300Tdi throws timing belt - but why?

[Taz]

Hoping someone can shed some light here...

A few weeks ago my brother-in-law changed his timing belt in his D1. A brand new belt, sprocket and tensioner pully.

250km's later she went BANG! ...damage was 4 broken push-rods and 4 valves.

Upon removing the timing belt cover - the belt had shedded itself (see pics).

Any idea's why?

My brother-in-law offered the following description...

"Photos attached. You can see the flange on the crankshaft sprocket had been ripped off. Cause of valve/pushrod failure was a shredded timing belt, cause of belt failure is tracking issues. Not sure why the belt did not track properly.
The belt was installed to instructions as per difflock - however we did take the belt off after rotating it. At first my injection pump alignment pin was too large and was not locking in deep enough. We turned the engine over - but it would not fire because the injection pump was out of time. We removed the belt and reinstalled it again with the correctly sized locking pin. We didn't turn the engine over after this. Perhaps this was a mistake?
During first installation, then belt tension idlers where replaced and tensioned with a torque arm. After failure, the idler bolts seemed ok - they had not loosened. Tension was still on the belt after the failure.
Pulleys seem to be aligned with the naked eye. "

[BigJon]

Too tight belt tension will cause premature failure.

[Tank]

Hoping someone can shed some light here...

A few weeks ago my brother-in-law changed his timing belt in his D1. A brand new belt, sprocket and tensioner pully.

250km's later she went BANG! ...damage was 4 broken push-rods and 4 valves.

Upon removing the timing belt cover - the belt had shedded itself (see pics).

Any idea's why?

My brother-in-law offered the following description...

"Photos attached. You can see the flange on the crankshaft sprocket had been ripped off. Cause of valve/pushrod failure was a shredded timing belt, cause of belt failure is tracking issues. Not sure why the belt did not track properly.
The belt was installed to instructions as per difflock - however we did take the belt off after rotating it. At first my injection pump alignment pin was too large and was not locking in deep enough. We turned the engine over - but it would not fire because the injection pump was out of time. We removed the belt and reinstalled it again with the correctly sized locking pin. We didn't turn the engine over after this. Perhaps this was a mistake?
During first installation, then belt tension idlers where replaced and tensioned with a torque arm. After failure, the idler bolts seemed ok - they had not loosened. Tension was still on the belt after the failure.
Pulleys seem to be aligned with the naked eye. "
Looks like a good reason to change to gear drive, anyone done this and at what cost, Regardes Frank.

[incisor]

would be a good idea IF there was a viable option available...

[loanrangie]

Looks like a good reason to change to gear drive, anyone done this and at what cost, Regardes Frank.

Google the Zeus gear drive kit, more failures and problems than a belt will give. Chain would be the best solution but that involves sealing the cover and comingup with a lubricating arrangement and then draining excess oil back to sump.

[isuzu110]

What year D1 ?

Didn't pre '97 TDIs have a timing belt mis-alignment problem ? Even so, sounds early for this to manifest.

[haydofly]

I thought there was a mod for this. Not sure if that engine has it but the crank pulley should have a lip either side of the belt to stop it coming off. The mod may even have it on an idler pulley to, can't remember. Ring Davis Perf Landys.

[Taz]

Yes - mod kit was fitted. BIL says the damaged belt removed the flange on the crank sprocket.

[stock]

back in 1998 a problem of thes nature arose in new vehicles a recall was put in place and the vehicles were modified with these bits LHH100600/ DRIVE GEAR,LHV100150 IDLER ,LHP100860 TENSIONER. Brit part /bermach do these kits and to the best of my knowledge are the only ones that should be fitted not the earlier type up here on top the kit will cost 300 e . O! ya mind the tension too much breaks em eveytime

[JamesH]

Nothing useful to add ,but my sincere commiserations.

I lost a timing belt and did the same damage but it was 80 thou kms in and the dealer didn't think to tell about the known problem and the upgrade kit available.

[sclarke]

Gear drive is CRAP.... that is why they dont sell

The main reason the belts fail is poor alignment and not having the correct parts. Has the pump bracket been changed to the later type??? the new kits has a crank pully, Idler, tensioner and bolts..

[B92 8NW]

Gear drive is CRAP.... that is why they dont sell

The main reason the belts fail is poor alignment and not having the correct parts. Has the pump bracket been changed to the later type??? the new kits has a crank pully, Idler, tensioner and bolts..

Would gears not produce extraneous noise?? I can imagine that gears, without a proper pressure fed lubrication system and at those high speeds, would produce a hell of a lot of noise.

[Blknight.aus]

that looks like it has run over tightened to me OR you have something causing drag on one of the driven (not the crank) gears or idlers.

[rick130]

back in 1998 a problem of thes nature arose in new vehicles a recall was put in place and the vehicles were modified with these bits LHH100600/ DRIVE GEAR,LHV100150 IDLER ,LHP100860 TENSIONER. Brit part /bermach do these kits and to the best of my knowledge are the only ones that should be fitted not the earlier type up here on top the kit will cost 300 e . O! ya mind the tension too much breaks em eveytime

and further to this, the OE crank pulley has a habit of the guide lip failing (it is only spot welded on) whereas the Bearmach one is a one piece construction, and hence more reliable.

<edit>
https://www.aulro.com/afvb/images/imported/2008/01/218.jpg

from here 300 Tdi Timing Belt Question (http://www.landroveraddict.com/smf/index.php'topic=367748.0)

[Pierre]

Too high a belt tension has caused the outer edge of the belt to climb the crankshaft sprocket, it appears to me. I agree with Clarkie, too, that there must have been some misalignment as a result of the overtensioning. The tension on the toothed belt is much smaller than on a V belt.

Sorry about the damage. Hope all is well soon.

Pete

[loanrangie]

So where can you procure a 1 piece crank pulley and not the spot welded jobby ?

[DEFENDERZOOK]

yep.......it looks like it was overtightened.......

when the engine was running........could you hear the belt at all.......?
when they are too tight.......it sounds like the engine is supercharged.....or running a gear drive.......
did you manage to hear anything similar over the diesel knock......?

[agrojnr]

Rubber has had problems with separation before.

The rubber gets too hot and the ply in the rubber statrs to shrink and then the rubber falls apart ( I have seen this on mine site convayor belts )

But for that to happen the belt needs to be old stock?????


Adam

[Ivan]

So where can you procure a 1 piece crank pulley and not the spot welded jobby ?

Bearmach do these kits. My local independent had always fitted the lr kit. When I asked him to get me the Bearmach he was really surprised at what you got. He now orders Bearmach kits for all his cambelt changes.

HTH

Ivan

[CraigE]

Overtightening, I have had similar happen on my Duke. Went in for a service and some wad played with the tension for who knows what reason. 20kms out of shop and bang, belts and bent valves. The destruction and shredding of the belt is more due to it getting chewed up by the gear drives. Belts are very sensitive to overtightening.
May have also been a dodgy belt, but unlikely.

[camel_landy]

I thought there was a mod for this...

When the TDi came out, there was a series of different mod kits to prevent this kind of failure. However, they eventually found that the fault was finally cured by reducing the tensioner torque setting.

M

[rick130]

When the TDi came out, there was a series of different mod kits to prevent this kind of failure. However, they eventually found that the fault was finally cured by reducing the tensioner torque setting.

M

and came out as a TSB, and so isn't in the manual.
In other words, the tension as set out in the manual is too high.....
If you have RAVE, you can find the TSB.

The best instructions I've ever seen, including the correct tensions are here
DIFFLOCK - 300tdi Timing Belt Change (http://www.difflock.com/servicing/300tdi-timingbelt/index.shtml)

[Pedro_The_Swift]

yep,, tension is covered in the post
http://www.aulro.com/afvb/common-threads/41849-300tdi-timing-belt.html

in-- wait for it--

Common Threads,,


who'd a thunk it?

[horgan]

Taz's brotherinlaw here. Thanks for all the replies guys. Maybe it was belt tension. I had it set to 14Nm, the lower value for a new belt according to the manual. At the time, I thought 11NM was for a old belt. Will try 11Nm next go.

Valves looked ok, but I got the inlet valves replaced anyway and the head serviced while I was at it. I won't bother next time. $560 to service the head with 4 valves at M&D.

The 4 inlet pushrods were bent and will be replaced.

Didn't hear any noises coming from the timing belt during running - but I was moving along at 100 clicks.

Rick130's pic of the crankshaft sprocket looked the same as mine.

When I fit the new belt, I'm going to try running it for a short time without the timing cover and watch the belt tracking. I need the piece of mind. I'll have to fit the crachshaft pulley on to do so.

Thanks again.

[Disco_owner]

I'll have to agree with loarangie on Zeus gears , they have too many failures with zeus gears which is blamed on a DIY installation ,but they themselves recommend DIY. if something as critical as a Timing Belt why suggest that in 1st place?

[loanrangie]

Bearmach do these kits. My local independent had always fitted the lr kit. When I asked him to get me the Bearmach he was really surprised at what you got. He now orders Bearmach kits for all his cambelt changes.

HTH

Ivan

I'm a bit far from Bedfordshire, although i did live in Milton Keynes for a spell - why i dont know :(.

[justinc]

I'll have to agree with loarangie on Zeus gears , they have too many failures with zeus gears which is blamed on a DIY installation ,but they themselves recommend DIY. if something as critical as a Timing Belt why suggest that in 1st place?

A great pity with the Zeus gears, I have driven a few and they do go well, and almost zero smoke etc. but the conseqences of a failure are catastrophic. I don't recommend them.
It was A great idea and the kit is engineered well though. I've fitted them too and can't help thinking that DIY isn't a good idea if someone with limited aptitude and knowledge gets let loose with a socket set and toolbox....:o


JC

[JohnM]

Yep

Had the same problem. Have had my 97 300TDI since new, and let L/R dealer do the first timing belt change etc. Turned out they fitted the new kit, with the revised tensioner and idler pulley, but not the crank pulley. (Spot welded type) (Unknown to me, was told new kit fitted all okay.) Time went past and snapp....suffered similar loss, bent pushrods, and two rockers. I think I ordered a replacement kit from British4wd which included a one solid piece crank cog/pulley.

[rick130]

Yep

Had the same problem. Have had my 97 300TDI since new, and let L/R dealer do the first timing belt change etc. Turned out they fitted the new kit, with the revised tensioner and idler pulley, but not the crank pulley. (Spot welded type) (Unknown to me, was told new kit fitted all okay.) Time went past and snapp....suffered similar loss, bent pushrods, and two rockers. I think I ordered a replacement kit from British4wd which included a one solid piece crank cog/pulley.

the spot welded flange crank pulley is the genuine LR kit.
The solid design is a Bearmach (aftermarket) one. ;)

[llandro]

For what it is worth, the first time I replaced the belt (Sept.'97 build) I drilled/tapped for 3/8" bsp plug between the 2 top studs, front timing cover adjacent to the pump wheel rim.
Periodically remove the plug, can clearly see how the belt is tracking or if delaminating/deteriorating.
Gives at least some peace of mind.
Mine was built with all latest mods. including bushed pump mounting brackets etc.
llandro

[sclarke]

If your dead set on Zeus gears, call Fred Smith, he has many a set that he pulled out and converted to Belt again....

Telling you something???

[Dunnie]

And my built 1996, rego-ed 1997 300TDi Defender was from the same WA dealer as James. The dealer told me that they had carried out the mod, but all that they actually did was put a blob of yellow paint on the pulley. According to info. this was the LR recommendation to show that the mod. had been completed. Mine didn't break but it cost me $900 back in 1998 or 99 to have another reputable LR person fit the kit after James told me about his mishap. The dealer wouldn't even admit that there was a problem, let alone that they had defrauded both me and Land Rover, who presumably were charged back for the work. I contacted the Department of Fair Trading who advised me that at that time they were receiving about 6 complaints per week about the dealer, but that even the lawyer customers had failed to get satisfaction.

'Arthur Daley' (Minder) is alive and well in Perth.

[Taz]

We identified the cause of the belt breaking whilst we put a new belt on last night.

Human error.

It became evident that the idler pullers were tentioned an order of magnitude too high. The torque wrench used had units of KgM, not NM and no conversion was made. A very simple mistake to make, but one resulting in nearly a factor of 10 too much tension.

Many thanks for all the helpful posts. I was amazed at how many people diagnosed this problem correctly just by looking at a photo! A great reflection of the skill and knowledge on this forum - Thanks!

[damienb]

Good to hear Taz. Just finishing up mine, and was worried some voodoo factor would make it fail in 500 kms. According to records, mine had done 100,000 kms. It looked new. Everything in there looked almost new, even the oil seals. The only thing the _needed_ replacing was the crankshaft front seal. I hate replacing good parts :mad: