Adjusting Step Height for our clutch? + other q's

[Kruzen]

I'm getting ready to purchase a lightened flywheel to get machined down in preperation for my clutch change.

First of all, whats the process of going about this, Do i just take it to a machine shop and tell them to machine it down to (what lb'age?) anything to look out for?

Also, talking to my brother who is a DSM guy, he expressed concern about making sure they had the step height correct (because of the machined flywheel) if I were to take it to a shop (yes i'm feeling quite lazy and don't want to do my own clutch, but we'll see, maybe if i can get a lift to work on or some freinds over here). Is this just a DSM thing or is this a concern for our e30's as well?

[rs4pro3]

Yes the e30's flywheel have a step in them from the factory, where the outeredge where the pressure plate bolts, is stepped down just a tad from the surface the clutch disk grabs. There isn't a specific value, just some amount of clearence is needed.

[Kruzen]

Yes the e30's flywheel have a step in them from the factory, where the outeredge where the pressure plate bolts, is stepped down just a tad from the surface the clutch disk grabs. There isn't a specific value, just some amount of clearence is needed.

oh ok, so if i'm running a machined flywheel there's no step adjustment necessary?

[rs4pro3]

no pedal adjustment will be needed, just make sure when it's machined there is an difference in thickness between where the pressure plate bolts, and the clutch sits.

[tonytony]

why would you machine the front of the flywheel? Are you talking about getting it resurfaced? when i got my singlemass lightened they took the matearial off the back of the flywheel.

[AndrewBird]

^^^ What he said. You don't take wieght off the front of the flywheel where the clutch mates, you take it off the back.

[nando]

he is talking about having it resurfaced & lightened

if the shop has any idea what they are doing, they will know the spec for the step height. the shop that did mine had never even seen a BMW flywheel before and they were able to do it correctly.

just tell them to take off as much of the huge chunk of extra metal on the back as they are comfortable with. my shop took about 7lbs off, could have probably gone 2-3 more easily.

[Kruzen]

he is talking about having it resurfaced & lightened

if the shop has any idea what they are doing, they will know the spec for the step height. the shop that did mine had never even seen a BMW flywheel before and they were able to do it correctly.

just tell them to take off as much of the huge chunk of extra metal on the back as they are comfortable with. my shop took about 7lbs off, could have probably gone 2-3 more easily.

Thats what I figured, now to decide If I want to have a shop do my clutch or If I want to do it myself... sigh. such a pain in the ass.

[Ziggens96]

What happens if you try to install a flywheel that has the step completely ground down?

I just bought a lightened M20 flywheel that is 15-16 pounds, already machined on the clutch side. I was going to try to have a few more pounds removed, but couldn't find any local machine shop that would do it - 1 said they didn't have the proper equipment, the other was concerned about liability. So I think I am going to leave the flywheel as it is, but now I have come to realize that there should be a step on the clutch side...like I said, mine has been machined flat.

Pics: http://img841.imageshack.us/g/pict0629h.jpg/

What should I do? If I have to get the outer "ring" ground down to restore the step, will that affect the pressure plate bolt holes? Did I get screwed buying this flywheel?

[nando]

it won't engage properly or it will slip because there's a specific amount of pressure the pressure plate needs when it's clamped down to grip.

if the step is too big, you won't be able to disengage the clutch.

[Van Westervelt]

he is talking about having it resurfaced & lightened.

Sounded to me like he was buying a new lightweight fly and wanting to lighten it more.

But yes, you only resurface the clutch side. It is stepped as stated. Any material removal should only be done at the back, motor side.

[Ziggens96]

it won't engage properly or it will slip because there's a specific amount of pressure the pressure plate needs when it's clamped down to grip.

if the step is too big, you won't be able to disengage the clutch.

ok thanks nando...so I am looking at having to get the "outer ring" ground down then? Or is the flywheel somehow ruined? I'm guessing whoever resurfaced this flywheel at least knew enough to not grind down the front too much, but between that 1st resurfacing and then having to take it down again, are the bolt holes for the PP at risk of being too shallow?

[Van Westervelt]

Hate to say it, but you look screwed on that flywheel.

[Ziggens96]

Fuck. Seriously? Why?