Trimming down flywheel pillars to increase clutch clamping force
Turbo Mini Forums

I'll be using an "uprated turbo" verto clutch on an aftermarket steel flywheel. I want to get the most out of it before it starts to slip, so thinking about trimming down the 6 pillars.

Any advise on how to work out how much metal to take off, or even whether it's worth doing at all ?

If you still have a standard flywheel in good condition and a new sprung plate, i would assemble that and check the spring hieght, then assemble the parts you want to use and machine the posts so the spring height is the same. I don't think the flat spring thing is right for the verto. The thing you have ti watch out for, that i found out the hard way, is the throw out distance. Shaving the posts shortens the throw out to the point that you quickly bind on the center boss before you ever reach full throw out. Standard throw out is around 6.5mm which results in around 2mm lift on the pressure plate (this concurs with the lever ratio of the springs. AP type at least).

The standard clutch from the factory is set so that peak clamping force is mid wear, and the clutch will start to slip before it munches the friction plate rivets. Considering that a new clutch is on the up side of the ramp toward peak clamping, i dont think you can improve much which makes me question quotes by after market makers that their flywheel improves clamping.... how? Better friction coefficient?

One thing that has just come to mind though is whether there is already a subtle difference in post heights between AP types and valeo type flywheels.

Off to measure a few,......

Thanks Colin. I'm not sure how or where to measure the spring height, so I just compared the post heights of 4 old flywheels to my new flywheel. All 4 old ones have post heights very very close to 23.40mm and my new flywheel's posts are 0.35mm taller. Does that sound like it needs trimming?

I forgot to try the new clutch and plate on an old flywheel, but this is what it looks like on the new flywheel with the taller posts. I didn't know how to get it to show clearly, hope the photo makes sense (the burr is in front of the straight edge, not touching it):

In an attempt to shorten the posts to the same as the factory flywheel, I've just shaved a fraction off the posts and as I started cutting, noted that they weren't flat to start with. The flywheel posts slope down towards the friction surface; For the factory flywheels it's about 0.1mm across the posts' width, and 0.2mm for my aftermarket one.

The method I used to cut them down has now left them flat and level. How do other people do theirs? What's the reason for the slope and will flattening it cause problems?