| [GMCnet] Headers on a '76 GMC [message #165312] |
Wed, 04 April 2012 11:03  |
Dave Skowron
Messages: 46
Registered: March 2012
Karma: 0
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I had a mechanic look at the GMC my in-laws gave us (I still have not
seen it in person) and he told me there are a set of headers on it. I
was wondering if these would be stock, or an aftermarket addition. There
is a major issue with the heat they generate, and we are going to use a
race-car-style header wrap along with some insulating material under the
floor inside the engine compartment.
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| Re: [GMCnet] Headers on a '76 GMC [message #165314 is a reply to message #165312] |
Wed, 04 April 2012 11:13  |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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| Dave Skowron wrote on Wed, 04 April 2012 11:03 |
I had a mechanic look at the GMC my in-laws gave us (I still have not
seen it in person) and he told me there are a set of headers on it. I
was wondering if these would be stock, or an aftermarket addition. There
is a major issue with the heat they generate, and we are going to use a
race-car-style header wrap along with some insulating material under the
floor inside the engine compartment.
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Headers are not stock. Some here will tell you not to wrap them for corrosion reasons. You decide and do what you want. For insulation under the floor most everyone will tell you that is a good idea. There are lots of ideas on how to do that. I prefer, and am using, the mostly-rigid foil faced fiberglass insulation. Others have used this successfully.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: [GMCnet] Headers on a '76 GMC [message #165315 is a reply to message #165312] |
Wed, 04 April 2012 11:14 |
gbarrow2
Messages: 765
Registered: February 2004
Location: Lake Almanor, Ca./ Red Bl...
Karma: 3
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Dave,
The headers are after market addition.
Search this site for other's comments and experience with wrapping headers and "insulation blankets under cockpit floor.
Some say "Not a good idea"
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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| Re: [GMCnet] Headers on a '76 GMC [message #165330 is a reply to message #165312] |
Wed, 04 April 2012 14:08 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Dave,
The headers are Thorley 355Y for the GMC motorhome and are
aftermarket. Header use on the GMC Classic motorhome is very common.
As the stock exhaust manifolds become harder to find and the existing
ones crack and leak the header are the best solution to the problem.
As for you plan to wrap the header with a race-car style wrap you can
expect the header life to be reduced greatly depending on where you
live in the US. If you wrap the existing header without first
cleaning and using a high temp header paint then you can expect the
header to fail in a few years or less. The failure is caused by the
wrap trapping moisture next to the pipe during heating and cooling
cycles.
Your choice of using an insulating material under the floor is a
better choice.
It would also help that you put your home state in your signature line
so that we can better help you with your questions and also the year
and model of your coach.
Be Aware that allowing a mechanic that has NO GMC, Cad Eldorado or
Toronado experience can be hazardous to your coach and pocketbook!
Just a work caution!
You also need to join a local or regional GMC Motorhome club.
JR Wright
GMC Great Laker MHC
GMC Eastern States
GMCMHI
78 Buskirk 30' Stretch
1975 Avion (Under Reconstruction)
Michigan
On Apr 4, 2012, at 12:03 PM, Dave Skowron wrote:
> I had a mechanic look at the GMC my in-laws gave us (I still have not
> seen it in person) and he told me there are a set of headers on it. I
> was wondering if these would be stock, or an aftermarket addition.
> There
> is a major issue with the heat they generate, and we are going to
> use a
> race-car-style header wrap along with some insulating material under
> the
> floor inside the engine compartment.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: [GMCnet] Headers on a '76 GMC [message #165341 is a reply to message #165312] |
Wed, 04 April 2012 15:29 |
Dave Skowron
Messages: 46
Registered: March 2012
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I live in Eastern-Central Nevada. There hasn't been any humidity here
since the place was under water a million or so years ago. :-) The
mechanic I have hired has a wealth of experience with not only the GMC
motor coaches, but RV's in general. He was recommended by the GMC
Motorhome site. someone here pointed me to.
On 4/4/2012 12:03 PM, gmclist-request@temp.gmcnet.org wrote:
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> 1. Re: Tornado vs. GMC (Mike)
> 2. Re: GMC ? (Johnny Bridges)
> 3. Re: Tornado vs. GMC (Robin Hood)
> 4. Re: GMC ? (Jeremy)
> 5. Re: GMC ? (Johnny Bridges)
> 6. Coach damaged in Dallas Tornado (delve)
> 7. Got home OK (Marc Hogenboom)
> 8. Re: Got home OK (Dan Gregg)
> 9. Re: Casa rally/Morro Bay (Fin Beven)
> 10. Re: Headers on a '76 GMC (John Wright)
> 11. Re: GMC ? (John Shotwell)
> 12. Re: Got home OK (Don Adams)
> 13. Re: Tornado vs. GMC (John Shotwell)
> 14. Re: Hydrogen Generator/ hinderburg/ HHO safety (James Hupy)
> 15. Re: GMC ? (D C *Mac* Macdonald)
> 16. Re: Tornado vs. GMC (D C *Mac* Macdonald)
> 17. Re: Casa rally/Morro Bay (Gary Worobec)
> 18. Re: Casa rally/Morro Bay (Fin Beven)
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>
> ----------------------------------------------------------------------
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> Message: 1
> Date: Wed, 04 Apr 2012 12:45:32 -0500
> From: Mike<carcruse@comcast.net>
> Subject: Re: [GMCnet] Tornado vs. GMC
> To: gmclist@temp.gmcnet.org
> Message-ID:<285c9.4f7c88ba@gmc.mybirdfeeder.net>
> Content-Type: text/plain; charset="ISO-8859-15"
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> There is a John and Inna McGinnis from Arlington on the Black List. In Googling the name, it appears their street is very near somne of the streets mentioned in news articles. Unfornately, it could be their home and GMC.
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| Re: [GMCnet] Headers on a '76 GMC [message #165376 is a reply to message #165312] |
Wed, 04 April 2012 20:01 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
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| Dave Skowron wrote on Wed, 04 April 2012 09:03 |
I had a mechanic look at the GMC my in-laws gave us (I still have not
seen it in person) and he told me there are a set of headers on it. I
was wondering if these would be stock, or an aftermarket addition. There
is a major issue with the heat they generate, and we are going to use a
race-car-style header wrap along with some insulating material under the
floor inside the engine compartment.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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I have had headers on my coach and never had a problem with excessive heat. When I replaced the original manifolds with the headers I didn't notice any heat difference. My floor doesn't get hot either. I do have side vents added to the body on both sides to move the warm air out.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] Headers on a '76 GMC [message #165386 is a reply to message #165314] |
Wed, 04 April 2012 20:52 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Steve,
A hint for your duct board insulation: Find some thin aluminum, perhaps
even flashing, and make some angles to cover the outside, and perhaps even
inside corners. When I had the transmission out 2-3 months ago, I replaced
the aluminum foil tape that had peeled from those areas. When I dropped
the drive train yesterday I saw that almost all of the newly applied tape
was loose. It's almost impossible to get a clean enough surface for the
adhesive to stick to long term. I'll be using sheet metal angle and screws
with fender washers to repair it this time.
Ken H.
On Wed, Apr 4, 2012 at 12:13 PM, Steve Southworth wrote:
> ... There are lots of ideas on how to do that. I prefer, and am using,
> the mostly-rigid foil faced fiberglass insulation. Others have used this
> successfully.
> --
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Headers on a '76 GMC [message #165387 is a reply to message #165341] |
Wed, 04 April 2012 20:57 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Dave,
Georgia's not quite as hot as Nevada, but I've spent time with the GMC in
both -- and lots of other places between Key West and Fairbanks. I think
the only heat problem you'll have with headers is that the area of the
right wheel well liner nearest the header on that side will melt. You can
either leave the liner out, as many do, even in more inclement climates, or
replace the melting area with aluminum sheet pop riveted in place, as I did
many years ago.
Ken H.
On Wed, Apr 4, 2012 at 4:29 PM, Dave Skowron wrote:
> I live in Eastern-Central Nevada. There hasn't been any humidity here
> since the place was under water a million or so years ago. :-)
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Headers on a '76 GMC [message #165394 is a reply to message #165386] |
Wed, 04 April 2012 21:51 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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| Ken Henderson wrote on Wed, 04 April 2012 20:52 |
Steve,
A hint for your duct board insulation: Find some thin aluminum, perhaps
even flashing, and make some angles to cover the outside, and perhaps even
inside corners. When I had the transmission out 2-3 months ago, I replaced
the aluminum foil tape that had peeled from those areas. When I dropped
the drive train yesterday I saw that almost all of the newly applied tape
was loose. It's almost impossible to get a clean enough surface for the
adhesive to stick to long term. I'll be using sheet metal angle and screws
with fender washers to repair it this time.
Ken H.
|
Thanks for that timely hint. Just before dinner tonight (I "cooked", Broasted chicken from the deli) I was measuring for how much board I would need in addition to what I have. Bending angle from flashing should be doable or maybe I can find some appropriate angle.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: [GMCnet] Headers on a '76 GMC [message #165397 is a reply to message #165312] |
Wed, 04 April 2012 22:15 |
Don A
Messages: 895
Registered: October 2008
Location: Dallas, TX
Karma: 0
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Steve, my comment for your coach is what is oft repeated here on the net. Get the coach and use it. Fix/change what you want based on what you see. One man's heat is another's warm.
I think you will find many things to touch, adjust or modify before you even think the floor is warm.
Don Adams Dallas, TX
'76 26' Glenbrook, '90 Sidekick
rebuilt by R Archer, powered by J Bounds, Koba
[IMG]http://www.gmcmhphotos.com/photos/data/6109/G2.jpg[/IMG]
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| Re: [GMCnet] Headers on a '76 GMC [message #165422 is a reply to message #165397] |
Thu, 05 April 2012 07:19 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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| Don A wrote on Wed, 04 April 2012 22:15 |
Steve, my comment for your coach is what is oft repeated here on the net. Get the coach and use it. Fix/change what you want based on what you see. One man's heat is another's warm.
I think you will find many things to touch, adjust or modify before you even think the floor is warm.
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Don - I tend to agree with you. I do believe the phrase "if it ain't broke, fix it till it is" is very valid. However the engine is out for a rebuild due to a bad cylinder and the rebuild is delayed (see a previous thread of mine for that story) so I have this HUGE empty space staring at me and a block of time before the engine gets back. Just seems natural to do what is, right now, very easy to do.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: [GMCnet] Headers on a '76 GMC [message #165493 is a reply to message #165312] |
Thu, 05 April 2012 18:50 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| Dave Skowron wrote on Wed, 04 April 2012 11:03 |
I had a mechanic look at the GMC my in-laws gave us (I still have not
seen it in person) and he told me there are a set of headers on it. I was wondering if these would be stock, or an aftermarket addition. There is a major issue with the heat they generate, and we are going to use a race-car-style header wrap along with some insulating material under the floor inside the engine compartment.
|
I wonder how the coach got by for the previous 35 years without the headers wrapped? I would not wrap them until I experienced a heat problem for myself. I have headers and have never noticed that they generate too much heat or more heat than stock exhaust manifolds.
There are some things you might want to preemptively do to the coach but wrapping headers would not be on my list. I personally know of no GMCs with the headers wrapped.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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