Opinions Sought on Hill Engineering Cam Belt Tensioner Life Span

I say that if you’re going to replace it every 8 years even with only 1500 miles, at the price of the Hill tensioner bearing, I would just replace even if they say it’s still good just to have a peace of mind.

 

I agree with Mike just replace them .

 

Come on guys, the bearings should be spun by hand and if they turn free and smooth, and the grease seals are not damaged and oozing grease, then leave the bearings alone, they are fine. Grease does have a shelf life in sensible storage of about 10 years. Even then it does not spoil, it just means eg. grease in aviation application should be recertifed or renewed for critical applications.

The quality control on the Hill bearings is believed to be very good. The odds of bearing failure without an extenuating factor must be really low. If the car is stored in high humidity outdoors, has oil or antifreeze dripping on the seals from engine leaks, or the car is raced and has very high heat operating conditions, then sure a bearing can fail.

The spare bearings are also fine. Ship them to me if you plan to discard them!

 

Holy crap..change the belts and bearings.. dam it.. stop being a cheap ass. If you are questioning it replace it..jesus h christ almighty..

 

I always replace the bearings at every belt change. Admittedly, I don’t use the Hill bearings. You can spin them to see if they are ok. However, it may be another 5 years until you check them again. They will be 10 years old by then. The price doesn’t concern me as much as my conscience.

 

Funny, I was just looking at McMasters web page about greases and they mostly had a shelf life of 10 years. Based on that I tossed some old tubes and cans in the bin.

For the tensioners, something less critical I'd probably run it. For an expensive interference engine, I'd probably spring for new ones.

 

What about the alternator bearings, the water pump, the water pump idler bearings which no one ever seems to talk about, not to mention a whole host of other bearings and seals in the engine and differential, the wheel bearings, etc. Replace them all, even when everything is working, don't be cheap!
Change the belt, the low use is more a problem for the belts. The tensioner bearings are changed because of the labor cost to get at them, not because their service life is that short. Of course the materials cost is low compared to the effort, and there are plenty of practical arguments to replace the bearings at some interval so why not when doing a belt change, it is as cost effective a time as any.
But waste is still waste, and the facts as presented in the post suggest that bearings are not going to be this cars main event. I would buy new tires, and perhaps do a water pump with the belt change. This car needs to be driven more!

 

The petroleum industry is very conservative, some high pressure greases are good for three years shelf life, others for 10. They can not control storage conditions, and the product would have to be tested and recertified for eg. critical industrial and aerospace applications, for them to be willing to maintain their responsibility and avoid lawsuits. In cases of large industrial inventory, where cost effective the grease would in fact be retested and recertified, this is in fact done. Meaning the actual shelf life can be much longer than the stated shelf life. Amazing miracles of modern chemistry, this not the waxy waste byproduct of refining of a bygone era, which is where a lot of conservative practices originated.

 

The likely Chinese made oem bearings in the yellow box probably sat at an Asian dock at the ocean for a year and then on a dealer or resellers shelf for many years. Buy the Hill bearings, they are the only ones doing old school quality control, hence they charge more.

 

I would inspect and feel them and if the seals look good, no sign of grease coming out, and feel smooth, I wouldn’t hesitate to use both sets for another belt change. The NTN bearings are very good— viton seals and high temp synthetic Polyrex EM grease. I’ll buy them as spares if you are worried. As others have said, if it causes any discomfort, buy new
Ps. definitely check the drive bearings, they are marginal at best.

 

To put the bearings into perspective, here is the 6203 drive bearing (single bearing) and the tensioner (double bearings and bigger OD.) The forces on the tensioner are also less. I would change the small one far more often than the big one ... and there are many cars out there with 40 year old drive bearings
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My usual inclination is timing belts every five years and Hill Engineering ever 10 years. Water pump (and bearings) also changed every 10 years. As for other bearings, you will know it upon inspection.

 

FWIW this year I changed the t-belts, tension bearings and adjusted valves at approx 75k miles on the clock in January. By time I put her away next month I will have approx 90k miles on the clock. I will do the 15k service again, belts, tension bearings and adjust the valves. In between I change oil/filter at 5k intervals. I will also change the trans lube and inspect the clutch lining and air filter ...... just saying.

 

I have a 1987 328 that I purchased in early 1988. The tensioner bearings were replaced during the first and only professional service in 1997. From that point on I have done the servicing myself. Belts were changed every 5-7 years. Whenever I did the job I would carefully check the tensioner bearings. They always turned smoothly. There was no grease seepage so I never replaced them until early 2018 when I replaced them with Hill bearings. They still turned perfectly and were not leaking at that time. Besides the reasons already cited, the bearings are on the slack side of the drive when the engine runs. If there is any stretch in the belts whatsoever, the slack resides in the sections of the belts where the tensioners reside. Less tension in the belts means less load on the bearings.

 

Well, grease is made out of oil which is millions of years old, and clay, which is older.... It it's synthetic grease it is made out of stable synthetic oils, and stable synthetic thickeners, which are also stable for, oh, maybe hundreds of years?

If it hasn't separated, it is still good, i have some partial tubs of axle bearing grease over 50 years old, which looks and works just as good as the day it was made.

Don't forget to throw out the container of Morton table salt after its one year expiration date, that has several million year old salt in it... LOL
Doug

 

My originals were replace at 25 years. They were still fine by visual inspection and ran freely. Current bearing are 10. Just wondering. How often do you guys change wheel bearings? Every time you change tires? Have you even repacked the wheel bearing?


And I can personally testify that my 5 year past expiration date Viagra still works.

 

Some of us do consider changing the tensioner bearings at the same time you change the belt because if the bearings fail, there are much more at stake like destroying the engine. We don’t suggesting replacing wheel bearings, water pump bearing, alternator bearing because if any of those bearings break, nothing major is going to break, just that part but not the engine.

 

DANG! I hadn't thought about the table salt. What do you think, throw it away every 3 years or would 5 be OK?

 

I have replaced/packed my front wheel bearings, but only because I was replacing all the other bushings, ball joints, tires, etc in the front suspension. Excessive play in the old bearings was very minimal.

 

Milk is made of atoms older than the sun....I still chuck it after a couple of weeks. Not the same obviously, but it is a very long way from what is pumped out of the ground to what we use as a lubricant.

And was I overly cautious or even stupid to throw away a $4 tube of 20 year old grease? Maybe, but I feel better springing for a new $4 tube that will probably be on the shelf for the rest of my life.