m20 lightened flywheel

Post Mon Oct 27, 2008 7:02 pm

hi

its my daily driver
would any one be able to advise me on lightning my flywheel i am replacing the engine in my sport, big end bearing and cracked head at the same time,i am replacing with a second hand engine 89 spec of a fellow from the zone.

i would like to know is it worth my while as the engine is out ? plus i had just put a brand new bmw clutch in the origanal engine a month ago would i need a better higher spec 1. i am also putting on a hottunning 6 branch and samco hoses,

any help much greatly accepted thanks

Post Mon Oct 27, 2008 8:39 pm

Hi there, I have just done this in mine, apart from having to use a few more revs when pulling off there are no real disadvantages. Throttle responce is better, 1st and 2nd gear pull a little better, the idle is normal, for me the best bit is the speed at which a heel toe or duoble declutch can be done, great for zipping round country lanes at 60mph of course

standard clutch will be fine, just swap it over. Have a look in the group buy section , I think someone was getting some made up.

HTH maggs

Post Mon Oct 27, 2008 8:43 pm

it will make your engine more lively so definatly worth doing ive done this while swaping my engine over

Post Wed Oct 29, 2008 4:50 pm

thanks for the responses

it sounds like a good mod to me

did you buy a new lightened fly wheel or just get your own lightened and how much?

Post Wed Oct 29, 2008 8:30 pm

i didnt pay for mine just swaped it with a mate that had a spare and i gave him two standard flywheels

.
porsonally i didnt think it would do alot really but now i have it on the car its alot better

Post Thu Oct 30, 2008 5:54 pm

Sorry to hijack the thread but can anyone tell me how much material can be safely removed from the flywheel? Im struggling to get a figure anywhere, Cheers (by the way my fly is a B20)

Regards, Mark

Post Thu Oct 30, 2008 5:59 pm

just buy one of the zone..... there not expencive, plus i class it dangrous to skim flywheels

Post Thu Oct 30, 2008 7:07 pm

Fair play but i disagree with the skimming flywheels is dangerous comment. This has been a common mod for years and years, more so previously than at present if anything, and if done sensibly, without going overboard with the lathe, should be perfectly safe.

Post Thu Oct 30, 2008 7:46 pm

the most important thing to remember is to get it balanced again after it has been lightened, quite alot of meat can be removed safely, well mine is at 7000rpm

got a pic somewhere and the measurments give me a couple of seconds

Post Thu Oct 30, 2008 8:49 pm

Here you go

You can see how much can be removed from the standard one net to it.

Sorry i can't find my measurments at the minute

Post Thu Oct 30, 2008 9:03 pm

The amount of danger depends on what flywheel you are lightening, if you place a BMW flywheel next to a f*rd flywheel of the same era you will see exactly what I mean

This one that Iain did for me weighs less than 6kg

Post Fri Oct 31, 2008 10:27 am

The pics are helpful guys. Maggspower, has your lightened fly just had the raised edge turned down flush to the starter gear?

Post Fri Oct 31, 2008 9:13 pm

No, please bare with me here as ths is from memory

Imagine the flywheel has been taken down flush with the starter ring gear, then measure 20mm in towards the centre from the bottom of a tooth on the starter ring. This is where the cut starts at 90o into the wheel, towards the clutch side of the wheel as it where. This cut is 8mm deep, and removes all the material to the end of the chamfere shaped edge, the inner edge, of the weighted section of the fly.

That is very hard to explain

DanThe's pics are better than mine, but as the that particular fly was made by the same guy I reckon they are the same!! Top bloke is Iain

Hope that is of some help, and remember i was working from memory with the dimensions, but I will find them and correct them if they'r wrong!!

cheers maggs