Fan Belt size MCI

Jerry32 · March 25, 2007, 11:35:00 AM

I replaced the fan (blower) belt before starting home with the bus as the other one was dried out and cracked and shiny from slipping. The old belt had C120 on it so I replaced with the same size . The new belty seems loose and the air adjuster is at it't limit. Can someone with a part manual confirm the belt size 8V92 102c3 Jerry

plyonsMC9 · April 08, 2007, 05:44:35 PM

Jerry ,

How is this going? Is it resolved? Or still an outstanding question?

Kind Regards, Phil

Nick Badame Refrig/ACC · April 08, 2007, 06:00:15 PM

Hi Jerry,

My Part Manual for the 88' 102c3 8V92 says,# 8L-27-69 MCI #'s Engine/fan/drive

Good Luck
Nick-

Ednj · April 08, 2007, 06:06:29 PM

Do the 102's have a adjustment on the air cylinder like the 9's?

busnut104 · April 09, 2007, 03:50:15 PM

My air cylinder got leaking so I took it off and used a turn buckle. Our local bus co.does this to all there buses.

NJT5047 · April 09, 2007, 06:14:06 PM

Hi Jerry,
I looked on the spare for my MC9 and don't see any length indicators...just the MCI part number.
Maybe someone with a C3 could measure the distance from the fan drive center to to engine drive center and compare.
You may have a slightly displaced fan assembly. There is a good bit of rust in the area...is it possible that the fan blower assembly or the tensioner mount has sagged a little? Or maybe the fan tensioner cylinder isn't moving thru its full stroke?
Or, maybe you just got the wrong belt?
I was looking at my blower and the fan pully moves over a long arc...it will move so far upward that the belt probably wouldn't stay on. But the belt limits the travel to about plumb with the engine...reckon that's good. Is your fan drive moving through the full articulation?
Post what you find. Do you have a part number for the C3 belt? Is it the same as an MC9?
Best, JR

Oopsie...just read Nicks post again...not the same part number as my MC9...

Jerry32 · April 09, 2007, 06:52:50 PM

I'll have to try the part number for a conversion but the old belt on mine had a size of 120 C so I ordered that belt and it seems to large on there as the air cylinder is bottomed out and the belt is still lokks loose to me. I have been making a big pile of scrap out of some of the insides and have a lot of seats to go as well as parcel racks. I am down to the rest of the washroom as the foward wall and door are out now looks to be drilling rivits to get the stainless out. I had to take time to get my income tax done so will get back to itr when that is shipped off . My old MH is sold so that is out of the way. Took some 24.5's of a semi trailer out here and use them on the bus. Jerry

Paul · April 10, 2007, 05:57:33 AM

HI
After paying MCI price for a Gates belt, I called local Gates Rep to get a spare. Found out that MCI has Gates make a special size for them that can be bought from them only. The part number for the MCI belt they sent for a 8V92 in a 102A3 is 8K-27-7, lenght 122.12" + or - .50".

Paul · April 10, 2007, 06:06:32 AM

Back
MCI Has a SERVICE BULLETIN No.2539A
I can fax this Bulletin to you

Jerry32 · April 10, 2007, 07:33:59 AM

Maybe I should check the belt I have as if a 122 inch belt is right then why is a 120 inch belt too long?? Maybe a mis label or as JR says mechanical changes in the bus. I didn't have any cooling problems with it on the trip home allthough the warmest weather I went through was about 80 and wouldn't that feel good now. As for the frame in the back where the rust was seems solid as far as I can see . I took some of washroom out and the frame is clean and red with primer. I don't have a land line for fax paul. just cell and satellite internet. Jerry

DrivingMissLazy · April 10, 2007, 09:29:15 AM

The air adjuster being at its limit would definitely indicate that the belt is too long, in my opinion.
Richard

Stan · April 10, 2007, 09:49:59 AM

This info may or not help or may just confuse. A 120 C is an industrial belt with a pitch length of 122.9".

The pitch length is measured at a point somewhere between the top and bottom of the belt where power transfer takes place. This iwould be the spec MCI would give Gates and accounts for the lenght given in the part number.

Another consideration is that your bus will use an automotive belt, not an industrial belt. Dimensions are close but not alway identical. Automotive belts are designed for automotive use and if nothing else should give better service.

My personal opinion is that the 120 C should be a reasonable substitute for the MCI part number.

All of this is assuming that everything is original as the bus left the factory. If someone put a smaller pulley on the blower to get better cooling then the standard belt will be too long.

Jerry32 · April 10, 2007, 02:57:24 PM

After comparing the belts to each other I find the one I took off (old one) is a gates C120 and the new one a gates NAPA belt C120. The NAPA reads as 124" long X 7/8" and is longer than the original gates that came off.

?? Jerry

Nick Badame Refrig/ACC · April 10, 2007, 03:24:22 PM

There you go Jerry...

Sounds like a simple fix now...

Good Luck
Nick-

Stan · April 10, 2007, 05:37:34 PM

The standard tolerance on a C belt is +1.2" and -.5" at the pitch length. If you get two belts at the extreme tolerance they could be 1.7" difference. If your tightener cannot cope with that much you will have to ask the dealer to select a short one.

If you are interested, the pitch diameter on a C pulley is measured .505" down from the top so a C120 belt should maeasure 122.9" when measured about .5" down from the top.