From Nissan 350Z & 370Z Wiki
This article is part of our special collection:
This article is part of our special collection:
This is an introductory page for 350Z-TECH members to learn about clutches. On this page we will explain what a clutch is, how it works, provide recommendations, and provide all the specifications for currently available 350Z clutch systems.
A few items to note. Flywheels are not covered on this pages but are closely related to clutches and some clutches require that you use a specific flywheel. We will try to note these combinations where possible. Flywheels are covered on this page.
Please let us know what you think of this pages in our forums so that we can improve these courses in the future.
Contents |
Clutch Options
Supply Your Own flywheel
The 350Z clutches featured in this section are designed to work with the OEM flywheel and/or an aftermarket flywheel that is a direct replacement of the OEM one. You should consider upgrading to a lightened flywheel when upgrading the clutch to save in labor costs down the road as well as increase performance from your 350Z.
 ACT |
 ACT |
 Clutch Masters |
 Clutch Masters |
 Clutch Masters |
 Clutch Masters |
 JWT |
 Nismo |
 Spec |
 Stillen |
Flywheel Included
The prices on these clutches are a bit higher as they should be since the clutches featured here include lightened flywheels. In some cases they may be restricted to working with the included flywheels, but some may work with OEM-type or other aftermarket ones.
 ATS |
Exedy |
 Exedy |
 RPS |
 RPS |
What is it?
There is no sense in redefining a great definition. So here is a brief explanation of what a clutch is taken from Wikipedia.
Source: http://en.wikipedia.org/wiki/Clutch
A clutch is a subcomponent of an engine's transmission designed to allow engagement or disengagement of the engine to the gearbox or whatever apparatus is being driven.
There are many different clutch designs, but most are based on one or more friction discs, pressed tightly together or against a flywheel using springs. The friction material is very similar to the material used in brake shoes and pads and used to contain asbestos. The spring pressure is released when the clutch pedal is depressed and the discs are held less tightly and allowed to rotate freely. A wet clutch is immersed in lubricating fluid to keep the surfaces clean and to cool it, for improved performance and longer life; while a dry clutch is not.
In a car it is operated by the left-most pedal using hydraulics or a cable connection from the pedal to the clutch mechanism. No pressure on the pedal means that the clutch plates are engaged (driving), while depressing the pedal will disengage the clutch plates, allowing the driver to shift gears.
On most motorcycles, the clutch is operated by the clutch lever, located on the left handlebar. No pressure on the lever means that the clutch plates are engaged (driving), while pulling the lever back towards the rider will disengage the clutch plates, allowing the rider to shift. Some cars and mopeds have an automatic clutch, using centrifugal forces to engage the clutch above certain rpm, see Saxomat.
When engaging the clutch, the engine speed may need to be increased from idle, using the manual throttle (UK:accelerator), so that the engine does not stall. However, raising the engine speed too high will cause excessive clutch plate wear and cause a harsh, jerky start. This kind of start is desired in drag racing and other competition, however.
A clutch may also be a device on a shaft that will "slip" when higher than normal resistance is encountered on a machine. A example of a clutch such as this may be mounted on the driving shaft of a large grass mower. The clutch will "slip" or "give" if the blades were to hit a rock, stump, or other immobile object.
Components
An automotive clutch consists of a pressure plate, clutch disc and throw out bearing. Other components are the release fork, flywheel and clutch master cylinder (hydraulic piston). The only one you may get with a clutch kit would be a flywheel. More info on flywheels to come at a later date. The fork and clutch master cylinder are components of your existing transmission.
- Pressure Plate
- The pressure plate is what pushes clutch onto the flywheel. The pressure plate is rated in clamping force. The higher the clamping force the more pressure it will exert onto the clutch disc. Also, the higher the clamping force, the more pressure it takes to depress the clutch. This helps handle all of that horsepower. Some companies change the fulcrum point so that you can use a higher clamping force and not worry about your left leg muscle growing to three times the size as your right leg. But that's a lesson for another day.
- Clutch Disc
- The clutch disc contains a friction material so it will grab when it touches the flywheel. This causes the engine to spin the transmission input shaft. Depending on the friction material, it will slip more or less before grabbing the flywheel. Most OEM clutches are full faced. As you get into the more aggressive clutches, you will find different friction materials as well as different shapes and sizes. The clutch disc sometimes contains springs in the middle (hub) to aid in ease of use. A clutch disc that has a sprung hub (containing springs) will allow you to slip it. So it doesn't feel so grabby. This is the type of disc you get with your Z from the factory. A clutch disc without a sprung hub, will feel a lot more ON/OFF. These are for the drag strip/track and are usually NOT comfortable for daily driving.
- Throw Out Bearing
- The throw out bearing, or release bearing, pushes onto the center of diaphragm spring when you disengage the clutch (push the pedal down). Also the throw out bearing relieves pressure on the diaphragm by moving away when you engage the clutch (lift your foot). Causing the diaphragm to naturally press against the pressure plate which pushes the clutch disc onto the flywheel.
How it works
- Lifting the clutch pedal
- When you engage the clutch, the throw out bearing releases tension on the diaphragm spring. This action causes the diaphragm spring to exert force on the pressure plate causing the clutch disc to make contact with the flywheel. This lets the engine spin the transmission input shaft.
- The stock clutch allows significant "slip" when engaging. This allows for easy driving and "feathering" in stop and go traffic. Some hi-torque capacity clutches have a much more abrupt transition when engaging and require a little more concentration when shifting.
- Pushing the clutch pedal
- When you disengage the clutch, a hydraulic piston pushes on a release fork. This fork causes the throw out bearing to push onto the center of diaphragm spring. When this happens the diaphragm spring releases pressure on the pressure plate and also lifts the pressure plate away from the clutch disc. Without pressure on the clutch disc it won't engage the flywheel. And the engine can spin while the wheels of the car are stopped.
Types of clutches
There are various types of clutch discs. Ranging from your OEM, light duty, easy to use. To the more heavy duty, on-off clutches that handle greater than stock power. Different clutch discs have different friction coefficients. Or how much they grab. Generally there are three main types of clutches; full faced, puck, and multi plate style.
Full Faced
Full faced clutch discs contain a friction material on the entire face of the disc. Allowing for more contact area which helps make the clutch feel easier to use. The material can range from organic material to higher friction carbon or kevlar materials that grab better and also stand up to heat and abuse.
Puck Style
Puck style clutches have either three, four or sometimes six "fingers" or "branches" that contain the friction material. Since they have less contact area, they tend to slip less and grab more. Also they will feel more sharp. The more fingers, the less harsh it will be. Three will grab harder and slip less than six. They will also be less friendly to drive.
The clutch disc contains friction material on both sides. The side that makes contact with the flywheel can contain a different coefficient of friction than the side that makes contact to the pressure plate. By mixing the material you can have a clutch that grabs a lot better and also keeps its street civility. Typically a mixture like this has a higher rate of friction on the pressure plate side than the flywheel side. So it can slip a bit yet still grab firmly.
Multi-Plate
Multi-plate clutches utilizes two or more clutch discs and a primary and intermediate pressure plate. Increasing the clamping force and friction coefficient quite a bit. These clutches can handle a lot more power, yet still remain somewhat comfortable due to design. Multi plate clutches are also more expensive, since you have multiple pieces to the assembly.
Installation
At this time we do not have a full tutorial writeup for installing a clutch on a 350Z, however that should be changing shortly. Here are the basic steps involved in swapping out the clutch/flywheel assembly. Be very careful to replace everything just as it came off upon assembly. Someone had a problem with the car not starting due to some misplaced parts here: Clutch Install Problem Thread. It would be wise to obtain a Nissan 350Z Service Manual for a project such as this.
Removal
- Disconnect all speed and gear sensor plugs
- Pull the lower harness aside
- Remove catalytic converters
- Remove Y-pipe
- Remove sensor and catalyst mounting brackets
- Inside the cabin remove the shifter trim and shift knob
- Remove driveshaft for cleararance
- Remove slave cylinder
- Ten main transmission bolts are removed
- Starter is removed
- Separate tranny from motor - a pry bar can be used to aid in the separation process - but only if its wrapped and no major force is applied.
- Once the transmission is removed from the vehicle the clutch and flywheel become accessible.
Installation
- Install clutch disc and cover (pressure plate) onto flywheel.
- Insert the clutch tool into the clutch disc.
- Align the matchmarks on the clutch cover and flywheel.
- Torque the bolts on the clutch cover to the flywheel.
- Attach transmission (bell housing) to engine.
- Continue in the reverse of the removal process listed above
Recommendations
First thing, I would recommend that you dont overbuy a clutch. The more power a clutch is built to hold, the more difficult it will be to drive. You need to match the clutch to your driving style (street vs. track) as well as match the torque holding capacity of the clutch to your car's engine torque (not wheel torque).
Naturally Aspirated
Daily Driving (SPRUNG HUB IS A MUST) OEM, JWT, Nismo, Exedy (single disc), Clutch Masters FX100-300, Tilton Full Street (depends on user preference)
Track Driving (SOLID HUB OKAY) JWT, Nismo, Exedy, Tilton Full/ Semi Street
Forced Induction
Daily Driving (SPRUNG HUB OR SOLID HUB Depending on user preference) JWT with upgraded pressure plate, Exedy single (carbon) or twin plate, Clutch Masters FX300-400, Tilton multiplate
Track Driving Triple plate, solid hub
Other Relevant Info.
foot notes will be added
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This page is part of the Drivetrain category. To learn more about related items click the links below. Components: Drivetrain Accessories • Final Drive Gear Sets • Flywheels • Limited Slip Differentials (LSD) • Short Shifters FAQs: 5spd Automatic Transmission • 6spd Manual Transmission • Clutch (FAQ) • Drivetrain Definitions • Final Drive (FAQ) • Flywheel (FAQ) • Limited Slip Differential (FAQ) Tutorials: Automatic Shift Knob Swap • Automatic Shifter Removal • Automatic Transmission Fluid Replacement • Clutch Adjustment • Clutch Installation • Manual Transmission Fluid Replacement • Rear Differential Fluid Replacement • Shift Knob Removal and Replacement • Wheel Stud Replacement |
Categories: ACT | Clutch Masters | JWT | Nismo | Spec | Stillen | ATS | Exedy | RPS | Parts | Drivetrain
