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Honest Engagments

A sum of all clutch parts

Honest Engagements A Sum of all clutch parts

Nothing much beats heel and toe corner carving or spitting gravel while rowing through the gears. The 3-pedal soundtrack is a bonus to motoring amusement brought to you by the the clutch. One press on the clutch pedal disengages underhood mayhem from the transmission. Step off and tire smoking rock-spitting mayhem resumes. Again and again. Until it doesn't. The clutch is one of those parts that is designed to wear out. If things wear out together some unwanted slip or no more room for adjustment might mean clutch replacement time. Engine mods that send more horsepower down to the wheels can result in more spectacular clutch failures that mean clutch upgrade time.

Matched Set Matched Set Matched Set

Matched Set


One of the biggest mistakes is to bolt up a new clutch disc and pressure plate to a worn or scorched flywheel. The flywheel serves as a surface for the clutch disc to engage and stores inertia to to help with clutch engagement and smooth out low throttle cruising. Sending out the stock flywheel for resurfacing is option one, but excessive heat can result in hardness variations. Machining gets the surface flat but one spot harder than the other can result in engagement chatter. Take weight and material into consideration when opting for a replacement flywheel. Lower mass flywheels can bring improved throttle response and replaceable surfaces. Harder steel surfaces might not grip clutch disc material as well as that cast iron stocker.


Components Components Components


The clutch disc lives between the flywheel and the pressure plate takes most of the abuse of on and off clutch engagement. More forgiving organic clutch disc material can deliver noiseless and drama free driving, but incinerate under heavy launching or repeated clutch dumping. Metallic type materials will handle more heat and abuse but can have engagement characteristics unsuited for everyday street use. The clutch disc is also designed to dampen vibration and reduce noise. Unsprung discs are meant for race use only. Flywheel surface and material plays a role in clutch disc replacement. A full face organic clutch disc with a cast iron flywheel can hold better than a six-puck with a chromoly steel flywheel. Multi-plate setups add more surface area through additional discs and floater plates.


The pressure plate holds the clutch disc against the flywheel and with the help of the throwout bearing and diaphragm spring allows disengages mayhem when the pedal is pushed to the floor. Like the flywheel the pressure plate has clutch disc surface. An increase in pressure plate clamping force in along with a clutch material designed to stand up to higher heat can bring an increase in torque handling. More diaphragm spring clamping force can translate into a heavier clutch pedal and put more stress on the clutch fork, linkages and left leg. Greater clamping load clutch and overly aggressive clutch disc material can also translate into entirely unacceptable characteristics for street use.

The Whole The Whole The Whole

The Whole

The clutch is the sum of its parts matched not only to each other but also to engine output and transmission specs. Lighter total mass from a lighter flywheel or aluminum pressure plate cover can change throttle response and engagement characteristics but won't likely amount in any horsepower gains. Mis-matching components or cutting corners like installing a new clutch disc and pressure plate on a dished or scorched flywheel will lead to the same trouble that called for clutch replacement in the first place.


The best strategy when it comes time to replace or upgrade the clutch is a systems approach combined with an honest or dyno-proven horsepower and driving style assessment. While it might seem like stepping up to multi-disc unsprung disc race-only clutch is the answer, the reality is probably closer to a Stage1-style package using new components materials engineered to work together from flywheel to throwout bearing. Hit the sweet spot of power handling and engagement and all will be well with a clutch package that doesn't sound like a can full of bolts, make one leg bigger than the other or rattle out any teeth.


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