9 replies to this topic

[Broomer]

After some searching on the forum i cant find the answer to my problem.

clutch is nackerd. whiles it off i was thinking of treating it to a lightend flywheel, the mini spares ultralight fly states not suitable for road use? lumpy idle? or what reasons would that be for. this will be fitted on my 998 for a few months, then everything will be swapped to a 1275 hopefully.

[carl68]

The benefits of having a lightened flywheel is so that the engine doesn't have to spin a heavy flywheel up and this makes the engine more responsive and also be able to rev higher but the downside of it is a lumpy idle (easy to stall) as its the flywheels weight that smooths out the idle due to the laws of inertia. Race cars get around this by raising the idle revs up and thats ok for them because they aren't designed to be sat ticking over for long periods of time

Edited by carl68, 13 April 2008 - 10:06 PM.

[Broomer]

so would the ultralight flywheel be drivable on the road? im sure the lumpy idle would be worth it for sluggishness up hills etc.

[Ethel]

I think thewrite up on the Minspares site covers it pretty well. The other difference with race engines is they have much more cam duration and overlap so need higher revs to idle anyway. It will only make a difference when accelerating.

[Broomer]

ill get the ultra light then, thanks ethel,

[Broomer]

I read somewhere, it is necessary to have the fly balanced with the rest of the clutch assembly. how do i go about doing this?

[ginigwunkle]

yeah the minispares flywheel doesnt come balanced just lightened.....

depends on what cash youve got as for what to do,

i got a med st2 setup it comes with everything to just bolt onto the crank all balanced, but its £300+.....

unbalanced flys cause poor idle and a shakey engine, not good!

your local engineering shop should be able to balance it, youll need to bolt the fly, backplate, clutch plate and diaphragm inplace on the crank and remove..... take that to them and theyl do it...

price varies from place to place....

[Ethel]

Woah, I wasn't saying that as justification for as light a wheel as possible!

Balancing is a good idea if you have the engine stripped but isn't essential.

[Sprocket]

Balancing is very imoprtant on these flywheels, it can be miles out depending on which one you buy and how wopuld you know before hand if it is or isnt somewhere near.

Items that have been balanced before dont need any balancing as long as they have not been altered. However, things that are suposedly balanced can still be seen to be miles out. I bought a fully modified crank and that was suposedly balanced. Before i fitted it in the engine i had it checked only to find it was miles out!! that was last year, i again, this year, after using it for around 3k miles had it rechecked and again it was found to be out of balance for whatever reason.

Balancing makes for a much nicer engine, and for the cost, shouldnt be left out

[Ethel]

Fair point, if you got one of the aftermarket steel wheels that haven't been balanced deliberately, so you can balance it as part of your engine it would be worth getting it sorted, at least with the rest of the clutch if the engine is still together.