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[GMCnet] Re: It was not a cracked intake- it was the carb. now what? [message #369249 is a reply to message #369244] Thu, 24 March 2022 22:06 Go to previous messageGo to previous message
jimk is currently offline  jimk   United States
Messages: 6734
Registered: July 2006
Location: Belmont, CA
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Senior Member
One cannot use a car carb as the power valve is set for lower load.
It will run, but dump lot of fuel down the intake.

On Thu, Mar 24, 2022 at 8:03 PM Jim Kanomata wrote:

> Filling intake has never been a worthwhile project.
> The best we seen in last few years is a Stainless Steel plate with correct
> thickness gasket.
> Since we provide everything, we sell the ones Dick Patterson of
> Springfield supplies us.
> The main cause of hot intake is poor worn blown mufflers as one side can
> have high restriction causing exhaust to flow through the intake to the
> other side.
> Most are using car mufflers as they are less
> expensive.
> One should be using Truck style as they will hold up.
>
> On Thu, Mar 24, 2022 at 7:00 PM James Hupy wrote:
>
>> There are two kinds of cast iron manifolds. Those that are cracked, and
>> those that haven't cracked yet. If the cracks are accessible from the
>> bottom, a hole can be drilled at each end of the crack, "V" ing out the
>> crack with a die grinder, then tig welding the crack with rod intended for
>> cast iron repair. Or, use the same prep and use bronze brazing rod. When
>> you finish, then block off the crossover with stainless steel plates
>> between the heads and manifold. Some have filled the crossover passage
>> with
>> poured molten aluminum or other metals. I have not done either of these
>> methods, but I have practiced on a severely cracked manifold.
>> If the manifold is cracked through to the intake passages under the
>> carb, it is tough sledding to get effective welds in there.
>> Jim Hupy
>> Salem, Oregon
>>
>> On Thu, Mar 24, 2022, 6:32 PM CJV wrote:
>>
>>> Is there any way to satisfactorily repair a cracked manifold?
>>>
>>> CJ Vermeulen, Scribbler
>>>
>>>
>>> From: "Len Novak"
>>> To: "dave silva" , "gmclist"
>>> Sent: Thursday, March 24, 2022 6:20:48 PM
>>> Subject: [GMCnet] Re: It was not a cracked intake- it was the carb. now
>>> what?
>>>
>>> Just for grins look for a crack at the base of the carb. Been there,
>>> done that. Took forever to find that.
>>>
>>>
>>> Len Novak
>>>
>>>
>>>
>>> On 3/24/2022 4:15 PM, dave silva wrote:
>>>
>>>
>>> This coach had been fully rebuilt and then parked for seven years when i
>>> got it.
>>>
>>> This made it hard to troubleshoot. It would run OK and then bog down. So
>>> of course we looked at fuel lines, filters, old gas etc.
>>>
>>> Got all that sorted still no change. Chased vac leaks etc. No change.
>>>
>>> Then someone suggested a cracked intake- that fit the symptoms
>> perfectly.
>>> The issue would get worse as the engine warmed up but also, the severity
>>> would get worse over time. So it made perfect sense that a crack would
>>> open more as the engine wormed and get bigger over time.
>>>
>>> I scored a good intake and commenced to changing it. And when it was all
>>> back together there is NO CHANGEit still does not run right.
>>>
>>> So maybe the carb? The Revcon is sitting there, has not been run in
>> over a
>>> year. The original Toronado Carb has NEVER been rebuilt, but i swap it
>>> out and the Coach runs PERFECTLY!
>>>
>>> Ok, that was a long and winding road. Whatever is going on is happening
>> in
>>> the carb ONLY.
>>>
>>>
>>> Here's the symptoms- engine starts pretty easily, takes off smoothly and
>>> accelerates into second gear and then has no more power. If I give it
>> more
>>> gas is bogs down like it's gonna stall.
>>>
>>> This gets worse the longer i drive it (lately not more than a couple
>>> miles)
>>>
>>> This carb was freshly rebuilt for the Coop in 2013. it went 1000 miles
>> and
>>> did not move again so I'm not inclined to tear in all apart, it's not
>> like
>>> parts are worn or thousands of gallons of fuel have run through it.
>>>
>>> What Say the Brain Trust ?
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Len and Pat Novak 1978 GMC Kingsley The Beast II with dash lights that
>>> work and labels you can see! Las Vegas, NV new email:
>> B52srule@gmail.com
>>> http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
>>> www.bdub.net/novak/
>>> _______________________________________________
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>> _______________________________________________
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>
>
> --
> Jim Kanomata ASE
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.gmcrvparts.com
> 1-800-752-7502
>


--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.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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