Home Car Info/Mod List Photos/Project Updates Videos Blog Tech Info/Articles Other Cars Links
Clutch and flywheel install- April 2008

I'll start off this update by saying that I am completely, single-handedly responsible for destroying this clutch. If only I could have left good enough alone. If only I could've been satisfied with the stock 5psi setting that the fine folks at Greddy set their factory wastegate to and not installed a boost controller so that I could turn it up to 12psi, none of this would've ever happened. The clutch in this car was perfect, even after 70,000 miles. Well, until I got ahold of it! The fact is, the allure of more power is a strong one, and I needed more.

Slippin' & Slidin'
As I mentioned above, it only took a little more power for the stock clutch let go. It wasn't completely gone, but it would slip in 3rd, 4th and 5th gears under medium throttle.
This was my Miata's home while it received driveline surgery. The Mitsubishi flag is just to remind me of the years I've spent wrenching on those cars, in case I ever forget.
Miata garage

The transmission came out without any major problems. Compared to a Lancer Evolution or similar AWD car, this was a piece of cake! Here's the stock Miata transmission extricated from its home. I'll give it a little clean-up before going back in.
Miata transmission

Looking at the stock clutch setup from here, everything looks pretty good...
Miata clutch assembly

Until the individual components came out. That clutch disc surface is really slick from me cooking the heck out of it a couple times. Oops!
Miata clutch disc

The UPS man brought me some early Christmas gifts! ACT (and many other clutch companies) doesn't actually make a clutch kit for the 1.6 Miata, since the newer 1.8 Miata parts have more capacity to hold power and bolt right up with no modifications needed.
Miata ACT box

Here's all of the stuff that comes with the ACT clutch kit and Prolite flywheel. It's very comprehensive and gives you everything you need to do the job right, and the quality of all the included parts are top notch.
Miata ACT clutch kit

A look at the stock flywheel vs. the ACT prolite. The ACT is much lighter! I weighed the total weight of both clutch and flywheel assemblies, and the stock 1.6 was 27 pounds, while the ACT was 21 pounds. Not bad, especially since this is the larger 1.8L stuff.
Miata flywheel vs ACT

The stock clutch disc vs. the larger ACT.
Miata ACT clutch

You can clearly see the increased surface area of the larger 1.8L flywheel when you lay the 1.6L clutch disc on it.
Miata ACT Prolite flywheel

Comparing the stock 1.6L pressure plate to the ACT. I left a few sweet burn marks on the stocker.
Miata ACT pressure plate

Ewww! The transmission bellhousing was filthy! The front seal was leaking which caused this nasty oily, clutchy residue all over the inside. This is a job for those blue towels, a toothbrush and a bunch of carb cleaner.
Dirty miata transmission

Speaking of those blue towels, get them in bulk at Sam's Club. It'll save you a nice pile of change and you won't be running out anytime soon. I love these things.
Blue shop towels

Much better! You could eat out of this thing now. I made mac-n-cheese in mine.
Miata transmission bellhousing

Me turning a wrench and thus removing the front seal cover of the transmission. Even if yours doesn't appear to be leaking, it's a good idea to change it. Oh, and yes I wear gloves while I'm working on the car. No, I'm not a professional hand model.
Miata front transmission seal cover

Judging by the oily mess, the transmission and rear main seals needed replaced. Here's a shot of the transmission input seal, which was very brittle.
Miata front transmission seal

The ACT throwout bearing installed and ready to go.
Miata throwout bearing

I've been using anti-seize and threadlock since I can remember. Both are messy and difficult to apply, especially if you're lying on your back. Anyone who's used anti-sieze in the little bottle knows that it's almost impossible not to get some on you. And when it's on you, it sure as heck isn't coming off without a fight.
Anti Sieze

That said, I've gotta give a shout out to Loctite for making these stick applicators for their anti-seize and threadlocker products. I am amazed how much simpler this made the job vs. the old and messy ways. If you don't have these in your garage, go get em!
Loctite stick

The ACT flywheel installed. Kind of a shame that no one will ever see this shiny bit. It is very well made.
ACT Prolite Flywheel

Here's a shot of the ACT clutch and flywheel assembly bolted up and awaiting the transmission! I started the job on a Friday and finished it up the next day. All told, it wasn't bad at at all. Removing the exhaust and loosening (not removing) the turbo downpipe made re-install go quickly and without drama.
ACT Miata clutch installed

Driving Impressions
After a 500 mile break-in period of easy driving, (which seemed more like 20,000 miles) I finally got a chance to lean on it. The lighter weight of the whole clutch assembly seems to have made the car come on boost "quicker" under light throttle than before. Hard to explain, but it just moves out with less throttle than it used to need to do so.

But who cares about light throttle?!? At full throttle, it is all grip. Wan't to hear the best part? It will actually chirp gears 1-4! Day to day driving is great, the clutch pedal is stiffer than stock, but not bad at all. There's no chatter when taking off from a start and engagement is gradual and smooth. A very common Miata side effect of a "non-stock" flywheel is increased transmission/drivetrain noise. I have this is well, and although it did worry me at first, it is not a sign of any problems, there is just more noise being transmitted than before given the material that the components are made out of.

All told I give the ACT setup a big thumbs up! It does everything that you would need a good clutch setup to do and seems like it will hold much more power than I'm currently throwing at it.

Thanks for reading!