PowerTech fan belt

[Mike in GA]

Have a trusty Powertech 10 kW diesel generator (Kubota 4 cyl) in its own quiet box - about 7-8 years old. Original fan belt is still turning, but showing serious cracks. Must I get a replacement from PT? or is there a cross reference list somewhere for Gates, etc?
     Also, anything tricky about getting to the old belt, r & r, etc?
     Thanks in advance.
Mike in GA

[Len Silva]

If you have the PowerTech part number, it will probably cross to a common belt size.  If not, just take your belt to an industrial supply house to match it.  Not an auto parts place, though NAPA may be able to do it.

[luvrbus]

That will be a Kubota belt stop by any Kubota tractor place they will have it may you cost a little more but a better belt than off the self and I don't which series you have but some of the Powertech you need to roll the generator out and remove the side cover to replace the belt


good luck

[rv_safetyman]

Len, I think you might have it backwards.  An industrial distributor will have industrial belts that are not intended to be used for automotive accessory applications.  The industrial belts are standardized by RMA/ISO while automotive belts are standardized by SAE/ISO.  The belts have different geometry and sometimes construction.  Some folks will get away with using a 3V3VX  belt in place of an HC38 or HC47.  It will work, but you should really use the correct belt.

Your best bet is NAPA.  If you get a good counter man, they will be able to do the proper cross.  They use Gates belts and will have the benefit of the very large Gates database.  In addition, they are owned by Motion Industries who is the largest industrial distributor.  If it would turn out to be an industrial belt (very unlikely) they will be able to deal with that.

Also, as Clifford says, you will not make a mistake going to Kubota. 

If you use an OEM or NAPA/Gates belt, you will get about the best quality.  There are some very low quality belts coming in from off shore and you don't want that.  You want a name brand belt.

Jim

[justin25taylor]

I agree with Clifford (as usual). SOME of the Kubota,Yanmar, and maybe other imported engines use a belt that is slightly a different width. The pulleys a can be just a little bit wider than U.S. made ones. I remember using a "generic" auto parts belt on mine once and it kept jumping off. I was on the road and short on time so I tried a couple more "auto parts" belts to no avail. I finally called Powertech and they said the Kubota brand belt would fit correctly. They were right. It fixed me right up.

A little off topic but I did the same on my old 87 F-250 w/6.9 Diesel. I bought a new set of the best Gates belts I could find and it kept throwing them. I checked pulleys, alignment, water pump, etc and could find no problem. The old belts worked fine.
I went back to the auto parts store and the guy told me the only belts that would work were the Motorcraft (OEM) ones. He had them in stock and again my problems were over. (Best truck I have ever had. Wish I could find another low mile one)

In hindsight, that should have educated me about the Kubota belt problem later.

I guess it takes longer for boys.........

If you need the part number, post genset model number and I will get you a current Kubota part number for the belt. Around here (TX) we have tons of Kubota dealers, but they (say) can only look up agriculture equipment. If you go in with the part number you will be miles ahead. If they do not have it in stock, they will get it for you, fast.

Good Luck in whatever you decide.  Hope this helps you.

Best,
Justin

[Len Silva]

Jim,

You are right, of course. Don't know what I was thinking except that I didn't read the question correctly and was visualizing  generator drive belts, not fan belts.

[Mike in GA]

Thanks guys!  I have a Kubota dealer near here and I'll take the part number with me and the old belt.
Mike in GA

[rv_safetyman]

Justin, it has been a while since I served on the SAE and ISO committees (a bit over 10 years  ), but the Japanese standards (JASO) agreed almost exactly with the SAE and for sure the ISO standards for automotive belts.  That is not to say that Kubota did not do something strange, but that would not happen in the US (the belt manufacturers would not have made the belt for them).

Mike, now that Justin has my curiosity up,  will you post the Kubota number and I will see what I can find in the way of belt specifications?

Jim

[rv_safetyman]

Justin, why do you post this crap   .  You must know that it gets my poor feeble mind working overtime

Diesel engines can  be very hard on belts because of the crankshaft torsional vibrations.  There are times that we had to develop special belts, and it looks like we did that for the 6.9 liter engine.  The fan/alt for your '87 6.9L lists a 9570 and 9570HD belt.  My guess is that the 9570 did not cut the mustard on that engine.  I can't tell too much about the 9570HD, but it must have come about after I retired ('99).  It seems to be a fairly recent construction using EPDM (we were not that far along on that construction).  It is a bandless molded notch belt with a green top cover and is a part of the "Fleetrunner" product line that did not exist during my time.

The most challenging automotive belt we had to design was for the turbo Corvair.  As you may recall, that was a "mule" drive where the belt had to bend 90*.  We did OK with the normal Corvair engines, but the rate of engine acceleration on the turbo engine coupled with the ability to drive the car aggressively would throw the belt every time.  When I became the manager of the belt test lab in '76, I spotted this crazy tester that was not being used.  It was a special tester for the Corvair.  It had the correct geometry and a DC motor with two speed controllers.   We could set two different speeds and then change almost instantaneously between the two to simulate a speed shift and/or a very fast acceleration.  The belts at that time were wrapped in a envelope cover and we had to develop a special "bareback" cover which had no rubber on the outside (kind of white on the outside).  It would slip slightly under the extreme speed changes and stay on the drive.

The bareback cover is used extensively in the lawn and garden market for clutching drive so that grandma does not do a wheelie.  

In the Automotive aftermarket, Gates was the best in terms of research and catalogs.  Our quality was second to none.  BUT we did not sell much to the automotive OEMs (considerably more profit in the aftermarket).  That hurt us a few times when the OEM had worked with a belt manufacturer to make a special belt to solve a problem.  Probably the case with your 6.9L.  It is always safer to go to the OEM if you are in doubt.

Now, back to my "normal" life

Jim

[justin25taylor]

Justin, why do you post this crap   .  You must know that it gets my poor feeble mind working overtime Snip.

Jim,
I knew that "someone" here on the board was a long time R&D guy for Gates. I just could not remember who. I wasn't really trying to get your dander up, it was just a side benefit. 
I will say here and now that I am a BIG fan of Gates products. I always use a Gates product if available. Hoses, belts, whatever! Gates makes great quality easy to find products.

I am glad to hear that there should be no difference in pulley sizes due to JASO,SAE,ISO all shooting for standard sizes. I have always wondered how that worked.
It was not my intent to mis-inform anyone, I was just posting what had worked for me in the past.

Thank you for providing the part numbers for the F-250 belts. I no longer have that truck. Someone sideswiped me and it was a total loss.
I would like another one someday. It was great for my needs.

My trusty old 96 Crew Cab, single rear wheel K-3500 with 6BT Cummins transplant proudly sports both Gates hoses and serpintine belt, and always will. Now if you could get them to make wiper blades that last longer than 3 moths like the ones we have now I would be a happy camper.

Thank you again for all you do Jim.

Best,
Justin

[Mike in GA]

Regarding the part/model number, the bus has just been dropped off with a mechanic for a transmission swap, and it is a good 2 hours away. Replacing the venerable 740 with a close ratio 5 speed. Won't get back to see it until next week, Jim, but will eventually post the generator and belt number.
     Many thanks for your interest and guidance.
Mike in GA

[rv_safetyman]

Justin, I think you know that I was giving you a hard time.  I love to get into some of my old routine.  Had a good time until the Gates family sold to a holding company.  Even then it was not too bad.

Gates had an interesting OEM/replacement relationship.  Our Product Application group worked with the OEMs (industrial/agricultural/automotive) and we maintained a huge file system of the OEM drawings/designs.  The aftermarket folks were not allowed to go near those files.  The trial fit EVERY hose and belt on each car/truck.  We had several vans that went around Denver and found the cars to trial fit - usually at the dealer  They carried pans for the antifreeze and all the tools plus tons of belts and hoses to trial fit.  They were very good at what they did.

The OEMs knew that their design information was not shared with the competition (our aftermarket).

Mike not a huge deal on the part, just curiosity.  I have to change the oil on mine in the next few days, so I will see what belt mine uses (better get a spare )

Jim

[justin25taylor]

Justin, I think you know that I was giving you a hard time.  

Absolutely Jim.

Thank you for sharing your knowledge with us.