Don't clutch at straws!

Clutch takes the engine power and puts this down through the drive shaft to the driven wheels on the road. Power is potentially lost if the clutch slips – failing to make steady contact with the contact plate when the clutch is first released - power clutches have high friction surfaces and sometimes 2 or 3 contact plates. The surfaces are constructed of various composite compounds with some made of strong and light carbon fibre. The aim is for good adhesion when the clutch is in contact and low weight materials to allow the engine to respond and rev freely (this is no substitute for a light-weight flywheel).

The heavy-duty race clutches have less feel and are pretty much on or off. This can make it hard to drive smoothly in traffic or pulling away smoothly on a hill and requires a fair bit of leg muscle. The clutch release spring is somewhat heavier on most race clutches and I found to my cost that clutch cables need to be perfectly aligned and installed or they snap with alarming regularity (It was actually the plastic retaining clip that snapped rather than the cable but the clips come as part of the clutch. A fast road power clutch makes more sense for road use – although the high spec multi plate race solution would seem the best, it is not very well suited to domestic driving for most vehicle types. Most clutches come with a power rating - if your engines output is greater than the rated power of the clutch you will experience clutch slip (see below for explanation) while you are accelerating and the clutch will wear out very quickly.

As the clutch is a relatively straightforward job (although complete removal of the gearbox and or engine on some cars is required!) I would still recommend consulting a specialist or someone with a similar car to ask for their feedback on your requested application before your spend the money and end up with an impractical daily drive.

Clutch Slip
A sudden surge of power can cause the clutch to lose its grip and the power is not transferred to the wheels - evidenced by a rise in the revs but not in the road speed. Clutch Slip - a bit like pulling a table cloth off a table and all the crockery staying in place. A power clutch is more grippy and has a much stronger tension between the two plates and eliminated clutch slip. (A bit like trying the table cloth trick when the crockery has been glued down and the force of gravity has been doubled.)

Clutch judder
The clutch does not engage properly causing a kangaroo start or intermittent power to the wheels while the engine is engaged. To address this you need to check your 1) Driving style 'the clutch operation should be smooth', 2) The clutch release mechanism and 3) The cable.

Clutch problems
I had a Toyota with a worn release bearing - this meant that the clutch did not fully release the engine from the gearbox causing clutch drag. Gear changes became more and more notchy - particularly the 1st and 2nd gear. A new clutch almost sorted the problem but permanent damage to the syncromesh has been done and 1st remained notchy. Get a problem sorted out as soon as it manifests itself. When adjusting a hydraulic clutch remove the mats from the car - particularly if they are thick because this can reduce the pedal travel significantly and will make the clutch appear to wear out much sooner.

How to tell if the clutch is going
As the clutch wears out it will usually start to slip or even seem sticky, not fully engaging or disengaging. First and then Second gear will become increasingly hard to select. Eventually the car will stall every time you try to put it in gear from stationary (if your lucky 3rd and 4th might still work and you can limp to a garage). New clutch - New Cable - New release bearing DO NOT CUT CORNERS! If your clutch has gone you can generally engage 3rd and 4th easily without using the clutch if you carefully match your engine speed to the gear you select 'providing the car is moving' - I drove 400 miles including a stint on the M25 with a dodgy clutch cable changing gear just 20 times, and because I didn't stop the car and kept in 3rd and 4th gears I got home - I consider myself to be really lucky. A clutch cable stretching can also cause similar problems.

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