Is it worth it to skim a flywheel?

[s2_bo]

I have a lightened and zero balanced 3b flywheel that i have just picked up from my bead blasters.

It looks like new now but there is a little ware on the clutch side.

Is it worth skimming of .5mm or so to get a nice flush finish again?
Its being used with a custom made Spec unsprung friction plate and a uprated stage 3 pressure plate.

Will skimming ti throw out the balance or will ti be ok as the same surface arear will be removed all over the face? This will also move the pressure plate closer so it will not course clutch slip.

[Acidburn]

might be worth speaking to knight rider s4 and his hassle's with not skimming a flywheel.

[Jamo]

Skim is well worth it on a single mass, ask Rusty

[Jonnybravo]

You should by rights skim them anyway as it always says it in the clutch instructions.

Obviously don't forget what you remove off the face you should remove off where the pressure plate faces upto to guarantee nothing changes.

This is how I've always done them with Vauxhalls and plenty of people I know have had issues with worn flywheels and clutches, mainly paddle or plate clutches though but if its out I'd do it unless there is a reason not to on those flywheels (which I doubt)

If TTV don't make one I'd be inclined to speak to them about making some if your happy to ditch the dual mass setup as their prices are very good.

[Rusty]

I'd suggest that the bead blasting would throw it out of balance as much as a properly done skim

Get it done, I forgot to get mine done and it judders ever so slightly at slow speeds and revs. Fine up top though, my plan is to just burn it into submission.

[Rusty]

If it's zero balance then just send it to BDB and get them to do the whole lot

[20Vcqdriver]

Regards lightening 3B flywheel. What is the ideal weight loss? That is the weight reduction that provides a noticeable benefit without making the engine appear rough at tickover or low speeds. Cheers.
Someone told me that for each Kilo removed it is worth an extra 10+bhp in real terms , not sure if that quite right but sure someone can provide accurate info..

[Rusty]

10bhp in first maybe.

7-8kg final weight smells about right to me (from experience on other cars with 10kg FWs), any lighter and you should go for an alloy or custom steel one as you'll not have much left.

[Error404]

Bump to this thread - is it worth taking a bit of fat off the 3B flywheel?
I'll be sending my internals to BDB some time next year for a full balance, FW will be skimmed anyway but what are peoples thoughts on lightening the crank / flywheel a tad?
My car is really a weekend / track toy nowadays as I don't use it much, and with my 20vt engine build I'm hoping to eventually achieve an unstressed and reliable 400 ponies or thereabouts, wouldn't want to sacrifice too much civility but would like a smooth and free revving engine.
Is there a compromise worth going to extra mile for with the bottom end? Any BTDTs?

Alex

[Acidburn]

10bhp in first maybe.

7-8kg final weight smells about right to me (from experience on other cars with 10kg FWs), any lighter and you should go for an alloy or custom steel one as you'll not have much left.

Bump to this thread - is it worth taking a bit of fat off the 3B flywheel?
I'll be sending my internals to BDB some time next year for a full balance, FW will be skimmed anyway but what are peoples thoughts on lightening the crank / flywheel a tad?
My car is really a weekend / track toy nowadays as I don't use it much, and with my 20vt engine build I'm hoping to eventually achieve an unstressed and reliable 400 ponies or thereabouts, wouldn't want to sacrifice too much civility but would like a smooth and free revving engine.
Is there a compromise worth going to extra mile for with the bottom end? Any BTDTs?

Alex

i'd also be interested in knowing what the best weight to have a 3b flywheel taken down to is as its something I want done soon

[quattrostyle]

I'm curious about what would be the ideal weight too. My mate had a cq 2.2 10v with a lightened flywheel. I thought it was a bit less torque than my 90q 2.2 10V because it revs faster it will make less torque? Or is it just wrong interpretation from the butt dyno? Also the car will rev better but will the top speed be lower?

[JP]

Always skim a flywheel before refitting. the percentage change that you will see is less than 0.2% in terms of balancing which in the grand scheme of things is insignificant. Unless the flywheel is so warped you shouldn't be using it anyway.

As for ideal weight personal preference. idle has nothing to do with the flywheel unless you have gone seriously too light like an aluminium one which I would never recommend as the warp to ******y on high hp motors. It is to do with how easily your car pulls away on clutch engagement and how freely you rev through the rev range to peak rpm at the sacrifice of midrange torque.

So if you have a track driven car that needs to respond well in the upper part of the revrange that is naturally aspirated 6kg is a lovely territory to be in.

If you have a weekend warrior that you like to rev and it has a turbo fitted you want to compromise slightly and stick to around the 8-9kg area as it will improve pull away in traffic plus the rotating mass will help come back on boost when exiting the corner on track.

If you have a high powered motor that has no issues reving due to the insane power delivery I wouldn't go much below 10kg purely because the heavier duty clutches that are required will resonate the lighter flywheels to ******y on pull of and cause premature engine wear through harmonics.

[Error404]

Nice one JP..... what do you class as a high HP motor with insane power delivery? 500+?

[WabTheKing]

grinding gives a better and flatter finnish but not many people have the equipment to do it, skiming with a lathe will be fine for most unless the flywheel has seen some abuse and hard spots have been created within the material.

make sure you remove the locating pins for the clutch plate and skim the full face to maintain the pressure plate pressure

[20Vcqdriver]

I'm curious about what would be the ideal weight too. My mate had a cq 2.2 10v with a lightened flywheel. I thought it was a bit less torque than my 90q 2.2 10V because it revs faster it will make less torque? Or is it just wrong interpretation from the butt dyno? Also the car will rev better but will the top speed be lower?

Some good info but how does a lighter flywheel reduce torque. Surely you would gain torque as you require less torque to rotate the flywheel mass. Or am I missing something, apart from a few brain cells