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
Jerry ,
How is this going? Is it resolved? Or still an outstanding question?
Kind Regards, Phil
Hi Jerry,
My Part Manual for the 88' 102c3 8V92 says,# 8L-27-69 MCI #'s Engine/fan/drive
Good Luck
Nick-
Do the 102's have a adjustment on the air cylinder like the 9's? ???
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.
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...
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
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".
Back
MCI Has a SERVICE BULLETIN No.2539A
I can fax this Bulletin to you
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
The air adjuster being at its limit would definitely indicate that the belt is too long, in my opinion.
Richard
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.
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
There you go Jerry...
Sounds like a simple fix now...
Good Luck
Nick-
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.
Jerry, another thought is that the blower belt is not "tight" similar to the AC belt on my bus. If the tensioner tightens the belt and the blower pully stops in approx a horizontal position, it may be working normally.
You may want to check the pressure on the regulator (I may have missed something here in the thead too) for the belt tensioner. Does the blower pully move beyond the horizontal? Is it limited by lack of vertical travel? If so, a shorter belt will get the blower going, but you may want to check some dimensions. Compare to another similar coach. Nick has one.
It's possible that the other issues are causing what seems to be a belt problem. Maybe the drive sheaves are too close together? This would be easy to determine.
The width of a belt controls how deep in a pulley it settles. Is your belt the correct width?
Anyone feel free to correct, but I believe that the tensioner regulator pressure is about 21 lbs. May wish to verify the regulator pressure.
Then put the belt back on and see where the blower drive stops when aired up. What arc does the belt limit the blower drive at?
Is it above horizontal? If the fan drive is about horizontal, the system is working. If it goes beyond horizontal upward, belts too long.
Just some thoughts!
I'll catch the anwers tomorrow. Spousal component is making declarations that I should be upstairs about now. So I'm off...like a whupped puppy! We hope! Beat me! Hurt me please! :D
Best, JR 8)
I put the two belts side by side and did a strech and when the old belt gets taught the new on is loose and definiitely longer. So I am convinced that it is a belt problem. The old belt is stamped in red gates power belt C120 and the new one white gates C120 so it seems to be that the samew part number from the same company shud be the same but is not. Jerry
Hi Jerry,
I just checked my blower belt. I have the 89' C3 with a 8V92, should be the same setup.
GoodYear "8K-27-7" then there is a "0791" which may be the date and a # "16"
Hope this helps
Nick-
Quote from: Jerry32 on April 11, 2007, 06:50:19 AM
I put the two belts side by side and did a strech and when the old belt gets taught the new on is loose and definiitely longer. So I am convinced that it is a belt problem. The old belt is stamped in red gates power belt C120 and the new one white gates C120 so it seems to be that the samew part number from the same company shud be the same but is not. Jerry
Reckon the new belt was made in China? That may explain the difference. ;)
JR
Nick some one brought up the 8k 27 7 number before and I gave it to Napa but it didn't cross reference to gates so now I will try goodyear and see what happens. Jerry