Project EJ Civic, Building the Drivetrain

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The ACT clutch we chose is the HD street unit.  It has excellent daily driveability characteristics while having plenty of grip for our NA power level.  The kit is very complete with everything you need for the job.

The clutch’s disc also has a lot of engineering in it to make it more durable while staying smooth and easy to drive.  The disc’s friction material is organic.  Organic means that its constitution is much like a stock clutch. The friction material consists of cellulose with chopped strands of bronze wire and Kevlar fiber held together with heat resisting phenolic resin.  The organic material gives a smooth engagement and is non abrasive for long life while the wire and Kevlar act as reinforcement giving burst strength and helping with heat resistance.  Bursting is when the friction material fails and shreds apart due to a lack of tensile strength.  Friction material is under both shear and centrifugal load and has to have a degree of strength.

 
The ACT Pressure plate has 55% more clamping power than stock which helps the clutch hold 245 lb/ft of torque smoothly with a lengthy service life.

The ACT clutch disc also has a sprung hub.  The sprung hub helps with engagement smoothness and cushions the drivetrain from shock especially when dumping the clutch or shifting fast.  The stock hub is somewhat weak and tends to crack allowing the springs to fall out and jam up the clutch.  The ACT hub is much stronger in this area.

 
This discoloration on the diaphragm spring fingers is the result of induction hardening.  This hardening provides extra wear resistance where the throwout bearing rubs.

The clutch disc also has a marcel spring.  The marcel spring is a flat spring that is riveted under the friction material that compresses flat as the clutch engages.  This gives a more gradual engagement and allows the driver to start smoothly without grabbyness and stalling.  These features allow the clutch to hold up under track use and still be as easy as stock to daily drive.

 
Our clutch disc is an organic semi metallic part with a sprung hub.  The hub is extra strong to prevent spring fall out.  This disc will grip well but be very smooth engaging.

We ordered the clutch as a kit from ACT which also included a new throwout bearing, pilot bearing and a handy clutch alignment tool to ease installation.  It is easy to change these parts while the tranny is off so why not and with over 200,000 miles on our old parts, it is a pretty good idea to change it all.  As a note for safety, the ACT clutch is also SFI certified which means it has to pass grueling high rpm spin testing.

This is the marcel spring.  It gives the disc a little extra cushioning, making for a much smoother engagement.

 

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