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Author Topic: Flywheel timing belt snapped Jon Morgan Film Handler Posts: 60 From: Raleigh, NC Registered: Mar 2005 posted 08-23-2005 12:37 PM                     So I'm having a bad day... At the beginning of a show today a belt snapped on one of my projectors (Simplex 35). It appears to be the timing belt that runs from the projector motor to the flywheel. I'm about to call and order some more right now, and I'm going to do my best to get a tech out here tomorrow, but we've never had a reliable projection tech at this theater (yeah, yeah, I realize that's bad, but it's a long story). Anyways, what would have caused this? I'm assuming it's just something that happens over time (this belt has been on the projector for at least 1-3 years). Any advice?  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 08-23-2005 12:43 PM                        Do you inspect your belts on a regular basis, looking for wear or physical deterioration? Any obvious wear points or misalignment, seen by belt debris at the wear point? Does the mechanism driven by the broken belt turn freely, without drag or binding? I'm sure others will chime in asking for more details.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 08-23-2005 12:50 PM                     turn the machine over by hand to make sure it has not siezed up causing the belt to break  |  IP: Logged Dominic Espinosa Phenomenal Film Handler Posts: 1172 From: Boulder Creek, CA. Registered: Jan 2004 posted 08-23-2005 01:02 PM                     Is the old belt brittle? Does it have cracks? Also be conscious of the belt tension. I don't imagine you could do more than stretch it slightly but you'd be more likely to ruin the bearings.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 08-23-2005 02:26 PM                     Any fabric and rubber toothed belt will age over time by drying out and getting brittle. The same with our belt in our overhead cam cars-either import or domestic. Reason for mandantory belt replacement at a certain given time. Simplex belts needs to be inspected at least once weekly, especially the round tooth variety-being that they are much stiffer than the older, thinner flat tooth variety. If cracks are showing up on the flat outer surface of the belt, time for the changeout. When you get that "tech" out there, have him do a complete machine imspection of all the belts and do the replacement necessary. (and this goes for the ones who have the Christie 35/P35GPS models as well: mandantory belt checks and changeout every year) Too bad you don't know how to change one, or both of them out, for it's only a 20 minute to a half hour job to do, if one is trained properly on the procedure and proper tools at hand. Luckilly, it was the motor belt, not the drive belt, or if it was the other, you'd have a good mess on your hands. I've done changeouts inbetween showings. -Monte  |  IP: Logged Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 08-23-2005 04:59 PM                     Jon, the flat style "timing belts" for the Simplex 35 can be purchased at any good auto parts supply store. About $12.00 each.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-23-2005 08:26 PM                     quote: Monte L Fullmer Simplex belts needs to be inspected at least once weekly, especially the round tooth variety-being that they are much stiffer than the older, thinner flat tooth variety. If cracks are showing up on the flat outer surface of the belt, time for the changeout. When you get that "tech" out there, have him do a complete machine imspection of all the belts and do the replacement necessary. Reeally, why piss off customers for the sake of 30 dollars worth of belts. I replace belts every year if the theatre is running all 6 or more shows a day and every two years if running less than that.... Its just not worth loosing a show, refunding or handing out passes, and pissing everyone off including yourself. Mark  |  IP: Logged Frank Dubrois Jedi Master Film Handler Posts: 896 From: Cleveland, OH Registered: Mar 2005 posted 08-23-2005 10:51 PM                    How about belt dressing? Would that helped improve the belt strength and possibly prevented this?  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 08-23-2005 11:54 PM                     Belt dressing is usually okey for the "V" belts, but not as well for the toothed belts. "V" belts are made for extreme tightness, whereas the toothed belts can't be run as such. Toothed belts will bust in a heartbeat if run "fanbelt" tight-in as well as being excessively noisy when operating-being so thin. But, I'm never crazy in "cheating fate" or, "doing things half-assed" - if a belt approaches the need to be changed, do it. Don't crimp on additives to lengthen the life of such items. -Monte  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 08-24-2005 07:49 AM                        "Belt Dressing" does NOT strengthen a belt or reverse deterioration. It is usually just a solvent that increases the friction against the pulleys to reduce slippage and noise. Using a solvent on a belt may actually hasten deterioration.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-24-2005 08:58 AM                     Belt dressing usually reduces wear on the pulley itself. At Joe's suggestion I tried Film-Guard on a couple of sets of Christie belts and it does eliminate all belt shedding and doesn't seem to be detrimental to the belts either..... Mark  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 08-24-2005 10:44 AM                        The "belt dressings" I was referring to are the aerosol ones containing solvents like naphtha, perchloroethylene, acetone, etc. --- definitely can harm deteriorating belt materials.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 08-24-2005 12:10 PM                     quote: Mark Gulbrandsen tried Film-Guard on a couple of sets of Christie belts ...LOL...I used to do that continually at the 21 complex that I used to work at - got a noisy belt, just open up the back, turn on the motor, zap FG on moving belts and instant quiet.....until I figured out the proper belt tension on these beasts, then I eventually quit the practice. When it was time for belt change, those belts that were FG'ed, still had a bit of a rubbery feel instead of being dry-even the shutter belt wasn't all beat up as they are normally after the 6 month usage.  |  IP: Logged Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 08-24-2005 03:54 PM                     What is the proper tension on a flat belt on a Simplex 35?  |  IP: Logged Wolff King Morrow Master Film Handler Posts: 490 From: Denton, TX, USA Registered: Feb 2004 posted 08-24-2005 04:02 PM                        It would help if Strong actually made a guide booklet for doing this work. I had to use Monte as a guide writer for my instructions (thanks bro!).  |  IP: Logged

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