Lightening and balancing the intermediate shaft.

[subsonic]

I have been looking for some info on this.  I did a search on google but mostly came up with lightened aluminum intermediate shaft pulleys.

I did find a picture of a turned and balanced one on line.  It looks like it would be quite a bit lighter. I will give them a call and talk to him about it.http://portland.craigslist.org/clk/pts/605702921.html

Does anyone here have any experience with with this?  Anyone done it, or have a good link to some information on it?  

I would think that having this lightened and balanced will help extend the life of the intermediate shaft bearings, as well as reducing reciprocating mass.

[subsonic]

anyone?

[Turbinepowered]

How much does a stock intermediate shaft weigh? And isn't it's only point really to drive the oil pump?

I know the 5-cylinder diesels don't have them...

Also, I doubt the intermediate shaft contributes anything to reciprocating mass. Rotational mass perhaps, but since the intermediate shaft only spins instead of oscillating in any fashion, I can't imagine it contributing anything to reciprocation mass.

[jimfoo]

Also it looks like it turns at about 1/2 the engine rpm, so lightening it wouldn't have as much effect as weight off the crank/flywheel.

[hillfolk'r]

i may do it on my tdi-m right now,but yea,its not gonna be a big gain cause its 1/2 crank speed
but its somethin easy to do cause i got a lathe+im a nutty power junky

[subsonic]

I figure if it's out, it cant be that hard to do. Set it up on the lathe, back and forth, a few times.  Just like turning straight bar stock.  Finish up with the emory cloth.
It's been a while since I picked mine up, but I remember it was not light.  I think you could get some good weight off it, not to mention doing this would probably help true it up.

Like you said hillfolk'r, it may not be a big gain, but it's an easy gain. Take it where you can get it :lol:

[subsonic]

Just sent this to the guy who was selling the kit at the beginning of the post.  I will post the response when I get it.

Hey Josh,
I saw the add you have going on for the 2.0 engine kit.  I am building a high output 1.6TD. I am looking to go from 68 to 200hp.   I cant use what you have up for sale, but I do have a question for you.  I have been looking into getting my intermediate shaft lightened. I have it out allready. I know it only turns at half engine rpm, but it looks like easy weight to lose.  I have not been able to find much information on the subject.  I see people selling light weight pulleys, but nothing on the shaft itself.
I have just had my con-rods polished and shot peened, cranks done, new pistons are back from swain tech, etc.  I will be having the rotating assembly professionally balanced in a week or so.  I would like to have the shaft balanced as well.  
Did you keep track of the weight difference before and after?
I am kind of worried that if I take too much off of the shaft in the center I will get flex, even if it is balanced.
What did you mean in the add when you said the shaft had been clearanced?
 
Thanks, Jim

[subsonic]

I was looking at the IM shaft today.  I tried to take a picture but the batteries died right as I pushed tthe button. :x

There seems to be a pretty good taper to the shaft, much thicker on one end, running down to quite a bit thinner on the otherend.  There is also a fairly large offset lobe on the shaft near where it connects to the vacume pump. Perhaps 3-4 inches away.  The lobe looks like it sits right under the plate cover on the block that is held on by 3 bolts, right next to the vacume pump.  Pictures would help I know, I will try to get some tomorrow on the way to work.  What the hell is the lobe for?  Is that a throwback for a gasser engine?  It looks like if you ground off the lobe, and turned the shaft OD to the size on the small end, you could remove a fair amount of material.  What do you think?

[rabbitman]

Don't quote me on this but I think these diesel were meant to have a lift pump that runs off the lobe.

http://vwdiesel.net/phpBB/viewtopic.php?t=12943

See in the second pic it has a lift pump and on the filter it looks like there is a pressure relief valve, regulator or check valve, not sure which, so it supplies constant pressure. Someone on here said the IM shaft has opposite ground oil/vacuum drive gears so it is diesel specific. I think you would see small gains from balancing the IM shaft, the factory casting looks pretty sloppy.

[subsonic]

Just sent this to the guy who was selling the kit at the beginning of the post.  I will post the response when I get it.

Hey Josh,
I saw the add you have going on for the 2.0 engine kit.  I am building a high output 1.6TD. I am looking to go from 68 to 200hp.   I cant use what you have up for sale, but I do have a question for you.  I have been looking into getting my intermediate shaft lightened. I have it out allready. I know it only turns at half engine rpm, but it looks like easy weight to lose.  I have not been able to find much information on the subject.  I see people selling light weight pulleys, but nothing on the shaft itself.
I have just had my con-rods polished and shot peened, cranks done, new pistons are back from swain tech, etc.  I will be having the rotating assembly professionally balanced in a week or so.  I would like to have the shaft balanced as well.  
Did you keep track of the weight difference before and after?
I am kind of worried that if I take too much off of the shaft in the center I will get flex, even if it is balanced.
What did you mean in the add when you said the shaft had been clearanced?
 
Thanks, Jim

Got the response:

" Jim:
 
I can lighten your intermediate shaft. I lighten intermediate shafts regularly. I take about 50 grams off. Probably more important than taking the weight off the shaft is when it is machined it is also being balanced, because a stock intermediate shaft doesnt spin very true. I have many 200+hp naturally aspirated street engines with lightened intermediate shafts and they work perfect. I charge $60.00 to lighten and balance your intermediate shaft. I do intermediate shafts in batches, so it will take roughly 2 weeks. Just to let you know I also lighten connecting rods as well. I take 50 grams off each connecting rod. If you look at the picture on craigslist real close you will see that the connecting rods have been lightened. I will also have a display at the Woodburn bug run. THANKS"

[DVST8R]

http://scch-heads.com/viewpart.php?id=23

[burn_your_money]

IIRC the lobe is for the fuel pump on the old carbed gassers

[rabbid79]

I'm not absolutely sure of this, but I think I saw an application where the lobe was also used to help power a dry-sump oil system.

[subsonic]

Some more info:
"So do you take the taper out of the shaft?  What about the lobe that is on the shaft, near the gear end, that drives the vacume pump?  Do you take that off as well?"

Reply:
"I take the taper out of the intermediate shaft as well as the bump."


From doing a bit of reading, it appears that the IM shaft is pretty rough, and I suspect, not very balanced.  

 :idea:  I am going to put forth the hypothesis that the IM shaft being out of balance is one of the leading causes of the dreaded IM shaft bearing failure / flaking.
I would further suggest that balancing the shaft will reduce or eliminate many of these failures. :idea:

[jimfoo]

I wonder if the AAZ shafts are different. Not that I was looking for one, but I don't remember any bump on mine, just the 2 bearing surfaces and the gear. I think I would have noticed a bump.