[JT8Diesel]

Thanks for the great write up. I have about 225 km (140 miles) on my car, I've had it for the last 50,000 km or so. I assume an original pulley, but haven't checked yet. Waiting for a good sale on a cheap scope.

I'd like to try to do this proactively to avoid the guaranteed bad timing of a full-blown failure.

[sukutash]

Originally Posted by dextersl

Torqu3, thanks for the response!

I went ahead and ordered my parts from ecs yesterday. I know Mik325tds said he ended up not replacing the tensioner pulley/tensioner pulley assembly, and I did not see him make mention of replacing the deflection pulley either. So does anyone else have any advice on what specific process/tools are needed to remove replace these components? Just want to make sure I have everything I need before getting into it this weekend.

You probably already replaced the tensioner, maybe not. Anyway, in order to remove/reinstall the tensioner you need to move the power steering pump out of the way and remove the top bolt for the alternator and rotate it out of your way.

[TDIwyse]

Originally Posted by Mik325tds

...
It is important to only turn the engine in its running direction (see arrow on belt in below picture).

I haven't done this procedure yet, but was recently watching the instructional video from Lisle on how to use their belt stretch tool and noticed they turn the engine different directions for belt removal (0:46) and installation (1:21). So at least one of those directions has to be the opposite of the running direction...

I've always heard you are not supposed to turn the engine backwards, yet I see there are many accounts of people who routinely do like the Lisle video shows and have no issues. So I'm curious if anyone has heard of an M57 engine getting damaged by turning the engine backwards for a belt installation, and precisely how/why/what got damaged?

[Mik325tds]

Originally Posted by TDIwyse

I haven't done this procedure yet, but was recently watching the instructional video from Lisle on how to use their belt stretch tool and noticed they turn the engine different directions for belt removal (0:46) and installation (1:21). So at least one of those directions has to be the opposite of the running direction...

I've always heard you are not supposed to turn the engine backwards, yet I see there are many accounts of people who routinely do like the Lisle video shows and have no issues. So I'm curious if anyone has heard of an M57 engine getting damaged by turning the engine backwards for a belt installation, and precisely how/why/what got damaged?

I'm not 100% sure that the this is the reason for the rule but my explanation would be that the timing chain tensioner is on the "loose" side of the chain when the engine is turns in its running direction. Turning it into the other direction would put load on the chain tensioner and guides which is suboptimal. Probably won't kill it right away but put stress on the mechanism that is wasn't design for.

[TDIwyse]

Originally Posted by Mik325tds

I'm not 100% sure that the this is the reason for the rule but my explanation would be that the timing chain tensioner is on the "loose" side of the chain when the engine is turns in its running direction. Turning it into the other direction would put load on the chain tensioner and guides which is suboptimal. Probably won't kill it right away but put stress on the mechanism that is wasn't design for.

A Mik sighting :-) Hope you've been doing well.

Thanks for the reply. That's my understanding for the reason as well. However, there shouldn't be a large resistance being placed on those things when slowly hand turning the engine, should there (thinking of the Lisle video and/or manual transmission offroad vehicles where they often stall an engine and slide backwards down a steep section, which will spin the engine backwards until they engage the clutch, and I'm not aware of that causing issues)? When you were manually turning the engine did you find you needed to apply a lot of torque/tension to rotate the balancer?

Another question then on putting the belt on with the Lisle tool. You must've used it differently than the company recommends if you turned the harmonic balancer in the clockwise direction? But it still worked ok to get the belt to slide on, even though the tool is designed to slide the belt on when turning counter clockwise? It looks like the angle of belt engagement will be much steeper when trying to use it in the clockwise rotation.

[Mik325tds]

Originally Posted by TDIwyse

A Mik sighting :-) Hope you've been doing well.

Thanks for the reply. That's my understanding for the reason as well. However, there shouldn't be a large resistance being placed on those things when slowly hand turning the engine, should there (thinking of the Lisle video and/or manual transmission offroad vehicles where they often stall an engine and slide backwards down a steep section, which will spin the engine backwards until they engage the clutch, and I'm not aware of that causing issues)? When you were manually turning the engine did you find you needed to apply a lot of torque/tension to rotate the balancer?

Another question then on putting the belt on with the Lisle tool. You must've used it differently than the company recommends if you turned the harmonic balancer in the clockwise direction? But it still worked ok to get the belt to slide on, even though the tool is designed to slide the belt on when turning counter clockwise? It looks like the angle of belt engagement will be much steeper when trying to use it in the clockwise rotation.

I've been doing well, thanks. Just very busy. I hope you and your family is fine as well.
Yes, you're right the angle was fairly steep with rotating it clockwise for the install but really didn't make too much of a difference. Remember, I did use the 830mm length belt though. The engine did rotate easily in the running direction but I didn't try rotating it the other way.

[Asonchadwick]

I wonder if the balancers are failing because bme said tovise a shorter belt LMAO!

Maybe the extra load is killing the balancer prematurely and that's why some last longer than others ahhh i bet that's it.

[Torqu3]

Originally Posted by Tucson335d

I wonder if the balancers are failing because bme said tovise a shorter belt LMAO!

Maybe the extra load is killing the balancer prematurely and that's why some last longer than others ahhh i bet that's it.

My balancer failed at 71k with the 830mm belt. I replaced the balancer and put on the 824mm belt. No problems almost 30k miles later. Note that BMW didn't release an SB to use a shorter belt until AFTER the cars were out of production in the US. And the shorter belt is there to prevent the AC from squaling due to being too loose. Balancers are failing with the 830mm belt because the balancer is faulty by design.

[rulonger]

Originally Posted by TDIwyse

I haven't done this procedure yet, but was recently watching the instructional video from Lisle on how to use their belt stretch tool and noticed they turn the engine different directions for belt removal (0:46) and installation (1:21). So at least one of those directions has to be the opposite of the running direction...

I've always heard you are not supposed to turn the engine backwards, yet I see there are many accounts of people who routinely do like the Lisle video shows and have no issues. So I'm curious if anyone has heard of an M57 engine getting damaged by turning the engine backwards for a belt installation, and precisely how/why/what got damaged?

If you are using one of the HB torx-12 bolts to turn the engine, as most of us did, you could not effectively turn the engine in reverse or you would back out the bolt.

I used the Lisle tool in the direction of the engine rotation (clockwise) for both uninstall and install of the A/C belt.

[montr]

Originally Posted by Torqu3

My balancer failed at 71k with the 830mm belt. I replaced the balancer and put on the 824mm belt. No problems almost 30k miles later. Note that BMW didn't release an SB to use a shorter belt until AFTER the cars were out of production in the US. And the shorter belt is there to prevent the AC from squaling due to being too loose. Balancers are failing with the 830mm belt because the balancer is faulty by design.

+1. Mine failed at 67K miles with the original 830mm belt

[AlpineX]

Originally Posted by Mik325tds

I'm not 100% sure that the this is the reason for the rule but my explanation would be that the timing chain tensioner is on the "loose" side of the chain when the engine is turns in its running direction. Turning it into the other direction would put load on the chain tensioner and guides which is suboptimal. Probably won't kill it right away but put stress on the mechanism that is wasn't design for.

I thought it was bad for the diesel HPFP and fuel direction to go in reverse.

BMW factory tool turns crank clockwise for stretch belt installation

[Asonchadwick]

Originally Posted by montr

+1. Mine failed at 67K miles with the original 830mm belt

Mine failed after i put in the shorter belt😕

[Torqu3]

Originally Posted by Tucson335d

Mine failed after i put in the shorter belt😕

How many miles on the balancer? What brand was it? It was probably a coincidence, not a cause.

[Asonchadwick]

Originally Posted by Torqu3

How many miles on the balancer? What brand was it? It was probably a coincidence, not a cause.

Factory balancer, maybe 1000 miles after the new belt then failed

[Torqu3]

Originally Posted by Tucson335d

Factory balancer, maybe 1000 miles after the new belt then failed

I'm confused. You replaced the balancer and belt at the same time, then 1k miles later it failed?

[Asonchadwick]

Originally Posted by Torqu3

I'm confused. You replaced the balancer and belt at the same time, then 1k miles later it failed?

No it was the factory balancer that came with the car, i put the belt on and about maybe less than 1000 miles later it failed on me. Just a coincidence i am sure.

[Torqu3]

Originally Posted by Tucson335d

No it was the factory balancer that came with the car, i put the belt on and about maybe less than 1000 miles later it failed on me. Just a coincidence i am sure.

Oh yeah. If it was balancer form the factory it was probably gonna die soon anyways. That'd put you right in the mileage range for failure.

[Asonchadwick]

I was juat saying the extra tight belt may have accelerated things a little if it was putting extra side load in the balancer which i know it does because that's why its not slipping lol

[Mik325tds]

Originally Posted by AlpineX

I thought it was bad for the diesel HPFP and fuel direction to go in reverse.

BMW factory tool turns crank clockwise for stretch belt installation

That's interesting. Do you have any more information as to why the HPFP shouldn't turn backwards?

[AlpineX]

Originally Posted by Mik325tds

That's interesting. Do you have any more information as to why the HPFP shouldn't turn backwards?

I don't know where I picked that up. I thought I had read it in the training documents or maybe the tis but I can't find it now. Always a possibility that I adapted it into my memory from something else.

[vladmury]

What are the symptoms of a bad vibration damper? I have vibrations at idle when putting the transmission in D or R ..not sure if I should change the vibration damper. I looked at it when idling and looks fine, no wobble or visual damage, what do you think?

[Mik325tds]

Originally Posted by vladmury

What are the symptoms of a bad vibration damper? I have vibrations at idle when putting the transmission in D or R ..not sure if I should change the vibration damper. I looked at it when idling and looks fine, no wobble or visual damage, what do you think?

It's very unlikely that the harmonic balancer is your problem. The only signs you should be looking for is to visually inspect it every now and then to look for cracks in the rubber.
Rough idle can be caused by many factors, the most common one I'd say is CBU.