Who do people use to lighten one piece flywheels?
Is this recommended?
This is for a "fast road" 1330 engine.

A decent machine shop (I don't have a mill).
I recommend it for any big bore mini.
Have had one on every "fast road" mini I've owned, make a big difference for a small cost.

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Too many cars, and too little time.

If you cut the end of a old crankshaft you can mount it in a lathe, fit your flywheel to it and then machine as much as you like of it.

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Have a Nice Day.
If already having a nice day please disregard.

recently during my engine build, i was instructed by quite a few people NOT to use the one piece flywheel.

get a 2 piece one and have it machined up.

Alternativley, miniman matt read has them ready to, or did have a few left some months ago. definatley worth grabbing one that is proven to be good.

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'66 BRG Morris Mini Deluxe 60HP ATW

This is a miniman lightend 2 piece flywheel (pictured on the right). i weighted mine at 4.7kgs. much lighter than the origonal 1 piece i had in the car.

the standard 2 piece on is on the left in the below picture.

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'66 BRG Morris Mini Deluxe 60HP ATW

Nah just grab it by the ring gear, set it up to run true with a dial gauge, and turn away. You do need a decent size lathe to swing it.
You also need to make 3x thick steel washers to replace the .200" turned off the face. Otherwise the straps won't be parallel.
I charge $60 per flywheel for Sydney local yokels...

1 piece or 2 piece ones are OK for general road use, I don't machine the centre hub of either type.

[edit] IMO that RH light one in the pic is too thin, for an iron flywheel. The stuff is brittle.

Another trap people fall for is welding the ring gear on if it comes loose. It's a great way to crack a cast iron flywheel.

[edit 2] yeah it all needs dynamic balancing before fitment.

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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.

so you are aware also, make sure you have the flywheel balanced with the clutch and pressure plate etc, to ensure it is not out of balance after being machined.

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'66 BRG Morris Mini Deluxe 60HP ATW

I just bought a Med package, light,comes all balanced & pre assembled fit & forget. (verto) they do a better pre verto though.

the Med one is very good,

I'm sure matt's is good as well pre verto though so way more meat can be taken out, i would go matt for pre verto for sure.

im running one on my 1293 soon to be supercharged, mine also has a uprated pressure plate to hold it on better & no slip.

verto set up's are fairly crap & weak lol, feel nice though.

Doc,,, there are literally Hundreds of these (my) lightened flywheels out there, did my first one when i was 16 years old,,, now 47,,, with usually 20 odd machined per year,,, that makes for lots & lots of them now ,,, Not heard of one breaking up (now i`ve hexed myself havn`t i??? ) BUT!!!!!!!!! they`re still retaining the factory thickness in the right spot(s) & no need for extra washers under the straps

they`re qll CNC machined exactly the same,,, if it were balanced before we lighten them then they are pretty well still in balance after we finish ( i always suggest balancing anyways)

They`re not "THIN"

I`m not a fan of just machining them thin,,, Just simply thinning them down tends to make them warp (not a matter of if,,, more a matter of when)

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

I use this.


it just fits. with about 2mm either side or the lathe ways. I normally use a 4 jaw and a dial indicator but this pics for illustrative purposes really.

I have mounted one on a rotary table and gotten fancy on the mill like madmatt does.

I have done a grand total of 2 so far. One has held up well and the other has sat on my self.

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