Emery!! By the way, I found two gaskets in there to remove. Wow. The exhaust
> noise is now gone. It sounds soooooo much better quiet. I'm a happy camper. :)
>
> http://www.gmcmhphotos.com/photos/g7144-header-gasket.html
> --
> Russell Keith,
> 1978 Eleganza II "Harry" 403, Danny Dunn Tranny (w/shift kit, 3.50 sprockets, Allison), Thorley, Stock Brakes w/Remote Vacuum Brake Booster, Dakota
> Digital Dash, 6.5kW Onan, Dunedin, Florida
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| [GMCnet] Re: Header Gasket [message #369020 is a reply to message #369019] |
Tue, 08 March 2022 13:46 |
stu@97381.com, Emery
Messages: 232
Registered: June 2020
Karma: 2
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Senior Member |
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Glad to hear you fixed your problem. I got a rod knock last June and the rebuilder finally finished the engine. I’ll pick it up Thursday. I have to order a new remflex gasket. Thanks for the reminder.
Emery
> On Mar 8, 2022, at 12:29 PM, Russell Keith wrote:
>
> Update four years later.
>
> Emery, you were right. My Mr. Gasket copper gasket failed after four years. I have replaced it with a Remflex as you mentioned four years ago. Lesson
> learned the hard way.
>
> http://www.gmcmhphotos.com/photos/header-gasket/p68492-remflex-gasket-replacing-copper-gasket.html
>
> Thanks again for the help.
>
> Russell
> --
> Russell Keith,
> 1978 E2 "Harry" 403 (still carbureted), Danny Dunn Tranny, Thorley, Stock Brakes w/Remote Vacuum Brake Booster, Quad Bags, Dakota Digital Dash, 6.5 kW
> Onan, Dunedin, Florida
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| [GMCnet] Re: Header Gasket [message #369021 is a reply to message #369020] |
Tue, 08 March 2022 14:23 |
powwerjon
Messages: 849
Registered: March 2013
Karma: -2
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Senior Member |
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I have used the Remflex gaskets for the last 15 years. They make up for
uneven surfaces and I have never had one burn out.
Look as these 2 pictures;
http://www.gmcmhphotos.com/photos/general-pictures/p61527-remflex-gaskets.html
and
http://www.gmcmhphotos.com/photos/general-pictures/p61525-remflex-gaskets.html
Pay attention to the torque values. Do it in stages and they should NEVER
over torqued!! Always use new bolts and use the small hex headed bolts for
the headers and standard grade 5 (FIVE) for the manifolds. I would suggest
a high temp antiseize for the for all the threads.
<
https://www.mscdirect.com/browse/tnpla/64479298?&cid=ppc-google-Smart+Shopping+-+Lubricants,+Coolants+%26+Fluids&mkwid=%7cdc&pcrid=5348985 31105&rd=k&product_id=64479298&gclid=Cj0KCQiAmpyRBhC-ARIsABs2EApowvftDqQjmD_KJCPSx7roacc2a8WIiOSlnq_qDaqyPsasSusgvIEaAncyEALw_wcB&gcls rc=aw.ds
>
The copper could be used also.
<
https://www.amazon.com/Permatex-09127-COPPER-ANTI-SEIZE-226G/dp/B0771PQZ21/ref=asc_df_B0771PQZ21/?tag=hyprod-20&linkCode=df0&hvadid=5332364212 40&hvpos=&hvnetw=g&hvrand=13892053056664395494&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=903 0240&hvtargid=pla-572741252833&psc=1
>
J.R. Wright
GMC Great Laker
GMCGL Tech Editor
GMC Eastern States
GMCMHI
TZE Zone Restorations
78 Buskirk Custom 29.5' Stretch
75 Avion (Under going Frame up Restoration)
On Tue, Mar 8, 2022 at 12:46 PM Emery Stora via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Glad to hear you fixed your problem. I got a rod knock last June and the
> rebuilder finally finished the engine. I’ll pick it up Thursday. I have to
> order a new remflex gasket. Thanks for the reminder.
>
> Emery
>
>> On Mar 8, 2022, at 12:29 PM, Russell Keith wrote:
>>
>> Update four years later.
>>
>> Emery, you were right. My Mr. Gasket copper gasket failed after four
> years. I have replaced it with a Remflex as you mentioned four years ago.
> Lesson
>> learned the hard way.
>>
>>
> http://www.gmcmhphotos.com/photos/header-gasket/p68492-remflex-gasket-replacing-copper-gasket.html
>>
>> Thanks again for the help.
>>
>> Russell
>> --
>> Russell Keith,
>> 1978 E2 "Harry" 403 (still carbureted), Danny Dunn Tranny, Thorley,
> Stock Brakes w/Remote Vacuum Brake Booster, Quad Bags, Dakota Digital Dash,
> 6.5 kW
>> Onan, Dunedin, Florida
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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| [GMCnet] Re: Header Gasket [message #369028 is a reply to message #369021] |
Tue, 08 March 2022 15:59 |
Chris McBride
Messages: 35
Registered: June 2021
Karma: 0
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Member |
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Hello John,You mention headers here. I have to replace my leaky manifolds and have considered the headers, but have been told it will be louder and hotter in the cab? What are the pros of the headers?Thanks,Eric
Eric Roell, Aurora, Ontario76 Glenbrook "Safari" 76,000 miles,Alcoa, Continental Kit, Fender Flares, Stainless Exhaust, Macerator, Ragusa Step
On Tuesday, March 8, 2022, 03:23:43 p.m. EST, John Wright wrote:
I have used the Remflex gaskets for the last 15 years. They make up for
uneven surfaces and I have never had one burn out.
Look as these 2 pictures;
http://www.gmcmhphotos.com/photos/general-pictures/p61527-remflex-gaskets.html
and
http://www.gmcmhphotos.com/photos/general-pictures/p61525-remflex-gaskets.html
Pay attention to the torque values. Do it in stages and they should NEVER
over torqued!! Always use new bolts and use the small hex headed bolts for
the headers and standard grade 5 (FIVE) for the manifolds. I would suggest
a high temp antiseize for the for all the threads.
<
https://www.mscdirect.com/browse/tnpla/64479298?&cid=ppc-google-Smart+Shopping+-+Lubricants,+Coolants+%26+Fluids&mkwid=%7cdc&pcrid=5348985 31105&rd=k&product_id=64479298&gclid=Cj0KCQiAmpyRBhC-ARIsABs2EApowvftDqQjmD_KJCPSx7roacc2a8WIiOSlnq_qDaqyPsasSusgvIEaAncyEALw_wcB&gcls rc=aw.ds
>
The copper could be used also.
<
https://www.amazon.com/Permatex-09127-COPPER-ANTI-SEIZE-226G/dp/B0771PQZ21/ref=asc_df_B0771PQZ21/?tag=hyprod-20&linkCode=df0&hvadid=5332364212 40&hvpos=&hvnetw=g&hvrand=13892053056664395494&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=903 0240&hvtargid=pla-572741252833&psc=1
>
J.R. Wright
GMC Great Laker
GMCGL Tech Editor
GMC Eastern States
GMCMHI
TZE Zone Restorations
78 Buskirk Custom 29.5' Stretch
75 Avion (Under going Frame up Restoration)
On Tue, Mar 8, 2022 at 12:46 PM Emery Stora via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Glad to hear you fixed your problem. I got a rod knock last June and the
> rebuilder finally finished the engine. I’ll pick it up Thursday. I have to
> order a new remflex gasket. Thanks for the reminder.
>
> Emery
>
>> On Mar 8, 2022, at 12:29 PM, Russell Keith wrote:
>>
>> Update four years later.
>>
>> Emery, you were right. My Mr. Gasket copper gasket failed after four
> years. I have replaced it with a Remflex as you mentioned four years ago.
> Lesson
>> learned the hard way.
>>
>>
> http://www.gmcmhphotos.com/photos/header-gasket/p68492-remflex-gasket-replacing-copper-gasket.html
>>
>> Thanks again for the help.
>>
>> Russell
>> --
>> Russell Keith,
>> 1978 E2 "Harry" 403 (still carbureted), Danny Dunn Tranny, Thorley,
> Stock Brakes w/Remote Vacuum Brake Booster, Quad Bags, Dakota Digital Dash,
> 6.5 kW
>> Onan, Dunedin, Florida
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
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