so i figure no one ever post it beforethats before d21 going to machine shop (the rusted looking one)as u can see way larger contact surface on ka24e truck 240mm over 225mm on 240sx ka24e(de) but same bolt pattern/size. will take few pics after machine shop

by the way if u getting any machine work done get ur head beaded well worth the $$$

Now if they only made Stage-3 6 puck clutches for the D21....What ARE you going to use for a clutch?

Also, mayeb a stupid idea, but wouldn't it just take resurfacing the stock KA flywheel to the diameter of the gripping surface of the d21 wheel, to make them the same? it really looks like that's the only differemce, like you said... if the wheels are the same tihckness and diameter, why couldn't we just have the KA wheel clutch surface diameter widened? Any ideas?

sil80
Modified by sil80drifter at 1:49 PM 4/11/2006

u can use 300zx na clutch, 280z 240z any pickup clutch truck ka stage 1 or oem is holding up more torque than 240sx ka stage 3 haha and 300zx etc make stage 3 clutches etc.

u do make a good point there.!!! why not just resurface the ka fly into 240mm contact surface , machine shops may be able to do that any one on here that works at a machine shop???. And truck wheel weights morre than 240sx one.

The d21/280zx flywheel has a different offset than the 240sx flywheel. It bolts up and seems ok, it will work, but its about 1/4" off and your ring gear/starter will have a tendency to wear.

Thats why people install spacers, but this is not greatest idea either.

Use a truck crank and block, and an aftermarket billet steel 240mm surface flywheel.

Cant you use a 240z clutch on a ka flywheel. I think it holds more tq.

Didnt see it at first, but very nice gasket you have there.

Yeah, I think this would be a good solution, does anyone know if the bigger 240mm clutches can be used on a resurfaced to 240mm KA flywheel?I mean why even bother with a differemt flywheel when all you can do is resurface your stock one and run a bigger clutch.

I am not talking about the kind of resurfacing that makes your flywheel lighter (unsafe and stupid), but more about the clutch surface radius resurfacing. Anyone have any ideas?

sil80

dEVIOUS MORE INPUT PLEASE. So mine is about to drop in tomorow should i go get a auto tranny spacer? or just drop it in the way it is. Worst case i gotta change my starter more often? And yah since its the same diameter can i just machine up my 240sx flywheel ?? give machine shop both d21 and 240sx and go i want that surface to be machined on this wheell haha

Yah that is a good gasket i like their sealer technology.

it seems as if you are putting alot of though into something that "physically" does not make sense. it is simple physics that friction is independant of surface area. clamping force is what really matters. surface area is not part of the equation for clutch torque capacity, only the number of surfaces. Surface area actually does play into clutch capacity but only because it affects heat capacity, not so much torque capacity. If you decrease the amount of surface area you increase the pressure (more pounds per square inch), but the torque capacity remains relatively unchanged since you have less square inches. However when you add a second disc you are increasing the surface area by 100% without any change in pressure therefore increasing torque capacity 100%. Heat also influences torque capacity because of the change in the coefficient of friction. Depending on the nature of the friction material, the coefficient of friction may go higher or lower depending on increases in temperature.

SeanC wrote:it seems as if you are putting alot of though into something that "physically" does not make sense. it is simple physics that friction is independant of surface area. clamping force is what really matters. surface area is not part of the equation for clutch torque capacity, only the number of surfaces. Surface area actually does play into clutch capacity but only because it affects heat capacity, not so much torque capacity. If you decrease the amount of surface area you increase the pressure (more pounds per square inch), but the torque capacity remains relatively unchanged since you have less square inches. However when you add a second disc you are increasing the surface area by 100% without any change in pressure therefore increasing torque capacity 100%. Heat also influences torque capacity because of the change in the coefficient of friction. Depending on the nature of the friction material, the coefficient of friction may go higher or lower depending on increases in temperature.

sO u saying the dude running this combo and making over 500whp without slipping must be an idioT!!!considering that stock 240sx 225mm was slipping at 300whp area. and engeeners that designed the wheel must of been on crack , so people with 300zx 's should swap out their 250mm contact surface flywheel and swap in 200mm ones instead . i guess we should all also put 12" rims on our car and ditch lsd when we try to put more power to the ground

Ive never liked the spacer idea, but you could get a custom one made. It would best to actually press it into the flywheel.

The difference isnt quite 1/4", there is still a small amount of room left for the tail of the crank to fit into the flywheel but not much. Some people run this without problems (ones that they are aware of anyways), and some people even run the d21 part with no spacer at all. Your just going to experience some abnormal starter and ring gear wear, other than that I am not sure, never done it.

The 240mm flywheels should really only be used with L/Z/truckKA, the 240sx ka's are oddballs.