[GMCnet] Electric fan

[Thom High via Gmclist]

I drive truck for a living and on a semi, when the clutch fan kicks on, you can feel it in the power. Wondering if the clutch fan you guys are using,
does the same? Why not just electric, and if electric, push or pull? Seems like push is the obvious,for space sake, but looking for recommendations.

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[Matt Colie via Gmclist]

Thom,

(Me again) ;)

Several have tried electric fans, but I have heard of few that were truly successful. If you go that way be sure to upgrade to a 100 Amp alternator.
You can get more, but then the case changes and that make is unsimple.

When I still had the iron fan and a typical clutch, I could both feel and hear it when the fan came on. With the electric clutched fan kit, I can
still hear and feel it, but as bad as my hearing is I have to pay attention to hear it and feel it in engine power is almost not there.

At this time, I have three mods that I recommend for all the early coaches, reaction arms for rear brakes with no other changes, Pertronix 1181LS to
replace the points, and the electric fan clutch set. The first I class as a safety essential, the second is a Major Convenience and the last is just
really nice because it is quieter and you won't have to replace a fan clutch on the road (again).

My fan installation is a Mark 1 mod 0 and I am still working on a better control system. After I got it installed, #7 piston shed some rings and
about the time I got that squared away, we broke a lower control arm 900+ miles from home (still working on the repairs from that). This season I am
going to work on that when I can. Other people here may have good ideas.

Matt


thigh19 wrote on Sun, 26 April 2020 14:11

> I drive truck for a living and on a semi, when the clutch fan kicks on, you can feel it in the power. Wondering if the clutch fan you guys are
> using, does the same? Why not just electric, and if electric, push or pull? Seems like push is the obvious,for space sake, but looking for
> recommendations.

--
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

[Hal StClair via Gmclist]

It's been tried but with little success. It should be possible for certain but will take some engineering. The alternator in the coach will probably
need upgrading for the increased fan amp draw and finding a fan that will provide the required CFM is an expensive endeavor. The electric fans are
starting to be used in heavy duty applications like busses but they typically use multiple fans and have lots of room for the install. The HD fans are
normally quite deep so space can be an issue. Jim Bounds at the Co-Op was rumored to have a system in the works but I haven't heard how if it's panned
out.
It might be an expensive exercise, but good luck if you go there.
Hal

--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM

[John R. Lebetski via Gmclist]

Sounds like you are trying to save parasitic power loss. Best way is to not convert rotation to electric with heat loss and then back to rotation at
the fan with more loss through heat. It’s a different story in passenger cars with low GVW they get away with cheaper electric fans, but last time I
looked 3/4 and 1ton trucks still have clutch fans, with viscous clutches are now electrically controlled. The difference being the controls control
valving for the drive fluid. The Peterbilt style is an electromagnetic clutch similar in action to an AC compressor clutch. Yes you feel the jerk and
power rob when they engage. A working stock non electric thermal fan clutch is to a point a variable device only transmitting as much power as needed
at the time. Unlike the Peterbilt type, even when they are fully engaged they are RPM limited as the gas engine can rev much higher than a 4 stroke
Diesel.
--
John Lebetski
Woodstock, IL
77 Eleganza II

[D C _Mac_ Macdonald via Gmclist]

Jim Bounds at the COOP has a new aluminum radiator and dual (I think) electric fan setup that he says is cost comparable to buying a new radiator.

D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com

________________________________
From: Gmclist <gmclist...@list.gmcnet.org> on behalf of John R. Lebetski via Gmclist <gmc...@list.gmcnet.org>
Sent: Sunday, April 26, 2020 15:09
To: gmc...@list.gmcnet.org <gmc...@list.gmcnet.org>
Cc: John R. Lebetski <gransp...@gmail.com>
Subject: Re: [GMCnet] Electric fan

[Johnny Bridges via Gmclist]

The viscous clutched engine driven fans - temp or electric valved - will run between about 10 percent of engine RPM to a bit over 90 percent of engine
RPM. The M - B electric clutched one which Matt refers to moves substantially more air than the OEM, and it's lighter and quieter. Applied sells a
kit. So far I've heard of only one failure, which was mine. The internal connection to the valve coil failed someplace. I gave it to the originator
of the idea (Tom Pryor) to do some destructive testing. Ain't heard back, but I know he's busy. The Mark 1 Mod 1 that Matt has uses a fairly simple
off - on controller which is switched by a temp probe in the engine water jacket. Set points are determined by the probe spec.
Some folks, Pruor included, are investigating a variable speed controller for it, much the same as is used on the pickups mentioned above. This is
accomplished by feeding the fan pulsed 12 volts and varying the pulse width. Given the hysteresis in the valve system this results in partial
opening, with the amount dependent on the pulse width. You could consider the on - off setup the same, only the pulses are much wider than the
reaction time of the valve :)
I note, the few electric clutches I've seen on big rigs have the fan in a separate set of bearings, not on the crankshaft. The clutch engages all at
once, and the shock of the fan mass is eased by the drive belt. I wouldn't want that sort of thing on the front of a 455, I'd fear for the pump
bearings.

--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

[6cuda6--- via Gmclist]

Just to throw in my 2 cents worth...i know from our company vehicle testing that going from viscous fan to and electric setup gained 10% more fuel
economy even with having to add bigger alternators.

As for the trucking industry alot of the 2020 trucks you will see with closed loop cooling systems and electric fan now. Highway Coaches have been on
e-fans now for a couple years now as well.

So perhaps you may need to go to the 100amp alternator but if the fan shroud is done correctly you should be further ahead in my opinion.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

[Jim Kanomata via Gmclist]

I have been running the Electric Fan Clutch for over a year and over 12,000
miles and can tell you the fan does not SLAM on or off.

--
Jim Kanomata
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502

[John R. Lebetski via Gmclist]

Most highway busses (Prevost) are 24 VDC or mixed 24/12V. Makes a big difference when powering HVAC fans and cooling fans.

--
John Lebetski
Woodstock, IL
77 Eleganza II

[Hal StClair via Gmclist]

JohnL455 wrote on Mon, 27 April 2020 16:45

> Most highway busses (Prevost) are 24 VDC or mixed 24/12V. Makes a big difference when powering HVAC fans and cooling fans.

The 24 volt alternators used in buses range from 270 to 400 amps-that would be 540 to 800 amps 12 volts. Lots of juice....

Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM

[6cuda6--- via Gmclist]

Sure but we run anywhere between four X 20" to nine X 11" [they pull all together about 230amps at start up and then settle down to around 80amps once
spinning if they are all needed].....i can tell you that the 18" fan on my 66 Barracuda street car doesnt draw much or even run that often [its on a
stock rad with the old style 45amp stock alternator with a motor that makes over 500hp]

If you really think about it...how much does the fan run? [Any design...mechanical, electric or other]. Realistically its only one at idle or slow
speed once the thermostat opens....so without actually watching it, my guess is the fan is only freewheeling at highway speeds.

To each their own....stock works, so does electric with the proper shroud since it will really need to be a puller.


Hal StClair wrote on Mon, 27 April 2020 19:50

> JohnL455 wrote on Mon, 27 April 2020 16:45
> > Most highway busses (Prevost) are 24 VDC or mixed 24/12V. Makes a big difference when powering HVAC fans and cooling fans.
>
> The 24 volt alternators used in buses range from 270 to 400 amps-that would be 540 to 800 amps 12 volts. Lots of juice....
> Hal


--

Rich Mondor,

Brockville, ON

77 Hughes 2600

[Johnny Bridges via Gmclist]

JimK, you are using the electric clutched M-B fan, correct? It is very different from the electric clutches on semis. It has roughly the same
engagem,ent time as the OEM one, it is merel;y controlled by engine temp instead of radiator air tep.

--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

[Jim Kanomata via Gmclist]

Yes, I’m trying to get through my old brain that the radiator method of
sensing is better.
Hope this concept will light up one day soon and get enlightened😁

--
Jim Kanomata
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502

[Gerald Work via Gmclist]

Until quite recently the fans on the DD Series 60 Prevost buses like ours used three crankshaft driven V belts running to a right angle fixture which turned a drum with a wide flat belt driving a viscous clutch which drove the fan. The fan clutch and fan are mechanically similar to our GMCs, only much larger. All these belts were pneumatically tensioned by the engine driven air compressor so if a belt broke the driver could change belts on the side of the road without tools and be back underway quickly. Since the engine is at the back of a 40 foot tube and has a gazillion pounds feet of torque you really never hear or feel the fan coming on but it sure does cool the water temp quickly. Fan clutch failure is very rare and the belts seldom ever break.

Prevost (now owned by the Volvo truck and bus company in Europe) now uses Volvo diesel engines and they do use electric fans in the more recent versions. Those electric fans are just part of a carefully engineered cooling system and not something that turns slapped on the face of an existing radiator. For our GMCs I would imagine that it will take a similar whole system approach to finding a new radiator and electric fans in an engineered package. It looks like that is what Jim Bounds at the Coop is trying now.

Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR

glw...@mac.com
http://jerrywork.com
============
Message: 2
Date: Mon, 27 Apr 2020 16:45:38 -0600
From: John R. Lebetski <gransp...@gmail.com>
To: gmc...@list.gmcnet.org

Subject: Re: [GMCnet] Electric fan

Message-ID: <56795.5...@gmc.mybirdfeeder.net>
Content-Type: text/plain; charset="utf-8"

Most highway busses (Prevost) are 24 VDC or mixed 24/12V. Makes a big difference when powering HVAC fans and cooling fans.

--
John Lebetski
Woodstock, IL
77 Eleganza II

===============

[Matt Colie via Gmclist]

jimk wrote on Tue, 28 April 2020 09:55

> Yes, I’m trying to get through my old brain that the radiator method of sensing is better.
> Hope this concept will light up one day soon and get enlightened😁

> --
> Jim Kanomata

Jim,

Let me try to work that switch for you. I did work in the cooling group at Jeep for a couple of years.

The reason for the thermostatic clutch on the fan being controlled by radiator temperature is a very simple explanation. It was the least cost
method. As a supplier that got beat up by buyers for a one penny per piece price increase, I can affirm that they are that sincere.

Next, why the thermostatic fan clutch at all? One "word" -
CAFE (Corporate Average Fuel Economy)
A typical engine driven fan pulls a lot (~2~4Hp) depending on speed. The power drain is the CUBE of the speed. A bare engine without a fan will turn
in much better performance values.

Lots of smaller cars had electric cooling fans years ago. Yes, and most were trans-verse engine so a engine driven would be impractical. That pried
the door open.

Then, came along the ECU/C (Engine Control Unit/Computer). As these soon got to the stage where they were observing all the engine's conditions,
adding a coolant temperature switch was only adding a couple of lines of code to book the size of a city phone book and another pass transistor on the
heat sink. When engine power went up, the fan power had to increase too, so an number of vehicles had to have a fan control module to handle the
load.

Then they could loose the **** thermal clutch and the associated calibration issues and warranty. And as an added benefit, not having the fan on the
waterpump shaft reduces the load on those bearing and with it off the FEAD (Front Engine Accessory Drive) reduces the load that those components have
to address.

Now, I going to intentionally muddy the water just a little...
When running test engines for a client, they were always run with a regulated coolant out temperature because that is what the client specified.
When running a development engine for our own use, we would control the temperature of the coolant in and monitor the coolant out just as a
reference.
When I can finally do the study, I am going to change the control on my fan clutch to water in and let the thermostat be the control on water out.

If there is a question there that I did not answer, please ask away.

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

_______________________________________________

[Johnny Bridges via Gmclist]

If it works out, it would be a choice if one needed a new radiator anyway. In that the existing system, or OEM with the _B setup is perfectly capable
of cooling the engine there's not a great need to go for a new system. So far, the reliability of the M - B clutch seems to be excellent.

--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

[Mark Sawyer via Gmclist]

Matt.

Out of curiosity, what would you typically see on water in temps?
--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX

[John Wright via Gmclist]

What thermostat are you running?

J.R. Wright
GMC Great Laker
GMCGL Tech Editor
GMC Eastern States
GMCMHI
TZE Zone Restorations
78 Buskirk Custom 29.5' Stretch
75 Avion (Under going Frame up Restoration)