Flywheel options

[Rusty]

What are the single mass options nowadays? I've got a 3B on there at the moment but would like something in the 8kg region. I remember seeing billet FWs for sale but not sure on a new source for these. Another option is to get a 3B or 7A one lightened up but not 100% on how that will affect the mysterious art of engine balance... A Fidanza is too light for me.

All experiences and options welcome.

[Jamo]

034 do a non ali one in steel I think around that weight
I'd lighten the 3b one that's what Aelred use to do

[AQTdriver]

i've had my 7A lightened to 7.45kg...

[Rusty]

I know this has been discussed before but can you fit a lightened and balanced FW on an otherwise stock engine or does the FW have a major part to play in the engine balance?

The billet one is stronger but not really necessary for my modest requirements. Better source a spare 7A one to get lightened.

[driftin jo]

I know this has been discussed before but can you fit a lightened and balanced FW on an otherwise stock engine or does the FW have a major part to play in the engine balance?

The billet one is stronger but not really necessary for my modest requirements. Better source a spare 7A one to get lightened.

The flywheel on a standard bottom end is part of an external balance set.


Whatever flywheel you use you should have the bottom end assembly balanced with it.
Lots of people change to single mass and don't bother, you may 'get away with it' but it is not
balanced correctly.
The thing is you probably won't feel it but you may well wear out your main bearings in 20-30k miles instead of them lasting 200-300k miles.
Basset Down will have no problem balancing the bottom end no matter how light you go, so no
worries there. If your not sure you will like a really light one then you could have them balance two
flywheels to the bottom end assembly, that way you can change over if you like and still have perfect balance.

The other option is have them do a GP conversion, they lighten the crank and neutral balance it,
this way the front pulley and flywheel are neutral balanced and can be swapped for any other neutral balanced items whenever you like.

[macspring]

Sounds like the perfect advice.

Like the idea of the two matched flywheels, and the standalone balancing.

btw, what are the disadvantages of moving away from a dual mass ABY flywheel compared to having a dual mass one tweeked ? ( Not sure what the tweeking would be mind you ).

For the replies to the query, assume the above combinations are all balanced correctly by Basset Down.

Thanks.

[driftin jo]

Sounds like the perfect advice.

Like the idea of the two matched flywheels, and the standalone balancing.

btw, what are the disadvantages of moving away from a dual mass ABY flywheel compared to having a dual mass one tweeked ? ( Not sure what the tweeking would be mind you ).

For the replies to the query, assume the above combinations are all balanced correctly by Basset Down.

Thanks.

They advantages of single mass /light flywheel are less rotating mass so more acceleration, mostly in 1st and second gear, getting less the higher the gear you are in, the disadvantages are less smooth without the dual mass, having said that, have Basset Down do there stuff and it will be very smooth.
I'm not sure there are any advantages of having a dual mass one 'tweaked' as you say.

Basset Down 'can' balance a dual mass flywheel, they told me, but with most old ones it's impossible to get good result as they have too much movement in them. So basically you would need a new one.
I know what they mean as I took an AAN one of an engine not so long ago and you could move the two halfs back an forth by hand, about inch in rotation at the outer edge, there is now way on earth you could properly dynamically balance that.

[caterpillar]

i needed a new flywheel, so i bought a new at the 034 in FW steel, and new clutch kit; for normal use and in the street use... no prob whatsoever... for the 1/3 of the price by the main stealer....dualmass FW are ****** !!!!!

[Rusty]

Yeah, NPT wanting.to open up the engine for now, so will just have to accept that it's not perfect. Will speak to BDB and see what can be done.

[macspring]

Jo an Catterpillar,

Thanks for replies.

Handing back the tread to Rusty now.

Kind regards.

[DJones]

Andy

Take your old one to BDB and they will balance the new one to match it.... it only bolts on in one position... hey presto no strip down and balanced to match oem, if that's how it started life..

Darren.

[driftin jo]

Andy

Take your old one to BDB and they will balance the new one to match it.... it only bolts on in one position... hey presto no strip down and balanced to match oem, if that's how it started life..

Darren.

IIRC his old one isn't balanced with his engine anyway, good idea though.

[Rusty]

Old DM FW went in the bin about 5 years ago will give them a bell and see what can be done. Got a few things on the to do list at the mo