Home » Public Forums » GMCnet » [GMCnet] Re: Tips for installing engine vents.
| [GMCnet] Re: Tips for installing engine vents. [message #364678] |
Mon, 14 June 2021 01:54  |
BobDunahugh
Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA
Karma: 11
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Scott. I see very little value due to location, and small size. Data can be had simple. Some ribbons taped to the vents. Then have someone in the passenger seat take some temps around that area while driving. If the ribbons stand out from the vents. Then you have good air flow. If the ribbons just flutter next to the body. You have ZIP for air flow.
To me. That money on the vents. Would be better spent on a fan shroud. Like the one GM installed on all 403 equipped GMCs. I should be quiet on this. But the GMC that I just got for our daughter has them. Never knew how small the hole is.
I pull a 24 ft enclosed trailer. With a shop/car in it. My GVW comes in at around 24,000 lbs. ( It's been to some GMCMI events that way. ) With a 403 that's bone stock as to cooling. It never gets over heated. Even in Lake Havasue City Az. In July at 114 degrees. With the A/C on high.
Bob Dunahugh
78 Royale since 2003
4 COPO Yenkos
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| [GMCnet] Re: Tips for installing engine vents. [message #364687 is a reply to message #364678] |
Mon, 14 June 2021 11:49  |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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Len,
Yes, unless someone has removed them or they have deteriorated over the
last 40 years. There was no sign of them on The War Pig when I purchased it.
Sully
bellevue wa
On Mon, Jun 14, 2021 at 9:39 AM Len Len wrote:
> there are two stock baffles on either side of the radiator made out of some
> kind of fiberboard material that direct ram air into the radiator
>
> On Mon, Jun 14, 2021, 09:35 Todd Sullivan wrote:
>
>> What Bob said. I was having cooling issues only while underway at higher
>> speeds. Adding some vertical plywood baffles behind the grill to direct
> the
>> airflow through the radiator instead of around fixed the issue entirely.
>> And I had the fan shroud already.
>>
>> sully
>> bellevue wa
>>
>> On Sun, Jun 13, 2021 at 11:54 PM Bob Dunahugh
>> wrote:
>>
>>> Scott. I see very little value due to location, and small size. Data
> can
>>> be had simple. Some ribbons taped to the vents. Then have someone in
> the
>>> passenger seat take some temps around that area while driving. If the
>>> ribbons stand out from the vents. Then you have good air flow. If the
>>> ribbons just flutter next to the body. You have ZIP for air flow.
>>> To me. That money on the vents. Would be better spent on a fan
>> shroud.
>>> Like the one GM installed on all 403 equipped GMCs. I should be quiet
> on
>>> this. But the GMC that I just got for our daughter has them. Never knew
>> how
>>> small the hole is.
>>> I pull a 24 ft enclosed trailer. With a shop/car in it. My GVW comes
>> in
>>> at around 24,000 lbs. ( It's been to some GMCMI events that way. )
> With a
>>> 403 that's bone stock as to cooling. It never gets over heated. Even in
>>> Lake Havasue City Az. In July at 114 degrees. With the A/C on high.
>>> Bob Dunahugh
>>> 78 Royale since 2003
>>> 4 COPO Yenkos
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| [GMCnet] Re: Tips for installing engine vents. [message #364688 is a reply to message #364678] |
Mon, 14 June 2021 11:39 |
Len Novak
Messages: 676
Registered: February 2004
Location: Las Vegas, NV
Karma: -3
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Senior Member |
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there are two stock baffles on either side of the radiator made out of some
kind of fiberboard material that direct ram air into the radiator
On Mon, Jun 14, 2021, 09:35 Todd Sullivan wrote:
> What Bob said. I was having cooling issues only while underway at higher
> speeds. Adding some vertical plywood baffles behind the grill to direct the
> airflow through the radiator instead of around fixed the issue entirely.
> And I had the fan shroud already.
>
> sully
> bellevue wa
>
> On Sun, Jun 13, 2021 at 11:54 PM Bob Dunahugh
> wrote:
>
>> Scott. I see very little value due to location, and small size. Data can
>> be had simple. Some ribbons taped to the vents. Then have someone in the
>> passenger seat take some temps around that area while driving. If the
>> ribbons stand out from the vents. Then you have good air flow. If the
>> ribbons just flutter next to the body. You have ZIP for air flow.
>> To me. That money on the vents. Would be better spent on a fan
> shroud.
>> Like the one GM installed on all 403 equipped GMCs. I should be quiet on
>> this. But the GMC that I just got for our daughter has them. Never knew
> how
>> small the hole is.
>> I pull a 24 ft enclosed trailer. With a shop/car in it. My GVW comes
> in
>> at around 24,000 lbs. ( It's been to some GMCMI events that way. ) With a
>> 403 that's bone stock as to cooling. It never gets over heated. Even in
>> Lake Havasue City Az. In July at 114 degrees. With the A/C on high.
>> Bob Dunahugh
>> 78 Royale since 2003
>> 4 COPO Yenkos
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
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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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| [GMCnet] Re: Tips for installing engine vents. [message #364689 is a reply to message #364678] |
Mon, 14 June 2021 11:54 |
Len Novak
Messages: 676
Registered: February 2004
Location: Las Vegas, NV
Karma: -3
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Senior Member |
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interesting....still there on my 78.....original fasters were sheet metal
screws, now converted to nots, washers and bolts
On Mon, Jun 14, 2021, 09:50 Todd Sullivan wrote:
> Len,
>
> Yes, unless someone has removed them or they have deteriorated over the
> last 40 years. There was no sign of them on The War Pig when I purchased
> it.
>
> Sully
> bellevue wa
>
> On Mon, Jun 14, 2021 at 9:39 AM Len Len wrote:
>
>> there are two stock baffles on either side of the radiator made out of
> some
>> kind of fiberboard material that direct ram air into the radiator
>>
>> On Mon, Jun 14, 2021, 09:35 Todd Sullivan wrote:
>>
>>> What Bob said. I was having cooling issues only while underway at
> higher
>>> speeds. Adding some vertical plywood baffles behind the grill to direct
>> the
>>> airflow through the radiator instead of around fixed the issue
> entirely.
>>> And I had the fan shroud already.
>>>
>>> sully
>>> bellevue wa
>>>
>>> On Sun, Jun 13, 2021 at 11:54 PM Bob Dunahugh
>>> wrote:
>>>
>>>> Scott. I see very little value due to location, and small size. Data
>> can
>>>> be had simple. Some ribbons taped to the vents. Then have someone in
>> the
>>>> passenger seat take some temps around that area while driving. If the
>>>> ribbons stand out from the vents. Then you have good air flow. If
> the
>>>> ribbons just flutter next to the body. You have ZIP for air flow.
>>>> To me. That money on the vents. Would be better spent on a fan
>>> shroud.
>>>> Like the one GM installed on all 403 equipped GMCs. I should be quiet
>> on
>>>> this. But the GMC that I just got for our daughter has them. Never
> knew
>>> how
>>>> small the hole is.
>>>> I pull a 24 ft enclosed trailer. With a shop/car in it. My GVW
> comes
>>> in
>>>> at around 24,000 lbs. ( It's been to some GMCMI events that way. )
>> With a
>>>> 403 that's bone stock as to cooling. It never gets over heated. Even
> in
>>>> Lake Havasue City Az. In July at 114 degrees. With the A/C on high.
>>>> Bob Dunahugh
>>>> 78 Royale since 2003
>>>> 4 COPO Yenkos
>>>> _______________________________________________
>>>> GMCnet mailing list
>>>> Unsubscribe or Change List Options:
>>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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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| [GMCnet] Re: Tips for installing engine vents. [message #364690 is a reply to message #364678] |
Mon, 14 June 2021 11:35 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
|
Senior Member |
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|
What Bob said. I was having cooling issues only while underway at higher
speeds. Adding some vertical plywood baffles behind the grill to direct the
airflow through the radiator instead of around fixed the issue entirely.
And I had the fan shroud already.
sully
bellevue wa
On Sun, Jun 13, 2021 at 11:54 PM Bob Dunahugh wrote:
> Scott. I see very little value due to location, and small size. Data can
> be had simple. Some ribbons taped to the vents. Then have someone in the
> passenger seat take some temps around that area while driving. If the
> ribbons stand out from the vents. Then you have good air flow. If the
> ribbons just flutter next to the body. You have ZIP for air flow.
> To me. That money on the vents. Would be better spent on a fan shroud.
> Like the one GM installed on all 403 equipped GMCs. I should be quiet on
> this. But the GMC that I just got for our daughter has them. Never knew how
> small the hole is.
> I pull a 24 ft enclosed trailer. With a shop/car in it. My GVW comes in
> at around 24,000 lbs. ( It's been to some GMCMI events that way. ) With a
> 403 that's bone stock as to cooling. It never gets over heated. Even in
> Lake Havasue City Az. In July at 114 degrees. With the A/C on high.
> Bob Dunahugh
> 78 Royale since 2003
> 4 COPO Yenkos
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| [GMCnet] Re: Tips for installing engine vents. [message #364778 is a reply to message #364777] |
Thu, 17 June 2021 08:30 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Just a followup on my grille-to-radiator duct: After 9 years in there, the
truck mudflap material is still standing up well. And the duct really does
its job: My engine temperature stays within a couple of degrees of the
thermostat ALL the time. And the duct has, indeed, proven to be a handy
storage location. There's usually a shallow and a deep cooking pan on
there filled with odds & ends, like spare brake fluid. It's useful space
with no other commitment. That duct is one of the most useful of the MANY
mods I've done to the X-Birchaven.
Ken H.
On Thu, Jun 17, 2021 at 9:02 AM John Wright wrote:
> The front air baffles were on the 77 403 & later coaches. Number of
> albums on the photo site.
>
> http://www.gmcmhphotos.com/photos/gmc-part-numbers/p63294-air-baffles.html
> http://www.gmcmhphotos.com/photos/gmc-part-numbers/p63295-air-baffles.html
>
> and Ken H Baffle setup
>
> http://www.gmcmhphotos.com/photos/g6117-grille-to-radiator-duct.html
> Look at all the pictures in this series and read the captions under the
> pictures.
>
> Do not use plywood in the engine compartment. Use the materials suggested
> by Ken.
>
> J.R. Wright
> GMC Great Laker MHC
> GMCGL Tech Editor
> GMC Eastern States Charter Member
> GMCMI
> 78 GMC Buskirk 29.5’ Stretch
> 75 GMC Avion (Under Reconstruction)
> Michigan
>
>> On Jun 14, 2021, at 1:45 PM, Matt Colie wrote:
>>
>> The radiator baffles were not in all years. They seen to have arrived
> about the time that the engine mounted "horse collar" for the fan departed,
> but
>> that is just my impression and may be inaccurate or completely bull
> shit.
>>
>> 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
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
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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] Re: Tips for installing engine vents. [message #364779 is a reply to message #364678] |
Thu, 17 June 2021 09:14 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Remember the McDonalds McDLT commercial? The burger came in a double clamshell that “kept the hot side hot and the cool side cool” then you assembled the sandwich prior to eating. The shrouding helps with that. As does the add on under core support spoiler. I know my friend a GM mechanic when trouble shooting overheat complaints would visually check if that flap piece was missing first thing. Oddly we did not get that baffle, but the add on one was a big help on my coach.
John Lebetski
Woodstock, IL
77 Eleganza II
[Updated on: Thu, 17 June 2021 09:17] Report message to a moderator |
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| [GMCnet] Re: Tips for installing engine vents. [message #364797 is a reply to message #364778] |
Thu, 17 June 2021 13:46 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Since I started, I might as well finish the cooling tale: Early on, I
replaced the "horse-collar" with the fiberglass shroud from Frank Jenkins.
That helps the fan to pull cool air through the full radiator. It also
potentially poses a problem (as learned by Detroit's engineers): At road
speeds, the under-hood airflow can be impeded by the spinning fan. So, I
equipped the full shroud with spring-loaded doors which open when there's
pressure in the shroud, but close if the fan's creating suction. I really
didn't see any performance difference after that mod, but they're still
there working, so I only look at them occasionally.
I just realized that I posted photos of that mod 10+ years ago (it makes
most sense viewed last-to-first):
http://www.gmcmhphotos.com/photos/g5567-radiator-shroud-modification.html
I also found photos of the other significant cooling mod I did; addition of
an under-bumper scoop to limit air escaping around the lower portion of the
radiator:
http://www.gmcmhphotos.com/photos/g5632-under-bumper-air-scoop-26amp-3b-rock-guard.html
When I first bought the GMC in '98, Jim Bounds drove it around the block to
check performance before beginning work on it. When we got back, there was
a stream of water squirting from the thrown-rock created hole in that lower
radiator. While a can of Bar's Stop-Leak cured that one permanently, the
grille on the above scoop is intended to minimize the chances of my
aluminum radiator being similarly damaged.
After all this, I should note that the ONLY cooling problem I've ever had
was after installing the Cad500: Climbing the notorious Monteagle mountain
east of Nashville, the temp gauge got up to 237*F. The first person I saw
at the destination GMCMI Convention was Gene Dotson, with one of their new
radiators. My greeting to him was, pointing, "That's MINE.". Never had a
cooling problem since.
Ken H.
On Thu, Jun 17, 2021 at 9:30 AM Ken Henderson
wrote:
> Just a followup on my grille-to-radiator duct: After 9 years in there,
> the truck mudflap material is still standing up well. And the duct really
> does its job: My engine temperature stays within a couple of degrees of
> the thermostat ALL the time. And the duct has, indeed, proven to be a
> handy storage location. There's usually a shallow and a deep cooking pan
> on there filled with odds & ends, like spare brake fluid. It's useful
> space with no other commitment. That duct is one of the most useful of the
> MANY mods I've done to the X-Birchaven.
>
> Ken H.
>
> On Thu, Jun 17, 2021 at 9:02 AM John Wright wrote:
>
>> The front air baffles were on the 77 403 & later coaches. Number of
>> albums on the photo site.
>>
>> http://www.gmcmhphotos.com/photos/gmc-part-numbers/p63294-air-baffles.html
>> http://www.gmcmhphotos.com/photos/gmc-part-numbers/p63295-air-baffles.html
>>
>> and Ken H Baffle setup
>>
>> http://www.gmcmhphotos.com/photos/g6117-grille-to-radiator-duct.html
>> Look at all the pictures in this series and read the captions under the
>> pictures.
>>
>> Do not use plywood in the engine compartment. Use the materials
>> suggested by Ken.
>>
>> J.R. Wright
>> GMC Great Laker MHC
>> GMCGL Tech Editor
>> GMC Eastern States Charter Member
>> GMCMI
>> 78 GMC Buskirk 29.5’ Stretch
>> 75 GMC Avion (Under Reconstruction)
>> Michigan
>>
>>> On Jun 14, 2021, at 1:45 PM, Matt Colie wrote:
>>>
>>> The radiator baffles were not in all years. They seen to have arrived
>> about the time that the engine mounted "horse collar" for the fan departed,
>> but
>>> that is just my impression and may be inaccurate or completely bull
>> shit.
>>>
>>> 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
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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