Home » Public Forums » GMCnet » [GMCnet] Electric Fan Clutch
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| Re: [GMCnet] Electric Fan Clutch [message #189720 is a reply to message #189702] |
Fri, 09 November 2012 09:59   |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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Rob:
Those pictures were part of a fan clutch discussion quite some time ago. Fan clutch issues seem to take many different directions and cause a lot of concern for a lot of people on the net. Those discussions also indicate to me how many owners seem to not understand the clutches function and operation. I showed the electric fan clutch indicating that some pick ups and other cars for that matter, are now using the computer to control the clutch. Hence electric clutches. Heavy haulers are mostly using electric or air pressure controls. I suspect one could Adapt one for our 455 but I have never needed to investigate it myself.
I had a PM discussion where I wrote a complete description how a clutch worked, and some issues, but did not publicly publish it, when it was clear I did not really answer the question that was being asked. I still have it, as It may be suitable for others however.
Best regards
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: [GMCnet] Electric Fan Clutch [message #189729 is a reply to message #189720] |
Fri, 09 November 2012 11:33 |
Ray Erspamer
Messages: 1707
Registered: May 2007
Location: Milwaukee Wisconsin
Karma: -3
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Senior Member |
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I found the fan clutch I like and it works great, so I just carry a spare. From
under the coach I can change it in about 30 minutes once the engine
cools.....done !
Ray
Ray & Lisa
78 Royale "Great Lakes Eagle"
Center Kitchen TZE368V101144
Wauwatosa, Wisconsin 53226
Email: 78GMC-Royale@att.net
414-745-3188
Web Site: http://ray-lisa.page.tl/
________________________________
From: John Heslinga <rbeeper@hotmail.com>
To: gmclist@temp.gmcnet.org
Sent: Fri, November 9, 2012 9:59:23 AM
Subject: Re: [GMCnet] Electric Fan Clutch
Rob:
Those pictures were part of a fan clutch discussion quite some time ago. Fan
clutch issues seem to take many different directions and cause a lot of concern
for a lot of people on the net. Those discussions also indicate to me how many
owners seem to not understand the clutches function and operation. I showed the
electric fan clutch indicating that some pick ups and other cars for that
matter, are now using the computer to control the clutch. Hence electric
clutches. Heavy haulers are mostly using electric or air pressure controls. I
suspect one could Adapt one for our 455 but I have never needed to investigate
it myself.
I had a PM discussion where I wrote a complete description how a clutch worked,
and some issues, but did not publicly publish it, when it was clear I did not
really answer the question that was being asked. I still have it, as It may be
suitable for others however.
Best regards
--
John and Cathie Heslinga
1974 Canyonlands 260
TC4W "Too Cool For Words"
Retirement Projects Galore
Edmonton, Alberta
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Ray Erspamer
78 GMC Royale Center Kitchen
403, 3.70 Final Drive
Holley Sniper Quadrajet EFI System,
Holley Hyperspark Ignition System
414-484-9431
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| Re: [GMCnet] Electric Fan Clutch [message #189744 is a reply to message #189720] |
Fri, 09 November 2012 15:50 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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John,
I did a search on the Forum and found the message you posted about the electric fan clutches and you noted that they were very
expensive which explains why the discussion died! ;-)
I even commented about making a fan with variable pitch blades!
As I understand it the fan clutch we have now engages and disengages as a function of the temperature of the air that coming through
the radiator NOT the water temperature.
I am GUESSING that an electrically controlled fan clutch engages and disengages as a function of engine water temperature.
Is that correct?
If yes it seems to me that an electrically controlled fan would be MUCH better than what we have now.
I see one of your pictures has a label with the word "Behr" on it, I assume that's the fan clutch manufacturer? You wouldn't happen
to have any part numbers would you.
Regards,
Rob M.
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of John Heslinga
Rob:
Those pictures were part of a fan clutch discussion quite some time ago. Fan clutch issues seem to take many different directions
and cause a lot of concern for a lot of people on the net. Those discussions also indicate to me how many owners seem to not
understand the clutches function and operation. I showed the electric fan clutch indicating that some pick ups and other cars for
that matter, are now using the computer to control the clutch. Hence electric clutches. Heavy haulers are mostly using electric or
air pressure controls. I suspect one could Adapt one for our 455 but I have never needed to investigate it myself.
I had a PM discussion where I wrote a complete description how a clutch worked, and some issues, but did not publicly publish it,
when it was clear I did not really answer the question that was being asked. I still have it, as It may be suitable for others
however.
Best regards
--
John
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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: [GMCnet] Electric Fan Clutch [message #189751 is a reply to message #189744] |
Fri, 09 November 2012 17:39 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Keep in mind that the clutch you have now does NOT run the fan at full speed. The main difference between the OEM stock Heavy Duty clutch and the Severe Duty clutch that some people install is the speed at which it turns the fan.
I do not remember the exact numbers any more but it is something like 50% for the OEM one and 70% for the severe duty one.
If you think the Severe duty clutch is noisy, Think what you will need for belts and noise for a 100% one. I suggest you will need to reduce the fan pitch to use a 100% one.
Now if you change that electric clutch to an electric motor you could vary the speed of the fan by the voltage supplied.
I'm happy with one I have now and I see no need to change it.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Electric Fan Clutch [message #189766 is a reply to message #189702] |
Fri, 09 November 2012 20:00 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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When I drive our 2011 Peterbilt, the fan comes on in a startling way, and you can feel it sap the power especially for that second where the rotating mass is accelerating. It's not really a "clutch" as it'a a "NO or YES" engagement, sort of like engaging the PTO on your riding mower to the deck. Also as you are accelerting through the gears and it disengages, you feel the opposite effect. Diesels work in a narrower RPM range so overspeeding the fan is less of an issue. As far as an electric motor driven fan, the stock 80A alternator won't support the kind of horsepower you would need to come close to doing what the stock setup does as far as moving air. Unfortunately.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Electric Fan Clutch [message #189774 is a reply to message #189766] |
Fri, 09 November 2012 21:50 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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G'day,
I've learned enough in a few emails to say fagitaboutit as far installing an electric fan clutch goes.
Thanks!
Regards,
Rob M.
USAussie - Downunder
-----Original Message-----
From: John R. Lebetski
When I drive our 2011 Peterbilt, the fan comes on in a startling way, and you can feel it sap the power especially for that second
where the rotating mass is accelerating. It's not really a "clutch" as it'a a "NO or YES" engagement, sort of like engaging the PTO
on your riding mower to the deck. Also as you are accelerting through the gears and it disengages, you feel the opposite effect.
Diesels work in a narrower RPM range so overspeeding the fan is less of an issue. As far as an electric motor driven fan, the stock
80A alternator won't support the kind of horsepower you would need to come close to doing what the stock setup does as far as moving
air. Unfortunately.
--
John
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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: [GMCnet] Electric Fan Clutch [message #189780 is a reply to message #189702] |
Sat, 10 November 2012 02:00 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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Hi Robert:
(I write this mostly for the benefit of those that do not have the experience you and others may have)
I don't blame you about your “fagitaboutit” moment . Sometimes what we have, actually works OK with a little tuning and repair, and the extra effort is just that: Extra effort and a lot more work. I truly believe there are other ways to solve some of the heat problems, and this option is not it. Every time fan clutch conversations come up there seem to be as many people having problems as there are not having problems, and then there are the ones that have solved their own in some unique way. I believe a lot of problems are more complex than clutch problems but cooling system problems as well. I hope nobody thinks I am judging any response, because I am not. The problems and solutions are valid and make a lot of sense once the context is discussed. Mostly the solutions seem to be directing air through the radiator properly, finding a fan clutch that meets the personal needs, and correcting other cooling deficiencies. The reality to cooling problems is that there needs to be more cooling capacity in the cooling system than the needs of the engine working in its worst conditions expected. The thermostat, then, controls the amount of cooling that actually happens. I really cannot say much because, I personally seldom drive where the outside temperature is very high. (Living in the Great North, I live too far from the hot spots) Therefore I haven't had a problem I could not repair. Last year my fan clutch failed and would not engage. (Viscose fluid leakage) A replacement HD Clutch solved the problem. And no I don't get a roar unless the coach has had to work very hard, or for the short period of time after I start the engine. (Climbing the icefield parkway between Banff and Jasper and back, and the Cocohallla to Vancouver) I use a 180 thermostat so that the coolant going into the Radiator is not as hot and the clutch will not engage unless really needed. (operates as expected) (Please everyone I don't want to get into Temperature discussions!!!)
The electric actuated clutch used on small trucks uses electricity to open the silicone reservoir in the same way the bi-metal strip does on the regular clutch. It then is engaged in the same way as ours. John Lebetski's comment about the heavy truck clutches is really telling how it works for them. Just like you assumed, the idea that a computer, or water jacket temperature sensor, can control the engagement may actually offer better temperature control. The reality is that: in a longitudinally mounted engine a clutch and fan driven by the engine is actually cheaper to build and more effective than an electric fan needed for a transverse mounted engine. The computer now can control and manage the fan clutch in the same way as an electric fan. (The fan operation strategies are much more complex now than they were 30 years ago)
Everyone please remember that I am not assuming that what I do will work for others.
Best Regards
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: [GMCnet] Electric Fan Clutch [message #189781 is a reply to message #189780] |
Sat, 10 November 2012 02:33 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| John Heslinga wrote on Sat, 10 November 2012 02:00 |
Hi Robert:
(I write this mostly for the benefit of those that do not have the experience you and others may have)
I don't blame you about your “fagitaboutit” moment . Sometimes what we have, actually works OK with a little tuning and repair, and the extra effort is just that: Extra effort and a lot more work. I truly believe there are other ways to solve some of the heat problems, and this option is not it. Every time fan clutch conversations come up there seem to be as many people having problems as there are not having problems, and then there are the ones that have solved their own in some unique way. I believe a lot of problems are more complex than clutch problems but cooling system problems as well. I hope nobody thinks I am judging any response, because I am not. The problems and solutions are valid and make a lot of sense once the context is discussed. Mostly the solutions seem to be directing air through the radiator properly, finding a fan clutch that meets the personal needs, and correcting other cooling deficiencies. The reality to cooling problems is that there needs to be more cooling capacity in the cooling system than the needs of the engine working in its worst conditions expected. The thermostat, then, controls the amount of cooling that actually happens. I really cannot say much because, I personally seldom drive where the outside temperature is very high. (Living in the Great North, I live too far from the hot spots) Therefore I haven't had a problem I could not repair. Last year my fan clutch failed and would not engage. (Viscose fluid leakage) A replacement HD Clutch solved the problem. And no I don't get a roar unless the coach has had to work very hard, or for the short period of time after I start the engine. (Climbing the icefield parkway between Banff and Jasper and back, and the Cocohallla to Vancouver) I use a 180 thermostat so that the coolant going into the Radiator is not as hot and the clutch will not engage unless really needed. (operates as expected) (Please everyone I don't want to get into Temperature discussions!!!)
The electric actuated clutch used on small trucks uses electricity to open the silicone reservoir in the same way the bi-metal strip does on the regular clutch. It then is engaged in the same way as ours. John Lebetski's comment about the heavy truck clutches is really telling how it works for them. Just like you assumed, the idea that a computer, or water jacket temperature sensor, can control the engagement may actually offer better temperature control. The reality is that: in a longitudinally mounted engine a clutch and fan driven by the engine is actually cheaper to build and more effective than an electric fan needed for a transverse mounted engine. The computer now can control and manage the fan clutch in the same way as an electric fan. (The fan operation strategies are much more complex now than they were 30 years ago)
Everyone please remember that I am not assuming that what I do will work for others.
Best Regards
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What you are telling me is my assumption that is was a clutch is wrong. That means that it could be used jsut like out existing ones since it probably would not drive the fan at 100% of pulley speed.
I'm still not interested in doing it electrically.
My thought on a clutched fan is the fan should only be intermittently needed. The cooling system should be efficient enough without the fan to remove all necessary heat. Only in rare circumstances like excessive idling is very slow traffic or towing up a long grade should more heat be generated than the system gets rid of normally. Only then is when the clutch should be needed do it's job.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Electric Fan Clutch [message #189799 is a reply to message #189702] |
Sat, 10 November 2012 10:50 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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Ken
That is correct. Today's computers want to control the fan for things like the following. AC on, transmission range selector, ambient temperature, limp mode, temperature irregularities, fuel economy, and others. Not always heat related and therefore electric control works better. I really can't see much of a benefit for our application.
For others information::
Large trucks can lock up the fan because diesel engines have a narrow RPM range. But when they do the fan begins to operate more like a propeller. They really load the engine down and move a great deal of air. (maybe they even pull the truck along :>) ) Smaller units work very close to ours because gas engines have a wider RPM range, cant afford the torque losses, fan speeds do not really need to have such a range and noise in consumer vehicles is a bigger concern.
Here is my take on clutch operation
The reallity is, viscose fan clutches are torque limiting. Meaning that they control the torque delivered to the fan. The speed of the fan, then is a function of the load of moving the air and the torque delivered to the fan by the engine. ( ( we can assume the engine will provide way more torque than can be used by the fan) As the load needed to turn the fan increases so does the amount of "slip" happening between the viscose fluid and the plates of the clutch. The clutch will allow viscose fluid in and out of the plates to change the amount of torque transfer. The more torque, the more air the fan will be moving. The speed of the fan is simply a consequence of the differing variables. ( road speed, amount of air going through the radiator, air density, engine RPM, etc) The volume of air that the fan moves is really much more consistant across the RPM range with the fan slipping more at high speeds and less at low speeds. A fan of any particular design has an ideal speed and torque to move air with the most efficiency and the fan clutch helps keep the fan working in that range
The more air a fan needs to move the more torque needs to be applied to it. Larger, more aggressive fans, and air flow characteristics all contribute to the type and specification of clutch would be used for an application. Heavy duty clutches have more "fingers" in the viscose fluid and therefore will transfer more torque to high demand fans such as our GMCs. When most clutches are in "low torque mode" they really just "loaf" the fan compared with the amount of air the fan can actually move. But there is quite a bit af difference in tha amount of air that can be moved with the differing clutches available.
Sorry. No math to back my statements.
WOW. That was hard work on an I Phone!!
Best regards
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: [GMCnet] Electric Fan Clutch [message #189812 is a reply to message #189702] |
Sat, 10 November 2012 15:35 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Hope I didn't add to the confusion with the Peterbilt type entry. Though good to know this would not be a good GMC choice. The type John H mentioned is a clutch similar to ours but with computer controled instead of the bimetalic coil. The Pete im guessing is computer controled as well and also has a driver override ON toggle switch on the dash. I use that on decending hills along with proper gear choice it gives some marginal engine braking. I agree our poor natural airflow is a bit of an enigma with the frontal area we have it should be better. Is the bumper splitting the airstream above and below the radiator and leaving it in a dead zone? Need some wind tunnel streamers and a video camera.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Electric Fan Clutch [message #189818 is a reply to message #189799] |
Sat, 10 November 2012 16:48 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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John,
Double Trouble has an aluminum radiator, a 160° thermostat, air directing flaps on either side of the radiator, OEM shroud
(partially open), and one of JRWright's air dam spoilers.
This past summer I had a fan clutch "fail" out in Santa Fe, with Marc H's help I replaced it with a spare I got from JimB a long
time ago. I noticed that the new fan clutch "kicks in" a lot more frequently than the one I replaced. The new one seems to kick in
when the rpm's of the engine drop to idle and runs for a few minutes and then disengages.
I noticed in one of your pictures a tag on the electric fan clutch with the name BEHR so I Googled it and discovered they are one of
the major manufacturers for fan clutches for European cars. That's as far as I got I couldn't find any technical information or part
numbers. Anyone have any idea as to where I could find more info. I'd like to see if I could find a clutch that would be adaptable
to the Olds 455 or Caddy 500.
Regards,
Rob M.
USAussie - Downunder
-----Original Message-----
From: John Heslinga
Ken
That is correct. Today's computers want to control the fan for things like the following. AC on, transmission range selector,
ambient temperature, limp mode, temperature irregularities, fuel economy, and others. Not always heat related and therefore
electric control works better. I really can't see much of a benefit for our application.
For others information::
Large trucks can lock up the fan because diesel engines have a narrow RPM range. But when they do the fan begins to operate more
like a propeller. They really load the engine down and move a great deal of air. (maybe they even pull the truck along :>) )
Smaller units work very close to ours because gas engines have a wider RPM range, cant afford the torque losses, fan speeds do not
really need to have such a range and noise in consumer vehicles is a bigger concern.
Here is my take on clutch operation
The reallity is, viscose fan clutches are torque limiting. Meaning that they control the torque delivered to the fan. The speed of
the fan, then is a function of the load of moving the air and the torque delivered to the fan by the engine. ( ( we can assume the
engine will provide way more torque than can be used by the fan) As the load needed to turn the fan increases so does the amount of
"slip" happening between the viscose fluid and the plates of the clutch. The clutch will allow viscose fluid in and out of the
plates to change the amount of torque transfer. The more torque, the more air the fan will be moving. The speed of the fan is
simply a consequence of the differing variables. ( road speed, amount of air going through the radiator, air density, engine RPM,
etc) The volume of air that the fan moves is really much more consistant across the RPM range with the fan slipping more at high
speeds and less at low speeds. A fan of any particular design has an ideal speed and torque to move air with the most efficiency and
the fan clutch helps keep the fan working in that range the more air a fan needs to move the more torque needs to be applied to it.
Larger, more aggressive fans, and air flow characteristics all contribute to the type and specification of clutch would be used for
an application. Heavy duty clutches have more "fingers" in the viscose fluid and therefore will transfer more torque to high demand
fans such as our GMCs. When most clutches are in "low torque mode" they really just "loaf" the fan compared with the amount of air
the fan can actually move. But there is quite a bit af difference in tha amount of air that can be moved with the differing
clutches available.
Sorry. No math to back my statements.
WOW. That was hard work on an I Phone!!
Best regards
--
John
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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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