Belt tensioner bearings - need/basis for changing?

To be absolutely honest with you those timing belt tensioner bearings are pretty big, it's a wide belt, and they don't really have that much of a load on them. Even the belts themselves, on this engine there are two and they are pretty short because they have their own dedicated drive sprocket. So, in reality the belts are probably fine for 50,000 miles and the bearings 100,000 miles.

But nobody is gonna tell you that.

 

I replace mine every other service

 

The last 328 I worked on had the bearing grease leaking out all over the place. Will it last another 100,000 miles? Who knows but since I was in there anyway, they got tossed out and replaced with Hill Engineering Bearings. I know those last 10 years.

Your money, your chances, your choice.

 

FWIW, belts degrade with time, whether running or not; bearings pretty much don't degrade with time. I replace belts based on mileage or time, whichever comes first and bearings based on feel. IOW, if the bearings turn smoothly/no play, I don't replace them. That is true of any bearing - whether it's a cam tensioner bearing or a wheel bearing! In my experience, bearings provide a rather lengthy period of roughness/noise long before they actually fail...

I realize that others disagree but I do not believe in replacing components that are working fine. You can't break/strip/lose a fitting, etc if you don't take the item apart.

 

I always thought the bearings were changed when the belts were, pretty much universally.

 

I think we're challenging that need right now.

Most of us only put 5k to 10k miles on the car between belt changes which apparently is far below the service life of a bearing (although yelcab's grease comment is noteworthy).

Certainly when belts are done professionally and the job costs $3k (or $5k) (or $10k) the $200 cost of the bearings is trivial. The new bearings provide risk reduction (or at least do no harm) with the cost being pasted onto the customer.

A DIY belt change costs $72 and the risk stays with the owner no matter what is changed.

 

I would not use a garage that charges or needs 20 hours to swap belts

 

"I always thought the bearings were changed when the belts were, pretty much universally."

That does seem to be the case...

But does anybody change alternator bearings/bushings when they change alternator belts? Does anybody replace their wheel bearings when they install new tires?

Certainly they need to be checked for smoothness and appearance. In the case noted where a lot of the grease has leaked out is, of course, a concern.

Interestingly, bearings can fail early due to too much grease. A friend was a supervisor in a Corning glass plant that was having trouble with bearing failure on one of their large machines. They called in a rep from the machine supplier and he discovered that the Corning techs were over-greasing the bearings during normal maintenance. They figured that MORE Grease must be better then the machine-factory spec which called for a specific quantity of grease that looked to them "too dry." But the excessive grease caused early failure. When they applied grease per the spec, the failures disappeared.

Hey, maybe that tensioner bearing mentioned in post #4 was just trying to get rid of the excessive grease! Unfortunately, it could end up on the belts which is not the best thing for them...

 

I agree, though belts degrade from use much faster than time, and I've never heard of any other manufacturer recommending such a short time interval for belt changes. It's typically something like 100,000 miles or 10 years for interference engines, which is an indication of how long they expect belts to last. Are the belts we use on Ferraris of lesser quality than those used on all the other cars in the world? Not likely. As for the bearings, you are right that they wear out slowly and provide plenty of obvious warning when they reach the end of their life.

I think the practice wasn't challenged early on, and gradually became gospel. I don't think tensioner bearings need to be replaced every 5 years with the belts, but instead should be replaced as needed, with their condition being assessed at each belt change. it's my opinion that the adherence to the 5-year belt/bearing major service interval was borne more out of paranoia than common sense. I'm reminded of an independant Porsche tech's remark to me years ago: "Porsche owners love to spend money on their cars". If true, it's probably doubly so for Ferrari owners.

Another thing to think about is that when you decide to sell your car, prospective buyers may be put off by the fact that you didn't follow the universally accepted guidance, unwarranted as it might be.

 

For those of us who actually drive their Ferrari = yes

The Owners who (rightfully) have trouble with this decision are those who do the 1000 total miles in 5 years. In that situation, it's more about the grease life that you're comfortable with.

 

You forgot the $100 coolant drain.

 

It makes sense to change the tensioner bearings .Just had the main polybelt on a Bentley GT done .It’s Bentley lifed for 10 yrs .
seeing as the whole front of the car has to come off inc rad swinging out , fluids drained .Think what needs to be dismantled to access a 308 motors belts , then the single £40 tensioner is a no brainier as the serpentine poly belt is £100 .
It not the cost its more “ while we are in there “ .

If you are a DIY er then skip the Ferrari tensioners and skip the Bentley tensioner .
You can always another winters day “ dig in “ .Again !
But if you are paying a guy shop Labour hrs ……..get it done .

As said they are not catastrophic the Bentley squeals on cold start at tick over .When warm or revs the squeal disappears.You can put 10s of thousands of miles on them in this state .
So you do get tell take sounds .

 

No way in hell I am putting these back.


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Unless you open it up, how would you know what it looks like inside? And if it looks like this inside, what would be your recommendation?

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One thing to keep in mind is that if the tensioner bearing fails you're looking at 10k + in repair bills if not a new engine. With all the other bearings you're only replacing an inexpensive (in the Ferrari world!) part.

 

If you are being told you need to replace the water pump with every belt change, you are either being lied to or you are dealing with a shop with zero experience.

I have had this conversation many times.

 

Well, as has been said many times, do what you are comfortable doing. If you believe the cam tensioners need to be replaced at a belt change, do so. FWIW, in my '89 328 manual Ferrari didn't call for replacing the tensioners in a belt service. Did they change that in a later bulletin? If not, when/why did this 'tensioner change as a normal procedure' begin?

 

I suppose that when you consider that, AFIK, the warranty on these cars was one year for the earlier models, 2 years for the later ones, there may be good justification for the view that Ferrari's choice of ancillary parts/equipment was...uhh...less than stellar! It's also well-known that Enzo didn't care a whit about the road cars. So they probably didn't spend a dime more than they had to for parts adequate to sustain that one/two year warranty. Therefore, better bearings/other parts in the various locations could certainly be a good thing. Once installed, whether those better parts need to be changed regularly - like the Hill bearings - is a different, and personal comfort decision. Normally, in the automotive world, parts that are other than routine maintenance are not replaced until there is a sign they need replacing.

OTOH, my original 1989 water pump is still working fine. So the biggest problem might simply be lack of use if the cars aren't driven much. The worst thing for any mechanical device is to NOT be used.

My Hill bearings have a bit over 10k miles on them and were still smooth as silk when I replaced the belts a few months ago. Of course, 10,000 miles is nothing on a 'normal' car and if bearings had to be replaced in less than 100k miles, we'd call that a poor quality bearing/car. Go figure...

 

Are you being serious? You can't actually believe that crap do you?

 

"
Are you being serious? You can't actually believe that crap do you?"

I certainly do believe it.

Enzo's view of Ferrari's road cars is well known and documented. He stated that he only made them to make money to finance the race effort; he didn't care anything about them and said so in those words (well, the Italian equivalent) on several occasions.

Re lesser quality ancillary parts, several well known Ferrari-trained techs that frequent this site have stated exactly that - that Ferrari sourced lower cost ancillary parts, not necessarily parts of the best quality.

Just to emphasize, I'm talking about ancillary parts/systems, not the basic engine/drivetrain construction.

 

What we are looking at is a rusted bearing from inside an old 308 pump. Unlike others, my feeling about water pump (on all my cars from BMW, Audi, Porsche to Ferrari) is that they are a maintenance items. That means they are replaced BEFORE they go bad and leave the car either stranded by the side of the road, or one of the girls I care about standing by the car with the engine up in steam and a rebuild coming.

Rust comes from age, not mileage. Pick the age at the point where you want to replace the water pump and do that. For me, 10 years on a Ferrari water pump is plenty long for a $300 item. It so happens that coincides with every other timing belt jobs, how convenient?

My labor is free to me so I am very liberal with what I replace. For example, my BMW 530Xi gets its entire cooling system replaced at 100K miles, water pump, thermostat, radiator, all coolant and heater hoses, coolant tank. That job is coming up again... I have driven BMW long enough to know that at 101K miles, the radiator plastic neck breaks. So I don't let it happen. The Porsche 997 that the wife drives also gets its cooling system done at 60 K miles. Simple, do that or a $25k engine rebuild.

There are other things on a 308 that will leave you stranded and waiting hours for a damn tow truck. Don't let it happen to you.