fly wheel

[Jason B]

I did say I wouldn't do it without putting a big ol' steel scatter guard there!

However I think I've found a company that make proper lightweight steel ones from scratch for a reasonable price.

[foggyjames]

It'd have to be a very serious piece of kit to stop a flywheel. If you're bothered (and I wouldn't be....I know people who've taken a LOT of material off dished flywheels without having an issue), then a billet flywheel is probably a wise investment...or don't bother at all. Next to the weight of the rest of the rotating assembly, the flywheel isn't that big a deal. The crank weighs about 25kg by itself!

cheers

James

[Jason B]

yeah, but every kg off the flywheel (to a point) makes a mountain of difference in accelerative terms. Especially if you alter the radius of gyration at the same time.

[foggyjames]

Well indeed...and the most effective (and probably safest) lightening I've seen has been where lumps of the 'dish' have been milled out - lots of metal there, and it's around the outside!

Still, putting a set of 40s or 45s on would probably make more of a difference in terms of how fast it'll spin up A set of short pistons, long rods, and an extensively 'shaved' crank with an uber-light flywheel would make for an awesome setup, though. It'll show up any lack of balance pretty spectacularly

cheers

James

[Jason B]

while correct, you're suggestions don't really fit with what I am allowed and can afford. I would love to run twin 45's or MS but rally regs are a bit tight on such things. I still maintain that bang for buck it is lightening the flywheel that will give the most response and accelerative improvements (especially as lh2.4 is limited at 6200/6500 so the added benefits of lightened internals can't really come into play as I probably won't be revving up to 9k in the near future)

[sven360]

Only ever seen one flywheel let go big time.
Mk2 BDG flew off @10,000 rpm-nav still walked away.
Me mate fat Les blew a couple off of XE's @8,000 + but ARP bolts and loctite cured that.
I would imagine a lazy red block should be fine-A 640 has lightened and balanced flywheel and regularly saw 8k without problem.

[Chris_C]

A640 was done properly though Jason was on about taking it to the uni workshop last time I heard What age 240 are we talking about here? old style front lights? There was one in a scrappy, as to it still being there though.

You still competing with that Sven?

[Jason B]

No chris I was only joking about that, if I was to have it lightened it would be at a proper machining balancing shop. Though I really don't know what I want yet! need to sort rough prices for all the mini schemes and then decide on the ones to do for now.

[foggyjames]

I've got various pics of lightened dished flywheels I could dig out given a prod in a day or two.

If you've got access to a 240 with old style lights, pull them! Which sort are they? Round, square, or rectangular? I think 240s got the dished flywheel halfway through the 1984 model year (the same time that 240 Turbos were intercooled as standard, rather than as an option). 240s here got the 'late' headlights in 1981, so yes....that car would have a flat flywheel.

cheers

James

[sven360]

A640 was done properly though Jason was on about taking it to the uni workshop last time I heard What age 240 are we talking about here? old style front lights? There was one in a scrappy, as to it still being there though.

You still competing with that Sven?

I would think final yr engineering students should be able to lighten a flywheel no prob.As long as it's properly balanced it should be cool.IMHO the balancing is more important than the lightening.
For example if you shave 7kg off f/wheel but have to add 5kg to strengthen the tunnel you might as well go conservative and shed 3kg and maintain some rigidity.Either that or take a chunk out and not worry yasel' too much.

As for A 640 bought a boat and just use boggo std 360's on road events-they do the job and are bullet proof.In my experience tuning too much just moves the achilles heel from area to another.
Take A 640 ran fine for yrs on injection in the woods,a more recent owner decides twin gobblers are the way to go for tarmac events.Result the extra torque and transmission strain results in a plethera of snapped shafts.
Answer obtain Cossy Sierra ones and machine them to fit-cheap as chips,not
No more snapped shafts,just diffs exploding and a bust box.

For Nat B I'd say get summit reliable and ring it's neck for a year or two and then once you think it's incredibly pedestrian it's time to tune/change.
A std 360 can still give most things a run in the lanes and cause ya to $hit yasel' every now and then,ask our kid

[Jason B]

its not just the rallying behind tuning it! I enjoy the project as a challenge and want to build it the best I can within my budget. Handling is much higher up the list than I have made known, its just that I have an engine and can't help thinking about it

(with regards to 360 being scary enough, yes it is! got some almighty unexpected power oversteer on one pc this year) I just find that my carby engine is pretty appalling as it's all or nothing and there is no smoothness in the response.... the list goes on

[Chris_C]

Foggy: the 200 had the same round headlights Julies maroon 200 does. If they are that rare I'll see it's still there.

Sven: You havn't seen our eng students Most have never done practical work Nah, they arn't that bad, would probably be ok! I do know what you mean about moving the achilles heal though, I've seen that way more than I'd expect on project cars

[Jason B]

I'll agree with the mech eng students having a lack of "spanner time" they wouldn't know where to begin on a lot of mechanical stuff! If anyone in the workshop was to do it, it would be terry that old guy can lathe objects accurate to thousandths of a mm by hand so impressively quickly its astounding!

[foggyjames]

Ok, the rounds aren't rare. However, it's worth grabbing the grille, and if you're feeling adventurous, the bonnet. I'll let you know if my mate up here wants any bits from it...

cheers

James