Home » Public Forums » GMCnet » Intake Manifold Question (It's about the bolts)
| Intake Manifold Question [message #116698] |
Sat, 26 February 2011 19:24  |
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JShot
Messages: 485
Registered: October 2006
Location: NW Ohio
Karma: 0
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Our 455 intake manifold was bolted down with 12 bolts - 9 long and 3 short ones. Also, the bolt heads had different markings - a few were grade 8 and some were grade 5.
Should all the bolts be the same length, or are 3 of them short because of the thickness of the manifold at those points? And if I replace all of the bolts with new, is grade 5 ok?
Thanks,
John
John Shotwell
Ridgeville Corners, OH
78 Royale Center Kitchen
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| Re: [GMCnet] Intake Manifold Question [message #116705 is a reply to message #116698] |
Sat, 26 February 2011 19:52  |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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John,
I reckon someone has had this manifold off and went to the bolt bucket when
they replaced it.
Here's what John Sharpe and I did when we swapped the OEM manifold for the
Aluminum RPM manifold.
After cleaning the manifold bolt holes in the heads with a bottoming tap,
brake cleaner, and air pressure (lifter valley stuffed full with a BIG
towel) we sat the aluminum manifold in place without the gaskets and screwed
the OEM 2" long bolts and thick washers into the heads. We found that
without the gaskets the bolts were about 3/16" too long. The one stud was
the same.
We bought 1 3/4" long grade 8 bolts and thick grade 8 washers and cut 1/4"
off the bottom of the stud.
We had no problems torquing the manifold down after gluing the Mr. Gasket
(P/N 404) to the heads with Gorilla Glue. We used black Permatex silicone at
the front and rear of the manifold.
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 John Shotwell
Sent: Sunday, February 27, 2011 12:25 PM
To: gmclist@temp.gmcnet.org
Subject: [GMCnet] Intake Manifold Question
Our 455 intake manifold was bolted down with 12 bolts - 9 long and 3 short
ones. Also, the bolt heads had different markings - a few were grade 8 and
some were grade 5.
Should all the bolts be the same length, or are 3 of them short because of
the thickness of the manifold at those points? And if I replace all of the
bolts with new, is grade 5 ok?
Thanks,
John
--
John Shotwell
Archbold, OH
78 Royale Center Kitchen
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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] Intake Manifold Question [message #116717 is a reply to message #116715] |
Sat, 26 February 2011 21:04 |
Dennis S
Messages: 3046
Registered: November 2005
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Not Rob but I used antisieze. I also did not have a bottoming tap so cleaned out the holes, wire brushed the bolts (I reused the old) and hand unserted them into each hole to be sure they had no drag.
Do you remmeber a recnet thread about whether to start your torque sequence in the center or at the ends? Good reading and advice (but I would have to find it again to remember all the thoughts).
Good luck and let us know how it goes.
Dennis
Dennis Sexton
73 GMC
Germantown, TN
USA
-----Original Message-----
From: John Shotwell <jshot@rtecexpress.net>
To: gmclist@temp.gmcnet.org
Sent: Sat, Feb 26, 2011 8:56 pm
Subject: Re: [GMCnet] Intake Manifold Question
Rob,
hanks for the info. Did you coat the bolts with engine oil, like the manual
uggests, or didn't you have to using the aluminum manifold.
-
ohn Shotwell
rchbold, OH
8 Royale Center Kitchen
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Intake Manifold Question [message #116727 is a reply to message #116715] |
Sat, 26 February 2011 23:34 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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John,
I don't remember but knowing how bloody pedantic I am I confident I followed
the manual! ;-)
HOWEVER, I know I DID NOT start with the OUTSIDE bolts and work inwards,
after consulting with the GMCnet the consensus was with the Mr. Gasket 404
fibrous gasket to start on the inside and work out.
Having said that subsequent to that consultation I called Edelbrock and
asked why their instructions to install one of their Performer manifolds
using their fibrous gasket was to start on the outside and work in. They
noted that was the way Olds did it!
We then hashed it out a bit more on the GMCnet and someone noted if you
started with the outside bolts it might help keep the manifold aligned with
the end ports better.
What exactly are you doing with/to the manifold?
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 John Shotwell
Sent: Sunday, February 27, 2011 1:56 PM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Intake Manifold Question
Rob,
Thanks for the info. Did you coat the bolts with engine oil, like the manual
suggests, or didn't you have to using the aluminum manifold.
--
John Shotwell
Archbold, OH
78 Royale Center Kitchen
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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] Intake Manifold Question [message #116732 is a reply to message #116727] |
Sun, 27 February 2011 00:30 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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If I were as paranoid about the whole thing as some of you seem to be, I
think I'd start at the outside torquing to about 15 ft-lb, then iterate the
whole sequence increasing torque in only 5 ft-lb increments -- or less
dependent upon the intensity of my obsession. All on the assumption that
evenly applying the desired stress stress can't be a bad thing. :-)
Ken H.
On Sun, Feb 27, 2011 at 12:34 AM, Rob Mueller <robmueller@iinet.net.au>wrote:
> John,
>
> I don't remember but knowing how bloody pedantic I am I confident I
> followed
> the manual! ;-) ...
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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] Intake Manifold Question [message #116734 is a reply to message #116732] |
Sun, 27 February 2011 00:54 |
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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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Ken,
It's more curiosity than paranoia with me. I was taught that when torquing
anything long down you always started in the middle and worked outwards
towards the ends in an "X" pattern.
I've applied this to main bearing caps, cylinder heads, intake manifolds,
exhaust manifolds, etc.
Along comes the Olds manifold and it is opposite! Wonder why?
Since the Caddy 500 also uses a turkey tray I figger'd for the hell of it
I'd check and see what my 1972 Cadillac Shop Manual said.
Quote
1) Place rubber seals over rails at front and rear of cylinder block. Tabs
on gasket should be positioned in holes in rails and beveled ends of gasket
tucked into slot at mating of head and rail.
2) Cement sheet metal gasket and shield on engine. Holes in gasket should
engage dowel pins on cylinder heads.
3) Carefully position manifold on cylinder heads by lowering straight down.
Secure manifold with twelve screws. Tighten to 30 foot-pounds.
Unquote
THAT'S IT!
There are no figures showing the sequence to tighten the bolts either.
Things that make you go Hmmmm!
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 Ken Henderson
Sent: Sunday, February 27, 2011 5:31 PM
To: gmclist@temp.gmcnet.org
Cc: Rob Mueller
Subject: Re: [GMCnet] Intake Manifold Question
If I were as paranoid about the whole thing as some of you seem to be, I
think I'd start at the outside torquing to about 15 ft-lb, then iterate the
whole sequence increasing torque in only 5 ft-lb increments -- or less
dependent upon the intensity of my obsession. All on the assumption that
evenly applying the desired stress stress can't be a bad thing. :-)
Ken H.
On Sun, Feb 27, 2011 at 12:34 AM, Rob Mueller
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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] Intake Manifold Question [message #116735 is a reply to message #116734] |
Sun, 27 February 2011 01:04 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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On Sun, Feb 27, 2011 at 1:54 AM, Rob Mueller <robmueller@iinet.net.au>wrote:
> ...
Since the Caddy 500 also uses a turkey tray I figger'd for the hell of it
> I'd check and see what my 1972 Cadillac Shop Manual said.
> ...
> 3) Carefully position manifold on cylinder heads by lowering straight down.
> Secure manifold with twelve screws. Tighten to 30 foot-pounds.
>
> Unquote
>
> THAT'S IT!
>
> There are no figures showing the sequence to tighten the bolts either.
> ...
That's the real point of my comments: I suspect there's a general statement
somewhere in the manual cautioning about tightening in steps. And I don't
believe it matters WHAT the pattern is on much of anything IF the torque is
applied to all fasteners with small incremental increases.
And, like Edelbrock's answer, many of the "official" patterns are based more
on how some author, probably long, long passed, was taught. :-)
Ken H.
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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] Intake Manifold Question [message #116742 is a reply to message #116727] |
Sun, 27 February 2011 07:22 |
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JShot
Messages: 485
Registered: October 2006
Location: NW Ohio
Karma: 0
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| Robert Mueller wrote on Sun, 27 February 2011 00:34 |
John,
What exactly are you doing with/to the manifold?
Regards,
Rob M
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Rob,
I had Dick P. rebuild the carb, and as long as I was putzing around with the top of the engine, I had him send the manifold gaskets and block-off plates kit. Also, it made sense to get rid of the excess wires, rotting vacuum hoses, extra heater hoses (to the defunct water heater), do some general clean-up and some engine painting. That's all.
John Shotwell
Ridgeville Corners, OH
78 Royale Center Kitchen
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| Re: [GMCnet] Intake Manifold Question [message #116753 is a reply to message #116705] |
Sun, 27 February 2011 09:32 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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| Robert Mueller wrote on Sat, 26 February 2011 17:52 |
John,
We had no problems torquing the manifold down after gluing the Mr. Gasket
(P/N 404) to the heads with Gorilla Glue. We used black Permatex silicone at
the front and rear of the manifold.
Regards,
Rob M.
USAussie - Downunder
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The only thing I would add here is that if you are putting on an aluminum manifold, attach the gasket to the manifold, making sure the gasket is centered on the ports. I had to carve out the bolt holes about 1/8 inch after centering. (It was not on upside down.)
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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