Just as I thought

[Terryf]

Had my timing belts changed today on the basis of time, suspected they would be ok but not prepared to risk it.
Garage showed them to me when I collected the car. You would think they had never been anywhere near a car, not a mark on them.
Am I disappointed? NO. it could just as easily been the other way and been in tatters.
At least I know they are OK now.
Terry

[victorgte]

It’s an odd thing to see. Had my belts changed by time used but 4K early on mileage. They looked almost new. Just some wear of the writing the belts have on them from new. No cracks, splits or fraying.

[Comfortably Numb]

They don't last any time after you see splits, cracks or fraying - they just go bang! If the writing is worn off, it's time to change regardless. Turn it inside out and bend it - you will sometimes see cracks at the bottom of the teeth. Then you know you've been lucky! You have to compare a brand new one with the old one to see the wear in the teeth, and how much it has stretched (which isn't much!)

[Mike Trident]

Years ago I had one go on a Metro diesel that i had. The garage (Rover dealer) that collected my car and repaired it showed me the culprit.

The belt looked brand new, and was complete with white lettering. However it was minus about 4 or 5 teeth. This happens right on the crank pulley so the pulley rotates and the belt doesn't. I was driving at about 30 when mine went.

My brother who used to be a supervisor at Rocar (main Austin Rover dealer) Told me that more often than not they went when turning the key to start the engine. He explained that at start-up the belt was put under the most stress. Hence the reason for a time and not just a mileage. Perhaps a car may be quite low on miles but high on start-ups and heat cycles.

So, basically what I am saying is with a belt, don't expect it to look worn out or for it to have some dramatic breakage with bits flying all over. It could look perfect, even when teeth have gone.

[coab]

Remember its usually the tensioner that wears out and can lock up when it breaks up. Always best to get them done. My old ZT 190 had 115k on the original belts! The reason for not changing them? The chap said his local garage didnt know how to so he left them!

[Les4048]

You’ve done the safest and sensible thing, now you can enjoy peace of mind as you drive

[SD1too]

Originally Posted by Terryf

Had my timing belts changed today on the basis of time ... Garage showed them to me ... not a mark on them.

Originally Posted by victorgte

Had my belts changed by time used ... They looked almost new. No cracks, splits or fraying.

Thanks for posting your findings on this Terry and Victor. As you've no doubt noticed I have also posted good evidence on this subject.

Originally Posted by Mike Trident

He explained that at start-up the belt was put under the most stress. Hence the reason for a time and not just a mileage.

I'd agree with your brother about the stress Mike, but strangely the evidence does not demonstrate that this leads to failure on a time basis. Think how many cold starts my V6 has had in nearly nineteen years yet the belt doesn't have any damage.

Also, when I changed the timing belt on my urban runaround according to the manufacturer's recommendation for "severe use" it was in perfect condition; indistinguishable from the new one.

Originally Posted by coab

Remember its usually the tensioner that wears out ..

I wonder why MG Rover didn't recommend renewal on a time basis then?

Simon

[bl52krz]

Hi Simon. I followed your post with regards to belt changes. I would be amazed if the belts you took off were anywhere as good as new. Have you turned them inside out and bent them round to touch just under the top two inches of the belt? If there are no cracks there I would suggest that you get in touch with the manufacturer and offer them for analysis on the belts constitution. I am not being frivolous in asking you to do this. When I had my timing belt done on my 220sd at around 60,000 miles, when I went to pick it up from the only garage I have used in the last 30 odd years, my comment was ‘ blimey it looks new still if I had known I would not have had them changed.. I was told to turn it inside out make a circle at the one end of the belt and give my opinion. There were cracks at the bottom of ALL the teeth on the belt as I turned it round making the circles. Just my pennies worth of knowledge from someone who knew what to look for, but not me. Suffice to say, it was a lesson learned.

[SD1too]

Originally Posted by bl52krz

Have you turned them inside out and bent them round to touch just under the top two inches of the belt? ... When I had my timing belt done on my 220sd .... There were cracks at the bottom of ALL the teeth on the belt as I turned it round making the circles.

Thanks for this David. No, I haven't removed the belt yet but when I do I will examine it fully and compare it to the new one and post on its condition.

The point of my initial post on the belts in-situ is to demonstrate that the degree of excessive wear that might be expected after exceeding the manufacturer’s renewal schedule by three times is not present. I concede that some cracks may be found upon removal, but after 19 years that proves to me that the six year rule is far too strict.

Simon

[klarzy]

Even if no splits or cracks are visible the witness marks which appear on the plain side of the belt between the teeth are an indicator of wear and featuring of the material...
You will also have huge differances on time basis if a car is garage kept and never prone to freezing temperatures and moisture from dew etc.
I recently paid 450.00 to change the belt, water pump and pulleys on my Lexus... remember it's not just the belt that wears.... the cost of the belt itself is a small part of a much more important job....