| Author | Message | ||
| shawn bennear (Lilneoplan)
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I am picking my little bus up saturday morning in bloomsburg pa. I have to install new belts. I have had a few issues with fan belts throwing on the way from long island. The bus in question is my neoplan with the 8.2 liter engine. there are 6 belts on it, and the one from the crank/waterpump/air compressor is the one that keeps eating itself up. all kind of rubber grinds off of it, and it throws rapidly. Someone at work suggested doing away with the 2 seperate v belts and getting a "banded" v belt, which is like 2 v belts joined together. I ordered 2 of those. supposedly they will solve the whipping and throwing issue. has anyone else had these issues? and how did you correct it? is there anything else i should check? | ||
| David Hartley (Drdave)
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Something is out of alignment seriously or the belts were "automotive" style which won't work in a bus application. The width of the belt is very very important and belts should not ride in the bottom of the pulleys, If they do they are too narrow and will frag themselves out in short order due to slippage, heat and too much horsepower being required to be transmitted by the belts to the accessories. Banded belts won't fix a problem if the belts are the wrong dimensions for the pulleys. | ||
| TWODOGS (Twodogs)
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I agree....something is out of line or you have a bent shiv ..(pulley) | ||
| shawn bennear (Lilneoplan)
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yeah, they have been automotive style. Is there a preference in belts to use? thanks shawn | ||
| Mike (Busone)
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Something made in the USA like Gates. | ||
| Jim Shepherd (Rv_safetyman)
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Shawn, Neoplan had a huge problem with belts on a new bus configuration that was first used by LA. The bus was put into service just before the Olympics. Their busses were on the side of the road all of the time. I worked for Gates and we produced the belts for that application. Can you imagine what sort of priority that project had? Not sure if your bus might be of the same design or not. The big issue was that one end of the drive was mounted to the frame and the other to the engine. The engine mounts allowed the drive tension to change pretty drastically. In addition to that, the typical diesel engine crankshaft torsionals made the matter worse. For the life of me, I can’t remember what our solution was. However, I would think that there are Neoplan resources on the net that might help. Neoplan was not the only bus with this kind of problem. The general solutions are to use some sort of “soft” idler tensioning systems (often air cylinders, but can be spring loaded idlers). Also, some of the drives used “knock-down” bars that damped the large amplitude span vibration. These bars were usually round rod (at least ½ inch diameter placed just about the belt (about ½ inch from the belt in the static condition). My Series 60 conversion will have the same potential problem. Right now I have a pivoting idler with has a draw bolt to provide the belt tension. I have made a provision to place a spring between the draw bolt and the frame to soften the tensioning if needed. The problem with “soft tension” idlers is that they can get into their own sympathetic vibration. You will often see dampers on these systems. There is nothing wrong with automotive belts. Most typical “car” belt sections are pretty small and don’t work well on diesel engines for many applications. There are large automotive section belts (3/4 inch top width used to be standard belt for many applications). Some of the bus folks went with industrial section belts. In general industrial section belt construction is not as good as automotive belt construction because of the ambient heat involved. However, they did OK. As for joined belts (two or more belts joined together), they are not made in automotive sections (some rare exceptions and Neoplan may have been one of those exceptions). Joined belts are very common for industrial belts. As was pointed out earlier, the sheaves must be made to an industrial sheave standard in order to be able to use these belts. Bottom line, I would search out Neoplan technology and see what they did to resolve the problem. My guess is that the wrong belts are being used on your bus or that someone has modified the Neoplan design in some fashion. Sorry for the long post – especially since it does not have a real solution for your problem. Jim Shepherd Evergreen, CO ’85 Eagle 10 Bus Project details: http://www.rvsafetysystems.com/busproject.htm (updated 2/17/05) | ||
| Russ Barnes (Neoruss)
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Jim, I don't know if you helped Shawn, but your post may have helped me. I have an '81 Neoplan that was made just as you described the '84 Olympic double deckers that used 6V-92's. Mine had an 8V-92 and I also purchased an '86 8V-92 powered double decker from the KSC fleet used in FL and they also had the same design, so somehow it has worked. It's getting very difficult to get good factory support from Neoplan so Shawn may want to go to the Yahoo Neoplan group to at least get a network of nuts like me that have limited experience. I am installing a 60 Series and plan on using the original belt drive, but it will be many months before I buy and install the belts. I have the latest Prevost mounts for a 60 series, not the truck mounts so movement may be an issue for me. Neither of the Neoplan buses I have experience with have the "knock-down bars" or any idlers, but I may have to keep that in mind. Frankly I thought it was a poor design, but after seeing many of these in service somehow they made it work. The only clue I can add is that the 8V-92 mount for that end of the engine mounted in a circle around the crank, not on pads like my 60, that way the rotation of the crank axis may limit the movement to keep the belts from hopping. | ||
| Jim Shepherd (Rv_safetyman)
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Oops, I should have read your question a bit closer. Your problem is on the engine only. That is quite a different problem. I am going to leave the previous post in case someone else has an engine/remote fan drive problem. The first thing I would do is to find out what the Neoplan part number is for this belt. You will want to get either the OEM belt or a good DIRECT replacement belt. I looked in one of my old catalogs and several buses are listed, but not Neoplan. I did find several 8.2 engines and they use mostly automotive belts with a nominal top width of 31/64. In one application it appears that Gates made a special belt for the air brake application. If you can find the OEM number, I might be able to cross it for you and then you could go to NAPA and get the correct belt. (BTW, just walking into any of the big parts stores will generally get you the “deer in the headlights look”). You will need to do your research ahead of time. It bothers me that you say that the belt is “eating itself up”. That could be because the wrong belt is being used, or it could be a hardware or maintenance problem. As already noted, you should check the sheaves to make sure there are no dings or other defects. Secondly, you should check to make sure the sheaves are not worn out. If there is any polishing on the bottom of the belt or in the bottom of the groove, the pulley is worn out, or the wrong cross section is being used. In the area of maintenance, you need to make sure the belt is pretty darn tight. The typical air compressor requires quite a bit of power, and it looks like Detroit only used one belt (your description as well). That being the case, the belt will have to be pretty tight. I would guess that "Da book" for Neoplan would tell you how to tension the belt. Lets see if that helps. Jim | ||
| Jim Shepherd (Rv_safetyman)
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Russ, I am glad that my “misdirected” reply might have helped you in your thought process. As you will see, I posted another reply that was directed to Shawn’s problem. When you say that they somehow found a way to make it work, you have hit the nail on the head. The OEMs and belt folks probably worked closely on each of these applications (drives with center distances that move due to engine movement) to resolve the major issues. Sometimes that was a special belt design/construction (best example was the high performance engines in the Corvairs with the “mule drive” – every belt manufacture had a special belt just for that application). Sometimes it was a hardware solution that generally involved a lot of field testing. We, in our infinite wisdom, change those things as we make our conversions. Then we wonder why we have problem (grin). Even though I spent 34 years at Gates and retired as Chief Engineer, I am very nervous about my belt drives for the fan in the Eagle. I gave it a lot of thought and even made drawings of the various groove profiles involved. The engine and fan clutch use automotive grooves and the rest of the drive uses industrial sheaves. I think I made some pretty good design decisions, but the real test will be when I fire up the engine (hopefully in the next couple of weeks) and put it on the road. Jim Shepherd Putting a Series 60 in an ’85 Eagle 10 | ||
| RJL Rating: N/A |
Hey Jim - Remember GM part number 3780981???  RJ | ||
| shawn bennear (Lilneoplan)
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well, I called neoplan and talked to them today, and they told me that automotive belts were a no no. the 8.2 will eat them alive. he gave me dayco part numbers, which i found locally, and they are surprisingly inexpensive. i'm getting a surplus of these belts! thanks! shawn | ||
| Jim Shepherd (Rv_safetyman)
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RJ, I assume that is the famous Corvair number. I started working in belts after most of the work was done. I did inherit the Corvair tester when I took over the test lab in 1976. It was sure a neat piece of equipment. It was the mule drive configuration with idlers that could be moved to simulate the extremes of the application misalignment and had a two speed motor that would shift speeds almost instantaneously. We ran it a few times for another project and it was sure fun to see how BAAAAAAAAD the test was!!! Shawn, would you mind letting us know what the Dayco belt number is. I would really be surprised if it is not an automotive belt (as opposed to an industrial belt). Dayco makes a tremendous belt and I would guess that these belts will do the job. Again, be sure to tension the belt quite a bit so that it does not slip when the compressor reaches max pressure. Also, as someone mentioned, make sure the alignment is good. You can eyeball it pretty good by sighting down the sides of each pulley looking each way. However, it is best to use a straight edge. The secret to using a straight edge is to shoulder it on one pulley and rotate it into the each adjacent pulley. Then do the same process for each pulley in the system. It is difficult to see misalignment when you put the straight edge on both pulleys and look for clearance, but by using the "shouldering" method it jumps right out at you. Also look at the old belt and see if it is more shinny on one side. If the appearance is quite different from side to side, you have a pretty significant alignment issue. Jim | ||
| shawn bennear (Lilneoplan)
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and get this... the belts are also used in RIDING MOWERS!!! apparently they are better suited than a car belt. the dayco numbers are AP73, AP57, and AP46 gates and goodyear are the same, just take the "P" out of the number. we hopefully will be good to go now | ||
| Jim Shepherd (Rv_safetyman)
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Shawn, those are, indeed, industrial belts. The AP belt is Dayco's Super Blue Ribbon construction which has a premium high temperature(neoprene) construction. It is a wrapped belt (has fabric all the way around). Many manufacturers do not use neoprene in what is called Classical (that is industry nomenclature) belts (A, B, C, etc). The typical industrial application does not need high temperature resistance and for that reason the typical Classical belt uses a less expensive construction. Dayco has chosen to go to the higher cost construction for the AP product line and the customer benefits. If anyone goes this route, be sure that the belt is labeled AP. While the belt will interchange dimensionally with an A73, the AP is a premium construction and will give much better service in this demanding application. To the best of my knowledge, Dayco is the only manufacturer of premium Classical wrapped belts. There are notched premimum belts that are "cut" or raw edged belts and they are all premimum construction as far as I know. The wrapped construction is considered old technology, but it does a great job for certain tough applications. It is still the standard for most agricultureal belts where dirt, tough application conditions and misalignment can often occur. I am pretty sure that the typical 8.2 Detroit engine uses automotive belts, so I guess that using an industrial belt causes this falls into the category of “making it work”. Jim | ||
| shawn bennear (Lilneoplan)
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yes, the ap 73 is the belt for the air compressor, the ap 46 is the belt for the alternator, and the ap57 is for the cooling fan. it takes 4 of those. gates belts are a few bucks more, and are the same number, just without the P shawn |