what is going on with timing tensioner roller quality ?

[precopster]

I don't have the budget for Blue Box lately so I found some rollers sold by URO (yes I know the URO rubber parts saga)

The tensioner roller is a French made SKF and the idler is a Japanese NSK. Both are sold on Amazon.

The idler is actually a wider bearing than the newer OEM style which seems to have changed to multiple needle rollers in the last 5-7 years rather than a ball bearing style. The fact that a smaller diameter is used on the idler INA and other copies is a concern because at the same speed a smaller bearing race is turning much faster and generating more heat. This in turn changes the bearing grease into a more viscous fluid allowing it to escape from the seal.

A larger bearing with a bigger OD will always run cooler.

[cn90]

O.P.,

I looked at the photo, a bit of grease on the outside is fine.
Just relax.
Once a year, inspect the rollers:
- Visually when engine off
- And when engine running. Verify to be sure it is not wobbling around.

PS: I posted info on the engineering aspect of a hydraulic tensioner in forum.
Basically a strong spring (that is why you cannot compress with your hand, you need a big C clamp to compress it) + oil in separate chambers. The idea is to dampen "sudden movement". Conceptually, this is similar to a suspension strut engineering design.

[johnnyfd]

I don't understand the grease issue because I've heard so many say to replace if you see grease streaks . If some grease escaped is there some reason that the remainder will not come out , dry out the bearing , and render it very short lived as in maybe just a few months after ? My original goal was to have the shop install quality parts I could rely on (thats what I paid for and I don't think they delivered) without out it being something that I might need to check on with the frequency that I check tire pressure or oil level . Even if the bearing will not fail prematurely , a small amount of the grease ends up on the belt . I don't understand how this is acceptable . I would probably be more comfortable with a bearing that had few small steaks on it as opposed to this one which appears to have burped out blobs of grease all at once . What will prevent it from doing this repeatedly under the right conditions which could be something as simple as a drive that lasts longer than an hour . If that is what precipitates it then the bearing might run out of grease at the worst possible time like a long journey . I don't want to have to bring timing path components on trips because of inferior quality . Has the parts market become so bad that we have to accept significant levels of unreliability when paying for the best available critical engine parts ?

[johnnyfd]

area - you can see how the pivot bearing caught the flying grease that it was in the path of .

[precopster]

That's like saying if my car burns X amount of oil every month for the past 2 years I should absolutely fear that I should lose the entire contents of my sump next month.

The grease loss is controlled and measurable. Move on.

[johnnyfd]

level of experience which appears to be quite significant especially with these bearings . This is new stuff to me hence all the questions . Its not so easy trying to learn things when you here something like "if it streaks out any grease replace it" from people whos opinion is apparently respected and then have others with plenty of experience tell you not to worry about it . This just makes me want to try to clear up the inconsistencies as I think it should with anyone who is logical and has a memory for what they read . You might have a good idea how long the grease will stay in or even how much remains . I honestly can't tell at all so please don't tell me to move on .

[precopster]

Not trying to make this unimportant for readers; it is. However of the ten or so Volvos whose timing systems I've replaced ALL of them had cruddy grubby OEM bearings with dirt stuck to them and a wipe with a clean rag released a mixture of grease and dirt.

There is acceptable level of release and unacceptable level of release. Yours doesn't even look significant bearing in mind that you may have lost less than around 3% of the grease in the bearing. There are two sides to a bearing and they take a hell of a lot of grease. (I used to repack photocopier heat roller bearings of a similar size with disc brake rated grease and they had metal seals that I used to pick off with with jeweller's screwdrivers and reseal once again) The heat rollers sat at 180-200degC most of the time and would last another 500,000 revolutions before repacking was necessary.

Of course some grease leaked out. The worst case was that the OEM grease lasted LESS time than the quality blue Castrol grease I used to repack with. In the case of cheap unknown brand bearings the grease would leak out in under 40,000 cycles.

The Volvo rollers are far deeper than those I used to pack and would take twice the grease I used.

What sort of mileage did you cover in that 12 month period?

[mecheng]

People have responded correctly, a bit of grease purge is completely acceptable. It is typically due to the bearing "free rock". In fact, it shows that the inner lip is being lubricated which is what you want. The more free rock designed into the bearing, the more purge you will see. Typically, bearings will purge grease when they are new a bit and then will not continue to purge until the inner lip seal is completely worn.

[rspi]

As already stated, I check them, if smooth, quiet and tight, they get another round from me, no matter how dirty they look. Yes there are some that caution on the safe side and say "if you see grease, replace it". I'm sure those people don't recommend pulling the cover between intervals and replacing parts that have spun some grease.

At the end of the day, none of us want failure between change. If we had factual numbers, my educated guess would be that there is about a .1% failure rate of these rollers between change intervals when using new parts.

[johnnyfd]

Thanks for all the responses the information you guys gave me has been very enlightening . Your explanation of your experience with these bearings has proven to me that I really didn't have a good understanding of their mechanics . I feel so much better now that I understand their inner workings more and have a much better idea of what to expect when I go to check their condition . By the way I drove the car about 10,000 miles in the last 12 months .