Thread: Frayed timing belt at 45k

Hi Discomark

The bracket between the block and the injector pump needs a slight adjustment, moving the back of the pump away from the block.

As a belt runs to the higher diameter side, the movement or flex of the alloy housing where the injector pump is mounted, has to be countered by preloading the injector pump rear bracket.

I hope this helps.

Cheers Arthur

Had exactly the same problem the other day

JC took the timing cover off so I could do a swapsies to return a borrowed part and we found my timing belt to be in a similar condition

Which updated pulley do you have?

I was under the impression mine had the update, but it wasn't the latest update.

The previous update is a cast pulley with a flange with a sharp edge pressed into the pulley, this sharp edge shreds the front edge of the belt

The latest pulley is all one cast unit so there is no sharp edge to slice the belt

Hope that helps

"Which updated pulley do you have?"

I'm pretty sure its the older spot welded shoulder type. Any idea where to buy the new type?

Cheers

Mark

Originally Posted by wrinklearthur

Hi Discomark

The bracket between the block and the injector pump needs a slight adjustment, moving the back of the pump away from the block.

As a belt runs to the higher diameter side, the movement or flex of the alloy housing where the injector pump is mounted, has to be countered by preloading the injector pump rear bracket.

I hope this helps.

Cheers Arthur

Thanks Arthur,

I removed the timing cover and it does look like the belt has been rubbing the cover near the timing pump gear. The belt seems to be travelling very close to the outer edge, does the pump adjustment you mentioned make the belt move back towards the rear of the pulley?

Cheers

Mark

JC had one in stock with a new belt, idler pulleys and the updated bottom pulley

I imagine most decent Rover spare parts places would sell them

I source most of my parts through British 4WD Imports in Melbourne, I reckon they would have them or could find one

Originally Posted by Discomark

Thanks Arthur,

I removed the timing cover and it does look like the belt has been rubbing the cover near the timing pump gear. The belt seems to be travelling very close to the outer edge, does the pump adjustment you mentioned make the belt move back towards the rear of the pulley?
Cheers Mark

Hi Mark

Yes, its a bit hard to get your head around why belts behave that way, but there is a good write up on a web site that does explain this, I'll post the link if I can find it. But I can't find it!

You will find that the reduced load when tensioning the belt and a slight adjustment of the pump bracket, is all that is required to correct run-off when doing an upgraded timing belt kit.
Running the motor with out the timing case cover, is ok for a short while checking for any run-off by the belt, just dont let the motor get too hot!


First have a read of this useful thread by Blknight.aus, unless of course, you have already done so.
http://www.aulro.com/afvb/projects-t...ming-belt.html

some usefull tips here, but type of upgrade kits is a bit extreme.
Timing belt hints and tips - by Glencoyne 4x4 (Thetford)

Some more info Difflock.com Discussion Forum: 300tdi timing belt change

Also,
quote "Have also noticed the vehicles that have the full mod kit done (from new) at the factory some times use a plastic coated tensioner. I have had two of these shed their plastic coating resulting in a very slack timing belt.
Any of these tensioners get replaced with the all metal version as a matter of course as a precautionary measure now ."

Cheers Arthur

Originally Posted by wrinklearthur

Hi Mark

Yes, its a bit hard to get your head around why belts behave that way, but there is a good write up on a web site that does explain this, I'll post the link if I can find it. But I can't find it!

You will find that the reduced load when tensioning the belt and a slight adjustment of the pump bracket, is all that is required to correct run-off when doing an upgraded timing belt kit.
Running the motor with out the timing case cover, is ok for a short while checking for any run-off by the belt, just dont let the motor get too hot!


First have a read of this useful thread by Blknight.aus, unless of course, you have already done so.
http://www.aulro.com/afvb/projects-t...ming-belt.html

some usefull tips here, but type of upgrade kits is a bit extreme.
Timing belt hints and tips - by Glencoyne 4x4 (Thetford)

Some more info Difflock.com Discussion Forum: 300tdi timing belt change

Also,
quote "Have also noticed the vehicles that have the full mod kit done (from new) at the factory some times use a plastic coated tensioner. I have had two of these shed their plastic coating resulting in a very slack timing belt.
Any of these tensioners get replaced with the all metal version as a matter of course as a precautionary measure now ."

Cheers Arthur

Thanks again Arthur,
i had a look at the pump bracket and there appears to be no way to adjust unless you pack some washers behind it, is that what you mean? I would have thought that the back of the pump would need to move towards the block to get the belt to run towards the back of the pulley, but then my logic is probably reversed : )

Hi Discomark

Have a look at this site and it comes close to explaining the way belts behave.
what keep flat belts from sliding off - old machinery? - Practical Machinist - Largest Manufacturing Technology Forum on the Web

"This subject is a bit of a mystery to me. I had though a belt would climb up the crown. My recent experience was with a wood pulley. it was worn very low on the left. The belt climbed up the right and was running 1/2 inch out in space. That was right up the high end. I removed that pulley and put on another. Things were fine. The opposite end pulley was iron with a nice crown; so that maybe a factor here. And another complication, the iron pulley was more narrow than the belt. Like a super crown.

I just went down stairs and did a little experiment with my belt sander. I loosed the left side of the idler and the belt slipped right down the low side. A contradiction in behavior. In this case the low side was a result of non parallel drums and not wear or crown. A clue? How could the belt know?

Is leather different than paper? Or were there other variables at work with my wood pulley situation?

I have two books on belting and been looking at them this evening. No theory on the crown was given. "

In the case of the multivee belts the high side or crown is the top or apex of the pulley's groove.

Cheers Arthur