Flywheel corrosion?
 

Hey all, searched around and found a few old threads, so I'm pretty sure I already know the answer to this, but I figure I'd ask anyway. I'm in the process of changing out my clutch, and I had my flywheel re-surfaced as recommended. I did a "dry-fit" to check the re-assembly, but then I got distracted and didn't finish, so the flywheel sat on the engine (with no transmission) in my garage for about 6 weeks. When I went back out to look at it last week, I noticed that there was a lot of surface corrosion! I sanded off the really rusty stuff with some fine grit sandpaper, but there still some visible spotting left. When I run my finger across the flywheel, it's completely smooth. I'm assuming that whatever this mild corrosion is will just burn off the first couple times I engage the clutch? Just wanting to confirm my flywheel is in OK shape before I get it all back together. Thanks in advance.
https://cimg4.ibsrv.net/gimg/www.rx7...4d3f267706.jpg
Shiny!
https://cimg5.ibsrv.net/gimg/www.rx7...e26e02047c.jpg
Not shiny.

Looks like you’re fine on the clutch surface. But turn the FW over and double-check the snout...that portion that inserts into the rear main seal. You want that to be shiny clean and smooth. If there’s anything on it I’d take some fine emory cloth and clean it up. You can oil the snout to keep it from rusting if it’ll be a while before it all goes back together.
Also main seals aren’t expensive and easy to install. Consider a new one if you don’t know if your’s has been changed. And since you’ve been r & r’ing the flywheel in and out of it.

That's surface rust. The flywheel is cast iron and it will rust unless protected, just like a brake rotor.

You can use a Scotchbrite pad or something to knock down the surface and make sure to clean with brake cleaner and make certain it's degreased before installing the clutch.

The clutch itself will finish the job when you are driving, it will wear into that surface. You'll be fine.

Dale

I had the motor rebuilt...sh!t...must've been 15 years ago. I didn't do the clutch then cause I ran out of money (I had a lot more time, but a lot less money back then, ha!) But it's only seen about 20,000 miles in that time. I checked the rear main seal when I took the flywheel off and it still looks brand new. Thanks for the tips, though.

That's pretty much what I assumed would happen, kind of like brake rotors. I just wanted to check. Thanks for the quick replies!