Home » Public Forums » GMCnet » [GMCnet] Fan clutch follies
| [GMCnet] Fan clutch follies [message #272224] |
Wed, 18 February 2015 09:51  |
glwgmc
Messages: 1014
Registered: June 2004
Karma:
|
Senior Member |
|
|
When the new S&J engine was installed in the Clasco I also added the aluminum radiator, the new plastic fan, new water pump and 180 Robert Shaw thermostat. That combo cooled way too much. 150 to 170 all the time up hill or down and the fan clutch was always on to some extent so very noisy. Now three different fan clutches later and I still have not found one that will play properly with the plastic fan.
I had a Hayden 2797 severe duty on the coach when the new engine went in and could not get the belts tight enough not to screech like crazy at anything over 2500 RPM. Then tried an ACDelco recently purchased from Peter Huber which he described as a 2053 so not sure of what it is. I changed to a double belt drive and same story, way too much cooling, loud screetching, finally locked full on so really loud. Next came an AZ version of a Hayden 2705 standard duty. That was much better with no belt screetching (small chirp when downshifting) but it also came on and stayed on once at highway speeds.
We drove home yesterday down the I-5 and over the five passes between Roseburg and Grants Pass, OR. It was unseasonably warm, in the low 70's, and engine water temp never got above 175 and stayed at 165 to 170 most of the time. I have two independent water temp indicators (one in stock location at the front of the intake manifold and one in the heater hose) which were consistent at those temps and I confirmed with a hand held IR. At least the roar of that fan clutch stuck on was less than with either of the others, but I am going back to the stock metal fan until someone finds a fan clutch that will play properly with this plastic fan. When I purchased the 2705 I also bought an AZ boxed Hayden 2747 but don't see how it could be any better than the others and I am tired of changing fan clutches.
I have no explanation for why these fan clutches are locking up and staying on at such low temps, nor do I have an explanation as to why the engine water temps are staying below the thermostat set temp even when climbing the five passes yesterday. Yes, I did also replace the new Robert Shaw 180 thermostat with a new Mr. Gasket 180 that looks identical to the RS, just a different color, and that had no effect on the temps.
My only guess is that the plastic fan puts so much drag on the fan clutches, even at low speeds, that they get hot on their own and fool themselves into thinking the air coming across the radiator is hot enough to engage and stay locked on.
For the record, all the fan clutches I found cross referenced to one of three Hayden numbers and this info is from Hayden:
Hayden 2705, standard duty, 60-70% of input shaft speed when on, 20-30 when off, designed for 1 1/2" pitch fan.
Hayden 2747, heavy duty, 70-90% when on, 25-35 when off, designed for 2 1/2" pitch fan
Hayden 2797, severe duty, 80-90% when on, 20-30 off, designed for 2 1/2" pitch fan.
If any of you have found a fan clutch that works with the plastic fan, I would sure like to hear what it is.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
Visitors always welcome!
glwork@mac.com
http://jerrywork.com
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Jerry & Sharon Work
78 Royale
Kerby, OR
|
|
|
|
Current Time: Tue May 07 00:29:16 CDT 2024
Total time taken to generate the page: 0.01020 seconds
|
GMCforum
Search
Help
Register
Login
Home
