Exhaust Manifolds

R

richard waters

New member
Feb 8, 1999
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GMC Owners:
I'm currently in the process of having my exhaust manifolds
redone (and I think my wallet emptied) at Cinnabar. I wonder
if anyone is interested in what I have learned about manifolds,
carburetors and lean mixtures. If this subject has been talked about
in the past, then I won't start a new thread.
Richard Waters
'76 PB, Troy, MI
 
YES!

tw
1974 Eleganza SE

- -----Original Message-----
From: owner-gmcmotorhome
[mailto:owner-gmcmotorhome]On Behalf Of Richard Waters
Sent: Tuesday, April 27, 1999 9:30 PM
To: GMC Net
Subject: Re: GMC: Exhaust Manifolds

GMC Owners:
I'm currently in the process of having my exhaust manifolds
redone (and I think my wallet emptied) at Cinnabar. I wonder
if anyone is interested in what I have learned about manifolds,
carburetors and lean mixtures. If this subject has been talked about
in the past, then I won't start a new thread.
Richard Waters
'76 PB, Troy, MI
 
old carb, reformulated gas, lean mixture, exhaust manifolds warped, exhaust
manifolds at Cinnabar, empty your wallet. close?

>GMC Owners:
>I'm currently in the process of having my exhaust manifolds
>redone (and I think my wallet emptied) at Cinnabar. I wonder
>if anyone is interested in what I have learned about manifolds,
>carburetors and lean mixtures. If this subject has been talked about
>in the past, then I won't start a new thread.
>Richard Waters
>'76 PB, Troy, MI
>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
"The beautiful Mohawk Vally"
 
Close, but the carb had been rebuilt by Cinnabar by the previous owner a couple

of years ago, but they didn't change the jets....so I think you know the rest
of my story already. I don't know the complete story myself, that is I won't
get
the bill until later this week. I wondering if this is a topic for "Arch the
Myth
Slayer".
Richard

> old carb, reformulated gas, lean mixture, exhaust manifolds warped, exhaust
> manifolds at Cinnabar, empty your wallet. close?
>

> >GMC Owners:
> >I'm currently in the process of having my exhaust manifolds
> >redone (and I think my wallet emptied) at Cinnabar. I wonder
> >if anyone is interested in what I have learned about manifolds,
> >carburetors and lean mixtures. If this subject has been talked about
> >in the past, then I won't start a new thread.
> >Richard Waters
> >'76 PB, Troy, MI
> >
> >
> >
> Tom & Marg Warner
> Vernon Center NY
> 1976 palmbeach
> "The beautiful Mohawk Vally"
 
Richard,

Go ahead - I think it's been a while since we've gone there. Last year, one
of our group(Phil Stewart) was having a terrible time with his
carburetor. He spent a lot of time on the phone with the folks at C'bar
just getting the coach driveable. Turned out the guy that rebuilt his carb
had inadvertently installed two gaskets between the body and the air horn -
the two gaskets were stuck together and looked like one. Whenever the
secondaries kicked in, the carb went rich and black smoke poured out the
pipe.

IIRC, the guys at C'bar gave him some "starting point" jet and metering rod
sizes and after the coach was running properly, he drove up to Sandusky for
the full treatment. Phil, please correct me if I've screwed up any of the
details.

I'd definitely like to hear what the current thinking is at Cinnabar on this
subject. I just finished rebuilding my carb and, since it's still sitting
on the bench at home, now's the time to make any changes. I'd definitely
like to richen it up a little as I'm also installing a K&N air filter,
Thorley headers and Flowmaster mufflers - all of which I would think will
make the engine run leaner still(I'd love to hear any dissenting opinions on
this).

Patrick

>
> GMC Owners:
> I'm currently in the process of having my exhaust manifolds
> redone (and I think my wallet emptied) at Cinnabar. I wonder
> if anyone is interested in what I have learned about manifolds,
> carburetors and lean mixtures. If this subject has been talked about
> in the past, then I won't start a new thread.
> Richard Waters
> '76 PB, Troy, MI
>
 
Ok I'll give you the blow-by-blow details of what happened to my
coach and will share what I learned about lean air to fuel mixtures
later today. By then I should have the bill faxed here from Cinnabar
and their final analysis of what happened to my coach.

Right now I have to go out and earn some money to replenish my wallet.
Richard Waters

> Richard,
>
> Go ahead - I think it's been a while since we've gone there.
 
On Tue, 27 Apr 1999 21:30:24 -0400 Richard Waters

>GMC Owners:
>I'm currently in the process of having my exhaust manifolds
>redone (and I think my wallet emptied) at Cinnabar. I wonder
>if anyone is interested in what I have learned about manifolds,
>carburetors and lean mixtures. If this subject has been talked about
>in the past, then I won't start a new thread.
>Richard Waters
>'76 PB, Troy, MI

Of course, we are interested! There are lots of new folks on the Net and
as for me it takes me 2 or 3 times before I get it straight anyway,
sooooo, fire away.

David Lee Greenberg
GMC Motorhome Registry
200 Macfarlane Drive PH 4
Delray Beach, FL 33483-6829
800-827-9989
 
Yep - had them coated by HPC.

Patrick

>
> In a message dated 4/28/99 5:22:14 AM Pacific Daylight Time,

>
> would think will
> make the engine run leaner still(I'd love to hear any
> dissenting opinions on
> this). >>
>
> Patrick, did you have the headers ceramic coated?
> My headers were installed in 94 and recently had them ceramic
> coated by HPC.
> I do notice less heat in the the engine compartment after 40
> minutes driving
> and removing the cover.
>
> Manny Trovao 73 Custom/ex-Glacier
>
 
> Richard,
>
> Go ahead - I think it's been a while since we've gone there. Last year, one
> of our group(Phil Stewart) was having a terrible time with his
> carburetor. He spent a lot of time on the phone with the folks at C'bar
> just getting the coach driveable. Turned out the guy that rebuilt his carb
> had inadvertently installed two gaskets between the body and the air horn -
> the two gaskets were stuck together and looked like one. Whenever the
> secondaries kicked in, the carb went rich and black smoke poured out the
> pipe.
>
> IIRC, the guys at C'bar gave him some "starting point" jet and metering rod
> sizes and after the coach was running properly, he drove up to Sandusky for
> the full treatment. Phil, please correct me if I've screwed up any of the
> details.
>

Patrick,
This is pretty close to what Cinnabar did for me. The only difference was that
I didn't install any other jets or metering rods before going to Sandusky. As
Wes advised me, I just removed the extraneous air horn gasket and limped up to
Michigan. Once there Steve tuned the carb using the gas exhaust analyzer they
mounted in the coach while the GMC was test driven several times to get the
right combination of jets, metering rods, and float adjustment to get the fuel
to air ratio set correctly. Following this work my mpg increased from less than
7.5 to over 9.5 and the derivability was dramatically improved as well. Since
then I've driven the old 455 and Quadrajet from sea level to almost 11,000 feet
in elevation without any more enrichment or engine bogging problems. So overall
I was well satisfied with the assistance I got from Cinnabar.

Phil Stewart
'76 Transmode, TN
 
$60 last time I checked

J.R,

>
> It would be interesting to know what Cinnabar charges for machining exhaust
> manifolds.
> Justin
 
Phil,
That's sure good to hear! As you may know my coach is in
Steve's hands now. Ivan was up front when I limped in with my
manifolds cracked and gaskets blown. He said they could
just fix the manifolds or make sure it doesn't happen again
by calibrating the carb. If I get better performance and better
gas mileage then that will be great improvement.
So far I don't know how much the bill will be. I hope to run up
to Sandusky Friday or Saturday to get our "Green Lean Machine".

As soon as it is done I'll give everyone a full report on my experiences.
Richard Waters '76 PB, Troy, MI
- ---

>
> Patrick,
> This is pretty close to what Cinnabar did for me. The only difference was that
> I didn't install any other jets or metering rods before going to Sandusky. As
> Wes advised me, I just removed the extraneous air horn gasket and limped up to
> Michigan. Once there Steve tuned the carb using the gas exhaust analyzer they
> mounted in the coach while the GMC was test driven several times to get the
> right combination of jets, metering rods, and float adjustment to get the fuel
> to air ratio set correctly. Following this work my mpg increased from less than
> 7.5 to over 9.5 and the derivability was dramatically improved as well. Since
> then I've driven the old 455 and Quadrajet from sea level to almost 11,000 feet
> in elevation without any more enrichment or engine bogging problems. So overall
> I was well satisfied with the assistance I got from Cinnabar.
>
> Phil Stewart
> '76 Transmode, TN
 
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