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unreal808 · 03-29-2005

Flywheel step height is probably the most important thing when it comes to the clutch working properly on a DSM and it's most often overlooked. If you install a new clutch always machine the flywheel to the clutch manufacturer's specifications. DO NOT ASSUME THAT JUST BECAUSE YOU BOUGHT A FLYWHEEL FROM A REPUTABLE SHOP THAT THE STEP HEIGHT IS CORRECT FOR THE CLUTCH YOU ARE USING. This varies with each clutch but most DSM mechanics agree that ***.608-.610"*** is the preferred step height when using most aftermarket pressure plates and discs. By machining the step height shallow it puts the spring plate fingers more on center. This in turn gives a more effective release and less pressure required to disengage the clutch. When you pick the flywheel up, have them measure the step height so you can be certain that they cut it to your spec and not what the "book" says.

Also do NOT use any thing other than a ACT clutch disc with an ACT pressure plate. ACT uses a HD marcel, the wavy metal that the friction material is riveted to, and it's designed to work with their pressure plates. Using a factory 2nd gen disc will cause the clutch to drag against the flywheel and prematurely wear out the synchros in your transmission when used with an ACT pressure plate. This is important and not exclusive to ACT so please consult with the manufacturer of your clutch when choosing to run a different clutch disc than the one supplied or designed for use with their pressure plate.

Do not reuse the flywheel if it has deep cracks on the surface. Have the machine shop inspect the flywheel with a Zyglo, Magnaflux or dye & powder for cracks after it has been machined. Flywheel explosions can injure passengers and destroy the car so don't abuse the clutch or use cracked flywheels. Do not use a factory disc with an aftermarket pressure plate. Most aftermarket clutch manufacturers have different disc thickness specifications and the use of a factory disc with their pressure plate will cause the clutch to drag or have a poor engagement threshold. If you have questions about the clutch it is best to contact the people you bought it from or the manufacturer.

Shim the clutch pivot ball with a 1.0-1.5mm washer. By by keeping the angles at 90* you get the most effective stroke of the throw-out bearing for any given amount of pedal movement.

03-29-2005	#6
unreal808 Mr. Me Too Join Date: Oct 2003 Location: Albertville, MN Drives: Suzuki GSXR Posts: 999	Re: resurfacing... Flywheel step height is probably the most important thing when it comes to the clutch working properly on a DSM and it's most often overlooked. If you install a new clutch always machine the flywheel to the clutch manufacturer's specifications. DO NOT ASSUME THAT JUST BECAUSE YOU BOUGHT A FLYWHEEL FROM A REPUTABLE SHOP THAT THE STEP HEIGHT IS CORRECT FOR THE CLUTCH YOU ARE USING. This varies with each clutch but most DSM mechanics agree that *.608-.610"* is the preferred step height when using most aftermarket pressure plates and discs. By machining the step height shallow it puts the spring plate fingers more on center. This in turn gives a more effective release and less pressure required to disengage the clutch. When you pick the flywheel up, have them measure the step height so you can be certain that they cut it to your spec and not what the "book" says. Also do NOT use any thing other than a ACT clutch disc with an ACT pressure plate. ACT uses a HD marcel, the wavy metal that the friction material is riveted to, and it's designed to work with their pressure plates. Using a factory 2nd gen disc will cause the clutch to drag against the flywheel and prematurely wear out the synchros in your transmission when used with an ACT pressure plate. This is important and not exclusive to ACT so please consult with the manufacturer of your clutch when choosing to run a different clutch disc than the one supplied or designed for use with their pressure plate. Do not reuse the flywheel if it has deep cracks on the surface. Have the machine shop inspect the flywheel with a Zyglo, Magnaflux or dye & powder for cracks after it has been machined. Flywheel explosions can injure passengers and destroy the car so don't abuse the clutch or use cracked flywheels. Do not use a factory disc with an aftermarket pressure plate. Most aftermarket clutch manufacturers have different disc thickness specifications and the use of a factory disc with their pressure plate will cause the clutch to drag or have a poor engagement threshold. If you have questions about the clutch it is best to contact the people you bought it from or the manufacturer. Shim the clutch pivot ball with a 1.0-1.5mm washer. By by keeping the angles at 90* you get the most effective stroke of the throw-out bearing for any given amount of pedal movement. __________________ Take her to the limit! Last edited by unreal808; 03-29-2005 at 10:54 PM..