SteveG

Doing the TB on a '93. I have not been able to remove the tensioner arm/rollers. The tensioner arm shaft bolt (17MM on the smaller idler pulley) on this car is replaced by a small (IIRC 6mm allen head screw that holds a stablizing bracket that runs up and to the right, bolted (x2) into top of center cover. This small screw cannot be supporting the bulk of the tension assembly as the 17MM shaft bolt did previously. I have loosened the larger tension roller bolt (13MM). On earlier cars these two bolts are all that hold assembly in place. The 13MM bolt turns freely but is not backing out. It only needed maybe 20 lbs, to release, just a bit more than a water pump bolt; didn't seem like anything wrong, but if there isn't another answer here, I may be looking a helicoil already in place behind the 13mm?? I have not tried to pull the bolt other than turning it ccw. Tension is off the belt, the large pulley is still aligned with belt and seems firmly anchored.

Part 2. I had a very difficult 3 hours+ of tapping, heating, positioning a 3 prong puller, etc., over and over and will be replacing the harmonic balancer. It already had a 5/8" chip out of the circumference, but there are cracks (may have been there before) can flex it w/finger nail in the edge coating that I don't want to chance coming off later. Ken (Porken), are you interested in another project? I would suggest this. I've done two belts (almost) and this is by far the worst part of the job. I didn't destroy the other one, but both times it put me 3 hours behind and this time it will be several $$.

Mrmerlin

Hey Steve do you have any pictures it will help with diagnosis is there a chance the bolt your turning has a nut on the back of that you didnt see? the Crank pulley should come off without and puller it just takes some time and wiggling it back and forth and using PB or Kroil on the crank shaft

SteveG

I just love it when the instructions say "It should come off with patient tapping and wiggling." Coulda, shoulda, woulda, baby. Beverly Hills Porsche did the last belt, you can see the chunk they took out with a puller. (Note: otherwise I am happy with their attention, all bolts have fresh antiseize.) I spent a good 2 hours, using penetrating oil, tapping on a gently applied 3-prong puller. Lots of oil, let it stand overnight . Next day, 2 more hours w/hair dryer heat and various tapping techniques. The one that worked was tapping directly in toward crank on the threaded bolt and working around the bolt 360, at 20 degree spreads to approx the wobble pattern. When came it was slow all the way, rust around the keyway.

I will take pictures when I resume on it.

dr bob

Hi Steve-- I went and reviewed my how-I-did-it video TB to remind myself what you are talking about on the tensioner arm.

The small bolt/screw holds the arm onto the pin that's part of the water pump assembly-- This is the screw that goes through the lower/left (facing the front of the motor) end of that little support bracket. Once that bolt/screw is removed and the tensioner bolt and locknut on the back of the tensioner itself is relaxed, the whole tensioner arm will slide off the pin as an assembly. That assembly includes the arm and the two little press-in bushings where it pivots on that pin, plus the bearings and rollers. I suspect that bolt you are trying to loosen is the one that holds the lower roller to the arm; Once the assembly is free of that pin and on the bench, you'll see the nut on the back end of that bolt.

I'd send the video but it's almost 1gb AVI just for the segment on pulling the tensioner arm. Editing that whole thing down is on my to-do list now for over two years. I guess I need to get it done in the next few years if I want it for reference on my next TB job.

worf928

The harmonic balancer will come off with wiggling and tugging and a bit of PB Blaster - IF you heat it up first. The heat will allow it to expand and then it will come off. Works each and every time. 5 minutes with a heat gun is all it takes. Once it's just hot enough that you need gloves it will move.

Bill Ball

Yes, that small Allen head screw is holding the whole thing together. Once you remove the screw and bracket from the shaft on the water pump, the arm slides off the shaft. Removing the 13mm tensioner roller bolt accomplishes absolutely nothing. It won't come off because there a nut on the other side that you cannot get to UNTIL you remove the arm from the shaft by removing that tiny screw. The screw strips easily. If it does, cut a straight slot into it with a Dremel cutting wheel and use a screwdriver or chisel and hammer to knock it loose. I had to do this 2 days ago.

I've been very lucky. In 18 timing belts I still haven't encounterd a harmonic balancer that wouldn't wiggle off. This last one almost fell off. I could feel the antiseize coating the inside of the balancer that the last shop had graciously put there. But even the most stubborn balancer wiggled off after 15 minutes. The clue to eventual success is if there is ANY play whatsoever in the balancer when wiggled side to side, however slight. If it gets stuck at any point, it is worthwhile to knock it back to its seated position and start over.

davek9

This photo that was posted showing the newer type of WP and newer support bracket

SteveG

Thanks all, esp. Davek for the pic. I didn't want to put any force on the small idler pulley not knowing what was behind it. I've done two now and neither had any play; no wiggle room, no wobble. Once started, the first came along with no damage. Understand -- I hate hearing how easy it is -- makes me feel "special" I am still hoping to attend Frenzy this weekend. Taking off from work to finish, but can't rush on a job like this.

as I said it had rust around the woodruff, so I doubt there was any antiseize in there. but I do know now I can use more heat than I was using.

I still hope Ken will consider a replacement or mod to the existing balancer. It either moves or it doesn't and if it doesn't, there will be damage to the edge coating. How much is too much is the question -- the previous mech took out a 5/8" section (circumference) and I guess it was deemed usable, went for 9000 miles til I got hold of it. I have cell phone pictures (by someone else) of the damage but they have not reached me.

dr bob

Steve--

The threat on the missing piece is most likely imbalance of the assy, something that may eventually lead to failure of the rubber between the two sections. On the balancer, it looks like there's a lip formed on the front of the inner section that shields the rubber section and also prevents the outer section from coming forward of the inner section. After looking at that carefully at a TB party here, we decided that it's OK to use the three-jaw puller to put a little tension on the balancer during difficult removals. This isn't a substitute for the standard methods including the heat gun that Dave C recommends, but a way to make sure that when it does move, it comes off and is square to the crank nose during the removal. We put some tension on the puller bolt, tap the inner section, a little more tension and tapping and it moved a little. Add tension again, more tapping, moved a little. It will come off eventually.

There's nothing exotic about the balancer to the point where we need a custom Ken piece, at least nothing I can see. Maybe a prettier one, or we may find that the one from a Cayenne/Toureg/C7 motor is just right too. It would be cool if all the timing marks were the same. If there happened to be one that's close in size, the bore and keyway could be remachined to fit the 928 crank. So far there are used and new ones available for less than the cost of any custom pieces though.

SteveG

Limited pressure was my game, mucho moving of the tool; when you don't know exactly how it is binding, this results in a shot-gun approach, one pellet at a time. I was too spare w/heat. But I'm not familiar with the rubber.

I tried 3 suppliers. No used ones (green) available. You don't want to know what the new one is at now. Add $49 for 2 day delivery.

When this is done, I will look at it as another notch on the belt of 928 knowledge, and tricks needed in the care and feeding. Not there just yet.

marton

Worked for me, there was initially too little move to see but I could feel it & then I could very slowly wriggle it off. The second time (forgot some bits...!) I had to knock it back a couple of times. Secret is as soon as you feel any slight movement then you are on the way.

Marton

SteveG

Sterling. Parts Heaven $695, 928 Int'l $675.
[edit-- picture has been added]
To remove assembly : The idler assembly also benefits from a modification of the wobble technique: left hand grip the verticle of assembly and pull towards you, pulling assembly off the spindle on water pump; alternately push right-to- left across the front of engine against the large pulley towards the tensioner piston which results in pushing piston back into the chamber, push right, pull w/left, repeat vigorously.

THEN I removed belt to find WORN cam gears, in this case shiny is bad. It's written elsewhere (John Kelly's T-belt book is well worth the $16.00). Once the anodized coating is worn off the magnesium alloy (IIRC) wears much faster. (pics tonight). The lesson here (also been documented here) somebody must have overtightened the belt for this to happen at 69K miles. The mech either didn't have the tool or purposely got that pesky light to go off by giving the bolt another turn. Those are $112 each. Now I get to use Ken's timing tool when I replace the gear.

Note on technique: with the plugs out, the cams turn easily, tend to go clockwise fortunately. However be careful if you are removing the cam bolt. There is a 30mm washer for countering the 17 mm bolt. Mine were way tighter than the specified torque. Odds of you being able to keep it at the 45 mark as you muscle the 17 mm bolt loose, are small; I had to use a pipe extension to break it loose. [edit see Dr. Bob's comment later in thread, re crank locked at 45, you can turn cams either way w/o damage, it will tend to turn clockwise seeking an unsprung position around the 3 or 4 o'clock position.

dr bob

Steve-- The 928 Gods are looking over your shoulder, that's for sure. The normal penalty for too-tight belt and over-torqued bolts on the drive gears is broken cam noses. Living a clean life -finally- pays off!

On the cam revolutions-- With the crank still locked at 45 degrees, you can turn the cams in any direction any amount to get them where you need them. The 2:1 drive ratio comes into play only when the belt is on and the crank is turning the cams. From that point it takes two revolutions of the crank to get one full revolution on the cams. So getting from a tension-and-timing check at #1 TDC to the restest at #1 TDC, you'll turn the crank 2 full revolutions. The cams will turn one revolution at the same time.

SteveG

Thank you Bob for the information. Re Ownership: You just never know what's under there. It was an odd feeling when I uncovered the cams, reminiscent of a book about fishing/camping. "A Fine and Miserable Experience." My heart sank, but I am glad I have access and opportunity to correct it. As you know I got the car about 18 months ago. I checked the belt w/Kempf tool and it was centered in the window; I will look more closely at underside of the gear from now on when it is opened. I've been out and about, but no trips. I get into it once in awhile; I've chirped the tires a couple times, that's it. I guess that isn't the sort of clean living you were referring to.

As I said earlier, another notch in the belt.

Bill Ball

The gears can wear even with a belt that is tensioned correctly, especially if the tensioner is not holding oil.