Re: Hydraulic Fan Motor Upgrade/Replace Reply #25 – December 21, 2014, 01:32:37 pm Quote from: Chuck Pearson – December 21, 2014, 12:28:41 pm Curious, have you done any heat dissipation calcs based on radiator size and airflow? Will the front radiators have fans also? If so, won't the fans negate a fair amount of the ram air effect? Seems like you might be just shifting your load from hydraulic to alternator. Chuck,The radiators in the supplied link do have fans but with ram air, fans would only be used in stop and go traffic. As you may have noticed, the fans are not shrouded so ram air would go past them without much of an impedance. Using the heater lines will not be nearly as effective as larger dedicated lines but should be enough to allow the hydraulic system to be removed and smaller electric fans fitted. Larger coolant lines to the front would totally remove the need for the hydraulic system. The total load on the electrical system would be much less. CAT has a publication for RV hydraulic systems with a 20HP loss at low fan speed to a 50HP loss at the high speed setting. Any rear/side radiator just sits there with zero air moving through it at any speed without a lot of help. I'm trying to eliminate most of the energy needed to move air through the radiator core for the total amount of radiator area.With the removal of the hydraulic motor, a second matching alternator could be installed in the same location dedicated to the engine batteries or with a "boost" type switch, could be easily brought online to supply total electrical demand in case of the OEM alternator failure. I installed a Mercedes OM-617 engine in a Mercedes van where the longer engine extended where the radiator had been. I then put a radiator under the van at a bit of an angle so ram air was effective in cooling and totally replaced the original front radiator. One small fan was fitted to it. I just used the stock Bosch alternator and had zero problems with it as the fan rarely came on. In the outside case that the alternator had a fairly high draw on it, alternators are inexpensive, easy to find and can be install quickly by a fair percentage of Foretravel owners. The electrical wiring would be not prone to failure or leakage as hydraulic lines are. In short, a compact, neat installation. Rather than try to do any calculations based on heater hose flow, etc., I have always eyeballed it and done "empirical calculations" Has worked well in the past when certain elements of the calculation were missing.Pierce Quote Selected 1 Likes
Re: Hydraulic Fan Motor Upgrade/Replace Reply #26 – December 21, 2014, 01:53:25 pm OK I'm not the sharpest pencil in the box, but on my Eagle I had a side radiator and had a belt driven fan that ran off a 90 degree angle box. the crank pulley and two pulleys on the angle box with a belt tensioner to keep the tight. now looking at my 92 there are a few things in the way, however i think with a little thought one might be able to get something to work. I also had a front radiator with inch and half lines that ran under the bus that tied into the plumping for the radiator. just a option. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #27 – December 21, 2014, 02:20:28 pm Andy,Yes, my 4107 with a Detroit 8V-71 had a direct drive fan, alternator and AC compressor with zero belts anywhere. Nothing to adjust.I see where you are coming from. Do an all mechanical drive for fans coming off the crank pulley. Not a bad idea. Good thinking. With a 90 degree drive and a tensioner, it could work well.I did look at running a couple of large lines under the coach but wanted to keep from scraping them on the transitions from highway to side road with a steep shoulder. Perhaps I should think about a protective cover over the pipes.For other post concerns: An electric fan should work for Cummins intercoolers without sacrificing any cooling.Pierce Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #28 – December 21, 2014, 05:33:47 pm Andy,Foretravevel had a 90 degree gear drive fan whey back yonder. J. Holder may remember the exact age,but we looked at a FTX that had the same set up you are talking about. I don't remember what chassis it had but, it has been done in the past and would be a lot of work for the handy man. Pamela & Mike Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #29 – December 21, 2014, 07:16:14 pm There's nothing wrong with hydraulic fans. They have proven to be very reliable. And, I don't think it is very difficult to replace the existing motors with something off the shelf--it just takes a little bit of thinking.I'm trying to get ahold of a spare hydraulic system to keep in storage. If I get it, I'll see if I can cross reference pieces. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #30 – December 21, 2014, 08:00:00 pm Pierce,I can see the appeal of ram air and electric fans for sure. No doubt the hydraulic fans are huge power consumers, I saw the same Cat brochure, 20-50 hp. The problem with the hydraulic system, other than the fact that these are aging and $ to replace with oem is that brute force design seems to what was used to spec them. There's no way a 300 hp engine at low output needs a 20 hp fan to cool it. No real controllability. Lots of diesel pickups with similar or more hp manage to run most of the time with no fan engaged. Ram air will be a huge asset most of the time except when you need it most, pulling a 7% multi mile grade comes to mind. Too bad there's no good way to run finned tubing underneath to the new radiators... T'will be a grand thing if you're able to pull it off. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #31 – December 21, 2014, 09:42:21 pm Quote from: Andy 2 – December 21, 2014, 01:53:25 pmOK I'm not the sharpest pencil in the box, but on my Eagle I had a side radiator and had a belt driven fan that ran off a 90 degree angle box. the crank pulley and two pulleys on the angle box with a belt tensioner to keep the tight... I was wondering the same thing. Prevost used them: http://prevost-stuff.com/prevost_53_RearEngine.jpegHere's clutch that might work: http://www.surpluscenter.com/Power-Transmission/Clutches/Electric-Clutches/12-VDC-8-GROOVE-SERPENTINE-CLUTCH-FITS-9-1737-S-8-AND-9-1738-S-8-1-2184-S-8.axdAnd a right angle gear box: http://www.surpluscenter.com/Brands/Peerless/1-0-95-PEERLESS-20-HP-RA-GEARBOX-MODEL-1100-013-OPPOSITE-ROTATION-13-1514-C.axdDownside would be only a single speed (aside from engine RPM) with only an ON/OFF control. For unit with CACs a second sensor would be required with "either/or" logic.Another thing that has improved over the years is fan blades. If you have to spend money to have an adapter made for your old fan you might consider a new more efficient fan with the exact interface to the motor. Multi-Wing is what Country Coach used when I was there and they have adjustable pitches. High efficiency on-highway radiator fans :: Multi-Wing America This is a very interesting topic but I don't have to worry about this for myself - I have a rear radiator with a belt driven fan.I've heard the 20-50 hp number for fan usage but I wonder how much of that is just inefficiency of the older hydraulic units. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #32 – December 21, 2014, 10:52:54 pm Up to this point in my 97 U295 / 3126 Cat ownership, when I take it into my preferred truck repair shop (California Truck Center), they have been able to match the original part and make a professional repair they stand behind. http://www.californiatruckcenters.com/custompage.asp?pg=sacramentohomeIs this where I knock-on-walnut-cabinet-wood? It is certainly not reasonable to expect the factory to re-engineer cooling system parts for our older units. I'm pleased FOT can supply original equipment parts. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #33 – December 21, 2014, 10:55:43 pm Quote from: Chuck Pearson – December 21, 2014, 08:00:00 pmThere's no way a 300 hp engine at low output needs a 20 hp fan to cool it. No real controllability. I disagree completely. One reason for hydraulic fans is to allow variable output. On the older FT, it was high/low. Around 96 or so, it appears there is better control. The fan speed is controlled by the coolant temperature on my coach. It's variable. HP requirements drop greatly when fluid is bypassed and fans spin slowly.Here's a good post with a great PDF of how these systems work. Hydraulic fan drivesThere are mechanical loses in gear and belts and pulleys too. And having a fan either on/off on a mechanical drive likely eats up more HP. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #34 – December 22, 2014, 09:18:23 am Quote from: krush – December 21, 2014, 10:55:43 pmI disagree completely. One reason for hydraulic fans is to allow variable output. On the older FT, it was high/low. Around 96 or so, it appears there is better control. The fan speed is controlled by the coolant temperature on my coach. It's variable. HP requirements drop greatly when fluid is bypassed and fans spin slowly.Not so on my '96, can't speak for other years/models. There is no proportional fan control. I hope to address this someday. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #35 – December 22, 2014, 10:47:38 am My 1995 has high and low speed. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #36 – December 22, 2014, 11:14:53 am krush is right the 2 speed fan is a great feature. I put a indicator light on my dash to tell me when the fan is in low or high speed mode. It's almost always in low speed mode. The only time it's kicks into high speed is when you are on a long hill. Mine doesn't kick in until 198º or so. Personally I'd like for it to kick in at 190º. I've wired a rely/switch in so I can control it from the dash. When I get some time (and get off my lazy butt) I'll do a write up on it. It was an easy upgrade (costs less the $7!) that I highly recommend.see yaken Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #37 – December 22, 2014, 11:28:52 am Ken, there is no time like the present to do that sketch/schematic. JohnH Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #38 – December 22, 2014, 11:33:56 am Quote from: Chuck Pearson – December 22, 2014, 09:18:23 amNot so on my '96, can't speak for other years/models. There is no proportional fan control. I hope to address this someday. I haven't verified, but it was contention that the system on mine is variable. Barry posted a picture where he installed the valve. Manual fan speed control for our 99 U270 Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #39 – December 22, 2014, 12:12:13 pm Quote from: kenhat – December 22, 2014, 11:14:53 amkrush is right the 2 speed fan is a great feature. I put a indicator light on my dash to tell me when the fan is in low or high speed mode. It's almost always in low speed mode. The only time it's kicks into high speed is when you are on a long hill. Mine doesn't kick in until 198º or so. Personally I'd like for it to kick in at 190º. I've wired a rely/switch in so I can control it from the dash. When I get some time (and get off my lazy butt) I'll do a write up on it. It was an easy upgrade (costs less the $7!) that I highly recommend.see yakenKen,Excellent!Would it also be possible to add a fan speed indicator on the dash? It may only work on electric fans. I believe it could be either an analog or digital style with a tach light mounted on the fan. I would like to have a constant monitor of the hydraulic fan system since it causes so much worry especially on the older systems. A quick glance could tell you if there is a problem when running if the fan/fans aren't running at the proper speed. Thanks for the pdf on the fan speed, pump pressure test. Jerry Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #40 – December 22, 2014, 12:19:55 pm Cummins said my 97 320 is a variable speed setup Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #41 – December 22, 2014, 12:59:26 pm Quote Cummins said my 97 320 is a variable speed setup Doesn't a two speed qualify for "variable speed"? Pretty sure we are two speed as I assume our thermostat controller is either open or closed. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #42 – December 22, 2014, 01:01:11 pm Quote from: Barry & Cindy – December 22, 2014, 12:59:26 pmDoesn't a two speed qualify for "variable speed"? Pretty sure we are two speed as I assume our thermostat controller is either open or closed.Infinitely variable versus hi/lo Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #43 – December 22, 2014, 03:47:43 pm Personally I've only seen the 2 speed setup. So wondering how the "variable speed" would work. The fan speed (single or 2 speed) does vary with engine speed but don't think that qualifies as variable speed. Would a variable speed try to maintain a constant speed no matter the engine speed?? Not saying they don't exist just trying to understand how/why you would use one.see yaken Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #44 – December 22, 2014, 04:23:37 pm Quote from: kenhat – December 22, 2014, 03:47:43 pmPersonally I've only seen the 2 speed setup. So wondering how the "variable speed" would work. The fan speed (single or 2 speed) does vary with engine speed but don't think that qualifies as variable speed. Would a variable speed try to maintain a constant speed no matter the engine speed?? Not saying they don't exist just trying to understand how/why you would use one.see yakenCountry coach called it "a piloted wax capsule" Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #45 – December 22, 2014, 06:57:19 pm The fan controller on my '96 is a two speed, if the engine is running it's either high or low speed. When the engine is cranked in freezing temps, my fan is on low speed. Most likely the fan speed varies somewhat with engine speed and pump output. It's a pretty solid system but is somewhat of a power hog.A more modern system would be infinitely variable fan speed between off and max fan rpm. Fan speed is based on cooling demand, independent of engine speed. So, in practice, the fans would range from zero rpm to max speed, as needed. This saves some power and has some operational advantages and can also allow for operator override in unusual situations. This is a proportional controller, fan speed in proportion to cooling needs. I would expect but don't know that the later mod electronic engines incorporate proportional control. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #46 – December 24, 2014, 01:18:30 am Quote from: krush – December 22, 2014, 11:33:56 amI haven't verified, but it was contention that the system on mine is variable. Barry posted a picture where he installed the valve. Manual fan speed control for our 99 U270Our 99 U270 is definitely 2-speed, controlled by a wax capsule on the return line from the radiator. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #47 – December 24, 2014, 05:52:45 am I cannot get this link to copy and paste but there ids a lot of good sizing information here at the Eaton Fan drive site here is what I can get to paste. Google Eaton hydraulic fan drives and it should come upFan Drive System Application Guide - Eatonhttp://www.eaton.com/ecm/groups/.../@eaton/.../ct_233710.pd...Eaton CorporationFan Drive. System Application Guide. 4. EATON Fan Drive System Application Guide Technical Focus E-SYFD-TM001-E March 2003. Hydraulic Motor Selection. Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #48 – December 24, 2014, 08:19:50 am try thisPower Management, Powering Business Worldwidethen in the search box put 233710 Quote Selected
Re: Hydraulic Fan Motor Upgrade/Replace Reply #49 – December 24, 2014, 06:55:55 pm If you want to see what inside a typical motor looks like:Disassembling a gerotor-type hydraulic motorVideo on his page: hydraulics - disassembling a trocoidal motor, the RIGHT way, by Quote Selected
Topic: Hydraulic Fan Motor Upgrade/Replace