| Author | Message | ||
| Donald P H (Eagle19952)
Registered Member Username: Eagle19952 Post Number: 37 Registered: 11-2007 Posted From: 75.202.207.177 Rating: N/A |
So here is a follow up to my belt wear problemo!!! Well here I go again,I need your help again.I have analyzed and scrutinized my belt problem and I think I have identified the problem.I bought a set of Gates pulley and belt wear guages,and these have told me that the fan pulley is virtually un-worn,the guage for degrees of correct is designed to show sheave V wear at 3 different OS diameters.FYI> For the B and BX belts a pulley diameter 3.60" to 4.56" dia. should be 32 degrees. For the B and BX belts a pulley diameter 4.60" to 7.00" dia. should be 34 degrees. For the B and BX belts a pulley diameter OVER 7.00 dia should be 38 degrees. Using the guage I find minimal wear on the fan pulley ( over 7 inch) (this is good,I won't need to remove the radiator yet) the wear guage clearance in the fan pulley V's,is less or close to less than .005-.008 Using the guage I find severe wear on the adj,idler pulley in the 4.60" to 7.00" dia. range, the wear guage clearance in the V's is geater than .030-.050 per/on each side of the guage. Using the guage I find severe wear on the angle drive pulley greater than the wear on the adjuster pulley. So I quess what I need to know is who or where I can get these pulleys from, does anyone have spares,take offs or salvages ? At least these particular ones are more easily accessed. The pulleys/belts with the most wear show that the pulley V's wear the belts mostly on the V side nearest the radiator which I will refer to as the outside. The outside V's have more wear than the inside V's but still well worn.Thus perhaps the reason that the outside belt turned over in the groove.And the inside remained in the groove. I THINK that the alignments are good. Any Eagle fans, BusNuts or BCM folks got any suggestions. PS. I am posting this on all the boards,THANX for any help. | ||
| George M. Todd (George_todd)
Registered Member Username: George_todd Post Number: 1069 Registered: 8-2006 Posted From: 99.184.9.29 Rating: N/A |
Don, In reply to your previous post, I suggested that your pulleys were either offset, or out of alignment. My post was seconded by someone well known for sound advice! We need to get this into perspective also. .030-.050 is between 3 and 5 HUNDREDTHS of an inch, which isn't much! A worn pulley will let the belt bottom out, not turn over. Belt wear on one side, and then turning over, is the classic indication of misalignment. I read your previous post carefully, specifically the parts about the miter box being "bolted in place with no adjustment..." which doesn't mean that it is properly aligned. The bus could have been bumped in a rear corner in its previous life, and you mention that the fan is not stock. Pulleys out of alignment, (not offset) will cause one of a pair of belts to wear more than the other, which is a symptom you describe. So, my suggestion again is to get with a straight edge and verify your alignment and or offset. G | ||
| Donald P H (Eagle19952)
Registered Member Username: Eagle19952 Post Number: 38 Registered: 11-2007 Posted From: 75.202.207.177 Rating: N/A |
Maybe I am not to clear and I do appreciate your input. my wear dimensions are on both sides of the gage so in fact the wear of .050 thousandths would be doubled,(.060 = approx 1/16" or 1/8" total,this seems a lot to me...)and are only eyeball measurements,i will feeler guage them to be more accurate,just because I want to know,but they are badly worn and i believe that the belts are bottoming out because the sheave V's are showing slight rust appearance and not a clean "polish" as would be seen if the belt contacted the faces properly. I HAVE been wrong before,and I cannot pull the radiator where I am,I do believe that the pulley wear is much worse than the alighnment,i have checked each as good as I can with what I have...so I can only try to fix what i can in someone elses RV park as I don't have $$ for a shop right now. I will do my best to recheck the alighnment, I do have a reasonably good metal straight edge. thanks George. (Message edited by eagle19952 on July 13, 2010) | ||
| Donald P H (Eagle19952)
Registered Member Username: Eagle19952 Post Number: 39 Registered: 11-2007 Posted From: 75.202.207.177 Rating: N/A |
PS. if the rear corner of the coach was "bumped" it is very difficult for me to see it,the radius and tubing looks original on both rear corners and seems to have smooth factory looking contours.the tail light doors and hinging all seem to line up.... I DO appreciate ALL the help and input,I will solve this problem one dollar and step at a time. | ||
| Donald P H (Eagle19952)
Registered Member Username: Eagle19952 Post Number: 40 Registered: 11-2007 Posted From: 75.202.207.177 Rating: N/A |
PS I am hoping RV safetyman could pipe in and explain why the degree of sheave dimension/degree is different from one diameter to another. Perhaps a call to Gates is in order. | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 911 Registered: 8-2006 Posted From: 74.32.84.228 Rating: N/A |
Don, give Jim a call his number is public he is in SD now and may not have service good luck (Message edited by luvrbus on July 13, 2010) | ||
| Donald P H (Eagle19952)
Registered Member Username: Eagle19952 Post Number: 41 Registered: 11-2007 Posted From: 75.202.23.30 Rating: N/A |
Left a mesage on his phone,will try again,I had chkd his web site,wasn't sure if he was around THNXS DPH | ||
| Jim Shepherd (Rv_safetyman)
Registered Member Username: Rv_safetyman Post Number: 308 Registered: 1-2004 Posted From: 75.221.207.142 Rating: N/A |
DHP, we are in Devil's Tower, WY and do not have a cell signal, so I can't get my messages. All belts change angle as you change the belt radius of bend. You can kind of get the picture if you bend your finger and see that that bottom goes into compression and expands. In the early days, the belts had a ton of cotton fabric in the bottom under the cord/cord fabric and they "bulged" a lot more than today's belts. To compensate for that angle change the industry standardized on a sheave/pulley design that had compensating angle. Automotive pulleys only have one angle, but the belts are thinner and don't have as much angle change. If the wear is the same on each groove of the adjustment pulley, you might not need to change it. I am amazed that it is worn. The wear occurs when the belt is slipping slightly as it transmits power in the pulley. The belt becomes embedded with dirt and that forms a wonderful abrasive surface that wears the pulleys. Dirt is a real problem back there. I think you are describing wear that is worse on the outside groove of the pulleys and that is consistent with abrasive wear. Changing the driver (angle box) pulley and putting new belts on will probably solve the problem. Changing the adjusting pulley is a bonus. As I mentioned in a previous thread, this is a fairly long center drive that has no significant pulsating loads. As such the affect of misalignment is probably minimal. If the sheave grooves have wear that is different from groove to groove, the one with the most wear will have less tension and that belt will probably dance around more and turn over (often taking the other belt out as well. Jim Jim | ||
| Donald P H (Eagle19952)
Registered Member Username: Eagle19952 Post Number: 42 Registered: 11-2007 Posted From: 75.202.223.112 Rating: N/A |
Thank-you all. it is always good to bounce problems around,I have worked in the Heavy Eq/construction Biz for a long time,( retired now )around gravel crushers too..and have not seen pulley wear this bad. When I find new ones and am all done i will try to photo and post the worn ones. If the sheave grooves have wear that is different from groove to groove, the one with the most wear will have less tension and that belt will probably dance around more and turn over (often taking the other belt out as well. THEY ARE. JIM: if you get back here,I talked with a person at Motion Industries out of Mobile,AL. They seemed to think that ONE belt would be OK in a pinch...that the heat slippage caused by the most worn sheave contributes to the failure of the remaining belt. The belt that did not "flip" probably still had about the same deflection as when it was installed,.. MY hesitancy would be with one belt I would not have time to get off the traveled road....to a safe place. When the belt/belts start to slip i can actually smell them,smells like driving through a fresh asphalt paving job...and I've done a bunch of that.. BUT I am on the search for new pulleys. | ||
| Kyle Brandt (Kyle4501)
Registered Member Username: Kyle4501 Post Number: 586 Registered: 9-2004 Posted From: 65.23.106.193  Rating: N/A |
When you take into consideration the geometry & that is the driving surface, 0.030" is a large number. No question, replace the belt and pulley! (If the belt was soft enough to conform to the dished out groove, it wouldn't be hard enough to last.) Foreign stuff on the belt (like oil or belt dressings) can lead to premature sheave wear. The stuff allows grit to embed in the belt where it acts as an abrasive in the groove. It is worse on the smaller pulleys due to the higher surface pressure from the lower surface area (belt tension divided by pulley surface contact area). A worn groove allows a belt to ride lower, which shortens the effective belt path (reduces tension for a fixed center distance). Also, a worn grove doesn't support the belt properly - an unsupported belt will turn over in the groove lots easier than a properly tensioned & supported belt. For whomever wants to read a little more on V-belt installation & maintenance: http://www.bandousa.com/html/pdfs_tech/v_timing_install_maint_25168.pdf (Message edited by kyle4501 on July 13, 2010) (Message edited by kyle4501 on July 14, 2010) | ||
| Jim Shepherd (Rv_safetyman)
Registered Member Username: Rv_safetyman Post Number: 309 Registered: 1-2004 Posted From: 75.221.222.216 Rating: N/A |
DPH (sorry I got the letters mixed up last time), I suspect you can run on one belt for a while. You will need to increase the tension on that belt (about twice as much), but that drive is probably designed pretty conservatively given the need to keep a commercial bus on the road. Most folks consider the redundancy of two or more belts to be a "safe" thing. In truth, the belt that fails often takes out one or more of the remaining belts. Jim | ||
| Donald P H (Eagle19952)
Registered Member Username: Eagle19952 Post Number: 43 Registered: 11-2007 Posted From: 75.200.128.234 Rating: N/A |
I was able today to locate new pulleys,so in 3 days or so I WILL HAVE THEM REPLACED,I did temove the adj/idler pulley today and my old eyes in the sunlight can confirm that the sheaves are worn differently,that the groove outside/closest to the radiator was DEFINATELY bottoming out in the groove. I think I am on the right track. I should have got this fed up two sets ago.... I'll try to post pics in a day or so if there is any interest or "for the archive". | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1235 Registered: 10-2006 Posted From: 99.156.68.151  Rating: N/A |
Just a thought , If you are using dual belts , NAPA can get you matched sets , that seem to work better. FF | ||
| Jim Shepherd (Rv_safetyman)
Registered Member Username: Rv_safetyman Post Number: 310 Registered: 1-2004 Posted From: 75.221.102.74 Rating: N/A |
FF We went over that in another thread. These are industrial belts (not automotive) and they are made in what the industry calls a "no match system". Belts made by any of the big manufacturer will match each other (for that manufacturer). If NAPA is telling you they have special matched industrial belts, they are playing games with you. They sell Gates belts and I can assure you that the belts will match. Again, I need to make sure that we are talking about industrial belts (in this case "B" section belts). If you are talking about automotive belts, you are correct. Jim |