Home » Public Forums » GMCnet » exhaust manifold bolt size (what size)
| exhaust manifold bolt size [message #127663] |
Fri, 27 May 2011 15:54  |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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what size bolts for the exhaust manifold? going to install remflex gasket. it looks like a PO used a bunch of washers on a couple bolts. want to get new grade 8, but do not want to spend alot of time figure out what size/ thread.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: [GMCnet] exhaust manifold bolt size [message #127693 is a reply to message #127691] |
Fri, 27 May 2011 20:54  |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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G'day,
Ref: Parts Book 78Z
Page: 8-11
Key: 54
Qty: 10
Part Number: 9420462
Description: BOLT - intake & exhaust manifold to cylinder head (3/8 - 16 x 1
1/4) (300M)
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 Bruce Hislop
Sent: Saturday, May 28, 2011 11:41 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] exhaust manifold bolt size
I keep checking mine so I can tell you they take a 9/16" socket, that makes
them 3/8" NC bolts
I could be wrong though
--
Bruce Hislop,
S. Ontario Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI and ESC.
Hubler front end installed and WOW! !:)
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
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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: exhaust manifold bolt size [message #127704 is a reply to message #127663] |
Fri, 27 May 2011 22:06 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| Jon wrote on Fri, 27 May 2011 16:54 |
what size bolts for the exhaust manifold? going to install remflex gasket. it looks like a PO used a bunch of washers on a couple bolts. want to get new grade 8, but do not want to spend alot of time figure out what size/ thread.
|
Jon,
You can get and use Gr.8 if you want to, but do not tension (torque) them past Gr. 2 load. Gr. 8 fasteners are better alloy and quality all around, but the heat treatment that gives them the extra yield strength goes away at engine exhaust temperatures. So, as soon as they get hot they self-unload to mild steel yield point.
Read the cautions everywhere in the GMC sites about that center bolt.
Also, if you buy the disk set that has all this stuff, you can look it all up very easily. Not that anybody minds answering a question, but there are some hours that the only one at the keyboard is Rob and that is only when is at the down-under home.
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] exhaust manifold bolt size [message #128071 is a reply to message #127713] |
Tue, 31 May 2011 11:12 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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Ok, the remflex on the driverside went in flawless. I hope when i do the passenger side it goes as easy. but I have run out of time, and that side didn't leak. Can't afford the time if a bolt
I ended up purchasing 4 1 1/4" bolts. and needed one 1 1/2 inch bolt for the front engine bolt. that one had some goofy washers, and bracket on it for the alternator. didn't look factory, but was not going to argue because the bracket looked straight.
I bought grade 8, just because. MN has a fleet farm store, and bolts are cheap. just didn't want to put the rusted one's back in.
thanks for the help.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: [GMCnet] exhaust manifold bolt size [message #128073 is a reply to message #128071] |
Tue, 31 May 2011 11:21 |
Gary Worobec
Messages: 867
Registered: May 2005
Karma: -1
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John, the Remflex gaskets go on with such little torque you can get by with
softer bolts than G8's. In this application if a bolt does seize in the head
it;s easier to drill out a G5 than a G8. I think I tightened mine to 25ft
lbs and forgot about them.
If you have a stock intake manifold you may want to inspect the little
gasket that seals the choke stove. These are prone to blow out and if I
recall have been the source of some fires. I replaced mine with piece of
REMFLEX material. I called the guys at REMFLEX and for an SASE envelope they
sent me a piece.
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
----- Original Message -----
From: "Jon Roche" <lqqkatjon@gmail.com>
To: <gmclist@temp.gmcnet.org>
Sent: Tuesday, May 31, 2011 9:12 AM
Subject: Re: [GMCnet] exhaust manifold bolt size
>
>
> Ok, the remflex on the driverside went in flawless. I hope when i do the
> passenger side it goes as easy. but I have run out of time, and that side
> didn't leak. Can't afford the time if a bolt
>
> I ended up purchasing 4 1 1/4" bolts. and needed one 1 1/2 inch bolt for
> the front engine bolt. that one had some goofy washers, and bracket on it
> for the alternator. didn't look factory, but was not going to argue
> because the bracket looked straight.
>
> I bought grade 8, just because. MN has a fleet farm store, and bolts are
> cheap. ,
The just didn't want to put the rusted one's back in.
>
> thanks for the help.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] exhaust manifold bolt size [message #128075 is a reply to message #128073] |
Tue, 31 May 2011 11:35 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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While we are on the subject of manifold fasteners, I always use the longest
fastener that will go into the assembly, including brackets, washers, wire
looms. I then probe the hole with a vernier caliper to obtain the depth and
use a fastener that is 1/8" - 1/4" shorter. If the fastener bottoms in the
hole, it will appear to be tight, but the assembly is not clamped together,
and the gasket will fail prematurely. If you break a G8 fastener off in the
hole, you will need cobalt bits to drill it out. If Murphy is allowed to get
you, he will. Drilling out broken manifold fasteners is not any fun. I have
done it more times than I can count. Ounce of prevention and all that stuff
applies 100 percent of the time.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Tue, May 31, 2011 at 9:21 AM, Gary Worobec <gtw5@earthlink.net> wrote:
> John, the Remflex gaskets go on with such little torque you can get by with
> softer bolts than G8's. In this application if a bolt does seize in the
> head
> it;s easier to drill out a G5 than a G8. I think I tightened mine to 25ft
> lbs and forgot about them.
>
> If you have a stock intake manifold you may want to inspect the little
> gasket that seals the choke stove. These are prone to blow out and if I
> recall have been the source of some fires. I replaced mine with piece of
> REMFLEX material. I called the guys at REMFLEX and for an SASE envelope
> they
> sent me a piece.
>
> Thanks
>
> Gary and Joanne Worobec
> 1973 GMC Glacier
> Anza, CA
>
> ----- Original Message -----
> From: "Jon Roche" <lqqkatjon@gmail.com>
> To: <gmclist@temp.gmcnet.org>
> Sent: Tuesday, May 31, 2011 9:12 AM
> Subject: Re: [GMCnet] exhaust manifold bolt size
>
>
> >
> >
> > Ok, the remflex on the driverside went in flawless. I hope when i do
> the
> > passenger side it goes as easy. but I have run out of time, and that
> side
> > didn't leak. Can't afford the time if a bolt
> >
> > I ended up purchasing 4 1 1/4" bolts. and needed one 1 1/2 inch bolt for
> > the front engine bolt. that one had some goofy washers, and bracket on
> it
> > for the alternator. didn't look factory, but was not going to argue
> > because the bracket looked straight.
> >
> > I bought grade 8, just because. MN has a fleet farm store, and bolts are
> > cheap. ,
> The just didn't want to put the rusted one's back in.
> >
> > thanks for the help.
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: exhaust manifold bolt size [message #128078 is a reply to message #127663] |
Tue, 31 May 2011 11:57 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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quite clearly on the remflex package, it said "reccomended torque: 15-18 ftlbs."
so they are torqued at 17. with the top center bolt tight just enough to not fall out.
It is my guess/thought, that if these remflex work as described and told, the next time the manifolds are off, they will be bolted to a new/different motor.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: [GMCnet] exhaust manifold bolt size [message #128081 is a reply to message #128078] |
Tue, 31 May 2011 12:20 |
Gary Worobec
Messages: 867
Registered: May 2005
Karma: -1
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Senior Member |
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Some 25 ft. lbs, was on my mind but yes, the bolt torque is surprisingly low
for these gaskets.
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
----- Original Message -----
From: "Jon Roche" <lqqkatjon@gmail.com>
To: <gmclist@temp.gmcnet.org>
Sent: Tuesday, May 31, 2011 9:57 AM
Subject: Re: [GMCnet] exhaust manifold bolt size
>
>
> quite clearly on the remflex package, it said "reccomended torque: 15-18
> ftlbs."
>
> so they are torqued at 17. with the top center bolt tight just enough to
> not fall out.
>
> It is my guess/thought, that if these remflex work as described and told,
> the next time the manifolds are off, they will be bolted to a
> new/different motor.
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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