Clutchmasters vs JMTC
 

Looking at replacing my clutch and flywheel.
My options have narrowed down to...

Clutchmasters FX250 with steel single mass flywheel
Or
JMTC Stage 2 or 3 with steel single mass flywheel

I was also wondering if the JMTC is a sprung or solid disc? Don't SM flywheels need to be paired with sprung discs?
Also does the JMTC clutch kit come with a SMF?

Anyone with experience with these or advice is greatly appreciated!

I've seen a couple threads that say JMTC flywheels don't have the hole for locking the flywheel when setting / checking timing. Be sure to check for this feature with any flywheel you buy. There is no other acceptable method for setting timing than locking the flywheel.

I recently bought a JMTC SMF Stage 1 conversion for my R55. Mine came with a solid disc, and I can confirm that the flywheel does not have the timing notch on it. Based on the shape of it (concave), I’m not sure it is possible to add a notch at a machine shop either. While I recently did a timing chain swap, there is a part of me that is a little concerned given the reputation of the N14 timing chain tensioner and guides.

What does this all mean. Does it mess up the timing then or what exactly?

Like I said above, without this timing hole in the flywheel, timing CANNOT be set properly. It will not affect current timing, unless something else is done that causes timing to be disrupted. You'll be fine as long as the chain, guides, head and engine don't need to be taken apart --- LOL!

Well the previous owner had the timing chain and parts replaced so I believe it is fine. Do you know if timing needs to be adjusted after so many kilometers once replaced.
I feel that the CM option would be the best. Do you or anyone disagree? Why? Is there a better option?

I have the JMTC kit as well. With this clutch, doing the timing chain becomes an engine-out operation. You need to take off the transmission, clutch, and flywheel. Then attach a flywheel temporarily that has the timing tool notch to do the timing chain. Then reattach the JMTC flywheel and clutch, re-mate the transmission and put it all back in the car.

I've heard the most recent version of the OS Giken clutch kit has the notch, not sure about the Clutch Masters kit, I would email a dealer to find out.

Your choice of clutch and flywheel should depend on your intended use. If the CM satisfies your intentions, AND it has the timing hole, go for it. I can assure you, setting the timing as thebombardier shows is a PITA. The need for setting or checking timing depends on many factors, but if you need an aftermarket clutch / flywheel thats better than OEM, you'll eventually need to check timing.

I actually borrowed your pic of the OEM DM flywheel from elsewhere on the forum.

The more I look at this JMTC lightened SM flywheel, the more I'm thinking I could probably get the flywheel drilled. Initially my thoughts were that because it was concave it wouldn't work, but looking at it closer, I can still have it drilled, it is just that the OEM alignment tool likely won't work as I don't think it will go deep enough. Regardless, that should be easy enough to work around, as it will be the only hole in the flywheel.
https://cimg9.ibsrv.net/gimg/www.nor...a74fb4f445.jpg
https://cimg3.ibsrv.net/gimg/www.nor...75d1c054aa.jpg

The hardest part will be balancing it

I had to use two different machine shops, 1st one couldn't do the balance. Shop around for somebody that can do both jobs.