Home » Public Forums » GMCnet » OEM intake manifolds and cracks, symptoms?
| OEM intake manifolds and cracks, symptoms? [message #335480] |
Mon, 23 July 2018 00:34  |
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GMC2000
Messages: 193
Registered: March 2018
Location: Georgia
Karma: -3
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Senior Member |
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reading about the intake problems where the exhaust crossover heat becomes excessive, possibly when one side of the exhaust system has a leak. it seems to be a very common problem (both the exhaust manifold leaks and cracked intakes)
but what are the symptoms of a cracked intake as it develops and progresses? I read Jim Bounds blog post about how the engine runs fine until it gets up to operating temp then it wont take any throttle and just dies when you try to go above idle but is there any indications in drive-ability that it may be cracking before the crack gets this big?
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| Re: OEM intake manifolds and cracks, symptoms? [message #335486 is a reply to message #335480] |
Mon, 23 July 2018 07:37  |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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The simplest is to pick up the carb and have a look under there with a bright light.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] OEM intake manifolds and cracks, symptoms? [message #335495 is a reply to message #335480] |
Mon, 23 July 2018 08:41 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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G'day,
My take on the manifold crossover plenum follows.
The 455 was designed to go into a 4000 lb car when GMC installed it in a 10 - 12,000 lb motorhome the load as well as the heat it
produces went up BIGTIME!
The crossover plenum under the carb was there to heat up the carb when driving in Chicago winters.
I've noted that they crack in two locations:
1) the divider between the secondaries and the "floor" directly under it.
2) the "bottom" of the crossover plenum, quite often the crack is under the crack above.
JimB is correct in as much as while the engine is cold the crack doesn't open enough to effect engine performance noticeably. Once
at operating temperature you have engine vacuum sucking hot air from the crossover into the intake stream along with oil vapor from
the lifter valley.
The fix is easy, install a set of crossover block off plates from Dick Patterson:
http://www.springfield-ignition.com/gmc-motorhome/block-off-kits/
once you do that the crossover temps are:
http://www.gmcmhphotos.com/photos/aa-miscellaneous-photos/p63426-intake-manifold-internal-temp.html
If you're lucky the crack won't open up enough to effect performance.. You could possibly patch the crack with hi-temp epoxy of some
kind. If you blocked off the crossover ports with plates and evacuated the chamber you could suck the epoxy into the crack. I think
in that case I'd use hi temp (red) RTV.
Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of GMC2000
Sent: Monday, July 23, 2018 12:35 AM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] OEM intake manifolds and cracks, symptoms?
reading about the intake problems where the exhaust crossover heat becomes excessive, possibly when one side of the exhaust system
has a leak. It seems to be a very common problem (both the exhaust manifold leaks and cracked intakes)
but what are the symptoms of a cracked intake as it develops and progresses? I read Jim Bounds blog post about how the engine runs
fine until it gets up to operating temp then it wont take any throttle and just dies when you try to go above idle but is there any
indications in drive-ability that it may be cracking before the crack gets this big?
_______________________________________________
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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: OEM intake manifolds and cracks, symptoms? [message #335503 is a reply to message #335480] |
Mon, 23 July 2018 10:32 |
GatsbysCruise
Messages: 261
Registered: January 2017
Location: Waukegan, Illinois
Karma: 3
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GMC2000 wrote on Mon, 23 July 2018 00:34reading about the intake problems where the exhaust crossover heat becomes excessive, possibly when one side of the exhaust system has a leak. it seems to be a very common problem (both the exhaust manifold leaks and cracked intakes)
but what are the symptoms of a cracked intake as it develops and progresses? I read Jim Bounds blog post about how the engine runs fine until it gets up to operating temp then it wont take any throttle and just dies when you try to go above idle but is there any indications in drive-ability that it may be cracking before the crack gets this big?
I had a fuel system problem when we found by accident, the cracks in the exhaust crossover. So under this scenario, there were no symptoms. Also, the cracks could not be seen. We removed the manifold for a different reason and the cracks didn't show up until we attempted to clean it. I had cracks on both the top and bottom of the manifold and the crack lines did not show up until the cleaner was applied and wetted the metal. Even then, these long cracks were difficult to see
When the fuel tanks were bypassed and I was using an aux tank, no symptoms and the engine would run fine. After looking at the cracks it was determined that the cracks were not new at all, and had been there for a long time.
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO - UBUNTU VOYAGER - Berzin Auto Center
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| Re: [GMCnet] OEM intake manifolds and cracks, symptoms? [message #335507 is a reply to message #335503] |
Mon, 23 July 2018 11:11 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Cracked intake manifolds exhibit the exact symptoms you describe, as well
as higher than normal oil consumption. They run just fine when cold, but,
as the engine warms up, it runs worse and worse depending upon the severity
of the crack. If the floor of the inlet tract is cracked, it can easily be
seen by removing the carb and shining a powerful light source down the
intake.
If it is only cracked between the crossover and the engine valley, the
runability is not affected as much, but oil consumption will still be
prevalent.
Jim Hupy
Salem, Or
On Mon, Jul 23, 2018, 8:33 AM slc wrote:
> GMC2000 wrote on Mon, 23 July 2018 00:34
>> reading about the intake problems where the exhaust crossover heat
> becomes excessive, possibly when one side of the exhaust system has a leak.
> it
>> seems to be a very common problem (both the exhaust manifold leaks and
> cracked intakes)
>>
>> but what are the symptoms of a cracked intake as it develops and
> progresses? I read Jim Bounds blog post about how the engine runs fine
> until it
>> gets up to operating temp then it wont take any throttle and just dies
> when you try to go above idle but is there any indications in drive-ability
>> that it may be cracking before the crack gets this big?
>
>
>
> I had a fuel system problem when we found by accident, the cracks in the
> exhaust crossover. So under this scenario, there were no symptoms. Also,
> the cracks could not be seen. We removed the manifold for a different
> reason and the cracks didn't show up until we attempted to clean it. I had
> cracks on both the top and bottom of the manifold and the crack lines did
> not show up until the cleaner was applied and wetted the metal. Even then,
> these long cracks were difficult to see
> When the fuel tanks were bypassed and I was using an aux tank, no
> symptoms and the engine would run fine. After looking at the cracks it was
> determined that the cracks were not new at all, and had been there for a
> long time.
> --
> GatsbysCruise. \
> 74GMC260 Former Glacier Model style. \
> Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS
> FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
> UBUNTU VOYAGER - Berzin Auto Center
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: OEM intake manifolds and cracks, symptoms? [message #335553 is a reply to message #335480] |
Mon, 23 July 2018 22:26 |
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GMC2000
Messages: 193
Registered: March 2018
Location: Georgia
Karma: -3
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sellers wont want to remove the carb so a potential buyer can have a look though. and Im also trying to get an idea of what is happening to make them run bad (backfires or just lack of power or something other?) and stall out.
when the crack is that bad, is it pulling crankcase oil vapors in and then fouling out the spark? or is it pulling exhaust gases in or a little of both?
Ive seen some of the pics posted of the manifolds that were cracked but its still hard to tell what is actually happening and since Mondello and others have been filling the crossovers with various alloys and composites, I guess that if the manifold is cracked then its too late for block off plates then, right?
when they are running bad from this, I suspect most would think a fuel problem at first. if there is excessive oil consumption, that should show up on the spark plugs I guess but I doubt a seller would want to let someone pull them out or let them also do a compression test (hot) either. I dunno..
I havnt asked (I think it would be too much to ask unless the price was high and firm) but I do ask that it be stone cold when I arrive to look at it and will now ask for an extended test drive too.
there really is a whole lot to evaluate on these. ideally, I'd want to spend a few hours going over one instead of just rolling the dice. lol but there is always something even when you think you have everything covered.
If Explorer ever makes a GMCIII, I would get in that line!
[Updated on: Mon, 23 July 2018 22:28] Report message to a moderator |
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| Re: OEM intake manifolds and cracks, symptoms? [message #335608 is a reply to message #335480] |
Wed, 25 July 2018 08:17 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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'sellers wont want to remove the carb so a potential buyer can have a look though. and Im also trying to get an idea of what is happening to make them run bad (backfires or just lack of power or something other?) and stall out.'
"I'll offer you $XXX contingent on inspection of the intake manifold below the carburetor." No lookee, no interest.
--johnny
DOS Tip - have the seller take pictures while you're looking to save taking the carb off again.
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] OEM intake manifolds and cracks, symptoms? [message #335611 is a reply to message #335608] |
Wed, 25 July 2018 08:49 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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You need to be realistic and forget taking a carb off.
There are indicators by loving at both sides left and right of carb for
white heat signs.
On Wed, Jul 25, 2018 at 6:44 AM Johnny Bridges via Gmclist <
gmclist@list.gmcnet.org> wrote:
> 'sellers wont want to remove the carb so a potential buyer can have a look
> though. and Im also trying to get an idea of what is happening to make them
> run bad (backfires or just lack of power or something other?) and stall
> out.'
>
> "I'll offer you $XXX contingent on inspection of the intake manifold below
> the carburetor." No lookee, no interest.
>
> --johnny
>
> DOS Tip - have the seller take pictures while you're looking to save
> taking the carb off again.
>
> --
> 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> "I forgive them all, save those who hurt the dogs. They must answer to me
> in hell" - ol Andy, paraphrased
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.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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| Re: [GMCnet] OEM intake manifolds and cracks, symptoms? [message #335623 is a reply to message #335611] |
Wed, 25 July 2018 12:54 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Got it. Love both sides and hope you don’t leave white heat signs.
Check.
Sully
Bellevue wa.
On Wed, Jul 25, 2018 at 6:50 AM Jim Kanomata wrote:
> You need to be realistic and forget taking a carb off.
> There are indicators by loving at both sides left and right of carb for
> white heat signs.
>
> On Wed, Jul 25, 2018 at 6:44 AM Johnny Bridges via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> 'sellers wont want to remove the carb so a potential buyer can have a
> look
>> though. and Im also trying to get an idea of what is happening to make
> them
>> run bad (backfires or just lack of power or something other?) and stall
>> out.'
>>
>> "I'll offer you $XXX contingent on inspection of the intake manifold
> below
>> the carburetor." No lookee, no interest.
>>
>> --johnny
>>
>> DOS Tip - have the seller take pictures while you're looking to save
>> taking the carb off again.
>>
>> --
>> 76 26' Eleganza(?) with beaucoup mods and add - ons.
>> Braselton, Ga.
>> "I forgive them all, save those who hurt the dogs. They must answer to
> me
>> in hell" - ol Andy, paraphrased
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] OEM intake manifolds and cracks, symptoms? [message #335625 is a reply to message #335623] |
Wed, 25 July 2018 13:36 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Sully,
I have been on both sides of the fence, and if I asked a dealer if I can
remove the carb, they will brand me as another A Hole Asian.
I know I am, but do not need to have me reminded.
The White particales on the runner on the intake is a very positive
indicator that the intake can be cracked, or will be..
A set of Good Truck duty mufflers need to be used, not the standard car.
One side goes bad, the exaust takes the route through the intake and heats
it up good and Red, leaving a white oxide coating.
On Wed, Jul 25, 2018 at 10:54 AM, Todd Sullivan wrote:
> Got it. Love both sides and hope you don’t leave white heat signs.
> Check.
>
> Sully
> Bellevue wa.
>
> On Wed, Jul 25, 2018 at 6:50 AM Jim Kanomata
> wrote:
>
>> You need to be realistic and forget taking a carb off.
>> There are indicators by loving at both sides left and right of carb for
>> white heat signs.
>>
>> On Wed, Jul 25, 2018 at 6:44 AM Johnny Bridges via Gmclist > gmclist@list.gmcnet.org> wrote:
>>
>>> 'sellers wont want to remove the carb so a potential buyer can have a
>> look
>>> though. and Im also trying to get an idea of what is happening to make
>> them
>>> run bad (backfires or just lack of power or something other?) and stall
>>> out.'
>>>
>>> "I'll offer you $XXX contingent on inspection of the intake manifold
>> below
>>> the carburetor." No lookee, no interest.
>>>
>>> --johnny
>>>
>>> DOS Tip - have the seller take pictures while you're looking to save
>>> taking the carb off again.
>>>
>>> --
>>> 76 26' Eleganza(?) with beaucoup mods and add - ons.
>>> Braselton, Ga.
>>> "I forgive them all, save those who hurt the dogs. They must answer to
>> me
>>> in hell" - ol Andy, paraphrased
>>>
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>> --
>> Jim Kanomata
>> Applied/GMC, Newark,CA
>> jimk@appliedairfilters.com
>> http://www.appliedgmc.com
>> 1-800-752-7502
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.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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| Re: [GMCnet] OEM intake manifolds and cracks, symptoms? [message #335629 is a reply to message #335625] |
Wed, 25 July 2018 14:23 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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Jim,
I do not dispute or mock your intellect or knowledge. Only poking a little
fun at your typo
Sully
Bellevue wa.
On Wed, Jul 25, 2018 at 11:36 AM Jim Kanomata wrote:
> Sully,
> I have been on both sides of the fence, and if I asked a dealer if I can
> remove the carb, they will brand me as another A Hole Asian.
> I know I am, but do not need to have me reminded.
> The White particales on the runner on the intake is a very positive
> indicator that the intake can be cracked, or will be..
> A set of Good Truck duty mufflers need to be used, not the standard car.
> One side goes bad, the exaust takes the route through the intake and heats
> it up good and Red, leaving a white oxide coating.
>
> On Wed, Jul 25, 2018 at 10:54 AM, Todd Sullivan wrote:
>
>> Got it. Love both sides and hope you don’t leave white heat signs.
>> Check.
>>
>> Sully
>> Bellevue wa.
>>
>> On Wed, Jul 25, 2018 at 6:50 AM Jim Kanomata
>> wrote:
>>
>>> You need to be realistic and forget taking a carb off.
>>> There are indicators by loving at both sides left and right of carb for
>>> white heat signs.
>>>
>>> On Wed, Jul 25, 2018 at 6:44 AM Johnny Bridges via Gmclist >> gmclist@list.gmcnet.org> wrote:
>>>
>>>> 'sellers wont want to remove the carb so a potential buyer can have a
>>> look
>>>> though. and Im also trying to get an idea of what is happening to
> make
>>> them
>>>> run bad (backfires or just lack of power or something other?) and
> stall
>>>> out.'
>>>>
>>>> "I'll offer you $XXX contingent on inspection of the intake manifold
>>> below
>>>> the carburetor." No lookee, no interest.
>>>>
>>>> --johnny
>>>>
>>>> DOS Tip - have the seller take pictures while you're looking to save
>>>> taking the carb off again.
>>>>
>>>> --
>>>> 76 26' Eleganza(?) with beaucoup mods and add - ons.
>>>> Braselton, Ga.
>>>> "I forgive them all, save those who hurt the dogs. They must answer
> to
>>> me
>>>> in hell" - ol Andy, paraphrased
>>>>
>>>>
>>>> _______________________________________________
>>>> GMCnet mailing list
>>>> Unsubscribe or Change List Options:
>>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>>
>>> --
>>> Jim Kanomata
>>> Applied/GMC, Newark,CA
>>> jimk@appliedairfilters.com
>>> http://www.appliedgmc.com
>>> 1-800-752-7502
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] OEM intake manifolds and cracks, symptoms? [message #335630 is a reply to message #335629] |
Wed, 25 July 2018 15:37 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
|
Senior Member |
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Sully,
My finger hae been in places that it did not belong, so it does strange
things, Ha Ha.
On Wed, Jul 25, 2018 at 12:23 PM, Todd Sullivan wrote:
> Jim,
>
> I do not dispute or mock your intellect or knowledge. Only poking a little
> fun at your typo
>
> Sully
> Bellevue wa.
>
> On Wed, Jul 25, 2018 at 11:36 AM Jim Kanomata
> wrote:
>
>> Sully,
>> I have been on both sides of the fence, and if I asked a dealer if I can
>> remove the carb, they will brand me as another A Hole Asian.
>> I know I am, but do not need to have me reminded.
>> The White particales on the runner on the intake is a very positive
>> indicator that the intake can be cracked, or will be..
>> A set of Good Truck duty mufflers need to be used, not the standard car.
>> One side goes bad, the exaust takes the route through the intake and
> heats
>> it up good and Red, leaving a white oxide coating.
>>
>> On Wed, Jul 25, 2018 at 10:54 AM, Todd Sullivan
> wrote:
>>
>>> Got it. Love both sides and hope you don’t leave white heat signs.
>>> Check.
>>>
>>> Sully
>>> Bellevue wa.
>>>
>>> On Wed, Jul 25, 2018 at 6:50 AM Jim Kanomata
>>> wrote:
>>>
>>>> You need to be realistic and forget taking a carb off.
>>>> There are indicators by loving at both sides left and right of carb
> for
>>>> white heat signs.
>>>>
>>>> On Wed, Jul 25, 2018 at 6:44 AM Johnny Bridges via Gmclist >>> gmclist@list.gmcnet.org> wrote:
>>>>
>>>> > 'sellers wont want to remove the carb so a potential buyer can
> have a
>>>> look
>>>> > though. and Im also trying to get an idea of what is happening to
>> make
>>>> them
>>>> > run bad (backfires or just lack of power or something other?) and
>> stall
>>>> > out.'
>>>> >
>>>> > "I'll offer you $XXX contingent on inspection of the intake
> manifold
>>>> below
>>>> > the carburetor." No lookee, no interest.
>>>> >
>>>> > --johnny
>>>> >
>>>> > DOS Tip - have the seller take pictures while you're looking to
> save
>>>> > taking the carb off again.
>>>> >
>>>> > --
>>>> > 76 26' Eleganza(?) with beaucoup mods and add - ons.
>>>> > Braselton, Ga.
>>>> > "I forgive them all, save those who hurt the dogs. They must
> answer
>> to
>>>> me
>>>> > in hell" - ol Andy, paraphrased
>>>> >
>>>> >
>>>> > _______________________________________________
>>>> > GMCnet mailing list
>>>> > Unsubscribe or Change List Options:
>>>> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>> >
>>>> --
>>>> Jim Kanomata
>>>> Applied/GMC, Newark,CA
>>>> jimk@appliedairfilters.com
>>>> http://www.appliedgmc.com
>>>> 1-800-752-7502
>>>> _______________________________________________
>>>> GMCnet mailing list
>>>> Unsubscribe or Change List Options:
>>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>>
>>
>>
>> --
>> Jim Kanomata
>> Applied/GMC, Newark,CA
>> jimk@appliedairfilters.com
>> http://www.appliedgmc.com
>> 1-800-752-7502
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
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jimk@appliedairfilters.com
www.appliedgmc.com
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| Re: [GMCnet] OEM intake manifolds and cracks, symptoms? [message #335661 is a reply to message #335659] |
Thu, 26 July 2018 09:32 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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No Sh-t, not going to get better.
On Thu, Jul 26, 2018 at 7:26 AM, John R. Lebetski
wrote:
> Jim you should blame auto-correct. "I know one time I thought I was wrong,
> but I was mistaken".
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.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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| Re: OEM intake manifolds and cracks, symptoms? [message #335676 is a reply to message #335480] |
Thu, 26 July 2018 17:34 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Don't know if anyone has mentioned this yet, but here goes.
Take your manifold to your nearest foundry. Put a block-off plate on one or the other crossover ports and have them pour it full of aluminum. See this:
http://www.gmcmhphotos.com/photos/g4571-pouring-the-455-crossover.html
It did two things. Blocked the crossover, and even though the manifold did not have cracks, it would seal manifold cracks. Think I paid $25 or so. Still put the SS plates on the ports to keep exhaust gasses from reaching the aluminum. Didn't think it would be a problem, but did it anyway as a safety measure. JWID
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
[Updated on: Thu, 26 July 2018 17:35] Report message to a moderator |
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| Re: [GMCnet] OEM intake manifolds and cracks, symptoms? [message #335678 is a reply to message #335676] |
Thu, 26 July 2018 18:07 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Or, for those who insist on DIY:
http://www.gmcmhphotos.com/photos/g3115-plugging-intake-manifold-exhaust-crossover.html
Ken H.
On Thu, Jul 26, 2018 at 6:35 PM Larry wrote:
> Don't know if anyone has mentioned this yet, but here goes.
>
> Take your manifold to your nearest foundry. Put a block-off plate on one
> or the other crossover ports and have them pour it full of aluminum. See
> this:
>
> http://www.gmcmhphotos.com/photos/g4571-pouring-the-455-crossover.html
>
> It did two things. Blocked the crossover, and even though the manifold did
> not cracks, it would seal manifold cracks. Think I paid $25 or so. Still
> put the SS plates on the ports to keep exhaust gasses from reaching the
> aluminum. Didn't think it would be a problem, but did it anyway as a safety
> measure. JWID
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
>
>
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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] OEM intake manifolds and cracks, symptoms? [message #335679 is a reply to message #335676] |
Thu, 26 July 2018 18:00 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Don't know if that aluminum pour is necessary, but it should work,
particularly if the block off plates are used. It can't hurt anything. Some
people, the money to pour the aluminum is no big deal, yet, some would
resist that expenditure like having their wisdom teeth pulled. Each his
own, I say.
Jim Hupy
Salem, OREGON
78 GMC ROYALE 403
On Thu, Jul 26, 2018, 3:35 PM Larry wrote:
> Don't know if anyone has mentioned this yet, but here goes.
>
> Take your manifold to your nearest foundry. Put a block-off plate on one
> or the other crossover ports and have them pour it full of aluminum. See
> this:
>
> http://www.gmcmhphotos.com/photos/g4571-pouring-the-455-crossover.html
>
> It did two things. Blocked the crossover, and even though the manifold did
> not cracks, it would seal manifold cracks. Think I paid $25 or so. Still
> put the SS plates on the ports to keep exhaust gasses from reaching the
> aluminum. Didn't think it would be a problem, but did it anyway as a safety
> measure. JWID
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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