Friday, August 10, 2007

Balancing the Flywheel/Clutch

Okay, since I take Fridays off, this gives me a chance to take the flywheel into a machine shop for balancing. I took the flywheel and clutch pressure plate to Portland Engine Rebuilders. They basically said that they couldn't balance the flywheel because they couldn't attach their balancing machine to the small center hole. Many thanks to Alan at A&P Specialties (Audi and Porsche repair) for lending me a 1.7Liter 914 crankshaft so I could provide something for P.E.R. to balance.

Here's the crankshaft from a 1.7L 914 that Alan graciously let me borrow.

Here's the crankshaft with the connecting-rods removed.

Here is the crankshaft with the bolted on flywheel. I delivered this to Portland Engine Rebuilders to 1) remove the outer 1/2" of the flywheel (basically the starter motor teeth) and 2) balance the whole assembly along with the clutch pressure plate so everything is stable. Ted, the owner of P.E.R., was very kind and explained the whole process as well as making some suggestions for how to lighten the flywheel without losing strength up at 6000 RPM. Machining the flywheel and balancing should take about a week.

Back at home, I purchased new 10-24 x 1" allen head bolts to re-attach the adapter hub to the AC motor shaft. Since the face of the adapter seemed shallow on the side where the motor key sat, I tightened up the bolts on the opposite side first to try and bring that side deeper to flatten out the face.

Here I'm using a piece of plastic (yes that's a filler plate for the 5.25 inch drive on a computer case) to determine if the face of the adapter is flat. By holding the piece of plastic in the right place and bracing it against non-moving parts, I can turn the motor shaft by hand and hear where the face scrapes the plastic. This second time around I think the adapter is flatter, but still slightly off. I smeared some red loctite on the deeper surface to act as a liquid shim to try and flatten it out more. We'll see what happens when the flywheel comes back.

Next Up: Taking a break for a few days and possibly installing the PakTrakr battery monitor.

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