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B5.5 TDI balance shaft conversion from oil pump chain to oil pump gear

33K views 23 replies 9 participants last post by  ScanPaav 
#1 · (Edited)
As some of your B5.5 folks may know, VW put a pretty screwy setup for balancing engine vibrations in the B5.5 BHW vw tdi motor. I am posting this so that you know that some enterprising folks at www.tdiclub.com have discovered a conversion in the VW parts bin. If you go to the B5.5 Passat area of that club's web, there is a .pdf with all the instructions on how to do this procedure. Its pretty much a bolt-in operation, but it is clearly not for the faint of heart. Apparently VW had a mid-production change on Skoda cars that essentially use the same motor. What happens is that when these cars get higher miles this chain can and will snap. Some have failed as low as 70k. The symptoms are that the car sounds like marbles in pulsing like noise. When this happens the motor can fail while in operation. If any of you folks have had a situation with this unique and particular motor setup, I urge you to post your situation on the survey that has been started. If you've had an issue make sure you write VWoA. Most of all, go over and look over the .pdf that MoGolf and Oilhammer have created detailing the procedure. I might add that it is not cheap as the parts are around $1200 for the balance gear assembly alone. You must do a timing belt job at the same time adding those expenses on top of that. Members who have had it done say it is around 3k to have it done. The folks who have had it done say the engine is really smooth after the fix is applied. Right now in the USA there are under a half dozen of these cars converted. If you thirst for knowledge, read the below link:

http://pics.tdiclub.com/data/3419/BHW_Balance_Shaft_Module_Replacement.pdf
 
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#4 · (Edited)
The reason why it fails it seems is that is because of the unique work the balance shaft mechanism has to do with a diesel engine. It seems to fail sooner in cars that have been subjected to lots of city driving or have been chipped and driven hard. The fact remains it can fail. When this baby fails, its can ruin the motor. If you have one of these and the STOP ENGINE NOW light goes on, do so immediately and you will have saved your motor. It is also imperative that with these cars that you do use a vw certified 505.01 motor oil. It is not so much for the oil pump mechanism but rather the lobes of the camshaft which has extra lobes to operate the pump duse injection pumps.
 
#6 ·
Chains are as exact as gears -- or at least, as predictable as gears, if not as exact. It's very simple to predict the amount the chain will wear and stretch per crankshaft rotation, if you know the tension on the chain and the strength of the metal.

They probably made the chain links too thin while trying to save weight, or some nonsense like that. (Either that, or they made it too weak intentionally, so they could offer to replace it every few years for a nominal fee.) It's an engine; it has a shitty job and it's expected to do it for years with little to no maintenance. (In America, anyway.) Overbuild it accordingly.
 
#9 ·
Chains are as exact as gears -- or at least, as predictable as gears, if not as exact. It's very simple to predict the amount the chain will wear and stretch per crankshaft rotation, if you know the tension on the chain and the strength of the metal.
In this particular application the chain blance mechanism rotates at 2x the speed of the crankshaft. So what this means is when you are cruising at 70 with the motor turning over 2100 rpm, your poor little oil pump chain will be rotating that balance shaft double that.
 
#8 ·
B5.5 TDI'rs report really smooth motor after new balance system

Early viewpoints are in and the overall report is that the 2.0 BHW motors that have been converted from the oil pump chain system (which is no longer available) to the oil pump gear system are significantly smoother and quieter following the expensive surgery.

www.cardocautomotive.com has a technician by the name of Brian who extremely well versed on the procedure. He did five conversions this past weekend with more on the way. He is known as Oilhammer on the www.tdiclub.com boards.
 
#11 · (Edited)
A chain is a machine with moving parts, there for, can and will fail if it is not assembled 100% correctly. The chains are hydrolicly tensioned unlike gears that mesh with only thousanths of an inch of backlash, also you have a hard ass time streaching a gear.:poke: So they are NOT as exact as a gear, are they? You may know grammer but you will not get me on gearing my friend.
 
#14 ·
A chain is a machine with moving parts, there for, can and will fail if it is not assembled 100% correctly. The chains are hydrolicly tensioned unlike gears that mesh with only thousanths of an inch of backash, also you have a hard ass time streaching a gear.:poke: So they are NOT as exact as gear are they you may know grammer but you will not get me on gearing my friend.
I bike, so yes, I'm familiar with chain stretch, and I have had a chain pop in half at the rivet when I didn't reassemble it correctly.

Nonetheless, this is an automobile and they should be using parts that will never break (within the bounds of reason) for critical jobs like driving the oil pump. Stop making excuses for their shitty design.
 
#15 ·
Just rattling your cage man. I work on crane gear boxes and strength and alignment are critical, chains are old school. I also repair VW and Audi cars and pretty much fix anything you can come up with, not to mention, weld and fabricate. So relax I am usually looking for your posts to mess with you Deus.:D
 
#19 ·
It looks like more and more dealerships are now gathering the knowledge to replace the balance shaft mechanisms with the newer gear driven version. However if any of you have this car, check with www.tdiclub.com as they have a list of well known gurus who can fix it right the first time.

Notes on my car since my conversion last June. It seems to be getting smoother by the day I swear. My fuel economy is quite good. Most freeway trips I am getting 40-41 mpg. I continue to use Pentosin 5w40 505.01 oil. I changed oil early due to break in of the new components. Many folks on the tdiclub who have had the conversion done who do UOA report that their aluminum counts have spiked. Most are not worried because the aluminum comes from a special break-in coating on those gears. That is why many of us go with 5-8k OCI instead of the factory 10k.
 
#20 ·
has anyone ever seen the message that this was recalled and from what country? I know in CAN/US it hasn't. I would like to get a copy of it. I bought one of these and I love it. The is a law (in Canada at least) where a dealer has to tell you what's wrong with the car. So, in my opinion, a chain driven pump car @ 100,000 Km can break at anytime thus not road worthy.

I would really love to see that message if anyone has it

Cheers
Brent
 
#21 ·
has anyone ever seen the message that this was recalled and from what country? I know in CAN/US it hasn't. I would like to get a copy of it. I bought one of these and I love it. The is a law (in Canada at least) where a dealer has to tell you what's wrong with the car. So, in my opinion, a chain driven pump car @ 100,000 Km can break at anytime thus not road worthy.

I would really love to see that message if anyone has it

Cheers
Brent
 
#24 ·
There is little change in the how loud the engine is at idle. The swirling slapping noise is gone that sound is not very loud. Just their in the back ground.
Seen some pics of the worn gears would lead me to believe the noise would be a lot louder as the millage increased.
I have not seen the neighbor with 192k on 05 TDi lately, he was of to Calgary last time i talked to him.
You can hear his car coming now the street. Would be nice to have the cars line up & do a sound test as the engines idle to an untrained ear or two.
His take was, if the dealer says it is fine why should I worry.
Stu
 
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