KV6 timing belts: is the tensioner the problem? - Page 3

freelancer · 27th April 2018, 15:08

Might it be worth considering sending the "used" belt that SD1 is about to replace back to Gates or similar for an independent Vernier measurement and assessment?

Gate Keeper · 27th April 2018, 15:09

Quote:

Originally Posted by SD1too

Hello Philip; it is nice to hear from you again. We met many years ago at The Star and at Gaydon and had friendly conversations I seem to remember.

I hope that you have all the information you need to make your own decision Philip. As you find this thread fascinating I recommend the others in the series which you may find helpful.

Best wishes,

Simon

Hello Simon,

We have met several times over the years and it is fact that our conversations were friendly, enjoyable and I add, engaging. On one occasion in 2014, whilst on tour of the West Country, I put out an appeal to the forum for urgent help as the thermostat packed up and the coolant tank in the V6 was cracked, the guys and yourself coached me on how to get back to London, what to do. Happy memories

My V6 is currently being looked after by Shiner whilst I am out of the UK and whilst he has it, I am thinking what jobs can he do to keep the car in tip top condition.

My question therefore was an innocent question and as you said it is one, I can answer for myself. If the belts are to be changed every six years, then it is what it is, but I do not have the service book with me in Nairobi, can't recall what the mileage recommendation is for the next change after the belts were changed at 70K.

Thats all for now

SD1too · 27th April 2018, 15:45

Quote:

Originally Posted by freelancer

Might it be worth considering sending the "used" belt that SD1 is about to replace back to Gates or similar for an independent Vernier measurement and assessment?

Thanks for your suggestion Ian. I could do that yes, but Gates defers belt replacement scheduling to the vehicle manufacturer, they do not publish an independent opinion, so I doubt that they would be interested.

My view on the vernier measurement of the belt is that arguing for tolerances to one hundredth of a millimetre really is taking the exercise to an extreme and questionable limits. I have always agreed that the belt will wear due to friction. The measurement was intended to show that the degree of this wear is so tiny that it could not reasonably be considered to cause failure of the belt.

The point of this thread in particular is to draw members’ attention to the risk posed by the worn bearings of the tensioner pulley and, to a lesser extent, the idler pulley.

Quote:

Originally Posted by Simondi

I really dont want to have to close the thread as its important ...

I agree Simon so thank you for leaving it open.

Quote:

Originally Posted by Gate Keeper

... can't recall what the mileage recommendation is for the next change after the belts were changed at 70k

The mileage recommendation is every 90,000 Philip.

Simon

mileshawk56 · 27th April 2018, 15:55

Doesn't seem unreasonable to replace the tensioner pulley at the same time as the belts-that seemed to be the conclusion that could be drawn from Simons examination of the two pulleys. This was not mentioned or advised by MGRover, perhaps it should have been but wasn't. Chris.S.

Ennine · 27th April 2018, 16:03

Surely one has to take into account degeneration of the belt structure. That cannot be measured in this way (stress test of course). Belts fail without any other factor. I have a Megane here that did 170,000 on its original belt before it was changed. I rebuilt Jim's 1.8 after belt failure. tensioner, pulley water pump all fine (but they were replaced of course) One simply cannot roll the dice with timing belts. Change them when due along with everything they run on. I have seen enough failed belts in the past and repaired the damage done on four occasions, replaced belts countless times and towed a few perfectly good cars to the scrap yard. I'm not taking sides here and I do see some points made here but some of the issues and ideas are plain and simple madness. Yes, of course there is a little leway built into change periods, there has to be, so many belts will appear fine when removed but sure as heck they are not. Just take a look at the belt route, forget tension but the very nature flexes the belt, failure is inevitable, luck factor is when.

Dallas · 27th April 2018, 17:03

In my experience, there are a number of factors that can cause a timing belt to snap. Temperature changes is one wear factor, belts will stretch and contract when hot and then become cold again. Dont forget hot and cold temperature changes can cause the rubber to develop cracks, this can obviously aid the belt to eventually snap.

Dont forget timing belts can become damaged if they get contaminated with oil or water, also become hard and brittle if car is stood for long periods and not used daily. The fabrics used in belts are prone to failure, the same with all materials, its the same for the metal tensioner, wear/failure will eventually happen.

In my ZT's case, the tensioner had worn out, but its always best to replace all timing belt components at the same time. No component is bulletproof, all materials eventually wear, its inevitable.

Dorset Bob · 27th April 2018, 19:38

I must admit that I was disappointed that the other thread was locked, as there were many points that were not addressed.
Probably because the opening post was throwing down a gauntlet against another member, which got a reaction. Justifiably IMHO.

It is not surprising though, as this is controversial, as we have a situation where someone is discarding engineering practices and justifying it by blaming the marketing department.

Here we go again:

Quote:

Originally Posted by SD1too

.................But the marketing department would not have liked it.

I am very confused, as marketing departments do not lay down technical specifications or maintenance schedules. However, they use features and benefits to promote the products that they market.

Imagine if it was true, that Rover had invented an everlasting timing belt system that only needs changing every 90,000 miles irrespective of how old it is! The marketing department would have had a field day!

A question to the OP and this is for all of the other engine manufacturers, in the world.
Are all their maintenance schedules wrong too, or is it just your engine?

Gate Keeper · 27th April 2018, 20:02

Quote:

Originally Posted by mileshawk56

Doesn't seem unreasonable to replace the tensioner pulley at the same time as the belts-that seemed to be the conclusion that could be drawn from Simons examination of the two pulleys. This was not mentioned or advised by MGRover, perhaps it should have been but wasn't. Chris.S.

A few years ago I met a chap who designed the diagnostics software for MG Rover and he was of the opinion that some of the members here know more about our cars, than MG Rover knew themselves. I add that it’s not my specialty, car stuff and I have to rely on the gurus on the forum for advice.

kaiser · 27th April 2018, 20:04

Closing threads is so childish, if you can't stand the heat, don't cook!

marinabrian · 27th April 2018, 20:17

Quote:

Originally Posted by SD1too

The mileage recommendation is every 90,000 Philip.

Simon

Phil, the manufacturer states, belt replacement is required at 90,000 miles or six years, whichever occurs first.

So based upon that statement, yes your belts are due for replacement, a job if you are paying a professional to carry out will cost circa £450.

Broken down into a cost per year, is £50, or 95 pence per week.

The result of timing belt failure in any interference engine is catastrophic, not nice to pick up the pieces from, and I have in the case of a KV6

Just hold that thought

Brian

27th April 2018, 16:03	#25
Ennine Posted a thing or two Ford Join Date: Nov 2012 Location: Portmahomack Posts: 1,330 Thanks: 545 Thanked 317 Times in 193 Posts	Surely one has to take into account degeneration of the belt structure. That cannot be measured in this way (stress test of course). Belts fail without any other factor. I have a Megane here that did 170,000 on its original belt before it was changed. I rebuilt Jim's 1.8 after belt failure. tensioner, pulley water pump all fine (but they were replaced of course) One simply cannot roll the dice with timing belts. Change them when due along with everything they run on. I have seen enough failed belts in the past and repaired the damage done on four occasions, replaced belts countless times and towed a few perfectly good cars to the scrap yard. I'm not taking sides here and I do see some points made here but some of the issues and ideas are plain and simple madness. Yes, of course there is a little leway built into change periods, there has to be, so many belts will appear fine when removed but sure as heck they are not. Just take a look at the belt route, forget tension but the very nature flexes the belt, failure is inevitable, luck factor is when. __________________ Ni9e How to: Replace touch screen Navall II [SIGPIC][/SIGPIC]

27th April 2018, 20:04	#29
kaiser This is my second home 75 Tourer 2.5 Auto, 1.8T, 75V8ZT Join Date: Jun 2007 Location: Johannesburg ZA Posts: 6,200 Thanks: 1 Thanked 859 Times in 613 Posts	Closing threads is so childish, if you can't stand the heat, don't cook! __________________ Worth his V8 in gold

27th April 2018, 15:08	#21
freelancer Avid contributor Rover 75 Saloon Connoisseur SE 2.5V6 Join Date: Oct 2011 Location: Aberdeen Posts: 225 Thanks: 56 Thanked 12 Times in 11 Posts	Might it be worth considering sending the "used" belt that SD1 is about to replace back to Gates or similar for an independent Vernier measurement and assessment?

27th April 2018, 15:55	#24
mileshawk56 Posted a thing or two MGZT Join Date: Jul 2015 Location: Berkshire Posts: 1,281 Thanks: 1,738 Thanked 299 Times in 216 Posts	Doesn't seem unreasonable to replace the tensioner pulley at the same time as the belts-that seemed to be the conclusion that could be drawn from Simons examination of the two pulleys. This was not mentioned or advised by MGRover, perhaps it should have been but wasn't. Chris.S.

27th April 2018, 17:03	#26
Dallas This is my second home 1979 Capri 1.6L, 1982 Capri 1.6L, 2016 Dacia Stepway Join Date: Jun 2009 Location: Dorset Posts: 8,595 Thanks: 3,496 Thanked 3,397 Times in 2,218 Posts	In my experience, there are a number of factors that can cause a timing belt to snap. Temperature changes is one wear factor, belts will stretch and contract when hot and then become cold again. Dont forget hot and cold temperature changes can cause the rubber to develop cracks, this can obviously aid the belt to eventually snap. Dont forget timing belts can become damaged if they get contaminated with oil or water, also become hard and brittle if car is stood for long periods and not used daily. The fabrics used in belts are prone to failure, the same with all materials, its the same for the metal tensioner, wear/failure will eventually happen. In my ZT's case, the tensioner had worn out, but its always best to replace all timing belt components at the same time. No component is bulletproof, all materials eventually wear, its inevitable.