B5 BHW engine noise revisited

maktas

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abctdi said:
As far as tuning vs. failure rate...my guess is that even though the engine has more power and torque, the amount of resistance force through the chain depends more on oil pressure and viscosity, which is the same no matter the power. We all use the correct spec oil and have the same oil pump, so the chain stress requirement is the same for all no matter the tune.
Bottom line is that because of the weak chain design, it and its related parts do not last for the life of the engine, period.
The viscosity factor is interesting.... I wonder if a failure rate can be correlated to the people using the old 505.01 (5W-40) vs the new 505.01/507.00 (5W-30)
 

Topolog

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Oilhammer,

Would you be so kind and train the rest of us in in the art of 'wooden wedge roadside repair' of window regulators? It might come in handy some day.

Also, many thanks to you and MOGolf for all your efforts to get the BS issue solved!
 

2004PassatTDI

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If a tune increases the rate of acceleration, then the stress on the chain/sprockets also increase. If you let go of the accelerator pedal, do the crankshaft’s RPMs decelerate faster than the BS’s RPMs in an unlinked condition? The high compression may be the major component that slows the crankshaft down, while the oil pump is probably the major component that slows the BS. If the crankshaft slows the BS, you now stress the other side of the sprocket’s teeth.

I never really liked using the manual mode for shifting. Maybe using the manual mode for shifting lashes the sprockets back and forth more than easy acceleration/deceleration. The tensioner, as MOGolf’s picture indicates, may not be beefy enough to compensate? Just thinking out loud.

My replacement parts arrived today :) .

abctdi said:
As far as tuning vs. failure rate...my guess is that even though the engine has more power and torque, the amount of resistance force through the chain depends more on oil pressure and viscosity, which is the same no matter the power. We all use the correct spec oil and have the same oil pump, so the chain stress requirement is the same for all no matter the tune.
Bottom line is that because of the weak chain design, it and its related parts do not last for the life of the engine, period.
 

MOGolf

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I measured the used chain that came out of my car, and a brand new, never been used, out of the box chain. There are 30 links in the chain. Over the distance of 9 links chosen at random, the chain had stretched 1 mm in 89,100 miles. It is a bit difficult to measure total stretch in the entire chain. If it consistently stretched, that would be a bit over 3mm total length of stretch. I suspect less than that would be realistic.
 

volkswagendude

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MOGolf said:
I measured the used chain that came out of my car, and a brand new, never been used, out of the box chain. There are 30 links in the chain. Over the distance of 9 links chosen at random, the chain had stretched 1 mm in 89,100 miles. It is a bit difficult to measure total stretch in the entire chain. If it consistently stretched, that would be a bit over 3mm total length of stretch. I suspect less than that would be realistic.
Is that measured distance due to stretch a significant number you think, or well within a specified window of safety?
 

MOGolf

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I have no idea. I have no specs on what the tolerances are for brand new chains or what is expected over the life of the part. This is a sample of one each new and used. Random link selection on both. Would another new chain measure differently? Would another used chain of same miles measure differently? I don't know. I do know it didn't break, it just made noise.
 

jayb79

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MOGolf said:
I measured the used chain that came out of my car, and a brand new, never been used, out of the box chain. There are 30 links in the chain. Over the distance of 9 links chosen at random, the chain had stretched 1 mm in 89,100 miles. It is a bit difficult to measure total stretch in the entire chain. If it consistently stretched, that would be a bit over 3mm total length of stretch. I suspect less than that would be realistic.
1mm divided by 9 pins is .111 worn off each pin. What is the diameter of the pin? If they are 2mm and i did my math correctly, then 5.5% of the pin is worn away.
 

dkveuro

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jayb79 said:
1mm divided by 9 pins is .111 worn off each pin. What is the diameter of the pin? If they are 2mm and i did my math correctly, then 5.5% of the pin is worn away.
All of this thread is very enlightening and kudo's to all who have offered insight into this ....dear I say it...rare condition..

I find this very interesting. For why ? The 240/300D Mercedes 4/5 cylinder engines use a chain to drive the oil pump as does the V8 116 and 117 series engines, among others....as well as the cam/s.

Never seen an oil pump chain fail...apart from one that eat a piece of metal and jammed.
These commonly run 300K and a 240D I just took of the road had logged 720,000 miles.

Perhaps VW should have stayed with the T1 engine design and stuck with Porsche's gear drive in the first place..:rolleyes:

But having said that...the boxster engine is having similar problems with it's balance shaft.:cool:




Note: There are no chains driving anything in aircraft engines...apart from Wilber's that is. Here's a little write up I found interesting.
http://www.epi-eng.com/propeller_reduction_technology/chain_drive_issues.htm Note the comments about chain life and temperature.
 
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maktas

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dkveuro said:
All of this thread is very enlightening and kudo's to all who have offered insight into this ....dear I say it...rare condition..

I find this very interesting. For why ? The 240/300D Mercedes 4/5 cylinder engines use a chain to drive the oil pump as does the V8 116 and 117 series engines, among others....as well as the cam/s.

Never seen an oil pump chain fail...apart from one that eat a piece of metal and jammed.
These commonly run 300K and a 240D I just took of the road had logged 720,000 miles.

Perhaps VW should have stayed with the T1 engine design and stuck with Porsche's gear drive in the first place..:rolleyes:

But having said that...the boxster engine is having similar problems with it's balance shaft.:cool:



Note: There are no chains driving anything in aircraft engines...apart from Wilber's that is. Here's a little write up I found interesting.
http://www.epi-eng.com/propeller_reduction_technology/chain_drive_issues.htm Note the comments about chain life and temperature.

The key difference is that the BHW chain drives both the oil pump and the balancer shafts simultainiously, which probably results in a different loading condition on the chain itself. Also, if you have ever seen a BHW chain, its as large as a bicycle chain if not smaller!!:eek: (the links seem very small to me). Other design factors are whether they used properly heat treated parts (sprockets and chain), the design of the tensioner, guides which all contribute to noise development and eventual failure.
 
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PlaneCrazy

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2004PassatTDI said:
If a tune increases the rate of acceleration, then the stress on the chain/sprockets also increase. If you let go of the accelerator pedal, do the crankshaft’s RPMs decelerate faster than the BS’s RPMs in an unlinked condition? The high compression may be the major component that slows the crankshaft down, while the oil pump is probably the major component that slows the BS. If the crankshaft slows the BS, you now stress the other side of the sprocket’s teeth.

I never really liked using the manual mode for shifting. Maybe using the manual mode for shifting lashes the sprockets back and forth more than easy acceleration/deceleration. The tensioner, as MOGolf’s picture indicates, may not be beefy enough to compensate? Just thinking out loud.

My replacement parts arrived today :) .
I have wondered about the tranny's input on this issue. I specifically wonder about the "lag" or rough take-off we often get with the transmission in "economy" mode. I cured mine with the 1134 re-code, but fairly late in life. I did notice with mine in city driving, when you'd nail the accelerator, the tranny would be sort of "confused", and then suddenly would figure out I'm trying to go (especially noticeable from a rolling stop...), and would load the engine very suddenly. This perhaps causes sudden changes in crank speed, which stresses the chain/tensioner assembly.

I may be wrong but I recall reading somewhere that this issue seems to affect people with a high ratio of city driving, sooner. My own beast did about 90-95% steady highway cruising for maybe the first 75,000-80,000 miles of its life; when the chain assembly was removed the chain had very little visual wear, and the tensioner was nowhere near as deeply gouged as on some of the photos seen here. You could see where the chain went over the tension shoe, but the wear was barely noticeable, more like a change in colour (slightly blacker).

Anyway that's my take. I think for those who have not had the BS done, the 1134 VAG-COM tranny re-code won't hurt and if anything, will make the car more driveable, until you can get around to the conversion.

As for the manual mode, I can't say if this would make a difference. I use it occasionally while downshifting onto an off-ramp mostly, or going down a steep hill. ISTM that the manual mode is less harsh shifting than the non-1134 "normal" mode. At least if you put it manually in first or second on a rolling stop you shouldn't get that "moment of confusion" while the tranny tries to figure out that you're launching.

Methinks it's that harsh launch in town that lashes the components and leads to at least some of the premature wear.

Me-also-thinks we'll never really know for sure what the failure mode is, and most of this is brain farts... best just get down to business and fix before fail.
 

Tetraptous

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jayb79 said:
1mm divided by 9 pins is .111 worn off each pin. What is the diameter of the pin? If they are 2mm and i did my math correctly, then 5.5% of the pin is worn away.
It's been many years since I worked in the timing chain biz, but when I did I broke down and examine many returned parts. Now, I haven't seen much roller chain and certainly not this system, but a few millimeters of chain stretch doesn't seem abnormal - however, I don't know what the spec would be for this system. I can guarantee you that there is one, however.

Most of that stretch was in the links and not the pins. In general, after an old chain was returned, I'd see no noticeable wear on the pins, even with considerable chain stretch. If the pins when measured are notably worn, that's a big problem.

As for load on the chain, both the oil pump and the balance shafts will contribute significantly. Balance shafts don't impose much load at constant speed, but are a significant portion of the rotary inertia of the accessory system and will certainly load the chain when the crank speed is accelerated. In addition to their weight, remember that they do their job because they are designed with an intentional mass imbalance. The oil pump will provide a load at all speeds, depending on the system that load may vary a lot or a little with RPM. On top of all of this, fatigue may really be driven by second order dynamics of the system which comes down to the chain inertia and the tensioning system. The problem could just as well be in the tensioner design as anything else, and no change in driving style or maintenance schedule may affect the problem.
 

MOGolf

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Another broken one

I was contacted by the driver after an area mechanic said the car was one of the noisiest he had heard and referred the driver to me. After driving through a snowstorm a couple of weeks ago I met the driver in a McD's parking lot. The noise of this car was so bad that I could not hear my car running next to it, or even the normal diesel engine noise of this car. The best description was "bones in a garbage disposal". My recommendation: STOP DRIVING IT!! He did manage to drive it home and parked it until it could be towed here.

I could hear the chain links on the sprockets as I manually turned the engine to top dead center. Clearly no tension.

This is one lucky driver. It is amazing that the car maintained oil pressure.

The tensioner has the characteristic break.



Pitting and wear on the movable shoe (notice anything missing?).


This is where the rigid wear piece was jambed.


Making a nice groove in the seal carrier.


All the bits that fell out:


That's right folks. This one had the tensioner plunger completely fall out. Piston, spring and screw-in plug all fell out when the oil pan was removed. It has clearly been broken for quite awhile as evidenced by the smoothness at the break. Also, there is not enough wear material for the rigid wear piece to be re-assembled.

Fortunately, this engine can be repaired. :) Mileage: 158818.

To add insult to injury, the left engine mount is freshly bleeding and dripping down on the sway bar.
 
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MOGolf

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PlaneCrazy said:
He just won a $6000 lottery prize (price of a new engine minus a BS/TB job from OH). What are the odds of him winning a second time? :D
Only one winner per car.

It won't break again. ;)
 

leicaman

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johnboy00 said:
So now a "nasty bump" will cause a chain failure?

Is there any evidence of this whatsoever?:confused:
What I meant by that is the part was broken INSIDE of the motor and good old jolt could possibly have moved the broken mess which MAY have caused more mayhem.

MoGolf is right the owner already "won" the BHW lottery! :)
 

MOGolf

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The driver of this latest patient was fortunate that the guide/wear piece jambed between the crank sprocket and seal carrier. This is the only thing that kept the chain on the sprockets and driving the BSM/oil pump assembly. The tensioner part had fallen apart. Eventually that jambed piece was going to wear out, or wear through the seal carrier (as evidenced by the groove it was starting to make), or fall out of that position. That would have turned this into a disaster case.
 

PlaneCrazy

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Clearly the unmodified BHW engine is a 100,000 mile engine at best. Anything more is borrowed time.

And most people don't buy diesels to last only 100,000 miles. Shoot, even a '65 Impala could outdo that...
 

johnboy00

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leicaman said:
What I meant by that is the part was broken INSIDE of the motor and good old jolt could possibly have moved the broken mess which MAY have caused more mayhem.

MoGolf is right the owner already "won" the BHW lottery! :)
OK, I get it. When I originally read Oilhammer's post I read it as if it was another passat he saved, not a comment about Mogolf's work. Now it all makes sense.

I'm a little slow sometimes.:eek:
 

jennogle

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Over a year "post-op" and still going strong!

Sorry, it's been quite a while since I was last on this site! My car is still running great over a year and 28,000+ miles after the big oil pump chain failure and subsequent major "surgery". I never did hear back from VW despite sending them the whole story with invoices and photos. :(

Jenn
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leicaman

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jennogle said:
Sorry, it's been quite a while since I was last on this site! My car is still running great over a year and 28,000+ miles after the big oil pump chain failure and subsequent major "surgery". I never did hear back from VW despite sending them the whole story with invoices and photos. :(

Jenn
Silver 2005 Passat GLS TDI Wagon ~108,000+ miles
Somehow I am not surprised.

Only if one of the other automakers develops a reliable diesel car and properly supports it will they get the message. Can you just see it? No showroom traffic at all? Yeah while I would feel sorry for some dealerships, I would never feel sorry for VW. They've dug their own grave in that respects.

Can you just see how quickly the good word would get around if they just pulled their pants up and said, here is a check for $2000, plus $1000 for our bad behavior. Won't happen, but then...if competition arises...
 

miles1965

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rebuilt balancer shaft

I just drilled out my worn hole and incerted a 6 point 6 mm scocket in mine, I put my shaft in the oven at 400 degrees and put the socket in the freezer and pressed it in with a drop of lock-tite better than new. cost about $10 made the shaft out of a 6mm allen wrench perfect fit
 

s4phillips

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I just drilled out my worn hole and incerted a 6 point 6 mm scocket in mine, I put my shaft in the oven at 400 degrees and put the socket in the freezer and pressed it in with a drop of lock-tite better than new. cost about $10 made the shaft out of a 6mm allen wrench perfect fit
The one that is driven by a chain & sprockets or gear drive?
 
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