Is there any 'proper' method or areas of removing weight from a flyhweel?
The engine will be predominantly having the living daylights thrashed out of it, 98% of its time.
I am a hoon.

Camshaft is a RE13
Rockers are TOYOMINI 1.5:1
Head is a hottie GR Special
Manifold is 3006 GR ported
Carb is 45DCOE

(I suppose most of those don't matter a pinch of crap)

What I am getting at, is the final weight, and where the best place to remove weight from is.


Also, what about the clutch backing plate?

Ur not doing it urself are you . The flywheel's weight is what helps the car keep going, keeps the momentum up. Lighten a bit will let it rev more freely, lightened too much will result in the need for very high idle spees jsut to stay going and a way more increased chance of stalling. For hoonage and racing when revs are kept up it's great. They generally remove weight evenly from the centre of the radius from the centre. A machine is used to make sure it's prefectly balanced. Unbalanced would do all sorts of nasty things, it would most likely kill you big end bearings etc.

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

Errr no... just want some more info to give to the person that is doing the flywheel machining.

Take both copies of your Vizards books to the machine shop with you.

I'm not doubting the machinist at all... he's been doing Minis for 30+ years; I just want to make sure he gets it 'right' but I suppose its 'just a flywheel'.

Meh...

yeah 'tis best to use a replaceable one such as a standard clubby type steel one. easily replable, thats probalby what you got.

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

It is for my race motor.
The one i have spent copious amounts of dollars on



I thought all Mini flywheels were cast...

yeah im not sure. MiniSport sell a real nice titanium one, ultralight, messes with the idleing but for racing, who cares? That's 600?? i think can't remeber i'm sure machining would be cheaper. I reckon they are all he same material, jsut on my parts list it says late model steel flywheel. So I dunno, but cooper s had a lighter version with a tougher spring on the clutch plater, cooper s had a thicker clutch plater for extra clutch thrashing ability!

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

For a road car, I just take .200" off the outer face, down to within 8mm of the centre shoulder.
Then, turn up 3 steel spacer washers 20mm dia x .200" thick with 3/8" hole, to go under the straps (with the 3 flat washers it has now).
It will need dynamic balancing when this has been done, regardless of how well you set the flywheel up in the lathe. The flywheels are cast iron which has `variable density' (I'm being kind here).

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Dr - what's your final weight using this method?

You are right there Doc, The "variable density" part is the scary part of the whole thing. Like it says in the David Visard book exploding flywheels take driver's feet off with ease and that is where variable density is scary.

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DID I MENTION THAT I AM THE BEST SUPPLIER FOR MINI ELECTRICAL PARTS AND REPAIRS?
"Let us remove your "SHORTS"

We never did resolve this cast/steel thing. I have definitely seen somebody who should know say that of course they're not cast.....but damned if I know where....

Dunno- I'll weigh one next time..
Some people like TheMiniMan and GR drill bloody big holes thru it too, I think it's a bit much for a road motor.

Weight can also be saved by lightening the backplate, but it takes a fair bit of work to reshape it.

Vizard's HTMYM has dimensions and weights for both, but IMO he goes a bit far by machining the engine side of flywheel under the ring gear.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

This is also one of my next tasks, but does anyone else get a little scared, i meen cast iron isint that stable, varyiable density and all (oh convertable mini has covered this) anyways, if it flys apart, im a little worried about my feet, and legs, but very very woried about other parts! how likley are they to break up, and if so, make it into the pssenger compartment?

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speed costs....how fast do you want to go...

I have a very very much lightened one that I'll post a pic of when I get home (tomorrow) - along with a lightned back plate. It's seen track time in a mini7, and was done by Lyn Rogers. I rang him about it and asked if he'd have any qualms about using it. He said it would be fine for the application it was made for - ie chuck it into a small bore. However he would not recommend putting it on my 1380. I spent the money and got a new light one (as opposed to lightened). He was not so much concerned with density etc or integrity at high speed (those race small bores do insane rpm), more with the lack of metal to hold it together under the high acceleration a big bore would create. Yes I've heard lots of stories of bits of flywheel ending up in the passenger compartment, but have yet to speak to somebody who has experienced it first hand, so who really knows.