Technical Flywheel lightening

[cinqsandminis]

I am building up a tuned 8v 1242 - nothing crazy and still driveable. Its got a Tricker TB, McCrich chip and Punto 75 cam - I'm fitting new piston rings and I want to lighten the flywheel. Can anyone let me know how much I can take off and still allow the car to tickover at 1000 rpm? I've searched the forum and someone else suggests 25% but their engine is a turbo with a Novitec 268 cam.

Thanks,

David.

 

[arc]

i had either 2 or 3kg taken off mine, i can't remeber. it idles fine though. i'll go check receipts and get back to you.

edit:

it was 2kg, from the edges.

 

[Badger_Benji]

Have you got that fitted to your car yet arc? Any problems? Hows it run?

 

[arc]

been fitted since january when the engine went in. didnt notice the difference at first but after driving a cento with a standard flywheel.. mine def revs up quicker!

 

[Badger_Benji]

You couldnt have timed this thread better, im dropping mine of at the machine shop on thursday

2Kg from the outside please

 

[M@nticore]

I want to lighten my flywheel on my uno aswell when I take my engine out. in another thread I read that it's not safe to remove metal in the middle of the flywheel as it makes it weaker, I would also rather take some off the outside.

 

[Badger_Benji]

It is unsafe to remove from the middle as you have all the mass surrounding it still, thus giving potential for a failure. It also has more effect the further away from the center the mass can be removed from.

 

[Oldschool]

The way Marks flywheel is done is the correct way on the back of the flywheel. You can take some material from the other side too but do not remove anything from the surfaces that touches the friction plate.

On my 16v Cinquecento I have taken 3kg off, which brings it to about 3.6kg, which is not safe for any abuse. According to the Fiat engineers going below 4.7kg can be an issue.

 

[nitrane.co.uk]

This is a very relevant question for me, the race engine in my project 500 cinq will obviously have a lightened flywheel, how light is the question.

edited to say: just noticed arc, is that the lounge rug you've dumped that mucky flywheel on...

John

 

[arc]

edited to say: just noticed arc, is that the lounge rug you've dumped that mucky flywheel on...

maybe

doesnt everyone keep spare engines and stuff in their bedroom?

http://tackycheese.net/gallery/main.php?g2_view=core.ShowItem&g2_itemId=5027

http://tackycheese.net/gallery/main.php?g2_view=core.ShowItem&g2_itemId=5537

 

[Oldschool]

This is a very relevant question for me, the race engine in my project 500 cinq will obviously have a lightened flywheel, how light is the question.

edited to say: just noticed arc, is that the lounge rug you've dumped that mucky flywheel on...

John

I have got a nice one for you. Looks a bit like an Emmental. It is stored on the CNC.

 

[nitrane.co.uk]

Looking forward to it. By the way you should have a big box arrive on your doorstep tomorrow morning!

John

 

[Badger_Benji]

I think its a stafford student thing, i was as bad when i was there, the hall warden had a fit one day when he walked in the kitchen, oops

 

[arc]

ahh i can beat that, when i was in halls - we were raided for drugs by the police (and sniffer dogs!) and i was quized about what exactly the OMP strut brace was that was on my floor!

 

[TurboCinqy1250]

25/30% doesn't give any problems. After that it should be done right and there is a change that your engine runs a little bad at low rpm's

I did mine to. A little at the front and the most at the back. 25% lighter.

Now it's 5kg. The flywheel of the 1.1 and 1.2 are the same.

And you need to balance it after that.

 

[Oldschool]

25/30% doesn't give any problems. After that it should be done right and there is a change that your engine runs a little bad at low rpm's

I did mine to. A little at the front and the most at the back. 25% lighter.

Now it's 5kg. The flywheel of the 1.1 and 1.2 are the same.

And you need to balance it after that.

The FIRE flywheels do have 3 different bolt patterns on the crank. They are not all the same.

Also the FIRE flywheels have different clutch sizes.

 

[cinqsandminis]

Thanks for all the replies - I've dropped mine off with instructions to take 1.8kg off the back and 0.4 kg off the front, then balance it.

Lets see if it makes much difference.

D.