Home » Public Forums » GMCnet » GMC Intake Gasket Lore (Urban Legend?)
| GMC Intake Gasket Lore [message #111749] |
Wed, 12 January 2011 11:20  |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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I was idly wondering who discovered that when putting on a manifold gasket, a smart GMC guy was supposed to throw away the molded rubber gasket for the valley ends and squirt a wad of RTV on the skinny little metal dam, perhaps even dimpling the manifold and the valley ends.
Have there been reports of failure of the rubber gaskets? Or is this like the "Drink 8 glasses of water a day," rule that we have discovered has no basis is science.
I ask because after putting the intake on twice (see Oil Sucking 1 & 2) I have dutifully laid aside what appear to be splendid gaskets and smeared gooey RTV down twice. (I got to clean it up twice, too.) During the last effort, I nicked a place setting the manifold in, in back probably with the low hanging bottom plane, and had to re-goo. I must say I looked longingly at the preformed gaskets at that point.
So, does anyone know where the disdain for the formed rubber gasket started? Apparently Fel-Pro and Mr. Gasket have not gotten the news. Maybe the RTV manufacturers suggested the idea. *smile*
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
[Updated on: Wed, 12 January 2011 11:22] Report message to a moderator |
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| Re: [GMCnet] GMC Intake Gasket Lore [message #111752 is a reply to message #111749] |
Wed, 12 January 2011 11:33  |
Gary Worobec
Messages: 867
Registered: May 2005
Karma: -1
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George,
Edelbrock actually recommends the RTV procedure in their instructions. I
think you are supposed to leave the RTV just til it skins over then drop the
manifold down on it. SteveF. , who has done a ton of V8's should probably
chime in here.
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
----- Original Message -----
From: "George Beckman" <gbeckman@pggp.com>
To: <gmclist@temp.gmcnet.org>
Sent: Wednesday, January 12, 2011 9:20 AM
Subject: [GMCnet] GMC Intake Gasket Lore
>
>
> I was idly wondering who discovered that when putting on a manifold
> gasket, a smart GMC guy was supposed to throw away the molded rubber
> gasket for the valley ends and squirt a wad of RTV on the skinny little
> metal dam, perhaps even dimpling the manifold and the valley ends.
>
> Have there been reports of failure of the rubber gaskets? Or is this like
> the "Drink 8 glasses of water a day," rule that we have discovered has no
> basis is science.
>
> I ask because after putting the intake on twice (see Oil Sucking 1 & 2) I
> have dutifully laid aside what appear to be splendid gaskets and smeared
> gooey RTV down twice. (I got to clean it up twice, too.) During the last
> effort, I nicked a place setting the manifold in, in back probably with
> the low hanging bottom plane, and had to re-goo. I must say I looked
> longingly at the preformed gaskets at that point.
>
> So, does anyone know where the disdain for the formed rubber gasket
> started? Apparently Fel-Pro and Mr. Gasket have not gotten the news.
> Maybe the RTV manufacturers suggested the idea. *smile*
> --
> '74 Eleganza, SE, Howell + EBL
> Best Wishes,
> George
> _______________________________________________
> GMCnet mailing list
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| Re: GMC Intake Gasket Lore [message #111754 is a reply to message #111749] |
Wed, 12 January 2011 11:57 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| George Beckman wrote on Wed, 12 January 2011 12:20 |
I was idly wondering who discovered that when putting on a manifold gasket, a smart GMC guy was supposed to throw away the molded rubber gasket for the valley ends and squirt a wad of RTV on the skinny little metal dam, perhaps even dimpling the manifold and the valley ends.
Have there been reports of failure of the rubber gaskets? Or is this like the "Drink 8 glasses of water a day," rule that we have discovered has no basis is science.
I ask because after putting the intake on twice (see Oil Sucking 1 & 2) I have dutifully laid aside what appear to be splendid gaskets and smeared gooey RTV down twice. (I got to clean it up twice, too.) During the last effort, I nicked a place setting the manifold in, in back probably with the low hanging bottom plane, and had to re-goo. I must say I looked longingly at the preformed gaskets at that point.
So, does anyone know where the disdain for the formed rubber gasket started? Apparently Fel-Pro and Mr. Gasket have not gotten the news. Maybe the RTV manufacturers suggested the idea. *smile*
|
George,
In the trade, those end gaskets are called China Wall Seals. They exist in both cork and molded rubber for most V engine lines.
When assembling an engine on an engine stand with clear view, good light and great working position, they can be successfully installed. They are faster to install than a properly done formed in place (RTV) seal as there is no required time to "skin over". This is why contract houses or rebuilders still use them.
They are, however, very short of "Sense Of Humor". If things aren't real close to dead on right, they will end up:
seeping because there is not enough compression,
shearing and falling in and out because of too much compression, some casting misalignment, or
spitting out and making a big leak (usually because they shifted out of place during assembly.
Every time I work on a V engine, I do a trial assembly of the intake. Sometimes the cork or rubber gasket looks real good, others, not so much. If I was doing a manifold in a coach, I'm not sure I would bother considering it. My time just is not that valuable and I don't want to do it twice.
You are going to end up putting RTV in the tri-corner (where the head, intake and china wall all meet) anyway. It works pretty well(, if you actually follow the instructions).
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] GMC Intake Gasket Lore [message #111757 is a reply to message #111749] |
Wed, 12 January 2011 13:04 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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George,
See my messages:
Edelbrock intake manifold installation procedure [message #111522]
And
Edelbrock Intake Manifold Gasket P/N 7284 [message #111662]
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of George Beckman
Sent: Thursday, January 13, 2011 4:21 AM
To: gmclist@temp.gmcnet.org
Subject: [GMCnet] GMC Intake Gasket Lore
I was idly wondering who discovered that when putting on a manifold gasket,
a smart GMC guy was supposed to throw away the molded rubber gasket for the
valley ends and squirt a wad of RTV on the skinny little metal dam, perhaps
even dimpling the manifold and the valley ends.
Have there been reports of failure of the rubber gaskets? Or is this like
the "Drink 8 glasses of water a day," rule that we have discovered has no
basis is science.
I ask because after putting the intake on twice (see Oil Sucking 1 & 2) I
have dutifully laid aside what appear to be splendid gaskets and smeared
gooey RTV down twice. (I got to clean it up twice, too.) During the last
effort, I nicked a place setting the manifold in, in back probably with the
low hanging bottom plane, and had to re-goo. I must say I looked longingly
at the preformed gaskets at that point.
So, does anyone know where the disdain for the formed rubber gasket started?
Apparently Fel-Pro and Mr. Gasket have not gotten the news. Maybe the RTV
manufacturers suggested the idea. *smile*
--
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
_______________________________________________
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] GMC Intake Gasket Lore [message #111760 is a reply to message #111749] |
Wed, 12 January 2011 13:13 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
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Senior Member |
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George,
That would be me, and hundreds of other engine assemblers.
I have had those fail on me more than once and have taken apart dozens of
engine that leaked because those gaskets have hardened to the point of
shrinking and becoming brittle.
Any surfacing of the heads, or block decking, will always show up as a
larger gap between the intake and block.
On Wed, Jan 12, 2011 at 10:20 AM, George Beckman <gbeckman@pggp.com> wrote:
>
>
> I was idly wondering who discovered that when putting on a manifold gasket,
> a smart GMC guy was supposed to throw away the molded rubber gasket for the
> valley ends and squirt a wad of RTV on the skinny little metal dam, perhaps
> even dimpling the manifold and the valley ends.
>
> Have there been reports of failure of the rubber gaskets? Or is this like
> the "Drink 8 glasses of water a day," rule that we have discovered has no
> basis is science.
>
> I ask because after putting the intake on twice (see Oil Sucking 1 & 2) I
> have dutifully laid aside what appear to be splendid gaskets and smeared
> gooey RTV down twice. (I got to clean it up twice, too.) During the last
> effort, I nicked a place setting the manifold in, in back probably with the
> low hanging bottom plane, and had to re-goo. I must say I looked longingly
> at the preformed gaskets at that point.
>
> So, does anyone know where the disdain for the formed rubber gasket
> started? Apparently Fel-Pro and Mr. Gasket have not gotten the news. Maybe
> the RTV manufacturers suggested the idea. *smile*
> --
> '74 Eleganza, SE, Howell + EBL
> Best Wishes,
> George
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Steve Ferguson
Sierra Vista, AZ
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| Re: [GMCnet] GMC Intake Gasket Lore [message #111764 is a reply to message #111760] |
Wed, 12 January 2011 13:35 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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| Steven Ferguson wrote on Wed, 12 January 2011 11:13 |
I have had those fail on me more than once and have taken apart dozens of
engine that leaked because those gaskets have hardened to the point of
shrinking and becoming brittle.
|
Duh. I had not thought of the rubber getting hard, cracking or shrinking.
Thanks to all who answered. I now feel pleased with my decision to use RTV rather than the lesser product.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] GMC Intake Gasket Lore [message #111771 is a reply to message #111752] |
Wed, 12 January 2011 15:22 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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There is always a good chance the rubber will work out and you'll en
up inserting RTV where the gasket is slipping out.
We must do over 30 engines per year so our guys use the rtv route.
On Wed, Jan 12, 2011 at 9:33 AM, Gary Worobec <gtw5@earthlink.net> wrote:
> George,
> Edelbrock actually recommends the RTV procedure in their instructions. I
> think you are supposed to leave the RTV just til it skins over then drop the
> manifold down on it. SteveF. , who has done a ton of V8's should probably
> chime in here.
>
> Thanks
>
> Gary and Joanne Worobec
> 1973 GMC Glacier
> Anza, CA
>
> ----- Original Message -----
> From: "George Beckman" <gbeckman@pggp.com>
> To: <gmclist@temp.gmcnet.org>
> Sent: Wednesday, January 12, 2011 9:20 AM
> Subject: [GMCnet] GMC Intake Gasket Lore
>
>
>>
>>
>> I was idly wondering who discovered that when putting on a manifold
>> gasket, a smart GMC guy was supposed to throw away the molded rubber
>> gasket for the valley ends and squirt a wad of RTV on the skinny little
>> metal dam, perhaps even dimpling the manifold and the valley ends.
>>
>> Have there been reports of failure of the rubber gaskets? Or is this like
>> the "Drink 8 glasses of water a day," rule that we have discovered has no
>> basis is science.
>>
>> I ask because after putting the intake on twice (see Oil Sucking 1 & 2) I
>> have dutifully laid aside what appear to be splendid gaskets and smeared
>> gooey RTV down twice. (I got to clean it up twice, too.) During the last
>> effort, I nicked a place setting the manifold in, in back probably with
>> the low hanging bottom plane, and had to re-goo. I must say I looked
>> longingly at the preformed gaskets at that point.
>>
>> So, does anyone know where the disdain for the formed rubber gasket
>> started? Apparently Fel-Pro and Mr. Gasket have not gotten the news.
>> Maybe the RTV manufacturers suggested the idea. *smile*
>> --
>> '74 Eleganza, SE, Howell + EBL
>> Best Wishes,
>> George
>> _______________________________________________
>> 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
>
--
Jim Kanomata
Applied/GMC, Fremont,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] GMC Intake Gasket Lore [message #111782 is a reply to message #111778] |
Wed, 12 January 2011 17:31 |
Gary Worobec
Messages: 867
Registered: May 2005
Karma: -1
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Senior Member |
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Same subject and confusing. Why is it that both Edelbrock and the GMC
manual say to torque the intake manifold bolts from the outside toward the
middle. Conventional wisdom seems to indicate as with cylinder heads you
start in the middle and work outwards.
Any thoughts,,
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
----- Original Message -----
From: "Larry" <weidnerl@wwt.net>
To: <gmclist@temp.gmcnet.org>
Sent: Wednesday, January 12, 2011 3:03 PM
Subject: Re: [GMCnet] GMC Intake Gasket Lore
>
>
> I've done a lot of motors and now I ALWAYS use the RTV option. A couple
> of times the RTV *with* the rubber gasket made the gasket so slippery
> that it just squished out when I set the manifold in place and bolted it
> down. Other times with a dry gasket, when the manifold was not set *JUST
> RIGHT* it leaked. So now, I clean the manifold and block surfaces to
> within an inch of its life. Lay a nice bead of RTV on the block surface
> and VERY CAREFULLY lower the manifold down to the block. I then only move
> the manifold enough to get the bolt holes to line up and run the bolts in
> finger tight only. Then let the RTV set for two days while I work on
> other coach stuff. After two days, I then tighten the manifold to proper
> torque. This way the RTV dryss down and when you tighten the bolts it
> squishes it slightly like it was an "O" ring. Using this method, I've
> never had a leak....qualify this...in that area. Just what I do....
> --
> Larry :)
> 78 Royale w/500 Caddy
> Menomonie, WI.
> _______________________________________________
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| Re: [GMCnet] GMC Intake Gasket Lore [message #111794 is a reply to message #111782] |
Wed, 12 January 2011 18:27 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Gary,
Bob Drewes noted:
3. When starting to snug the bolts down, do the four corners first, very
slowly and not much torque and about a 1/4 turn on the bolts at one time.
This will help center the intake manifold into the valley/heads. Check often
and see if the manifold is setting in evenly.
I called Edelbrock Tech Support and the guy I spoke to said "that's a good
question - that is the reverse of every other manifold I've ever installed -
I've been asked this before but I don't remember the answer - stand by for a
minute."
I then heard him talking to someone else in the background but couldn't make
out what they were saying.
When he came back on he noted that the sequence was correct and that was the
way the factory (meaning Olds) did it so Edelbrock followed suit. I noted
that the gasket the factory used was a thin metal "turkey tray" that had
raised bosses around the ports not a 0.060" thick fibrous one.
He agreed but noted that as far as he knew they didn't have complaints about
the Performer leaking so I was good to go.
I agreed with him but noted "I wonder how many people actually read the
instructions and having read them actually followed them! - I'll bet a lot
of guys just said this is nuts I'll just torque the bolts from the inside
out!"
He agreed and noted the only way we could find out why Olds did it in the
first place it to find one of the engineers that worked on that engine and
they were probably long gone!
For the hell of it I looked for the Caddy 500 Performer manifold (P/N 2115)
but the installation instructions were not on line.
I checked the 403 Performer and it starts on the outside and work in too.
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Gary Worobec
Sent: Thursday, January 13, 2011 10:31 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] GMC Intake Gasket Lore
Same subject and confusing. Why is it that both Edelbrock and the GMC
manual say to torque the intake manifold bolts from the outside toward the
middle. Conventional wisdom seems to indicate as with cylinder heads you
start in the middle and work outwards.
Any thoughts,,
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] GMC Intake Gasket Lore [message #111799 is a reply to message #111782] |
Wed, 12 January 2011 19:14 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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| Gary Worobec wrote on Wed, 12 January 2011 15:31 |
Same subject and confusing. Why is it that both Edelbrock and the GMC
manual say to torque the intake manifold bolts from the outside toward the
middle. Conventional wisdom seems to indicate as with cylinder heads you
start in the middle and work outwards.
Any thoughts,,
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
|
My thoughts, exactly. Earlier there were conflicting thoughts so the second time I cast caution to the wind and went from the inside out. I could not get my head around doing the ends first. I wanted mine to "flatten" from the center out. From what I can see, it did. I think it looks very good. I also took it to 50 lbs and will check again later. Got to get my baby back on the road.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] GMC Intake Gasket Lore [message #112889 is a reply to message #112863] |
Mon, 24 January 2011 08:18 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| ljdavick wrote on Mon, 24 January 2011 00:17 |
Any guesses why Oldsmobile used the turkey tray as a gasket? Was it's secondary purpose to keep oil from burning on the underside of the exhaust heated intake manifold?
How hard would it be to reproduce the turkey tray with the exhaust crossover blocked? Was it some special type of soft metal, or was it heavily embossed, or, or or???
Larry Davick
The Mystery Machine
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Larry,
I can answer that quite definitively.
Yes
Yes
Very
Not really, Yes
????
More explanations:
The "turkey tray or turkey pan intake manifold gaskets were used by a number of manufactures over the years because:
It was inexpensive (big reason)
It was easily installed on the assembly line.
And yes, it did sever to keep the oil from coking on the bottom of the intake heater runner.
The tooling to make these parts was costly, massive and cantankerous. If any company still makes it they could easily “pull a punch” and make parts without the port for the “crossover”, but the soft steel that those thing are made from would never stand the heat.
Yes, they were/are very heavily embossed, but the steel parts still don’t work all that well. When the engines get old and primary castings have become distorted or machined to get back to flatness, they work even less well. When at McCord (RIP), I set up the aftermarket to reproduce this, the Ford 460 and 2 other (CRS here) to be kits of a pair of composite side gaskets, a steel pan for the above reason and the pair of original china wall seals (just because some shops still like them). I can not tell you what of those is still available as Fel-Pro as that was a long time ago.
I think I answered all your questions, but if I missed one or think of another, I can try again.
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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