• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Hydraulic Fan Drive (HFD)

S

Sand

Well-Known Member
Messages
267
Reaction score
387
Location
Canada
Ive been through nearly every variation of cooling upgrades to try and get a 6.5 TD in a Hummer to keep cool while working. Balanced Waterpump, Tanked Radiator, new pressure cap, Kennedy early engagement fan clutch, Duramax fan. Even a wired up fully 100 percent locked fan.
Its a basically stock engine. Dont get me wrong - it works and I drive it every day, but on a long hill or pulling a medium load the temp gauge climbs on a one way trip. And you have to pull over. Boring.

I did have a broken shroud that I tried to repair at one point and I had the idea to extend the shroud depth around the fan further. I fussed with it a bit and then replaced the shroud in the end (it was only 50 bucks new).
While doing this I found some good info on the internet from fan manufactures - I think Flexolite and Hayden, with general parameters on ideal fan shroud designs.
Guess where a Hummer fan shroud rates. It does not.
Its so far off on all counts Im amazed they move air on a good day. Fan blades should be 1" from the radiator. Huge Fail. Fan swept area should not be outside of Radiator surface area. Big fail. I estimate that nearly half the fan area is outside of the radiator area. Fan blades should be partly in and partly out of the shroud. I found this interesting. It seems a good portion of the air "spills" off the tips of the fan. The blade tips need to be partly in the open to allow this air to move.
The basic Hummer fan is 18-19 inches in diameter and all the air flows through a massive Prism shape from the leaned over Rad to the upright fan running off the front of the engine.
20170714_073344.jpg
20170714_073317.jpg
There are good designs out there of horizontal Rads that flow enough air to run in hot dusty conditions at redline all day long. I happen to have one. A CAT Skid-steer loader.
20180124_150714.jpg
Enter the Hydraulic Fan Drive.
Now I see huge potential. With the fan no longer mechanically linked to the engine there are a multitude of benefits.
The fan can be moved to be flat against the Radiator.
The size constraints of an engine mounted fan change. I can move from a 19" Diameter fan (283sq inches) to a 24" diameter fan (452SQ INCHES!!!)
The fan is no longer restrained to operating at engine speed. It can be run slower or faster than the current rpm you are running at. This means faster than a viscous clutch fan a full lock up.
The fan motor can be reversed to blow leaves and pine needles out of the Rad stack.
Viscous (useless) fan clutch becomes a thing of the past.

I had been thinking of this since getting my H1 a couple years ago but a short clip of a H1 testing a hydraulic fan drive inspired me to move along a little. The test setup in the video was not fully implemented for reasons I'm exactly sure of. Something about components not being up to scratch.

Recently I saw a Cummins powered bus at a local Wrecker and salvaged some of the parts for my project.
535318575.jpg
 
The bus got me a nice hydraulic motor. Matching fan, most of the hoses and a Tandem hydraulic pump.
The pump is not very useful. 2 pumps in one. Massive. Long. And gear driven from the timing gears of the cummins.
The motor is the score. Its matched to the fan. Runs at an idle speed and has a solenoid that switches it to full speed when triggered by an engine temp switch or intake temp switch.
 
Plus I can lay my Rad back EVEN further and make room for an intercooler. Most Hummers need a 2+ inch lift to make toom for this. I already have 17" ground clearance. Plus I dislike lift kits.
 
Thats what I was starting to look at as I hijacked a snowplow thread about a day ago. Power steering pumps run about 3-4 GPM and 1100 psi. A hydraulic motor needs more like 15 GPM and 3000 psi. I need a dedicated pump.
Im looking at the Vickers V10 series by Eaton. They are a vane style pump and used as power steering/hydraulic supply pumps on big commercial trucks.
Now I need a place to put it. Ive got the AC compressor on the drivers side serpentine setup. The pump needs to run at crank speed so any pulley will need to be the size of the crank pulley. Thats big....20160807_184622.jpg
 
I have one other "thought" have you considered using a variable displacement pump? It could be sped up and slowed down and reversed mechanically or with linear actuators. A lot of commercial mowers use this type of pump. easy to come up with ideas for someone else's money BTW.
 
smokymtn65 said:
I have one other "thought" have you considered using a variable displacement pump? It could be sped up and slowed down and reversed mechanically or with linear actuators. A lot of commercial mowers use this type of pump. easy to come up with ideas for someone else's money BTW.
Click to expand...
I`m watching.
Smaller and more efficient too.
They can be set up with load sensing to adjust the angle of the swash plate too.
 
smokymtn65 said:
I don't know if this will help at all,there a couple outfits that make factory brackets for 6.5 hyd pump maybe only have to re-invent part of the wheel? http://cwkits.com/clutch-pump-kits/
Click to expand...
I've used a half dozen or more of their mounting kits, they fit nice but are not cheap. Still a lot cheaper than the Eaton kits I priced out.
 
Im checking the mounting kits out. Nice. Navigating the list to identify a 6.5 TD is a little confusing.
I do want a piston pump. The Vickers is used and free to me from the local hydraulics shop that is helping me calculate and balance (and browse their back shelves) the system though.
I'm currently thinking of fitting a second pulley to the front of my Power steering pulley and a 3rd power steering pulley to the pump. Pump will be below the AC and above the power steering. A tensioner would be nice too. P/S pulleys are 5 bucks each at the local wrecker.
 
smokymtn65 said:
Anyone know if Predator ever marketed their Hyd fan kit?
Click to expand...

No. After a couple attempts they walked away and all their customers that have overheating 6.5s they just tak into dmax conversion since it handles higher operating temp. The extra power is nice selling point and they make more cash- so not worth it to them to improve 6.5.
 
My concern would be if the power steering pump is strong enough to take the extra load. I've had 2 or 3 shafts break in the last few years. What about replacing the power steering pump itself?
 
A pump large enough to run the fan motor would damage steering gear box and brake booster.

My understanding is trying to use a 2nd power steering pump is one of the things predator did unsuccessfully.

If I was a wealthy man, i would get an auxiliary pump system like used in dry sump pumps. They have pumps that all drive off one input shaft. So you could do hydraulic, vacuum, power steering, high pressure oil for centrifuge all off 1 unit. The price is the only draw back. Are you Friends any Nascar or Indy car team owners? Haha.
 
Sand said:
The bus stuff is old technology. But hard to track down components for. Buses seem to have pricy components and are built with running changes and custom parts everywhere.
This is the basic mold for my new fiberglass shroud tsking shape.View attachment 51674 View attachment 51675
Click to expand...

I hope this fan is for mock up only. It's got a chip off a blade, unbalanced, and could shatter if the impact that broke the blade also cracked it.

"Fan blades should be partly in and partly out of the shroud." This is absolutely the biggest concern of the ones you listed.
 
I looked briefly at those. Nice tidy stuff but they are replacing a 1/4 hp electric motor to cool a gasoline engine. My hydraulic motor is replacing a massive diesel driven fan that likely steals 15hp from my engine.
 
You must log in or register to reply here.
Back
Top