Exhaust manifold gasket

[olin r. boyer]

Thanks to Tom and Gene for the responses to my question
about exhaust manifold installation.

Sure enough, when I pulled the passenger side wheel liner, I
could see immediately that there was a 2-inch chunk of the
gasket that had just disappeared! After looking at all the
good information on the "California Eagle", I decided to
order a solid copper gasket set from JEGS. It was 35.99 plus
5.99 S&H, for a total of $41.98. I could have purchased a
FelPro gasket set at the local AutoZone, but decided to go
ahead with the copper set for a better chance at not having
to do this again!

When I pulled the other wheel liner and took a look at the
driver side, there appears to be a FelPro gasket already
installed there. The bolts were still very tight on the
driver side, so decided to just leave that one alone for the
time being.

On the passenger side, where there were pieces of the gasket
missing, the two front bolts were so loose that I just spun
them out with my fingers! The center bolt was almost as
loose, and the two rear bolts really didn't take much
pressure with the wrench to remove them, either! That was
apparently the problem. The bolts were so loose that the
gasket was not even "clamped in", but was just held in place
by the bolts in the gasket through-holes! Don't know what
kind of gasket it was. It had no metal surface like the
FelPro gaskets do, but seemed to be all fiber (Asbestos?).

At any rate, I will install a copper gasket, using Permatex
Copper Gasket Sealer (700degree rating) just as soon as they
arrive, hopefully tomorrow or Friday.

I did take the opportunity to "fix" the wheel liners and a
couple of the mounting holes in the edge of the front
fender. I cut a couple of pieces of nylon strapping from the
end of a tie-down set and used "J-B Weld-Kwik" to extend the
edges of the wheel liners and to fill in the torn-out holes
in the edge of the fender. I even bought a complete new set
of mounting hardware for the wheel liners and dipped the
screw-heads in the bottle of Trim paint that matches my
Clasco paint job!

Thanks again for the suggestions.

Olin Boyer
77GMCPB
Tulsa, OK

 

[olin r. boyer]

Thanks to Gary, Tom, and Lanier for their replies.

I guess some would say I have too much time on my hands, but
I have decided to hold off on installing the copper gasket
until I can get "locks" for the exhaust manifold bolts.
Pictured in the 78Z parts book, they appear to be metal
straps that are drilled on each end so each lock fits over
two adjacent manifold bolts. There is apparently a fold-up
tab (or tabs) on each end that can be folded up flat against
one of the six faces of the hex-head cap screw, keeping it
from turning and thus keeping it tight!

I suppose folks quit using them when they started using
gaskets for the exhaust manifold. When you use a fiber
gasket, even a metal-faced one such as FelPro, the
instructions are to re-torque the bolts after 500 miles,
because the fiber is bound to "crush" to an extent. With
lock tabs on the bolts, that may have been considered too
much trouble!

I discovered on the tube of Permatex Ultra Copper High
Temperature RTV the phrase "No re-torqueing needed". That is
probably true if all you are using for a gasket is the very
thin layer of RTV sealant.

Since I plan to use a solid copper gasket, I reason that
there should be no re-torqueing needed with it, either.

I located the "locks" at my friendly GMC dealer, but he has
to order them in. Only a couple of bucks apiece, so I
ordered four of them and nine of the specified washers to
use with them. I also picked up ten grade 8 hex cap screws,
3/8 X 16 X 1 1/4 , and I plan to use anti-seize on them when
I install them.

I figure if I use new bolts, new washers, new locks, solid
copper gasket, and seal everything up with Ultra Copper RTV,
torqueing everything to 25ft pounds, I shouldn't have to do
it again for a long, long time!

Olin Boyer
77GMCPB
Tulsa, OK

 

[rob teed]

I could use the copper gaskets if you still got them.
Rob Teed

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailtowner-gmcmotorhome]On Behalf Of Hanson9
> Sent: Thursday, June 15, 2000 4:59 PM
> To: gmcmotorhome
> Subject: Re: GMC: Exhaust manifold gasket
>
>
> Gosh, Olin, I wish I had known. I have a sst of Copper Gaskets
> that Didn't
> work that I will give anyone. Dean Hanson
>
_____________________________________________
NetZero - Defenders of the Free World
Click here for FREE Internet Access and Email
http://www.netzero.net/download/index.html

 

[rob teed]

That message was for Dean

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailtowner-gmcmotorhome]On Behalf Of robteed
> Sent: Thursday, June 15, 2000 10:10 PM
> To: gmcmotorhome
> Subject: RE: GMC: Exhaust manifold gasket
>
>
> I could use the copper gaskets if you still got them.
> Rob Teed
>
> > -----Original Message-----
> > From: owner-gmcmotorhome
> > [mailtowner-gmcmotorhome]On Behalf Of Hanson9
> > Sent: Thursday, June 15, 2000 4:59 PM
> > To: gmcmotorhome
> > Subject: Re: GMC: Exhaust manifold gasket
> >
> >
> > Gosh, Olin, I wish I had known. I have a sst of Copper Gaskets
> > that Didn't
> > work that I will give anyone. Dean Hanson
> >
> _____________________________________________
> NetZero - Defenders of the Free World
> Click here for FREE Internet Access and Email
> http://www.netzero.net/download/index.html
>

_____________________________________________
NetZero - Defenders of the Free World
Click here for FREE Internet Access and Email
http://www.netzero.net/download/index.html

 

[nate chase]

Olin,
I added the copper gaskets to my headers this spring. Big Difference! It
came w/heavy duty split washers for the bolts. I put them on dry. Found out
that the web in the center doesn't seal since the manifold has a recess
there. If I were to do it over (which I am sure I'll have the opportunity
someday) I'll add a bit of the RTV at the center web. Other than that I wire
wheeled my bolts (all in good shape), ran a die over them and used never
seize. I retorqued them after a few hours of running and cool down. They did
tighten a bit more. Might double check yours before you bend your tabs for
good. HTH.

Nate '75GB (Cool in the "Big O" today) Omaha

>>

Date: Thu, 15 Jun 2000 15:07:03 -0500
From: "Olin R. Boyer"
Subject: Re: GMC: Exhaust Manifold Gasket

Thanks to Gary, Tom, and Lanier for their replies.

I guess some would say I have too much time on my hands, but
I have decided to hold off on installing the copper gasket
until I can get "locks" for the exhaust manifold bolts.
Pictured in the 78Z parts book, they appear to be metal
straps that are drilled on each end so each lock fits over
two adjacent manifold bolts. There is apparently a fold-up
tab (or tabs) on each end that can be folded up flat against
one of the six faces of the hex-head cap screw, keeping it
from turning and thus keeping it tight!

I suppose folks quit using them when they started using
gaskets for the exhaust manifold. When you use a fiber
gasket, even a metal-faced one such as FelPro, the
instructions are to re-torque the bolts after 500 miles,
because the fiber is bound to "crush" to an extent. With
lock tabs on the bolts, that may have been considered too
much trouble!

I discovered on the tube of Permatex Ultra Copper High
Temperature RTV the phrase "No re-torqueing needed". That is
probably true if all you are using for a gasket is the very
thin layer of RTV sealant.

Since I plan to use a solid copper gasket, I reason that
there should be no re-torqueing needed with it, either.

I located the "locks" at my friendly GMC dealer, but he has
to order them in. Only a couple of bucks apiece, so I
ordered four of them and nine of the specified washers to
use with them. I also picked up ten grade 8 hex cap screws,
3/8 X 16 X 1 1/4 , and I plan to use anti-seize on them when
I install them.

I figure if I use new bolts, new washers, new locks, solid
copper gasket, and seal everything up with Ultra Copper RTV,
torqueing everything to 25ft pounds, I shouldn't have to do
it again for a long, long time!

Olin Boyer
77GMCPB
Tulsa, OK

 

[rob teed]

Hi Lanier,
All I can suggest is when you get ready to fix the broken bolt...think
about pulling the heads off and
redoing them...the machine shop can remove the broken
bolt..it worked real well for me....and its pretty cheap
to get the heads checked.
Rob Teed 74 Painted Desert

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailtowner-gmcmotorhome]On Behalf Of HLBF
> Sent: Friday, June 16, 2000 10:09 AM
> To: gmcmotorhome
> Subject: GMC: Exhaust Manifold Gasket
>
>
> In a message dated 6/16/2000 8:24:31 AM Central Daylight Time,

>
> that the web in the center doesn't seal since the manifold has a recess
> there. >>
>
> Just stuck a probe in my manifolds where the center bolts should
> be and guess
> what - it'll go only the depth of the manifold, so I assume that someone
> broke off the bolts. Also assume they're siezed, so it'll be no
> simple task
> replacing 'em. Also no washers on the other bolts. Since I'm not
> up to the
> job of tearing it down, guess I'll just run with it as is for
> now. I've put
> at least 1,000 miles on it like that, so why not?
>
> Any adverse ramifications??? Any suggestions??
>
> Lanier Foote
> Jackson, MS
> '73 GMC Excalibur (JimiSue)
> '29 Mercedes SSK Toad (Maybelline)
> '94 Tracker Toad (BN Toad)
> F-37894
>
> Reality Check:::::
> There's no free lunch;
> You get what you pay for;
> And Nothing's gonna come in the mail !!
>

_____________________________________________
NetZero - Defenders of the Free World
Click here for FREE Internet Access and Email
http://www.netzero.net/download/index.html

 

[scott shean]

Lanier, it may not be too hard to drill out the broken bolt. I had a rocker
arm bridge bolt drilled out at Alex Sirum's and it only took about an hour.
It was difficult, but sure beats removing the head. If I remember
correctly, they used a right angle drill because of space limitations.

Scott Shean
Baton Rouge, LA
78 Royale

- -----Original Message-----
From: HLBF
To: gmcmotorhome
Date: June 16, 2000 9:09 AM
Subject: GMC: Exhaust Manifold Gasket

>In a message dated 6/16/2000 8:24:31 AM Central Daylight Time,

>
> that the web in the center doesn't seal since the manifold has a recess
> there. >>
>
>Just stuck a probe in my manifolds where the center bolts should be and
guess
>what - it'll go only the depth of the manifold, so I assume that someone
>broke off the bolts. Also assume they're siezed, so it'll be no simple task
>replacing 'em. Also no washers on the other bolts. Since I'm not up to the
>job of tearing it down, guess I'll just run with it as is for now. I've put
>at least 1,000 miles on it like that, so why not?
>
>Any adverse ramifications??? Any suggestions??
>
>Lanier Foote
>Jackson, MS
>'73 GMC Excalibur (JimiSue)
>'29 Mercedes SSK Toad (Maybelline)
>'94 Tracker Toad (BN Toad)
>F-37894
>
>Reality Check:::::
>There's no free lunch;
>You get what you pay for;
>And Nothing's gonna come in the mail !!
>

 

[emerystora]

>Lanier, it may not be too hard to drill out the broken bolt. I had a rocker
>arm bridge bolt drilled out at Alex Sirum's and it only took about an hour.
>It was difficult, but sure beats removing the head. If I remember
>correctly, they used a right angle drill because of space limitations.
>
>Scott Shean
>Baton Rouge, LA
>78 Royale
>
Scott is correct. They can be drilled out fairly easily without
removing the head. That is one reason that GM doesn't use hardened
bolts. I have seen some recent postings that people are replacing
them with grade 8 bolts. The problem with using hardened bolts is
that if you break one off, you'll have a hell of a time trying to
drill it out.

You can unbolt the manifold and leave it attached to the exhaust
pipe. Lower the manifold, center punch the broken bold and drill
away! If the bolt is broken on an angle it may make it easier to
drill if you grind a flat on the surface of the broken piece first.

Emery Stora
77 Kingsley
Santa Fe, NM

 

[travism]

> >Lanier, it may not be too hard to drill out the broken bolt. I had a
rocker
> >arm bridge bolt drilled out at Alex Sirum's and it only took about an
hour.
> >It was difficult, but sure beats removing the head. If I remember
> >correctly, they used a right angle drill because of space limitations.
> >
> >Scott Shean
> >Baton Rouge, LA
> >78 Royale
> >
> Scott is correct. They can be drilled out fairly easily without
> removing the head. That is one reason that GM doesn't use hardened
> bolts. I have seen some recent postings that people are replacing
> them with grade 8 bolts. The problem with using hardened bolts is
> that if you break one off, you'll have a hell of a time trying to
> drill it out.
>
> You can unbolt the manifold and leave it attached to the exhaust
> pipe. Lower the manifold, center punch the broken bold and drill
> away! If the bolt is broken on an angle it may make it easier to
> drill if you grind a flat on the surface of the broken piece first.
>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM

Can I step in with a suggestion? What Emory is describing is a great idea,
but let me add this:

First, use a transfer punch to punch the broken bolts BEFORE you remove the
manifold; this way, the punch will be in the center of the bolt piece and
you won't damage the threads in the head.

Second, use a left-handed drill bit (with your drill set for
counter-clockwise rotation, of course) to drill the bolt...you'd be
surprised at how often a broken bolt will simply back out of the hole as you
begin to drill it with a left-handed bit. Sure saves a LOT of work when it
does. I'd use a 3/16" bit or smaller; if you drill too big a hole in the
bolt, an EZ out will expand it and make it stick to the hole, making for a
mighty tough job.

You can get both items at any reasonably well equipped machine shop supply
house. If you don't have one nearby, let me know and I'll get them and send
them to you.

If you can get to it, I'd even drill the bolt with the manifold in place to
guide your bit at the proper angle. You'll want to be careful to keep the
bit centered in the hole in the manifold to keep from cutting it, but this
will keep you from drilling the bolt fragment at an angle. If you wanted to
get fancy, you could make a drill bushing to keep the bit in exactly the
right place. Sounds like a job for Tom Warner---another GMC tool to put in
your box.

Travis

 

[olin r. boyer]

Sure sorry to hear the story about your "fifth bolt",
Lanier. The advice to pull the heads and have them "gone
over" by a machine shop sounds like the easiest way to go,
if not the cheapest!

I want to pass along a tip from Steve Clevenger concerning
removal of these bolts if they seize and break off. Steve
says it might be well to go to a grade 6 bolt instead of a
grade 8, just to provide for such a contingency. Apparently
a grade 8 bolt is so hard that it is very difficult to
drill.

For Tom Warner:

Tom, the center bolt hole for the exhaust manifold on MY
cylinder heads is not in a boss! The two bolts on each end
thread into bosses, and the four bosses are pretty well
lined up with spark plugs. The center bolt threads into a
tapped hole right into solid cylinder head, at right angles
to a head bolt that you would run into if your center bolt
was too long. Someone earlier mentioned that you could
easily apply Kroil or Liquid Wrench to the four end bolts,
but that it was almost impossible to get to the threads of
the center bolt! They even suggested drilling a hole for
penetrant access to the threads the first time you are
fortunate enough to have the bolt out in one piece!

By the way, keep comin' on the attachment for pressing the
hub from the knuckle. I want one to complete my tool set!

Olin Boyer
77GMCPB
Tulsa, OK

 

[olin r. boyer]

>If you have a 455 the center bolt should go into a boss on
the >head. I'm not sure on the 403.

Tom, there are "bosses" for the four end bolts on my 455,
because there is a "depression" in the casting where each
spark plug fits. The threaded hole for the center bolt is
not accessible from the rear. I'll send you a picture.

Olin Boyer
77GMCPB
Tulsa, OK

 

[olin r. boyer]

Well, I'm certainly glad that I wasn't really in a hurry to
go anywhere! I managed to get the copper gasket installed,
used a bit of Permatex Ultra Copper for good measure, and
torqued the bolts to 23 ft pounds . Mr. Gasket recommended
35 ft pounds if using oil, 23 ft pounds if using moly.
Since I used anti-seize (moly) on the grade 8 manifold
bolts, I followed their recommendations. Interestingly, on
the gasket packaging, there were different torque
recommendations based on whether you were using grade 5
bolts or grade 8 bolts!

I decided to wait 24 hours to start her up just to give the
Permatex a chance to cure. In the meantime, confident that
I'd done a complete job, I replaced the wheel liner, put the
wheel back on and torqued the Alcoa lugs to 140 ft lbs.,
removed the jack stands and put the floor jack away! Even
put all the tools in proper storage areas.

When I started that big old engine, expecting everything to
be quiet, it wasn't! A little better than with the blown
gasket, but still leaking badly!

Out came the wheel liner, back up on the jack stands, front
wheel off again, out came the bolts and what do I find?
Leaking all along the bottom edge of all three ports! I also
found the crack in the exhaust manifold that I hadn't
noticed before because I didn't remove the exhaust pipe
clamp bolts. I had just laid the manifold to one side,
leaving it attached to the exhaust system. When I got the
manifold clear out to examine in the light of day, I found
that it had cracked between the exhaust flange and the
rearmost bolt hole. It had done that, apparently, years ago,
and been welded. The weld didn't hold, or it cracked again
because it was weakened by the welding process itself. I may
have put additional stress on it by not disconnecting it
from the exhaust pipe. A detailed examination showed it had
been "surfaced" a number of times, until there wasn't much
left to grind off for resurfacing.

At any rate, I'm back to square one. GMC locally told me
they hadn't carried the manifold since 1994. Gateway told me
they no longer carried it, but would be glad to sell me a
set of "chrome over steel headers". I called Cinnabar and
"bit the bullet" to the tune of $185 for a new RH exhaust
manifold for a 455. It's supposed to be here in about 3
days.

I still plan to use the copper gasket, so I'll let you know
how it lasts, compared to using a FelPro.

Some other experience I'll share:

1. Don't get in a hurry to put everything back in it's place
until you've "smoke tested" your work!

2. Don't be lazy and fail to disconnect the exhaust pipe
before you pull the manifold bolts. Cast iron is not too
flexible, and you need to keep all stresses that you can out
of the picture.

3. Don't fail to get the manifold out into the bright light
of day to examine it!

Again, thanks to Nate, Dean, Steve, and others who have
helped with suggestions and recommendations. I'll let you
all know how I come out with the new manifold.

Olin Boyer
77GMCPB
Tulsa, OK

 

[gene]

headers

gene

>Well, I'm certainly glad that I wasn't really in a hurry to
>go anywhere! I managed to get the copper gasket installed,
>used a bit of Permatex Ultra Copper for good measure, and
>torqued the bolts to 23 ft pounds . Mr. Gasket recommended
>35 ft pounds if using oil, 23 ft pounds if using moly.
>Since I used anti-seize (moly) on the grade 8 manifold
>bolts, I followed their recommendations. Interestingly, on
>the gasket packaging, there were different torque
>recommendations based on whether you were using grade 5
>bolts or grade 8 bolts!
>
>I decided to wait 24 hours to start her up just to give the
>Permatex a chance to cure. In the meantime, confident that
>I'd done a complete job, I replaced the wheel liner, put the
>wheel back on and torqued the Alcoa lugs to 140 ft lbs.,
>removed the jack stands and put the floor jack away! Even
>put all the tools in proper storage areas.
>
>When I started that big old engine, expecting everything to
>be quiet, it wasn't! A little better than with the blown
>gasket, but still leaking badly!
>
>Out came the wheel liner, back up on the jack stands, front
>wheel off again, out came the bolts and what do I find?
>Leaking all along the bottom edge of all three ports! I also
>found the crack in the exhaust manifold that I hadn't
>noticed before because I didn't remove the exhaust pipe
>clamp bolts. I had just laid the manifold to one side,
>leaving it attached to the exhaust system. When I got the
>manifold clear out to examine in the light of day, I found
>that it had cracked between the exhaust flange and the
>rearmost bolt hole. It had done that, apparently, years ago,
>and been welded. The weld didn't hold, or it cracked again
>because it was weakened by the welding process itself. I may
>have put additional stress on it by not disconnecting it
>from the exhaust pipe. A detailed examination showed it had
>been "surfaced" a number of times, until there wasn't much
>left to grind off for resurfacing.
>
>At any rate, I'm back to square one. GMC locally told me
>they hadn't carried the manifold since 1994. Gateway told me
>they no longer carried it, but would be glad to sell me a
>set of "chrome over steel headers". I called Cinnabar and
>"bit the bullet" to the tune of $185 for a new RH exhaust
>manifold for a 455. It's supposed to be here in about 3
>days.
>
>I still plan to use the copper gasket, so I'll let you know
>how it lasts, compared to using a FelPro.
>
>Some other experience I'll share:
>
>1. Don't get in a hurry to put everything back in it's place
>until you've "smoke tested" your work!
>
>2. Don't be lazy and fail to disconnect the exhaust pipe
>before you pull the manifold bolts. Cast iron is not too
>flexible, and you need to keep all stresses that you can out
>of the picture.
>
>3. Don't fail to get the manifold out into the bright light
>of day to examine it!
>
>Again, thanks to Nate, Dean, Steve, and others who have
>helped with suggestions and recommendations. I'll let you
>all know how I come out with the new manifold.
>
>Olin Boyer
>77GMCPB
>Tulsa, OK
>
>
>
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/

 

[olin r. boyer]

Thanks to Gene, Dean, and Tom for their suggestions.

I think the jury is still out on whether or not my coach
needs headers, although the phone rep that I talked to at
Gateway said something that may get me to thinking about
headers a little more seriously. Seems that they don't sell
manifolds anymore because "they crack".

I want to try to get things working with manifolds, at this
point. As to the suggestions for sources for used manifolds,
I appreciate them, but think that the PO may have followed
that path. How else could he possibly get
a manifold in as bad a shape as he apparently did! In
considering a used manifold, from either someone who had
swapped them for headers, or from a source such as Alex
Sirim, I have to ask myself: "Why is this manifold no longer
installed on an engine?"

I know the price seems a bit high for a new manifold from
Cinnabar, but even including shipping, not as much as I
spent on gasoline on my last trip to Houston to see the kids
and grandkids!

Olin Boyer
77GMCPB
Tulsa, OK