How do I know if I need a new clutch
 

My clutch seems to be slipping a little when I engage with a little too much gas. Usually it grabs and accelerates but it's been slipping and revving instead.

How do I know if I need a new clutch?

Thanks,

-P

I think you just answered your own question. Unless it is out of adjustment (something to check first), slippage like you mention means you need a new clutch.

Okay. Bummer. Do you know if there is a way to check visually?

Park with nose against a substantial wall, select 5th gear, give it some revs and disengage clutch, If it stalls you don't need a clutch yet.
Thats the Car Talk technique.

Like IROC says, check your clutch pedal freeplay first, 25 mm as I recall.

There can be different causes for the symptoms you describe. The disc could be worn (too thin). The pressure plate could be weak (spring weakened). Or there could be some friction somewhere preventing free movement of the mechanism.

Assuming everything is adjusted properly.

And if it doesn't stall? Did you just crash your car?

I would read about clutch cable adjustment. From reading, this seems to be the first thing to check, and can be done at home.

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Packy... visual inspection requires the gearbox and engine to be separated. Pressure plate comes off. Clutch comes out. Then clutch's thickness can be measured for visual confirmation of status. There's no way to "peek" into the gearbox and make a visual determination.

Check your adjustments & cable before bumming out.

If it's slipping a little and you continue driving it, it won't be long before its slipping a lot.

When you do a clutch you will also do (recondition/replace) the pressure plate, the flywheel, and the throw out bearing, so driving it a little past its "gee it's slipping" point isn't a disaster.

That said there isn't any reason to abuse the clutch to test it. Just put it in an upper gear at a lower speed and floor it. If the tach and the speedo don't rise completely in concert then you are slipping. Take it easy until you are at a point where you can replace it. If you have some restraint you could get thousands of miles out of it.

A couple things to take note of:
- A diaphragm pressure plate will increase the clamp load as the RPMs increase.
- A diaphragm pressure plate will have decreased clamp load if the clutch disk is to thin and if it is too thick. (Yes that isn't a misprint.)
- More clamp lamp load then the engine torque requires isn't generally required. (Prostock drag cars use less clamp load then a lot of "high performance" street clutches.)

Just don't dump the clutch when you are in a hurry. Get it engaged when starting from a stop and then shift smoothly. That is how a sports car should be driven anyway.

No the clutch will slip, you ARE again a wall.

When torque loading it helps if you are going up a steep hill.

Like previously stated, check adjustment first. If the clutch can't be adjusted, or it's back out of spec after you've depressed the clutch, begin by replacing the clutch cable and helper spring (omega spring) before replacing the clutch. A fairly simple, albeit messy and uncomfortable job.