Exedy/Daiken 06025 Clutch Kit for 1970 2000 - Sources?

[Acotyk]

So in searching this site, I see that the Exedy 06025 clutch kit is the correct kit for the 1970 2000. Is there a preferred source for this kit? Is it the same as a 510 clutch kit.
AC.

[DAC21]

So in searching this site, I see that the Exedy 06025 clutch kit is the correct kit for the 1970 2000. Is there a preferred source for this kit? Is it the same as a 510 clutch kit.
AC.

Summit Racing is legit and they have it for $181 + tax, inc. shipping. Dropped shipped from Excedy (a few weeks to receive) The 510 is Excedy 06020 for the 1600's. The later 510's, 2000cc motors is Excedy 06008. Curtis has bought the 06020 kit for his Roadster (1600). He may well have gone for something else for his 2000 stroker pushrod motor?

[Stick]

Would the 06025 work for 68-70? At some point in the near future I'm pulling my engine/trans for 5th gear replacement and I'll likely just do the clutch at same time ..... nothing wrong with my clutch, but since the trans is out, might as well refresh it.

[DAC21]

Would the 06025 work for 68-70? At some point in the near future I'm pulling my engine/trans for 5th gear replacement and I'll likely just do the clutch at same time ..... nothing wrong with my clutch, but since the trans is out, might as well refresh it.

AFAIK it will work for all 1600/2000 as long as a previous owner didn't put in a competition clutch which I believe has an increased sized flywheel which wouldn't work with the 06025 kit (low probability you will have a Comp. Clutch) Folks more knowledgeable than me can can chime in if I got that wrong?

[david premo]

Just a really big FYI, the Exedy clutch cover in that kit only 990 pounds of clamping force which is fine for a stock 1600. The U-20 cover from Nissan has 1430 pounds of clamping force. I would think that if your R-20 stroker makes enough torque the clutch is going to have a very short life. It was designed for about 100 hp engine.
Dave

[DAC21]

Just a really big FYI, the Exedy clutch cover in that kit only 990 pounds of clamping force which is fine for a stock 1600. The U-20 cover from Nissan has 1430 pounds of clamping force. I would think that if your R-20 stroker makes enough torque the clutch is going to have a very short life. It was designed for about 100 hp engine.
Dave

Dave are you referring to the 06020 kit or the 06025 kit?

If 06025 I found this thread, granted 8 years ago and things may have changed on the clamping pressure. 06025 kit doesn't even show up on the Exedy website, yet you can order it from 3rd parties.

viewtopic.php?t=24841

[david premo]

Exedy no longer has a cover that’s 200mm and will supply sufficient clamping force for the 2000. Does not matter what kit you use, they discontinued the cover.
Dave

[DAC21]

Exedy no longer has a cover that’s 200mm and will supply sufficient clamping force for the 2000. Does not matter what kit you use, they discontinued the cover.
Dave

OK, gotcha. So what's left for 2000 owners? Deans spendy Datsun Comp. kit? Do you know if that is the 210mm (or is it 225mm?) disk that requires the flywheel upgrade? Jim at Datsun restoration has a "heavy duty" kit, but clamping pressure isn't mentioned (photo shows an Exedy box) He has a reasonably priced 225mm kit, but requires a $800 billet flywheel.

[david premo]

Alright here’s how it works, the bigger the diameter of the friction area the greater holding force of the clutch with the exact same clamping force. This is because you are moving out further away from the center and giving it mechanical advantage. Also if you increase the number of friction plates you can decrease the diameter and maintain higher loads as it divides the work over the friction plates. This is how multi plate motorcycle clutches work, they have up to as many as 9 friction plates and race car clutches are the same.
Dave

[Solex68]

Any input on the Kevlar disks Dave? I have always been tempted to get one.

[JT68]

Exedy no longer has a cover that’s 200mm and will supply sufficient clamping force for the 2000. Does not matter what kit you use, they discontinued the cover.
Dave

OK, gotcha. So what's left for 2000 owners? Deans spendy Datsun Comp. kit? Do you know if that is the 210mm (or is it 225mm?) disk that requires the flywheel upgrade? Jim at Datsun restoration has a "heavy duty" kit, but clamping pressure isn't mentioned (photo shows an Exedy box) He has a reasonably priced 225mm kit, but requires a $800 billet flywheel.

Racing clutches and street clutches are totally different and putting a racing clutch in a street car is foolish- nothing good comes of it. Race clutches are for race cars.

For street cars our HD 200mm clutch is a decent clutch, it is only 50kg lighter than the 2000 roadster clutch, so would be fine with most street U20's and any other roadster engine under about 200hp.

That being said, the 225mm is superior in just about every way for a street car since it has lighter pedal pressure and greatly increased torque capacity over the 200. (the 225 was originally a 6 cylinder clutch). The much larger surface area also doubles the life of the clutch at least, so it pays for itself easily just like that. Paired with the billet FW it is hands down the best improvement you can make to a U20(or any other roadster engine) for 1k. Ask anyone that has one!

That mod alone makes more difference in drivability, performance and acceleration than a cam, carb swap and header, etc - BUT you can't do many of those other things for only 1k! I always tell folks who buy them that if you don't agree and love it, you are free to return it (we'll use it on a project car), but no-one ever does- it is absolutely the best 1k you will spend on a healthy roadster engine 2L/16/stroker hands down. It also makes a wonderful improvement on a totally stock rebuild. That's not BS advertising, just great roadstering advice.

Also, FYI a Kevlar disc is totally compatible with either the 200 or the 225mm plates, but they do result in increased FW wear and are more expensive. They really are not needed except possibly for track use.

[david premo]

I would agree with Jim running a race clutch on the street is a big mistake. A true race clutch has no spring pockets and no marcel spring, making engagement a tricky experience for street purposes. So when a race clutch is designed, it’s intended for a vehicle that see extremely high maintenance cycles and short life as it is a race car. So first you might ask what is a marcel spring? It’s the spring between the friction material on each side of the disk that allows the clutch to slowly engage with a gentle slip as is released. Without this spring the clutch is a toggle switch either in or out, this is why you always see race cars spinning the tires as they leave the pit stop, if they did not do it this way they would almost for sure stall the engine.

The spring pockets are there to protect the transmission from the power pulses generated by the engine as every cylinder fires going down the track, as well as instantly delivering power when the hitting the throttle. On the street when you back out of the throttle or get on it the spring pocket cushion the transmission from those actions. It would be very uncomfortable to drive the street with this type of disk, it would also destroy your transmission if you were driving on rough roads that would cause choppy power beating up your transmission.

The final thing that they do with race clutch’s is the use multiple disks so as to reduce the overall diameter of the clutch since multiple disks divides the work over multiple surfaces increasing the grip factor of the clutch without increasing spring force.
Dave

[drieseck]

Thanks Dave & JT, appreciate the time you've taken to get me (us) up-to-speed, very helpful. And literally -----gently, on driver and trans. Dave