Hi, I just busted the water pump/alternator belt. It had been squealing and I did not re-tighten it therefore it failed. The WP bearings are fine as well as the alternator's. But I also think that the belt is really dinky. It looks like something should be in a VCR or cassette deck. What would be the draw-backs in reworking the pulleys from the alternator, WP and harmonic balancer to be able to use a beefier belt? Possibly one benefit is that it should be cheaper to buy it. It seems that there is enough metal on the pulleys to be able to perform this easily. Any thoughts? Thanks, Gianluca
Hi Gianluca, Was the belt old? I think sometimes people are tightening belts repeatedly when they should be replacing them instead. As I'm sure you know the rubber hardens with age. Maybe the pulley grooves have oil or grease on them, coolant etc. Re-tightening an old belt many times or using various sprays on an old belt seems like a band-aid to me. Not saying this is the case with your situation. I think if you put on a beefier belt you would have more trouble setting it to the right tension and more chance of getting the tenison too strong and end up damaging the water pump bearings. The water pumps seem to be a bit fragile to start with. How did you belt fail? Did it melt or break apart? If it broke apart it sounds like it may have just been old age more than lack of tension causing slipping. Erich
I have been wondering what the avg. life is of this belt. Specificly the single belt early 308's. I have had my belt on fo about 5 years and it still appears to be good. No noise and functions well. So is the general concensis to run to fail or is there a time/mileage interval in which most folks change them. I had also seen at our local track during the vintage races that a 308 had a tooth belt setup but I could not get info on it. So is/has anyone checked into pulleys and belts. I assumed that a timing type belt setup was better due to the tooth design compensated for belt tightness. So are there standard pulleys available?
It seems like a pretty wimpy belt for all the important stuff it has to run. I replaced mine when I was doing all the other major stuff like the timing belts. That belt doesn't cost much as I recall. Sure beats breaking down because it snaps.
I thought it looked whimpy too the first I seen one. But they seem to hold up fairly well. So you really have to wonder why Ferrari would use it. Perhaps at the very high speeds its moving, the smaller belt can negotiate the small pulleys easier.
I never had much trouble with the WP belt on my carbed ex-308 -- it's the 308i and 308QV, where they added an extra 15~20A load on the alternator to run the K-Jet system that have the trouble (i.e., a WP freezing up and breaking a WP belt on a carbed 308 doesn't count as a "belt problem") It's really a unique V-belt system -- it has much lower HP losses, not just because it's a physically small belt, but due to the large angle of the "V" (doesn't "stick" so much into the "V" of the pulley so less losses). IMO, the later 3-belt fix is approaching "too many belts" so can understand why F tried to stay with the 2-belt design from the carbed 308.
My belt was installed new when I did my engine-out service about 2-3 years ago. It did snap but just because it started wearing thinner and thinner once it started slipping. I beleive I should have re-tighten it. I did put some belt dressing on it and, while it may have made it a little quiter, it probably did accellerate the wearing from the increased friction but with slippage. I was very close to home and at first I thought the alternator had failed because the idiot light on the instrument panel was solidly on. Good thing that light is there! Of course the first thing I checked, just in case, was the belt. It seems that the consensus it that the belt is a little small but it does the job is supposed to. Probably I was too tentative when I tighten it for fear to damage the WP bearing. I purchased the $ 36.00 alternator mentioned in the sticky thread for replacememt parts. I will post my impression of it when I get it. The new belt is already here. The belt is, in the hreater scheme of things, cheap but it is still expensive as far as a belt is concerned. I noticed that about the same time I started having the belt slippage, the car was running pretty rough. After the belt broke, it seemed that the car was running better. Is that a possibility or it was my immagination? Could a slipping belt cause a rough running car? Gianluca
Gianluca, Maybe this guy in London can help you out with a better pulley system for your car (see photo). In the thread he is referring to cam pulleys but have a look at his water pump. If your belt was slipping a lot your output voltage may have been dropping low now and then. You may have been getting low or erratic voltage from the coils causing rough running. The voltage regulator can only do so much..... Still waiting to hear from you regarding a soft top! Erich >>>>> #128 Today, 12:46 PM dell550 Rookie Not Subscribed Join Date: Aug 2005 Location: London Full Name: george c Posts: 46 Hey just happened across this thread-been making these for my 308 race engines for the last 10 years with no problems-currently out of stock but a new batch will be ready in 6-8 weeks and will then fix prices if any body wants them.I also have drawings for 328 and Testa Rossa pulleys.<<<< Image Unavailable, Please Login
Ahhh, the wonder of poly-belts...... I break one about every year. If you hear the SLIGHTEST squeal, you need to tension the belt like right now. it has about a 10-15 second life at 3000 rpm once you hear noise. The worst belts ever conceived I've given a lot of thought to reworking the pulleys, I have a lathe, so it's just an afternoon job to pull, cut, replace. The problem is that because the poly belt is so small, it works on small diameter pulleys were a larger cross-section belt won't. So just re-cutting the grooves would be a mistake IMO. You would need to make new larger pulleys or sleeve the originals maybe to get a diameter that will work properly with a larger belt. The other option is a 3 or 4 rib serpentine, similar to the posted picture, but again new pulleys are required.
Before y'all go re-engineering everything, check the bearings inside the idler pulley. There are 2 pressed back-to-back inside the pulley. These are not normally replaced during a major service and I have seen these start to fail now that they are 20+ years old. When those bearings fail and the pulley starts seizing, the Gates belt (properlytensioned "guitar-string tight") will start squealing as it drags across the aluminum pulley. The ribbed/reinforced outer edges of the belt will then start cutting grooves into the pulley. This will be easy to spot as you will be able to see the shiny aluminum "grooves" on either side of the "V". If you engineer/machinist types wanna help, start whittling pulley's out of steel instead of the no longer available and very rare Aluminum/Unobtainium alloy the pulleys were originally constructed in.
I am in the position of having to make a new set of the pulleys for water pump and A/C tensioners on my (newly acquired) QV. The mechanic who did the last belt job (1) put the wrong belt on the alternator and (2) put the A/C compressor out of line with the balancer pulley with the result that both pulleys are now scrap as well as the one on the A/C compressor. If anyone is interested I can make up a few extra since the CNC will be set up anyway. I priced them at Ferrparts. ha ha ha ha ha. Does anyone have an opinion as to know whether steel would be a better choice that anodized aluminum?
