Rusty flywheel, and other questions.

[Jiggerachi]

I could have sworn I felt my clutch slip the other day, which reminded me that im at 160K+ and as far as I know on the stock clutch, it has been shuddering lately too.

Anyway, being the cheapass that I am (really just trying to do what I can while supporting a new kid) I've been reading about the TCB lighweight flywheel on Miata.net...installing an OEM 1.6 flywheel and clutch on a 1.8 engine for smaller rotating mass, that fits my situation perfectly. I'm going to source a cheap OEM flywheel beforehand and have a machine shop shave off the weight ring thus taking another 4 - 5 lbs safely and rebalancing it.

So now im tracking down a 1.6 flywheel, I found this one on CL for $25, fits my budget, but it's all rusty.

http://dallas.craigslist.org/ndf/pts/1742805258.html

I've never actually seen an old used flywheel, do they get rusty like old brake rotors? That would make sense since they are sort of the same thing. Should I pass on this or no?? Does anyone have an old 1.6 flywheel laying around? I'll take it off your hands.

[sammm]

The important parts (where the 'contact' happens) will be bright and shiny after it's machined.


EDIT - That might be the non-contact side (near the engine) shown in the pic.

[POS Racing]

EDIT - That might be the non-contact side (near the engine) shown in the pic.

Yep it is!

Here is the bidness side!

[Jiggerachi]

Wow...so shiny! Yea that's what I was thinking. The side in the pic seems like the side with the weight ring on it...what people get machined off...???

3n53o73lb5U15P55X2&#9.jpg


I really don't care what it looks like, just making sure it's not a bad thing to be rusted.

[Jiggerachi]

I might go pick up that flywheel this weekend. Anyone know or have a machine shop that can do this and balance it...for cheap of course

[jrj512]

One trick in SCCA AX classes where you must use a stock flywheel is to "true" it down to minimum factory tolerance in order to lighten it, so you are on the right page. I would like to do this if I am ever in there, again. I guess the min tolerance is in the service manual.

[sammm]

machine shop that can do this and balance it...for cheap of course

There's a guy in Keller on the corner of 1709 & 377. He did mine a few months back for $30 (he likes cash).

LINKIE

[CarCar]

Could you weigh it after it is machined and give us the before and after results?

[Jiggerachi]

Picked it up this weekend and the rusty side pictured is the buisness side. It looks a little different that the one POS posted, it doesn't have those raised posts outside of the friction plate area. Is that from a 1.8?? Maybe that's what makes the 1.6 flywheels a little lighter, the surface on this one is mostly flush.I took a pic to show what im talking about, but forgot to put it on photobucket, i'll post later.

A little steel whool and Barkeepers Friend took care of most of the rust, and the rest would be taken care of at the machine shop or when I start the car.

We have a nice accurate postal scale here at work, I might be able to talk the shipping guys into weighing it for me before and after. I'll be sure to post the numbers here.

[juxt3r]

Yup, the flywheel POS posted is a 1.8 critter.

Interested in the difference you get with the lightening.

[Jiggerachi]

There's a guy in Keller on the corner of 1709 & 377. He did mine a few months back for $30 (he likes cash).

LINKIE

I called this guy just now, he says he shouldn't have any problem grinding the weight ring off and wouldn't charge any extra than he would for resurfacing. But he says, first of all, that he's never done anything like that before, and second that he has no way of balancing it. He did make a good point that since it's going to be spinning on a lathe when he grinds it that it should be balanced afterwards, he didn't see any reason it wouldn't be balanced, but didn't have any way of guaranteeing it was balanced.

Any thoughts?? I'm planning on doing the clutch install this Sunday so if i'm going to get this flywheel lightened I need to get it done pretty quickly.

Thanks in advance, and yes i'll get it weighed before and after lightening.

Edit: one more question. If I really needed to get it balanced, (which im thinking is the case) does anyone know of a shop that can balance a machined flywheel correctly for super cheap?? It's gotta be a simple job if you have the right tools i'd imagine.

[Jiggerachi]

Ok so calling around basically there's only one machine that will balance a flywheel and it's super specialized. There's only one or two shops in the metroplex that have one and they will charge $50 - $75 just to put it on the machine, then it's about $40 for surfacing, and another $50 or more for machining... Oh and there's at least a 2 to 3 week waiting time.

Screw this. I didn't realize it was going to be such a PITA to machine the flywheel. I'm just going to get the guy to resurface it and run the stock 1.6 flywheel since I can't afford a $300 lightweight flywheel at the moment...

If anyone has a hookup for a balancing shop let me know before tomorrow around noon, i'll be taking it to the resurfacing guy at that time.

[trickyrix]

These guys have done engine work for me and flywheel work for a buddy of mine.

This is probably a stupid question, but is a Miata flywheel internally counterweighted or anything goofy?

[Jiggerachi]

^ not from what I have read. I am still unsure if it really needs to be balanced, since it would be machined evenly on a lathe, since apparently nobody ever balances a flywheel.

The only thing I've read that has me concerned is somebody on Miata.net said that the steel in a flywheel is not a homogeneous mixture, so the weight is not necessarily spread evenly throughout the metal even though it's shape is balanced. Since I know how anal those miata.net guys can be i'm not sure if I buy this.

If i'm wrong though it would destroy my engine. I'm not sure I want to take that gamble.

Edit: just called your guy and he can do it for $35 on his balancing machine. Only thing is he's backlogged and they couldn't get it back to me till tuesday. But he can do it no problem. I might think about going this route if I decide to push off the clutch install for a week.

[trickyrix]

The only thing I've read that has me concerned is somebody on Miata.net said that the steel in a flywheel is not a homogeneous mixture, so the weight is not necessarily spread evenly throughout the metal even though it's shape is balanced. Since I know how anal those miata.net guys can be i'm not sure if I buy this.

+1 on this... it sounds like retarded Pointy Board Theory to me. I've never heard of balancing through some mystery process of using "non-homogeneous" metal. Also, I've never heard of a flywheel having to be "rebalanced" after a simple resurfacing. A lightened flywheel may be another matter altogether, but I think my guys could look at it and tell you what's what.

And maybe some of our other experts will see this and chime in...

[Jiggerachi]

Bringing this back from the dead.

My clutch is making some funny bearing noises so I guess I need to get moving on this clutch job. I've still got this 1.6 flywheel i'm looking to get the weight ring milled off the back of it for a ghetto lightweight flywheel.

The guy Sammmm reccommended does not seem interested in that kind of work now, only resurfacing, told me to look elsewhere, must have been in a bad mood. The guy Trickyrix reccommended is good for balancing after machining, but doesn't have the equipment for milling off that ring. Called another shop (Matsco) they seem reasonable but couldn't tell me how many hours that kind of work would take, so it could get expensive, plus I'd have to pay for balancing to do it 'right.'

Seems the general response i'm getting is "what the hell is this guy smoking, don't want the liability." If it gets over $100, it might not be worth it. I might just scrap the idea and look for a cheapish lightweight flywheel and be done with it.

Any thoughts, advise, or lightweight 1.6 flywheels?

[POS Racing]

Ya got a picture of what they machine off the flywheel? How much weight does it cut off the flywheel??

[Jiggerachi]

Supposedly 5 lbs or so, you can get more but obviously would start compromising structural rigidity at some point.

From Miata.net

Found a better pic:


more pics.

Before:


After:

[Rob®]

Well they definitely had that one balanced, and by a good deal, so that might be a good idea if you go about cutting stuff off it.

[juxt3r]

Is this something Day Custom Engine could take care of for you? Their work seems to get high praise among the local Miata crew...though I mostly see the shop mentioned in reference to machining of blocks, heads and whatnot.