Cummins 4BT & Diesel Conversions Forums banner

21 - 32 of 32 Posts

·
Registered
Joined
·
272 Posts
When you say clockwise or counter clockwise, where is that rated from , from front or rear of engine,! I have been wondering about a fan clutch for my tractor, or would it do any good?
 

·
Registered
Joined
·
11,259 Posts
Papa, for that you would want to look at the rotation of the crank shaft at the front. If the grooved side of the belt is on the fan pulley then it rotates the same as the crank. If the pulley runs on the back side then it's reverse rotation. All the 4bt and 6bt engines up through I believe 2002 were the same rotation. Reverse rotation came along with the ISBe engines. Your engine most likely has the industrial fan hub which has 4 10mm bolts in a 60mm pattern. Finding a clutch fan for that hub might prove a bit tricky. Most 6bt or possibly 6ct engines other that the ones used in the Dodges could possibly have that hub so that might be a possible source. The 4bt industrial catalog I have only has direct drive fans like you probably have. Many of the medium duty engine fans were electric instead of mechanical. They had a temperature switch in the head that turned them on when necessary. Those are not cheap.
 

·
Registered
Joined
·
272 Posts
Yes Char. Bolt pattern sounds right (never measured) & fan pulley driven by groves in belt, rotating clockwise same as crank.
 

·
Registered
Joined
·
156 Posts
Discussion Starter #25
Thanks for this! I'll check that part number and see if I can find a fan to go with it. I did turn down my pilot to fit these clutches. If this route dead-ends, I may consider a basic electric fan set-up--the engine's been running well with no fan at all for awhile, and only goes up to 200 degrees on big uphill pulls.
Thanks again, everyone!
Stephen


This is a bit puzzling. You cannot use a different rotation fan clutch unless you change the hub pulley assembly. The clutch inside the unit is designed for one direction only. That fan hub you have was not designed for a B series Cummins. Did you turn down the pilot on the hub or increase the pilot in the clutch flange? Cummins hubs and fan clutches should have a 1" pilot. Base 4bt hubs used 4 8mm bolts in a 50mm circle. Industrial hubs used 4 10mm bolts in a 60mm circle. You might check fan hub 922707 which is clockwise but it's not HD. Don't know what the pilot hole size is either. I found a listing for a 4bt hub and fan but don't know if it's the industrial bolt pattern or the standard. Whichever, you would need some smelling salts if you bought one of those as it's over $500 for the clutch assembly and fan blade. Ouch. I checked Uptime Truck Parts and they show an 18 fan blade, but no clutch assembly. Cost wise, you could probably change the hub assembly and pulley to one from a Dodge and use a Dodge fan clutch assembly if the fan isn't too big.
 

·
Registered
Joined
·
11,259 Posts
Like I had mentioned earlier, you might consider using a fan hub assembly from a '94-02 Dodge Cummins. It would be the same offset as a standard 4bt hub. Main issue might be the fan blade which is 22" in diameter. Here's a listing on ebay for a complete unit for $200. That's the bracket, pulley, clutch, and fan blade. Not sure how much it extends out from the block compared to what you have now. https://www.ebay.com/itm/Engine-Cooling-Fan-with-Clutch-Bracket-94-02-Dodge-Ram-Cummins-Diesel-5-9/113854755198?hash=item1a8245b17e:g:1wwAAOSwWa5dVY6t:sc:FedExHomeDelivery!28658!US!-1 You could do an electric. Just be sure you have a good fan shroud. Any cooling fan without a shroud isn't very effective.
 

·
Registered
Joined
·
272 Posts
I just went out & measured my fan - 17-1/2", 7 blade, 50mm bolt pattern , don't know the size if arbor without removing it, but it seams it was about 5/8 or 3/4. Shroud is about 18-1/2 opening.
 

·
Registered
Joined
·
11,259 Posts
Papa, if you're talking about the pilot on the fan hub, it is 1" exactly on all the B series Cummins. A bit unusual that your engine has the 50mm bolt pattern. We only find that on road use 4bts'. All the industrial engines used a 60mm pattern with 10mm bolts instead of 8mm.
 

·
Registered
Joined
·
156 Posts
Discussion Starter #29
Thanks for that! I've been parked for the past 6+ months, but now getting back into it. This link is now dead. Anyone have a source on a deal for the entire set up now? As I look around, there's plenty of options, but some are different than others. Some of 6bt fan pulleys are smooth (while mine is grooved, for clockwise rotation). I'd be happy to swap out the entire set-up to a 5.9 setup. Really anything that'll work. Thanks for all the help!
Stephen


Like I had mentioned earlier, you might consider using a fan hub assembly from a '94-02 Dodge Cummins. It would be the same offset as a standard 4bt hub. Main issue might be the fan blade which is 22" in diameter. Here's a listing on ebay for a complete unit for $200. That's the bracket, pulley, clutch, and fan blade. Not sure how much it extends out from the block compared to what you have now. https://www.ebay.com/itm/Engine-Cooling-Fan-with-Clutch-Bracket-94-02-Dodge-Ram-Cummins-Diesel-5-9/113854755198?hash=item1a8245b17e:g:1wwAAOSwWa5dVY6t:sc:FedExHomeDelivery!28658!US!-1 You could do an electric. Just be sure you have a good fan shroud. Any cooling fan without a shroud isn't very effective.
 

·
Registered
Joined
·
43 Posts
Here's what worked for me. I turned the pilot nub on the hub down to 3/4 inch and used a Hayden 2799 which cross references to the widely available Duralast 922799 at AutoZone. I used the Hayden clutch because it seemed to be a higher quality for about the same price, however instead of being slotted to accept two different bolt patterns like the Duralast it had both patterns drilled out so I took the dremel and reemed one set a little to match the Cummins pattern.


As far as a fan blade the factory 4bt fan, or one off a v8 Chevy truck pre 1987 or big block Ford of the same vintage fits that clutch.

Glendon
 

·
Registered
Joined
·
43 Posts
Just now noticed that you have the 50mm hub but according to my Hayden catalog the flange that bolts to the hub is 65mm wide so there should be enough material to slot the holes to fit 50mm pattern. Might be a good idea to take a tape measure along if you get the Duralast and make sure the flange is wide enough to accommodate the 50mm pattern.

Also remember to leave a 1/8in lip to center the pulley when turning down the hub pilot.

Glendon
 

·
Registered
Joined
·
156 Posts
Discussion Starter #32
OK! Here's what I did: went ahead and ordered the full new set up for a 12 valve 6bt from Rock Auto. Around $300 for Fan pulley bracket, fan clutch, and fan. $50 for the pulley elsewhere. All parts here and fit well, but I had to source a new fan belt (new pulley is smaller diameter than old one). Part I ended up ordering for a drive belt is the gates K080507RPM, which is around 2" shorter in diameter than my OEM belt (NAPA micro v 25 080537). This one is pricier, but I just want it all to fit. I had to cut around 1/2" off each fan blade to make it fit in my fan shroud, but this fan is 7 blades, vs the OEM 5, so I should have a good bit more cooling power. Otherwise everything fits as-is. Once the new belt gets here, I'll report back. Everything else is installed.
Stephen
 
  • Like
Reactions: Yoder repower
21 - 32 of 32 Posts
Top