Thread: Project Lazarus
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Old 04-08-2020, 09:19 PM   #46
husker boxster
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Got the exhaust buttoned back up on Sun, but wasn't happy with a couple of the bolts in the kit, so I bought some longer ones on Tue and finished the job to my satisfaction.




Then moved on to measuring the thrust bearing play in the flywheel. Apparently 85 and newer 928s with auto trans have an issue with the flywheel moving on the 'drive shaft'. It moves forward on the shaft and puts pressure on the thrust bearing. If not checked and the pressure released, the bearing will wear out and ruin the engine. Earlier 928s don't have this issue because Porsche used shims to keep the play out but decided in 85 that the clamp alone should be able to do the job. It didn't on some cars and caused a panic across the community (not unlike IMS).

So, you start by removing the bell housing cover's 6 bolts. You'll recall 4 of the bolts are easy and 2 are impossible with the exhaust in place. But I had the plate off. You measure the length of teeth showing before releasing the clamp.



Mine looked good as there wasn't much showing - 4.51mm. The guy who wrote the tutorial on RL was sitting at 7.5mm. Next step is to release the clamp. Wasn't looking fwd to this considering my past experiences with nuts & bolts. I'd given it a couple of shots of AeroKroil a few days ago. It was an 8mm hex bolt and I used a breaker bar on it. Was very careful and it came loose. The flywheel moved slightly backwards, releasing the pressure on the thrust bearing.



I measured the teeth showing and came up with 3.88mm. The flywheel only moved .63mm back. Very good. The author's moved 2mm.

Next test was to measure the distance between the flywheel and the engine. I came up with 40.24mm, which meant the flywheel was quite a ways from the engine. The author's was 19.xx mm. The next step was to push the flywheel fwd and measure how far it traveled. Was supposed to be a max of .4mm. As hard as I tried, I couldn't get it to move fwd. I used a pry bar on several places but it wouldn't move. I wasn't going to push my luck, so I called it good. Tightened the clamp back up and painted some teeth so whoever owns her next yr can check for movement.



Put the bell housing cover back on with only 4 bolts, which is acceptable and necessary if you want to remove it next time w/o having to drop the exhaust. That completes my underside work for a while. I need to chase down a fuel pump leak and then I can pull her off the jack stands. Will be able to turn her around in the garage. She's backed into the garage b/c that's how she came off the trailer, but I'd like to have her turned around and centered better.

I went out for a walk to enjoy the nice weather late this afternoon and started formulating a new check list of repairs. I've been so focused on fuel lines and starting for so long, I've almost forgotten the other things that need attn. Now I can work on them.
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