Dougs951S

I'm adjusting the tension on my belts after doing the front seals, rebuiilt head, water pump, head gasket, and cam tower/cam seals and noticed an issue

The upper balance shaft is fine, the issue is in the lower balance shaft


it spins perfectly smooth with the pulley off, but as soon as the pulley is tightened on the shaft is binding. I followed the torque sequence when replacing the front shaft housing and all bolts are tight, including the one you have to get to from the back. I did not actually take off the balance shaft housing (the one that runs length wise front to back and has ~20 some off bolts holding it to the block).

I just want this car to run and I'm slamming my head into a wall in frustration, this is my last issue before I can start it. The car's been down for 13 weeks and I just want to hear it run today. Please help

Dougs951S

This is the only thing I touched with respect to the lower balance shaft. I pulled it off again just to look at it and it looks fine. Everything is there, even the onion skin mylar seal.

I noticed that before I took it off again, the upper balance shaft has some in and out play which it is supposed to have.

the lower shaft has zero in an out play with the pulley torqued on (it does when it isnt torqued), and I realized that the shaft is getting pulled back toward the block as the pulley is torqued on and its driving the woodruff key into the race directly behind it and locking the shaft up.

944hal

I just had the same problem, except with the upper balance shaft. I'm doing a total engine rebuild, new pistons, mains, rod bearings, everything. I also replaced the balance shaft bearings, including the one in the cap. I could tighten the top and right cap bolts and the balance shaft would spin free. As soon as I tightened the lower left one, it binded. The only difference in the cap was a new bearing and seal. I dug out an old cap and it tightened OK with no binding. Since the bearing looked OK, I replaced the seal and used it. I still can't figure out what's wrong with the one that came off the car, unless the bearing is not aligned properly. Did you replace the bearing in the cap? In both cases, the pulley was torqued. I also removed the pulley a few times which necessitated removing and reinstalling the key.

Dougs951S

I also did basically a full rebuild minus bearings and rings. No, same race was used. I've tried different woodruff keys, ect. I'm about to tear my hair out. This wasnt an issue before the new seals. It spins freely until juust at the point where the torque on the pulley bolt exceeds hand tight, then I can physically see the shaft get pulled back several mm's as the torque increases, which drives the woodruff key against the race until the shaft wont turn. What the hell?!?!?


Should there be a washer of some sort behind the pulley? That seems like it would space the woodruff key out a bit and possibly prevent binding, but it would also put the pulley out of alignment.

Dougs951S

I think its extremely telling that the upper, free spinning shaft has plenty of in and out clearance. With the pulley torqued, I can easily slide a flathead screwdriver between the front of the housing and the rear of the pulley. There is maybe 1/8" of clearance.

On the lower shaft, there is zero in and out play, and zero clearance between the back of the pulley and the housing. This is the key, I'm just not sure why this is the case or what I can do to fix it.

markoS2

I had the same problem Doug. In the end, I shimmed the bearing cap housing at the upper bolt hole and also added a thin washer at the end of the balance shaft. Spinned very freely after that. Only way I could get it to work.
You may have a different problem, but this link might be worth a read.
http://forums.pelicanparts.com/porsc...g-tight-2.html

944hal

Doug,
Maybe a slightly different problem. Mine was binding, without the pulley being torqued, as soon as I tightened the left lower bolt. So I don't think my problem had anything to do with in/out shaft play or the key. Especially, since it worked with a different cap.

Dougs951S

I think shimming the pulley with washers is the key, glad to hear it didn't throw the alignment of the pulleys off too much. Can you please tell me what size washer you used? I'm guessing 7/8"?

I'd still like to know why this is suddenly now an issue when all that changed was that the shaft got new front seals. I didn't remove the long balance shaft covers like you did. All the research I'm doing on this issue has to do with misalignment of the covers, but I didnt touch them at all. Havnt found anyone who had this issue just from changing the front seals.

Charlie

If I am looking at the picture correctly it looks like the sleeve is on wrong, backwards? The flange on the sleeve should be on the backside of the seal with the onion skin behind it.

Dougs951S

WHAT?!?!

That's impossible, if you look at the back side of the front housing shown in the first picture, there is a flange there thats part of the housing that would prevent the race from going on any way other that the way I have it. Can anyone please confirm I have it together correctly?

Or is the flange on the race meant to sit on that lip?

Charlie

The flange is behind the seal. You put the onion skin on first, next slide the sleeve on with the flange toward the back of the car next to the onion skin, then you put the seal on over the sleeve into the housing.

Dougs951S

WOW....you just saved my bacon. I did the same thing incorrectly on the upper shaft I think. I'll need to pull that one apart too and repair it. Thanks SOO much

Dougs951S

So this is correct? And the sprocket just butts up against the seal with nothing between? Is the upper shaft the same, the race goes behind the seal and the sprocket butts up directly against the red seal with nothing in between?

audi49

Yup. Here's what it should look like minus the oil leak. :-)

porscharu

Nope, Everything is inserted from the outside. In order of onion skin, race (flat side against the onion skin), seal. Like below.