That's the cool thing living in the 1st world we got choice. You are free to choose whatever you want. What you call popular opinion I call hard won over decades of experience. You see I have used only Ferrari bearings when that's all there was. I used the 1st Hill bearing when they had no serial numbers. I did not need to be a scientist to see the grease puking out of the OEM tensioner bearing yet the grease staying in the Hill bearing. I could feel the roughness of a used OEM bearing that still was not near failing. But a similarly used Hill bearing was smooth. I don't need to be a scientist to feel a 0.001" of play and want something better. For the very little difference in cost I'll take the hill bearing and a Ferrari branded yellow T belt. I do my own work so I can spend it in parts. Some DIY'ers are still changing T-belts with nail polish timing marks. The 8 year old NOS dayco belt is perfect for that person. And the cool thing is it all works within the service life specified. But if you want a little more you have to do a little more just like you have done with sticky parts. It seems you have taken that to the next level. Why? The same reason you buy a Ferrari branded yellow T-belt. Unfortunately there is so much history between you and me that we could not agree if a turd stinks.
LOL! Carl, many on the coast know you well. Your experiences, like others here, with these cars spans many decades. I hope that I am not embarrassing you here but You, like many other of the great contributors here have intuitive and hard won experience that goes beyond what a book or measurement or "scientific" sum offers. Frequencies, harmonics and the combination of the components that deliver the overall performance of Ferrari goes beyond what is found in most other car manufacturers. On paper, a lot of it doesn't even make any sense, but it works and it's that magic that sets Ferrari apart. I bet if you went through Cralls books you would find notes on every single component that would turn many "scientific" scenarios on their head. Many of us here that have racing experience, in my case motorcycles, you experience builders and tuners that have the ability and the magic who are able to pull it together to provide a faster car/bike than anyone else on the field. Anyone has access to science or the ability to follow where those have gone before. Anyone can read a micrometer or read a book. It's in the realm that lies between the lines where the innovation and magic lie.
Same story for Audi's. The belt will last 15 years (don't ask) but the tensioner and water pump will not.
When I bought My 348 a couple of years ago from The Ferrari Centre in the UK, I got talking to the owner Roger Collingwood about how often the cambelt should be changed and he informed Me that the belts themselves are actually very robust, and that in their experience, on the 348 and 355 it's always been either a failed belt tensioner or a failed water pump that has taken out the timing belt - They had never seen a belt fail on it's own. He also said that on the 348 he would have no worries extending the cambelt service from 3 years to every 5 years, but on the 355 they recommend sticking with the 3 year changes as the belt tensioners on the 355 can be more temperamental. Make of that what you will, agree/disagree, whatever - That's what I was told.
Phill, No argument, just a discussion..... The belts have been given the 3 year term based on time, not usage. Perhaps that is understandable for a belt? But for items like bearings, unless the car is in a poor environment, bearings will fail mostly due to usage so in that case, mileage should be a leading criteria over time.
Agreed. No argument just discussion. I don't think there is any data for your last statement. I think bearings once put in use fail over idle time just as much as with higher miles for reasons like a 5 y/o timinig belt with only 500miles should be replaced with as much urgency as a young belt with 30,000miles. There is a difference between a bearing on the shelf in the yellow box and a bearing sitting idle installed on the car even with its only mileage to drive it off the lift and both bearings live in the same garage. I have seen this kind of sitting bearing failure of time in real life. I'm not a scientist but I can guess why. Bearing once put in use scrapes grease off balls. There is metal to metal contact upon sitting giving rise to pitting and fretting corrosion. Use the bearing let sit get this corrosion in new spot. Rinse and repeat until bearing death. Contrast that with bearing used everyday. There is no corrosion only wear that engineers have accounted for in their service life recommendations. None of this matters of course if reasonable service intervals are used.
The idea of replacing bearings every 3 years on a street car, is just over servicing unless said bearings are poor quality to begin with. 5K miles and 4+ years on my OEM tensioner bearings (often seeing 8500 RPM) and no issues presently... Carl, given your statement above, we would be replacing many other bearings on regular intervals too like the ones for the wheels
+1. I agree with Dave. Its mileage for the tensioners, not time. As for belts, mileage should be taken into account. But for most of us who don't put on many miles each year, a 355's belts are better judged on time. And it should also be remembered, unlike the 348s, 355 belts don't turn anything but the tensioners and cams. So tensioners aside, the only thing of concern is the belts themselves. However these belts will last a surprisingly long time, easily more than 3 to 5 years. I know of several that were changed at 7 and 8K (and one at 13K!!!) but still looked just fine. Not that I'm advocating 8 years between belt changes, just that they are more robust than most give them credit for.
Bottom line is, these things fall apart and it gets hot in there so just like oil changes are an excuse to get under the car and look for what else might be going on, 5 years is a good marker for getting the engine out and looking over what you can't see during regular use. I pull them out every 5 years unless I see, hear or smell something going on beyond the visual once over whilst doing regular operational maintenance.
Going to install these 3 inch poly carbon bets on my 355 I'm a safety man I wear belts and suspenders ~ Image Unavailable, Please Login
Yeah screw that unless you have an oil leak or open belt drives I have blown my share of open primary belts I mean the BIG STRONG ones not these pee shooter one we use 2 main causes of failure are foreign object and out of true belt pulleys. Laser test/align your pulley alignment all the time
I just tried googling that belt and don't readily see a P/N. Is that made for the 355 or have you substituted specs? Do you have a P/N you can share? Thanks
Well, I can speak to the tensioner bearing on the 308. Mine were replaced for the first time at 27k miles, 25 years. There is noting obviously wrong with them. Seals good. No play. Spin smoothly. I guess applying Carl's logic, vis-a-vie the GCK, I can generalize that T bearing last at least 25 years. No problems, no worries. FWIY, when shopping for my 355 I looked at several cars that had 10 years or more since the last major. No broken belts, bearing, etc.
By the way. Pretty obvious everyone is bored. Seems topics are being invented to discuss. Let's talk about headers next. Then we can revisit valve guides, lead down tests, dash shrinkage,...what else, tires, top tier gas, skinny blonds, penis size?
Damn, wish I could. Think I tossed it. Plugzit saw it and, in fact, it came apart in his hands when he helped me with my last major. I don't think all 348's (or 355's) do this, but it did happen to me with a stock replacement part. Just wanted to react to the comment about bearings not failing.
Science seems to look at absolutes. If a the parameters that made the tacoma narows bridge perfect are held to then the bridge is perfect. The problem was having full grasp of other parameters especially those that caused the bridge to collapse. A wheel bearing is not equal to a tensioner bearing just because they have "bearing" in their name. Ferrari has had an interesting issue with wheel bearings. They don't seem to fail. In fact this wear item on so many other cars is a NLA item on some models of "modern" ferrari or are so expensive that we use aerospace bearing rebuilders to refurbish them. For just about any other car you buy them at the autoparts store. Why? I can only guess that this is one place ferrari seems to over build for durability. Remember, I'm not a scientist but from my limited understanding if my corrosion theory holds them big giant balls in a wheel bearing is going to corrode from sitting quite a bit differnt from very small diameter tensioner bearings. Add that to the ability of any end user to "tech" inspect his wheel bearings just like every amater racer who goes out on track. Tensioner bearings are hidden and some you can't even see covered by covers. Tell tail puking of grease is often not seen until the next major or until it gets so bad they make noise. Then you have to consider other bearings use. If you have a layshaft tranny bearing living in oil that is a very different environment. You can't shear lubricant off an immersed bearing like you can in a packed in gease bearing. So the answer is no. I think you have to look at the entire context especially if one uses the car outside the typical envelope. For example when I raced my 348, I changed my T belt annually. Was that overkill? I dont know. There is no data.
Every belt failure I've seen began with either bearing or installation problems. I haven't seen a belt fail independently on a 348. WATCH OUT! GRENADE IN THE FIRE!
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