Home » Public Forums » GMCnet » Metal to Metal exhaust manifold?
| Metal to Metal exhaust manifold? [message #103585] |
Wed, 20 October 2010 14:26  |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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I really LOVE the REMFLEX gaskets recomended on this forum but over in Revcon land there is a lot of support for shaving both surfaces (head and manifold) and going metal to metal with grade 8 bolts. My head will never be smooth enough but i am curious if anyone has gone this route with their GMC?
Thanks
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
[Updated on: Wed, 20 October 2010 14:27] Report message to a moderator |
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| Re: [GMCnet] Metal to Metal exhaust manifold? [message #103589 is a reply to message #103587] |
Wed, 20 October 2010 14:51  |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
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| Dennis S wrote on Wed, 20 October 2010 14:36 |
Maybe you can help the Revcon owners so they do not have to pull and machine the heads and manifolds to achieve leak free exhaust -- aka, use Remflex.
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I hear you. I love my Revcon but there are probably more GMC's at a single rally than there are 455 Revcons on the entire East Coast.
It's silly to not latch on to well esablished solutions.
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: Metal to Metal exhaust manifold? [message #103597 is a reply to message #103585] |
Wed, 20 October 2010 15:50 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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| hertfordnc wrote on Wed, 20 October 2010 12:26 |
I really LOVE the REMFLEX gaskets recomended on this forum but over in Revcon land there is a lot of support for shaving both surfaces (head and manifold) and going metal to metal with grade 8 bolts. My head will never be smooth enough but i am curious if anyone has gone this route with their GMC?
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I am not sure of the grade of bolts, but I understand our GMC's left the factory without exhaust manifold gaskets. I have been told this has something to do with heat transfer and reduces cracked manifolds.
Degradation of the surfaces from leaks and years make it harder to get a good seal. I have always used some kind of a gasket.
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: Metal to Metal exhaust manifold? [message #103603 is a reply to message #103585] |
Wed, 20 October 2010 17:33 |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
Karma: 0
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| hertfordnc wrote on Wed, 20 October 2010 14:26 |
I really LOVE the REMFLEX gaskets recomended on this forum but over in Revcon land there is a lot of support for shaving both surfaces (head and manifold) and going metal to metal with grade 8 bolts. My head will never be smooth enough but i am curious if anyone has gone this route with their GMC?
Thanks
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the other alternative is to use Dick Patterson's copper gaskets. this way you get a seal and heat transfer.
i had my manifolds belt sanded to get them level and used the copper gaskets with success. i bought a set of copper gaskets from Autozone but they don't fit the manifold worth a hoot.
Fred V
'77 Royale RB 455
P'cola, Fl
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| Re: [GMCnet] Metal to Metal exhaust manifold? [message #103606 is a reply to message #103601] |
Wed, 20 October 2010 17:55 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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I have had moderate success repairing cracked exhaust manifolds in the
following way. Remove the manifold from the head and media blast it. Do not
wash it in solvent. Locate the ends of the crack(s) and center punch there
and drill a 1/8 in hole through the manifold on each end of the cracks. Use
a die grinder with a tree radius or round ball carbide burr and go over the
crack(s) cutting down about 1/3 of the thickness of the manifold. the ground
out area should be about 5/16th of an inch wide and brite shiny clean. blow
off the grindings with compressed air and pre heat the entire manifold to
about 400 degrees. I have an old kitchen range that I use in the shop for
curing powder coat and it works well for this purpose. Set the manifold on
fire bricks so it doesn't cool too quickly and weld up the cracks using a
tig welder and stainless steel stick rod as it will flow out nicely and
adhere to the shiny area of the manifold. Weld from the holes towards the
middle about 1/2 inch or so, then go to the other hole and do the same
thing. work back and forth with short beads until both ends meet. As soon as
you are finished welding, put the manifold back in the 400 degree oven until
the element goes off. Gradually reduce the temperature of the oven by 50
degree increments, pausing at each temperature for a half hour or so. When
you get down to 200 degrees, turn the oven off and leave the manifold in
there until it returns to room temperature. Finally inspect the weld
affected zone & make sure that no new cracks have started next to the welds.
Check the gasket surface for flatness. Mill if necessary and replace it onto
the head along with the gasket of your choice. I have done both GM and Mopar
manifolds this way & they held up for years although not in motorhome
service. The preheating and slow cooldown seem to be a PITA but they are
essential steps to equalize the welding stresses. Some welders I know peen
the weld beads to do the stress relieving. I personally prefer the heat &
slow cool method. If this seems like too much trouble, throw away the
manifolds and put on a good set of headers for about $450.00 or so. Just
what I do, I'm cheap and my labor cost me nothing but time. I kinda like
rescuing old junk from the scrapper.
Jim Hupy
Salem, Or
78 Royale 403
On Wed, Oct 20, 2010 at 2:51 PM, Mr.erf ERFisher <mr.erfisher@gmail.com>wrote:
> >
> > Degradation of the surfaces from leaks and years make it harder to get a
> > good seal. I have always used some kind of a gasket.
> >
> >
> whats the question folks???
>
> use manifolds until they crack , then use headers....
>
>
> gene
>
>
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://gmcmotorhome.info/
> Alternator Protection Cable
> http://gmcmotorhome.info/APC.html
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
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| Re: [GMCnet] Metal to Metal exhaust manifold? [message #103608 is a reply to message #103606] |
Wed, 20 October 2010 18:13 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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Senior Member |
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Omg
Gene
On Oct 20, 2010, at 3:55 PM, James Hupy <jamesh1296@gmail.com> wrote:
> I have had moderate success repairing cracked exhaust manifolds in the
> following way. Remove the manifold from the head and media blast it. Do not
> wash it in solvent. Locate the ends of the crack(s) and center punch there
> and drill a 1/8 in hole through the manifold on each end of the cracks. Use
> a die grinder with a tree radius or round ball carbide burr and go over the
> crack(s) cutting down about 1/3 of the thickness of the manifold. the ground
> out area should be about 5/16th of an inch wide and brite shiny clean. blow
> off the grindings with compressed air and pre heat the entire manifold to
> about 400 degrees. I have an old kitchen range that I use in the shop for
> curing powder coat and it works well for this purpose. Set the manifold on
> fire bricks so it doesn't cool too quickly and weld up the cracks using a
> tig welder and stainless steel stick rod as it will flow out nicely and
> adhere to the shiny area of the manifold. Weld from the holes towards the
> middle about 1/2 inch or so, then go to the other hole and do the same
> thing. work back and forth with short beads until both ends meet. As soon as
> you are finished welding, put the manifold back in the 400 degree oven until
> the element goes off. Gradually reduce the temperature of the oven by 50
> degree increments, pausing at each temperature for a half hour or so. When
> you get down to 200 degrees, turn the oven off and leave the manifold in
> there until it returns to room temperature. Finally inspect the weld
> affected zone & make sure that no new cracks have started next to the welds.
> Check the gasket surface for flatness. Mill if necessary and replace it onto
> the head along with the gasket of your choice. I have done both GM and Mopar
> manifolds this way & they held up for years although not in motorhome
> service. The preheating and slow cooldown seem to be a PITA but they are
> essential steps to equalize the welding stresses. Some welders I know peen
> the weld beads to do the stress relieving. I personally prefer the heat &
> slow cool method. If this seems like too much trouble, throw away the
> manifolds and put on a good set of headers for about $450.00 or so. Just
> what I do, I'm cheap and my labor cost me nothing but time. I kinda like
> rescuing old junk from the scrapper.
> Jim Hupy
> Salem, Or
> 78 Royale 403
>
> On Wed, Oct 20, 2010 at 2:51 PM, Mr.erf ERFisher <mr.erfisher@gmail.com>wrote:
>
>>>
>>> Degradation of the surfaces from leaks and years make it harder to get a
>>> good seal. I have always used some kind of a gasket.
>>>
>>>
>> whats the question folks???
>>
>> use manifolds until they crack , then use headers....
>>
>>
>> gene
>>
>>
>> --
>> Gene Fisher -- 74-23,77PB/ore/ca
>> “Give a man a fish; you have fed him for today --- give him a URL and
>> -------
>> http://gmcmotorhome.info/
>> Alternator Protection Cable
>> http://gmcmotorhome.info/APC.html
>> _______________________________________________
>> GMCnet mailing list
>> List Information and Subscription Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
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List Information and Subscription Options:
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| Re: [GMCnet] Metal to Metal exhaust manifold? [message #103611 is a reply to message #103608] |
Wed, 20 October 2010 18:39 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Gene, was that a good OMG or a bad one? Did I give too much info or not
enough? Always trying to improve & all types of comments are considered
positive ones, Kinda like the famous one, " You know for a fat person, you
sure don't sweat much!"
Jim Hupy
Salem, Or
78 Royale 403
On Wed, Oct 20, 2010 at 4:13 PM, <mr.erfisher@gmail.com> wrote:
> Omg
>
> Gene
>
>
>
>
>
>
>
>
> On Oct 20, 2010, at 3:55 PM, James Hupy <jamesh1296@gmail.com> wrote:
>
> > I have had moderate success repairing cracked exhaust manifolds in the
> > following way. Remove the manifold from the head and media blast it. Do
> not
> > wash it in solvent. Locate the ends of the crack(s) and center punch
> there
> > and drill a 1/8 in hole through the manifold on each end of the cracks.
> Use
> > a die grinder with a tree radius or round ball carbide burr and go over
> the
> > crack(s) cutting down about 1/3 of the thickness of the manifold. the
> ground
> > out area should be about 5/16th of an inch wide and brite shiny clean.
> blow
> > off the grindings with compressed air and pre heat the entire manifold to
> > about 400 degrees. I have an old kitchen range that I use in the shop for
> > curing powder coat and it works well for this purpose. Set the manifold
> on
> > fire bricks so it doesn't cool too quickly and weld up the cracks using a
> > tig welder and stainless steel stick rod as it will flow out nicely and
> > adhere to the shiny area of the manifold. Weld from the holes towards the
> > middle about 1/2 inch or so, then go to the other hole and do the same
> > thing. work back and forth with short beads until both ends meet. As soon
> as
> > you are finished welding, put the manifold back in the 400 degree oven
> until
> > the element goes off. Gradually reduce the temperature of the oven by 50
> > degree increments, pausing at each temperature for a half hour or so.
> When
> > you get down to 200 degrees, turn the oven off and leave the manifold in
> > there until it returns to room temperature. Finally inspect the weld
> > affected zone & make sure that no new cracks have started next to the
> welds.
> > Check the gasket surface for flatness. Mill if necessary and replace it
> onto
> > the head along with the gasket of your choice. I have done both GM and
> Mopar
> > manifolds this way & they held up for years although not in motorhome
> > service. The preheating and slow cooldown seem to be a PITA but they are
> > essential steps to equalize the welding stresses. Some welders I know
> peen
> > the weld beads to do the stress relieving. I personally prefer the heat &
> > slow cool method. If this seems like too much trouble, throw away the
> > manifolds and put on a good set of headers for about $450.00 or so. Just
> > what I do, I'm cheap and my labor cost me nothing but time. I kinda like
> > rescuing old junk from the scrapper.
> > Jim Hupy
> > Salem, Or
> > 78 Royale 403
> >
> > On Wed, Oct 20, 2010 at 2:51 PM, Mr.erf ERFisher <mr.erfisher@gmail.com
> >wrote:
> >
> >>>
> >>> Degradation of the surfaces from leaks and years make it harder to get
> a
> >>> good seal. I have always used some kind of a gasket.
> >>>
> >>>
> >> whats the question folks???
> >>
> >> use manifolds until they crack , then use headers....
> >>
> >>
> >> gene
> >>
> >>
> >> --
> >> Gene Fisher -- 74-23,77PB/ore/ca
> >> “Give a man a fish; you have fed him for today --- give him a URL and
> >> -------
> >> http://gmcmotorhome.info/
> >> Alternator Protection Cable
> >> http://gmcmotorhome.info/APC.html
> >> _______________________________________________
> >> GMCnet mailing list
> >> List Information and Subscription Options:
> >> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >>
> > _______________________________________________
> > GMCnet mailing list
> > List Information and Subscription Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
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List Information and Subscription Options:
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| Re: Metal to Metal exhaust manifold? [message #103614 is a reply to message #103585] |
Wed, 20 October 2010 18:49 |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| hertfordnc wrote on Wed, 20 October 2010 15:26 |
I really LOVE the REMFLEX gaskets recomended on this forum but over in Revcon land there is a lot of support for shaving both surfaces (head and manifold) and going metal to metal with grade 8 bolts. My head will never be smooth enough but i am curious if anyone has gone this route with their GMC?
Thanks
Dave & Ellen Silva
|
Dave,
They have a decent plan, but it won't stay good real long. The head and the manifold run at very different temperatures, so the castings move relative to each other. A copper faced gasket is really good for this. Thermal expansion is limited only by the compressive strength of the hot metal.
We had the discussion about grade 8 in exhaust systems a while back, and as I related, there is a problem that hardened fasteners actually anneal at automotive exhaust temperatures. So, you can use Gr8 if you want to, but don't go near the yield load. Tension (torque) them for gr.3 and they will work better.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Metal to Metal exhaust manifold? [message #103618 is a reply to message #103612] |
Wed, 20 October 2010 19:02 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
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Gene, thanks for the comment. You are absolutely right from a standpoint of
making any sense. I have always looked for the impractical solution first,
then when I try it with little or no success, I don't get too disappointed.
Oh well, those grapes were probably sour anyway. Only time I do repair those
cracks is when there are no replacements available & I need to salvage one.
I also have similar techniques for repairing cracks in cylinder heads & even
cylinders. I always am working on old obsolete stuff that parts are NLA for.
Satisfying when you bring one back from the junk pile. Necessity is the
mother of invention I guess.
Jim Hupy
Salem, OR
78 Royale 403
On Wed, Oct 20, 2010 at 4:43 PM, Mr.erf ERFisher <mr.erfisher@gmail.com>wrote:
> I am out here working on my 23 with tons of things to do, and I cannot
> imagine doing all that work to save manifolds that will soon crack any way
>
> omg - what a lot of work ;>)
>
> but JWID
> gene
>
>
>
> On Wed, Oct 20, 2010 at 4:39 PM, James Hupy <jamesh1296@gmail.com> wrote:
>
> > Gene, was that a good OMG or a bad one? Did I give too much info or not
> > enough?
> >
>
>
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://gmcmotorhome.info/
> Alternator Protection Cable
> http://gmcmotorhome.info/APC.html
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
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| Re: [GMCnet] Metal to Metal exhaust manifold? [message #103624 is a reply to message #103606] |
Wed, 20 October 2010 19:50 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Jim,
Great explanation, thanks. I don't weld -- but I do save damaged, scarce parts that may someday be justifiable to repair. If you followed your prep technique but then brazed the crack would it hold up or are the temps/conditons too severe?
Dennis
Dennis Sexton
73 GMC
Germantown, TN
USA
-----Original Message-----
From: James Hupy <jamesh1296@gmail.com>
To: gmclist@temp.gmcnet.org
Sent: Wed, Oct 20, 2010 5:55 pm
Subject: Re: [GMCnet] Metal to Metal exhaust manifold?
I have had moderate success repairing cracked exhaust manifolds in the
ollowing way. Remove the manifold from the head and media blast it. Do not
ash it in solvent. Locate the ends of the crack(s) and center punch there
nd drill a 1/8 in hole through the manifold on each end of the cracks. Use
die grinder with a tree radius or round ball carbide burr and go over the
rack(s) cutting down about 1/3 of the thickness of the manifold. the ground
ut area should be about 5/16th of an inch wide and brite shiny clean. blow
ff the grindings with compressed air and pre heat the entire manifold to
bout 400 degrees. I have an old kitchen range that I use in the shop for
uring powder coat and it works well for this purpose. Set the manifold on
ire bricks so it doesn't cool too quickly and weld up the cracks using a
ig welder and stainless steel stick rod as it will flow out nicely and
dhere to the shiny area of the manifold. Weld from the holes towards the
iddle about 1/2 inch or so, then go to the other hole and do the same
hing. work back and forth with short beads until both ends meet. As soon as
ou are finished welding, put the manifold back in the 400 degree oven until
he element goes off. Gradually reduce the temperature of the oven by 50
egree increments, pausing at each temperature for a half hour or so. When
ou get down to 200 degrees, turn the oven off and leave the manifold in
here until it returns to room temperature. Finally inspect the weld
ffected zone & make sure that no new cracks have started next to the welds.
heck the gasket surface for flatness. Mill if necessary and replace it onto
he head along with the gasket of your choice. I have done both GM and Mopar
anifolds this way & they held up for years although not in motorhome
ervice. The preheating and slow cooldown seem to be a PITA but they are
ssential steps to equalize the welding stresses. Some welders I know peen
he weld beads to do the stress relieving. I personally prefer the heat &
low cool method. If this seems like too much trouble, throw away the
anifolds and put on a good set of headers for about $450.00 or so. Just
hat I do, I'm cheap and my labor cost me nothing but time. I kinda like
escuing old junk from the scrapper.
im Hupy
alem, Or
8 Royale 403
On Wed, Oct 20, 2010 at 2:51 PM, Mr.erf ERFisher <mr.erfisher@gmail.com>wrote:
> >
> Degradation of the surfaces from leaks and years make it harder to get a
> good seal. I have always used some kind of a gasket.
>
>
whats the question folks???
use manifolds until they crack , then use headers....
gene
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
______________________________________________
MCnet mailing list
ist Information and Subscription Options:
ttp://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Metal to Metal exhaust manifold? [message #103627 is a reply to message #103624] |
Wed, 20 October 2010 20:30 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
Dennis, I actually started out with an oxy/acetelyne torch and body shop
phosphor bronze lo temp initial melt, high temp remelt rods. Very expensive
stuff and a oxy/acetylene flame is dirty compared to a tig. I also have a
now outlawed carbon arc torch that gets very hot but the nitrogen in the air
affects the weld affected zone. When I brazed exhaust manifolds, they would
work for a while but eventually lose adhesion because of the cast iron
graphite content. On other castings that don't get so hot, it would probably
work ok but the tig is simpler and better. I had some broken pieces on my
zip dee awning legs that were jury rigged by the PO with stove bolts &
square nuts. Every time I walked by that mess it would aggravate me to look
at it. After a couple of years I finally had enough and took the legs apart
and heliarced the aluminum pieces back together and welded up the holes.
Took the better part of a day to do it, then some well intentioned soul told
me that those pieces were still available for little $. I wonder where he
was at before I started welding on that crap. Got to be a personal pride
thing with me, making something out of nuthin' no matter what. I have been a
hot rodder all my life and when we first started out you couldn't find
adapters for matching different engines to different transmissions, or motor
mounts ready made, So we fabbed up our own stuff. Now you just go onto the
internet, open up your wallet and order what you need. UPS delivers right to
your door. My current hot rod project is a 1948 Willys Jeepster that I am
putting an independent front suspension, tubular A arms, factory produced
crossmember, Mustang II rack & pinion, Disc brakes, 2" dropped spindles, the
whole package came ready to weld in place. Roller cam 5.0 L Ford w/
multipoint fuel injection and a ready made wiring harness using the stock
computer. Ford AT & Rear end with disc brakes in the back & using a
hydroboost MC. Probably throw away the leaf springs and put in a 4 link
setup. Should go, stop and steer like a high performance sedan when I am
finished. Interior and exterior will be mostly stock with some custom
touches like shortened bumper horns & hidden gas cap door & antenna & stuff
like that. When I get that done I've got a 55 Olds Super 88 Holiday hardtop
that is going to get repowered with a 455 and a Turbo 400 AT. I am like some
of the other guys on the GMC net too many projects, too little $ & time.
Jim Hupy
Salem, Or
78 Royale 403
On Wed, Oct 20, 2010 at 5:50 PM, Dennis S <dennisfsexton@aol.com> wrote:
>
> Jim,
> Great explanation, thanks. I don't weld -- but I do save damaged, scarce
> parts that may someday be justifiable to repair. If you followed your prep
> technique but then brazed the crack would it hold up or are the
> temps/conditons too severe?
>
> Dennis
>
>
> Dennis Sexton
> 73 GMC
> Germantown, TN
> USA
>
>
>
> -----Original Message-----
> From: James Hupy <jamesh1296@gmail.com>
> To: gmclist@temp.gmcnet.org
> Sent: Wed, Oct 20, 2010 5:55 pm
> Subject: Re: [GMCnet] Metal to Metal exhaust manifold?
>
>
> I have had moderate success repairing cracked exhaust manifolds in the
> ollowing way. Remove the manifold from the head and media blast it. Do not
> ash it in solvent. Locate the ends of the crack(s) and center punch there
> nd drill a 1/8 in hole through the manifold on each end of the cracks. Use
> die grinder with a tree radius or round ball carbide burr and go over the
> rack(s) cutting down about 1/3 of the thickness of the manifold. the ground
> ut area should be about 5/16th of an inch wide and brite shiny clean. blow
> ff the grindings with compressed air and pre heat the entire manifold to
> bout 400 degrees. I have an old kitchen range that I use in the shop for
> uring powder coat and it works well for this purpose. Set the manifold on
> ire bricks so it doesn't cool too quickly and weld up the cracks using a
> ig welder and stainless steel stick rod as it will flow out nicely and
> dhere to the shiny area of the manifold. Weld from the holes towards the
> iddle about 1/2 inch or so, then go to the other hole and do the same
> hing. work back and forth with short beads until both ends meet. As soon as
> ou are finished welding, put the manifold back in the 400 degree oven until
> he element goes off. Gradually reduce the temperature of the oven by 50
> egree increments, pausing at each temperature for a half hour or so. When
> ou get down to 200 degrees, turn the oven off and leave the manifold in
> here until it returns to room temperature. Finally inspect the weld
> ffected zone & make sure that no new cracks have started next to the welds.
> heck the gasket surface for flatness. Mill if necessary and replace it onto
> he head along with the gasket of your choice. I have done both GM and Mopar
> anifolds this way & they held up for years although not in motorhome
> ervice. The preheating and slow cooldown seem to be a PITA but they are
> ssential steps to equalize the welding stresses. Some welders I know peen
> he weld beads to do the stress relieving. I personally prefer the heat &
> low cool method. If this seems like too much trouble, throw away the
> anifolds and put on a good set of headers for about $450.00 or so. Just
> hat I do, I'm cheap and my labor cost me nothing but time. I kinda like
> escuing old junk from the scrapper.
> im Hupy
> alem, Or
> 8 Royale 403
> On Wed, Oct 20, 2010 at 2:51 PM, Mr.erf ERFisher <mr.erfisher@gmail.com
> >wrote:
> > >
> > Degradation of the surfaces from leaks and years make it harder to get a
> > good seal. I have always used some kind of a gasket.
> >
> >
> whats the question folks???
>
> use manifolds until they crack , then use headers....
>
>
> gene
>
>
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://gmcmotorhome.info/
> Alternator Protection Cable
> http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] Metal to Metal exhaust manifold? [message #103632 is a reply to message #103605] |
Wed, 20 October 2010 21:21 |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
Karma: 0
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Senior Member |
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[quote title=Mr ERFisher wrote on Wed, 20 October 2010 17:55]Use lenzi copper for manifolds
Use mr gasket for headers
Gene
quote]
right Dave Lenzi. i always get those two mixed up.
Fred V
'77 Royale RB 455
P'cola, Fl
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| Re: [GMCnet] Metal to Metal exhaust manifold? [message #103661 is a reply to message #103627] |
Thu, 21 October 2010 08:03 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Jim,
Thanks for the additional thoughts on brazing.
You have a stable of interesting projects -- post some photos when you have time.
Dennis
Dennis Sexton
73 GMC
Germantown, TN
USA
-----Original Message-----
From: James Hupy <jamesh1296@gmail.com>
To: gmclist@temp.gmcnet.org
Sent: Wed, Oct 20, 2010 8:30 pm
Subject: Re: [GMCnet] Metal to Metal exhaust manifold?
Dennis, I actually started out with an oxy/acetelyne torch and body shop
hosphor bronze lo temp initial melt, high temp remelt rods. Very expensive
tuff and a oxy/acetylene flame is dirty compared to a tig. I also have a
ow outlawed carbon arc torch that gets very hot but the nitrogen in the air
ffects the weld affected zone. When I brazed exhaust manifolds, they would
ork for a while but eventually lose adhesion because of the cast iron
raphite content. On other castings that don't get so hot, it would probably
ork ok but the tig is simpler and better. I had some broken pieces on my
ip dee awning legs that were jury rigged by the PO with stove bolts &
quare nuts. Every time I walked by that mess it would aggravate me to look
t it. After a couple of years I finally had enough and took the legs apart
nd heliarced the aluminum pieces back together and welded up the holes.
ook the better part of a day to do it, then some well intentioned soul told
e that those pieces were still available for little $. I wonder where he
as at before I started welding on that crap. Got to be a personal pride
hing with me, making something out of nuthin' no matter what. I have been a
ot rodder all my life and when we first started out you couldn't find
dapters for matching different engines to different transmissions, or motor
ounts ready made, So we fabbed up our own stuff. Now you just go onto the
nternet, open up your wallet and order what you need. UPS delivers right to
our door. My current hot rod project is a 1948 Willys Jeepster that I am
utting an independent front suspension, tubular A arms, factory produced
rossmember, Mustang II rack & pinion, Disc brakes, 2" dropped spindles, the
hole package came ready to weld in place. Roller cam 5.0 L Ford w/
ultipoint fuel injection and a ready made wiring harness using the stock
omputer. Ford AT & Rear end with disc brakes in the back & using a
ydroboost MC. Probably throw away the leaf springs and put in a 4 link
etup. Should go, stop and steer like a high performance sedan when I am
inished. Interior and exterior will be mostly stock with some custom
ouches like shortened bumper horns & hidden gas cap door & antenna & stuff
ike that. When I get that done I've got a 55 Olds Super 88 Holiday hardtop
hat is going to get repowered with a 455 and a Turbo 400 AT. I am like some
f the other guys on the GMC net too many projects, too little $ & time.
im Hupy
alem, Or
8 Royale 403
On Wed, Oct 20, 2010 at 5:50 PM, Dennis S <dennisfsexton@aol.com> wrote:
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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