Bought that new electric clutch for the engine fan.

Does anyone know what the CFM output of the MB fan is engaged at 2600 rpm?
--
1977 Palm Beach
TZE167V100274
 
Am I missing something? Do we really need a fan at 2600 RPM? I am of the
opinion that the fan does little if your airspeed is 30+ MPH the fan is not
doing much for you. It is when you have been working hard and slow down or
stop that you need a more air flow. When you are stuck in traffic are you
running your engine at 2600 RPM? I let my RPM drop to 1000 or less. Have
the electric fans been investigated? I think there are some that would run
4000 CFM. Is 4000 CFM enough to keep things cool at low speed?

On Mon, Sep 25, 2017 at 10:05 AM, Donald W. Guttman
wrote:

> Does anyone know what the CFM output of the MB fan is engaged at 2600 rpm?
> --
> 1977 Palm Beach
> TZE167V100274
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*

*1974 26*

*Sacramento CA*
 
My fan engages coming off the tops of steep climbs when I'm still at
highway speed. The coolant temperature will work its way up to about
195-205, and the fan will kick in, dropping it back down to 180 (the
thermostat rating) in 20 or 30 seconds (yes, the stock fan is that
effective). Before anyone asks, my cooling system is tip-top, including an
aluminum radiator and a good mechanical gauge.

We've had extended discussions about airflow through the engine
compartment, and whether ducting of various types would help, but that's
how it is with my stock arrangement. And it happens even when we aren't
running the AC.

Rick "noting this is the primary control on the upper temperature boundary"
Denney

On Mon, Sep 25, 2017 at 3:30 PM John Phillips
wrote:

> Am I missing something? Do we really need a fan at 2600 RPM? I am of the
> opinion that the fan does little if your airspeed is 30+ MPH the fan is not
> doing much for you. It is when you have been working hard and slow down or
> stop that you need a more air flow. When you are stuck in traffic are you
> running your engine at 2600 RPM? I let my RPM drop to 1000 or less. Have
> the electric fans been investigated? I think there are some that would run
> 4000 CFM. Is 4000 CFM enough to keep things cool at low speed?
>
>
> On Mon, Sep 25, 2017 at 10:05 AM, Donald W. Guttman

>
> > Does anyone know what the CFM output of the MB fan is engaged at 2600
> rpm?
> > --
> > 1977 Palm Beach
> > TZE167V100274
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
>
>
>
> --
>
> *John Phillips*
>
> *1974 26*
>
> *Sacramento CA*
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
 
Does anyone have on of these in hand?

I'm curious why they went to the trouble and expense of including the fan? The factory fan is very effective, so why not just make an adapter kit for
the clutch?
Would be much less install trouble and more cost effective I'd imagine...
--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455
 
There are ( I think ) only a few of these in service at this point. Looking forward to installing the one I got in Elkhart from Jim K at Applied. Impressive kit. Yesterday it took us a little over 2 hours to travel 19 miles on I-80 in the Chicago area. With temps around 92. My Digi panel alarm would go off when we had to come to complete stops for any length of time. ( A/C was off. ) I was thankful that we have a 78. As the 77, and 78 GMC's have a much improved radiator shrouding on the front, and backside of the radiator. I have a new stock fan clutch on now. So why was my engines temps hitting 210. Hate to think of the temps if the A/C would have been on. I'm beginning to think that a car water pump was installed at the engine rebuild. But would that make any difference. On the other hand. GM thought so. Think I need to change the water pump when I install the Mercedes Benz unit. Any thoughts. Bob Dunahugh 78 Royale
 
> Does anyone have on of these in hand?
>
> I'm curious why they went to the trouble and expense of including the fan? The factory fan is very effective, so why not just make an adapter kit
> for the clutch?
> Would be much less install trouble and more cost effective I'd imagine...
> Looking again it looks like its one unit. Disregard previous post!

Justin,
The neolithic fan that is the stock part is very loud. It is good at moving noise and absorbing horsepower. That is about the sum of it.
This new fan has aerodynamic blades and that makes a big difference. I really wish I still had access to an ASHRE tunnel, because I would like to
know just how much better it is.

Warning, if you have one of these fans and are checking the transmission fluid, do not bump the switch. You may have a problem getting the stick back
in the tube.

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Richard,
Are you saying that your fan comes on while you are climbing at speeds over
30 MPH?
30 MPH should get should give us close to 8,000 CFM which should be more
than what the fan can deliver while stopped.

> > Does anyone have on of these in hand?
> >
> > I'm curious why they went to the trouble and expense of including the
> fan? The factory fan is very effective, so why not just make an adapter kit
> > for the clutch?
> > Would be much less install trouble and more cost effective I'd imagine...
> > Looking again it looks like its one unit. Disregard previous post!
>
>
> Justin,
> The neolithic fan that is the stock part is very loud. It is good at
> moving noise and absorbing horsepower. That is about the sum of it.
> This new fan has aerodynamic blades and that makes a big difference. I
> really wish I still had access to an ASHRE tunnel, because I would like to
> know just how much better it is.
>
> Warning, if you have one of these fans and are checking the transmission
> fluid, do not bump the switch. You may have a problem getting the stick
> back
> in the tube.
>
> Matt
>
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*
 
> There are ( I think ) only a few of these in service at this point. Looking forward to installing the one I got in Elkhart from Jim K at Applied.
> Impressive kit. Yesterday it took us a little over 2 hours to travel 19 miles on I-80 in the Chicago area. With temps around 92. My Digi panel
> alarm would go off when we had to come to complete stops for any length of time. ( A/C was off. ) I was thankful that we have a 78. As the 77,
> and 78 GMC's have a much improved radiator shrouding on the front, and backside of the radiator. I have a new stock fan clutch on now. So why was
> my engines temps hitting 210. Hate to think of the temps if the A/C would have been on. I'm beginning to think that a car water pump was installed
> at the engine rebuild. But would that make any difference. On the other hand. GM thought so. Think I need to change the water pump when I install
> the Mercedes Benz unit. Any thoughts. Bob Dunahugh 78 Royale
>
>
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

About the car vs motorhome pumps. I've reused the original pump impeller on two remanufactured pumps. The last reman had a 3.875" diameter open back
impeller and the original GMC was 4.25" diameter and closed back. Just the impeller diameter calculates to about a 12% increase in pressure across the
pump . All ready had the original design impeller so why not reuse it.
https://wallyandsue.blogspot.com/2015/09/coolant-pump-impeller-r.html
https://wallyandsue.blogspot.com/2015/09/coolant-pump-impeller-r.html
JWID
--
Wally Anderson
Omaha NE
75 Glenbrook
Megasquirt III injection
Bob Stone hydroBOOOOST
Manny reaction arm system
Branscombe Kelsey Hayes park brake
http://wallyandsue.blogspot.com/
 
Yes, I'm saying that.

Rick "noting the sometimes big difference between theory and reality" Denney

On Tue, Sep 26, 2017 at 5:17 AM John Phillips
wrote:

> Richard,
> Are you saying that your fan comes on while you are climbing at speeds over
> 30 MPH?
> 30 MPH should get should give us close to 8,000 CFM which should be more
> than what the fan can deliver while stopped.
>

>

> > > Does anyone have on of these in hand?
> > >
> > > I'm curious why they went to the trouble and expense of including the
> > fan? The factory fan is very effective, so why not just make an adapter
> kit
> > > for the clutch?
> > > Would be much less install trouble and more cost effective I'd
> imagine...
> > > Looking again it looks like its one unit. Disregard previous post!
> >
> >
> > Justin,
> > The neolithic fan that is the stock part is very loud. It is good at
> > moving noise and absorbing horsepower. That is about the sum of it.
> > This new fan has aerodynamic blades and that makes a big difference. I
> > really wish I still had access to an ASHRE tunnel, because I would like
> to
> > know just how much better it is.
> >
> > Warning, if you have one of these fans and are checking the transmission
> > fluid, do not bump the switch. You may have a problem getting the stick
> > back
> > in the tube.
> >
> > Matt
> >
> > --
> > Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> > Electronically Controlled Quiet Engine Cooling Fan
> > OE Rear Drum Brakes with Applied Control Arms
> > SE Michigan - Twixt A2 and Detroit
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
>
>
>
> --
>
> *John Phillips*
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
 
Wally,

Nice to see some data which clearly shows the increased pressure out of the cast iron impeller pump, I bought one of those from Ken
Frey at a rally and will be installing it in the Paterson Stage II engine I got out of the burned coach up in Canada.

Double trouble has an aluminum radiator in it and I don't understand how it does it but it runs BELOW the thermostat setting on cold
days at low speeds!

The link below shows the coolant flow through the engine.

http://www.gmcmhphotos.com/photos/engine-cooling-photos/p47662-455-coolant-flow.html

Does anyone have any idea why it runs below the thermostat setting?

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] On Behalf Of Wally Anderson
Sent: Tuesday, September 26, 2017 5:24 AM
To: gmclist
Subject: Re: [GMCnet] Bought that new electric clutch for the engine fan.

About the car vs motorhome pumps. I've reused the original pump impeller on two remanufactured pumps. The last reman had a 3.875"
diameter open back impeller and the original GMC was 4.25" diameter and closed back. Just the impeller diameter calculates to about
a 12% increase in pressure across the pump . All ready had the original design impeller so why not reuse it.

https://wallyandsue.blogspot.com/2015/09/coolant-pump-impeller-r.html

JWID
--
Wally Anderson
 
Rick mine does the same.
End of a big climb once it flattens out the temp goes up a bit and the fan kicks in for 30 seconds or so and the temp drops right back down. Mine runs
about 180 and will go up to 195 at the highest.
--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455
 
> Wally,
>
> Double trouble has an aluminum radiator in it and I don't understand how it does it but it runs BELOW the thermostat setting on cold
> days at low speeds!
>
> Regards,
> Rob M.

Rob,

I think I know.

When I had that wrong - runs too much - fan clutch, my engine rarely got to 195. I though it was the OE instrument's error, but the Digipanel (once
installed) agreed. I was a bit confused until I remembered doing heat balances on several different engines. These in test cells and there were flow
meters and thremocouples everywhere and a massive data-ack to accumulate a S-pot of data. At less than a sustained WOT, a large portion of the
cooling was actually done by the lube oil....

Our lube oil is cooled in a radiator that is out in the cold. It could easily be dissipating the majority of the rejected heat and the airflow over
the engine could do most of the rest. This would explain why my new fan that is only running when it should finally allows the engine to get to
operating temperatures.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
> > My fan engages coming off the tops of steep climbs when I'm still at
> > highway speed. The coolant temperature will work its way up to about
> > 195-205, and the fan will kick in, dropping it back down to 180 (the
> > thermostat rating) in 20 or 30 seconds (yes, the stock fan is that
> > effective). Before anyone asks, my cooling system is tip-top, including an
> > aluminum radiator and a good mechanical gauge.
>
>
> Do I understand this correctly? That the fan clutch engages after the steep climb is over and the vehicle is either going downhill or on level
> ground.
>
> JP

Mine does this also. Always has. Drives me nuts.
--
Thanks,
Jeremy Knezek
1976 Glenbrook
Birmingham, AL
 
Both of mine did/do that except pulling Culowee or Monteagle. On those it comes on about halfway up and stays on. Coming home fromLA with the 26',
did the same on long grades. I propose to simply turn the new on on manually at the bottom of the hill and back off at the top.

--johnny
--
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
 
As to an all electric fan, it's a common failure in my Mopar vans. The problem is, an electric fan fails off and there's no way to force it on when
it has failed. For the van it isn';t a problem - nearest AutoZone, they take my phone number and the failed one and hand me a new one which is good
for another 80k miles or so. For a one - off electric from Summit, you're dead it the water when it quits. Yall can have it, I'll let the engine
spin mine.

--johnny
--
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
 
Matt, maybe I missed something. What type of new fan do you have?

Bob Price

> > Wally,
> >
> > Double trouble has an aluminum radiator in it and I don't understand how
> it does it but it runs BELOW the thermostat setting on cold
> > days at low speeds!
> >
> > Regards,
> > Rob M.
>
> Rob,
>
> I think I know.
>
> When I had that wrong - runs too much - fan clutch, my engine rarely got
> to 195. I though it was the OE instrument's error, but the Digipanel (once
> installed) agreed. I was a bit confused until I remembered doing heat
> balances on several different engines. These in test cells and there were
> flow
> meters and thremocouples everywhere and a massive data-ack to accumulate a
> S-pot of data. At less than a sustained WOT, a large portion of the
> cooling was actually done by the lube oil....
>
> Our lube oil is cooled in a radiator that is out in the cold. It could
> easily be dissipating the majority of the rejected heat and the airflow over
> the engine could do most of the rest. This would explain why my new fan
> that is only running when it should finally allows the engine to get to
> operating temperatures.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> Matt, maybe I missed something. What type of new fan do you have?
>
> Bob Price

Bob,

I am now running the electric clutched fan that Tom Pryor was referencing. I am currently switching it on the coolant out temperature.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Just to make sure that it is totally clear to all. This fan is NOT an electric motor powered fan. It's powered by the same V belt that the stock fan is powered by now. It's turned on by electrical commands by a engine temp sensor, or by a switch that's operated from the drivers seat. The clutch, and fan are from a Mercedes Benz truck. I was impressed by what Tom Pryor put together. Looking to install mine next week. Bob Dunahugh 78 Royale
 
G'day,

I noted to Tom in an off net email I thought it would be a good idea if he / JimK add a photo of what they get with the kit.

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] On Behalf Of Bob Dunahugh
Sent: Wednesday, September 27, 2017 2:10 AM
To: gmclist
Subject: Re: [GMCnet] Bought that new electric clutch for the engine fan.

Just to make sure that it is totally clear to all. This fan is NOT an electric motor powered fan. It's powered by the same V belt
that the stock fan is powered by now. It's turned on by electrical commands by a engine temp sensor, or by a switch that's operated
from the drivers seat. The clutch, and fan are from a Mercedes Benz truck. I was impressed by what Tom Pryor put together. Looking
to install mine next week. Bob Dunahugh 78 Royale

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org