I might be trying a different clutch setup soon and getting the ACT flywheel resurfaced might be part of that.

If I do get it resurfaced, I was thinking it might need a shim for the clutch engagement to be at the right level. Does anyone have experience with this? Are flywheel shims even available or are there generic ones that could work?

 

Just wanted to follow up to my own post if anyone ever comes across this. I took another look at the flywheel (see below) and saw it's pretty obvious that shims won't do anything after a resurface. The attachment points on the flywheel where the pressure plate is bolted on are raised above the surface where the clutch disk is sandwiched, so the pressure plate mounting distance will stay exactly the same after a refinish.

However, it does seem like a refinish could shorten the life of the clutch disk a little bit depending on how much material is taken off.

 

I've never heard of shimming a flywheel after resurfacing. If you are heavily concerned about it, maybe your machine shop can skim the pressure plate mounts the same as the clutch surface?

 

When resurfacing a "stepped" flywheel, you definitely want the machine shop to maintain that step: Let's say there is 1/8" difference in height between the mounting flange and the friction surface. The locating pins are pulled, the friction surface is machined sufficient to get a smooth surface (keeping track of how many thousandths of material have been removed. The same amount of material is removed from the mounting flange, retaining the original 1/8" difference. Pins are re-installed. Any automotive machine shop should be able to do this.

Sometimes the locating pins can be removed fairly easily, using either a dedicated "pin puller" or even vicegrips. Other times you have to drill a small (5/32") hole through the back of the flywheel into the center of each pin recess, then use a 1/8" pin punch to drive the pin out from the back.

 

Thanks - all very helpful to know.

When I get everything apart in hopefully a week or two, if the flywheel looks okay, I'll probably just let it be with a light scuff with emery cloth and clean with brake cleaner. Clutch engagement now is smooth, but I'm not a fan of how quickly the clutch fully engages once it starts to catch (it's an ACT street sprung clutch paired with an OEM pressure plate). I believe the engagement behavior is due to the reduced marcel springs in the clutch disk. Not ideal for launches in daily driving around town which is pretty much all my wife and I do.

I'll probably start a new thread once I've done the repair with more details on the alternate setup I'm going to try.

 

Acts are grabby. Always have been. That’s part of their appeal.tbh.
Back in my DSM days 20 years ago, I had the act 2600, act lightened flywheel and pressure plate and the flywheel had replaceable inserts for the engagement surface. I quickly learned the “the act clutch dip” ie, slight engage till barely rolling, dip back in to recover revs for half a second then release as normal.