Swapping ALH IP Pulley

[UhOh]

Will be doing the TB on my car shortly and I am planning on taking this opportunity to change the pulley on the IP*.

* I will ONLY reveal what I'm up to after I've completed my work (later this month).

Any tips on doing this, such as looking to break the bolt loose when timing is locked and the belt is still on? Tips on what NOT to do when replacing the pulley (other than to not turn the pump shaft)?

Also, what is the torque spec on this bolt?

Thanks!

 

[Nero Morg]

Just to clear the air... Are you talking about the pulley that rides on the belt, or the pulley the other pulley attaches to?

Casue if you're replacing the one that the belt rides on... It's just the 3 bolts. If it's the other... then what the heck are you doing lol
Knowing you, it's most likely the latter. The big 22mm nut torques to about 70ftlbs if I remember right.

 

[burn_your_money]

You can not properly tighten the big nut without removing the pump from the car.

 

[UhOh]

Color me embarrassed! I'd recalled WAY too many comments/stories about the horrors of touching that nut and when I ran things through my head (which almost always seems to encounter situations of maximum effort) I just kind of figured it would come down to doing a battle with it in order to change the pulley. Nero's comment (thank you!) forced me to look a bit closer at things, in which case I was able to confirm from digging up pictures from the Internet that it is in fact only those three bolts that hold the pulley on the IP.

OK, I'll give away my "secret" now rather than leave people hanging...

I'm going to swap the stock pulley with a lightened one (which looks more like the cam pulley). The claim on this aftermarket pulley is that it'll reduce drag and therefore increase MPGs: one of the reasons why I've been trying to get optimal MPGs of late is for a benchmark. The pulley was given to me by a longtime friend from this forum (he won it as a prize and never was able to use it): I've been waiting a long time to report back to him on the validity of the manufacturer's claim (1 to 2 mpg improvement). I'll post a pic of it when I have time...

 

[Nero Morg]

Dang, hope to see some juicy data on that. On another note, any particular reason the IP gear is so beefy?

 

[UhOh]

More mass tends to provide for more rotational stability. I do have some concerns over this possibly introducing an undesired behavior. I know that people who go with lighter flywheels tend to see quicker revs AND also quicker drop-offs (easier to stall out). Not sure if this lighter pulley would really be able to affect the rotational inertia of the entire TB system enough to have this kind of influence: I'm thinking that it's really an overall drag issue.

I'm not normally someone that looks to be a guinea pig: I work on my cars only out of necessity (I've got so much going on that I don't really have time for hobbies- my life is like one huge all-consuming hobby!). I don't believe that I'm the first or only one to use one of these. Just figure that the cost of the pulley wasn't found to be justifiable enough to keep production running: not an uncommon occurrence; some products can be great, but the profit margins and volume of sales nixes them.

I'll try to remember to weight both pulleys. And, I'll also try to post up a picture here of the replacement: I start having anxiety over doing such as my memory of posting up pictures on this site don't seem to be pleasant ones.

 

[tgray]

I would be careful with messing with rotational weight changes until you know what is going on. Diesel engine produce vibrations and harmonics gas engines do not. There is a reason they installed a one way clutch on the alternator. From what I read the engines without this clutch would send vibrations into the crankshaft and cause it to break. The rotational force of the alternator causes too much force transferred through the belt. You can feel this in the gear shift when it fails. My guess is the TDI needs the heavy mass on the pump to smooth out the pulses from the injection cycles. You may find the timing belt doesn't last long or a crankshaft will break or the engine will vibrate your steering wheel. The camshaft does not have the same situation and so it is lighter. Look at the power steering pump and see how light that is. I know VW doesn't put metal where it doesn't need it. If you want to save a MPG just pull off the alternator, AC and power steering pump and charge your battery at home. That will cut more rotational mass and power load and not hurt anything.

 

[UhOh]

tgray, thank you for expressing your concerns. Note, however, that folks were saying the same thing with the clutches (going from dual mass to single mass).

 

[KLXD]

The AHU doesn't have that monster sprocket.

They didn't add the more expensive heavier part just to beguile folks and make a market for guys to sell a lighter part with the dubious claim of better mileage.

Never heard the alternator would cause problems with the crank. I think the clutch was just an improvement to smooth vibration in the belt for its own sake. Again, an improvement over the AHU.

 

[oilhammer]

It would seem that a lighter ALH injection pump sprocket would have meant cheaper, and in the quantities that VAG builds engines (many VE TDIs are built that never see an automobile's engine bay) that would be MILLIONS of dollars a year saved. So I would say that they had good reason to make them the way they did.

No, the AHU doesn't have that heavy of one, but the AHU is a leftover from early 1970s with some updated bits stuck on. The ALH is very different, and shares virtually no parts at all.

But hey, after 2+ decades of use, maybe there is some tiny positive modification secret left for what was (is) probably one of the best engines they ever made!

 

[jettawreck]

I really can't see how a marginally lighter sprocket in the belt path can have any measurable difference in the total vehicle mileage efficiency. There are just so many other aerodynamic, friction and resistance type improvements that could make bigger increases for less effort.
Very careful/accurate long term records would be needed to really prove anything.

 

[oilhammer]

It may make as much of a difference as what (if any) wax used on the paint.

 

[tgray]

I found this article that states the problem of the alternator pulley...
"On the early days of their serpentine belt implementation on the AAZ engine (MK3 chassis 1993+) VW used a standard (solid) alternator pulley, meaning that the alternator is directly connected to the crankshaft drive pulley via a serpentine belt.

This engine (and its gasser cousins the ABA and VR6) unfortunately became a bit infamous for wearing out the crankshaft sprocket, key, and keyway. It’s generally accepted that a large contributing factor to this problem was that the alternator has a small pulley and a lot of angular momentum; during deceleration it tends to want to overdrive the engine, putting large stresses on the crankshaft drive pulley (and the keyway) therein in a direction opposite to normal. Over time acceleration and deceleration results in the crankshaft sprocket rocking loose… on a diesel the result can be catastrophic. The small pulley on the alternator exacerbates the problem (over previous designs) by increasing the alternator RPM and giving it a mechanical advantage when overdriving the larger crankshaft pulley.

At some point just before they moved to the TDI engine VW switched to a 1-way ratcheting alternator pulley (which they continued with on the TDI engine). This pulley allows the alternator to automatically de-clutch from the drivebelt and freewheel on its own… preventing the alternator from applying reverse torque to the crankshaft pulley when the engine decelerates."

Another place they speak of a solid pulley ruining the vibration damper. Which would or could break the crankshaft. I have seen this first hand on the larger diesel engines.
But, any rotating mass changes do affect things in different ways. Vibrations at the right frequencies do strange things.
And, don't take me wrong, I do like to modify stuff if it does good or helps. If you want to try it out I would love to hear about the results both short term and long term. I love driving my single mass flywheel cars and they have done me well for many miles.

 

[UhOh]

This is no cheap Chicom part. Not that it qualifies on it's own, but it's made in Germany.

Has a part number of 028 130 111 J stamped on it. I can only find this number referenced for an AHH? A diagram of of the AHH's pulley, however, shows it being keyed (which is meaningless for ALH purposes), whereas this one is not.

I'm going to pick my truck mechanic's brain to see what he thinks. He's a high-performance diesel guy: he works on my 12v Cummins; knows TDIs [wife drives one].

Believe me, I don't want to do stupid things. It's just that this was a gift from someone special and I'd promised him I'd install it when I had a chance. If my truck mechanic says that he wouldn't run it then I won't: I've got an interesting story (that I've been waiting years to tell- it'll be disclosed in my thread "Meet Tanko") that demonstrates why I have a LOT of trust in this guy.

 

[KLXD]

I doubt it'll do any harm in the short term while seeing that it doesn't affect fuel consumption. Then you can decide whether you would cause hurt feelings by removing it.

As you can see I'm a doubter but will gladly learn otherwise. But be prepared to defend your methodology.


Tgray, I rescind my comment on the crank issue. It didn't occur to me that you were referring to the keyway. I was ass-uming you were talking about breakage of the crank. Sorry.

 

[UhOh]

I doubt it'll do any harm in the short term while seeing that it doesn't affect fuel consumption.

[emphasis added]

That doesn't sound like an objective scientific stance!

BTW - Physics would seem to suggest that there should be less energy required to spin a lighter mass. The ONLY questions are: 1) How much of a difference? 2) Will there be any negative impacts/consequences to reduced dampening? (I don't believe that timing would likely to be appreciably affected as pertains to changes in acceleration/deceleration. I could, however, see quicker advance on acceleration. The changes are going to be microscopic.)

 

[CasaEd]

When I put a ALH injection pump on my partners 1z Passat I just used the AAZ injector pump pulley because the ALH pulley would of needed machining down to fit behind the cover. Been running like that for more than 2 years without any issues.

 

[oilhammer]

The AHH is an early type VE90 engine used in 1999-early 2002 B5 Passats (obviously not here). And the very last of them use the J suffix pulley (earlier ones use the H suffix). The whole engine is essentially the longitudinal version of the AHU. VAG never put a longitudinal late type VE engine (like an ALH) in anything. The old style engine continued use until the PDs replaced them as I understand (someone in Europe please verify or correct this, I am just mostly going off of ETKA).

 

[tgray]

And don't forget this mass of metal is only spinning at half the speed of the crank so I have my doubts on any noticeable affect on the mpg.

 

[UhOh]

I talked with my truck mechanic and he agreed with me as to the only likely issues. He sees no reason for their to be any meaningful, negative consequences.

One positive with this puley is that one can readily see the pin slot in the pump. Though, I always take pictures so I can get a better look (and to eliminate parallax errors).

Weight of stock pulley measured at about 3.9 lbs.

A bit of a delay in getting things back together as I have to replace the [front] crankshaft seal...

 

[Andyinchville1]

I found this article that states the problem of the alternator pulley...
"On the early days of their serpentine belt implementation on the AAZ engine (MK3 chassis 1993+) VW used a standard (solid) alternator pulley, meaning that the alternator is directly connected to the crankshaft drive pulley via a serpentine belt.

This engine (and its gasser cousins the ABA and VR6) unfortunately became a bit infamous for wearing out the crankshaft sprocket, key, and keyway. It’s generally accepted that a large contributing factor to this problem was that the alternator has a small pulley and a lot of angular momentum; during deceleration it tends to want to overdrive the engine, putting large stresses on the crankshaft drive pulley (and the keyway) therein in a direction opposite to normal. Over time acceleration and deceleration results in the crankshaft sprocket rocking loose… on a diesel the result can be catastrophic. The small pulley on the alternator exacerbates the problem (over previous designs) by increasing the alternator RPM and giving it a mechanical advantage when overdriving the larger crankshaft pulley.

At some point just before they moved to the TDI engine VW switched to a 1-way ratcheting alternator pulley (which they continued with on the TDI engine). This pulley allows the alternator to automatically de-clutch from the drivebelt and freewheel on its own… preventing the alternator from applying reverse torque to the crankshaft pulley when the engine decelerates."

Another place they speak of a solid pulley ruining the vibration damper. Which would or could break the crankshaft. I have seen this first hand on the larger diesel engines.
But, any rotating mass changes do affect things in different ways. Vibrations at the right frequencies do strange things.
And, don't take me wrong, I do like to modify stuff if it does good or helps. If you want to try it out I would love to hear about the results both short term and long term. I love driving my single mass flywheel cars and they have done me well for many miles.

Interesting about the one way pulley on our TDI alternators ...

I used to have a step van with a with a Cummins 4BT engine (4 cylinder version of the 6 BT engine used in dodge pickups).

THAT engine made the serpentine belt tensioner dance up and down so fast you think it would blow up in short time .... I replaced the tensioner I don't know how many times and every brand tensioner would just dance and dance ... I eventually gave up and just ran it as is.

It always worried me me but it just seemed to work.

Would our tensioners "dance" if our one way pulleys locked up?

Now that I think of it I may google 1 way pulleys for Cummins 4BT (FWIW - on the 6 BT the tensioner was rock steady .... I'm guessing its a 4 banger thing).... Hmmmm I wonder if other 4 cyl cars have that issue?

Andrew

 

[Andyinchville1]

Dang, hope to see some juicy data on that. On another note, any particular reason the IP gear is so beefy?

I'm wondering if they were too lazy to machine it ? How can one tell is a part is cast rather than machined?

Andrew

 

[Nero Morg]

Machining usually leaves cutting buit grooves in it, whereas cast usually has a bit of a rough appearance to it.

 

[UhOh]

Minor update:

Car fired up instantly after TB work: VCDS shows timing is perfectly on-spec. Car runs as awesome as always. Perhaps it's a placebo effect, but it does seem a bit quicker. All in all things are extremely smooth and snappy.

Will go through the existing tank of fuel before attempting any true FE measurements. Weather is likely too start turning, which will make straight-up comparisons a bit harder.