V6 - lightened flywheel?

As far as I understand (which isnt very!!) if you lighten the flywheel then chances are the idle will become uneven. My bro's mate has a an R1 bike engined Caterham with a very light flywheel and he says it’s a nightmare in traffic and very easy to stall.. but ruddy good on the track!!

Yes very light flywheels are a complete pain on the road.

The momentum of the flywheel is what stops the engine decelerating between each cylinder firing.. So with a light flywheel, pulling away with no gas means you have hardly any momentum in the engine, and very likely you will stall it.

Originally Posted by strat24v

So, the theory for lightening the flywheel would be to remove an equal amount of material all the way round but without disturbing the area of counterbalance?, at the same time making sure that the thing won't grenade itself?

Any engineers out there care to comment on the best way? Maybe a series of holes around the perimeter or thinning the outer area?

John.

Sticking it on a lathe would be the most obvious thing to do I think... if you know someone with access to a machine shop, it'd probably only take an hour or so to setup/machine/finish/clear up.

If you really want to go down the route of a lightened fly wheel on a 2.5 or 3.0 V6 (which probably has a big ass DMF) then a swap to a GTA FW is the best option IMHO.

Although i havn't read the links, heres to disspell the myths....
the Alfa V6 is EXTERNALLY balanced! To those of you out there with multiple spares from various engines, compare the flywheels and front pulleys for there counterbalances! There WILL be subtle differences!

To convert my 24v 164 engine to RWD for my 75, i needed to swap the 164 flywheel for my 75 item....
The 75 'wheel was lightened considerably with total disssregard to its balance factor..
The balance factor for the 164 'wheel was measured then applied (by machining) to the 75 item.
This little lot cost me a cool £395! why bother with the hastle when an alloy version is available for not alot extra? simple, my cars primary use is for the road! Alloy is too light

Just a thought, before i get flamed for my previous post, i will weigh my flywheel (yes the lightened one!) when i remove my engine again in the next couple of weeks.
The other allternative to the balance solution is to remove the whole crank with pistons assy an have it all balanced together as a unit (inc pulley and flywheel) which costs the same as my flywheel job alone but then you have the cost of a gasket kit minimum on top

Originally Posted by alfaspence

Although i havn't read the links, heres to disspell the myths....
the Alfa V6 is EXTERNALLY balanced! To those of you out there with multiple spares from various engines, compare the flywheels and front pulleys for there counterbalances! There WILL be subtle differences!

To convert my 24v 164 engine to RWD for my 75, i needed to swap the 164 flywheel for my 75 item....
The 75 'wheel was lightened considerably with total disssregard to its balance factor..
The balance factor for the 164 'wheel was measured then applied (by machining) to the 75 item.
This little lot cost me a cool £395! why bother with the hastle when an alloy version is available for not alot extra? simple, my cars primary use is for the road! Alloy is too light

DUDE !!!!!!!!!!!!!

Trackstar and I have been saying this for years.

It was actually Tim (trackstar) who brought my attention to this issue but no-one's listening.....

Even the aux pull is ballanced to the crank....

anyone seen a DMF explode?....

You can see the counterbalance in the rear face of the flywheel and front face of the belt pulley.

One of the Chaps on the Stratos forums has clocked his 24v alfa flywheel up on a milling machine, and while taking into account the counterbalance area, removed an equally spaced set of holes all round. The car has run fine for sometime i believe. I'll try and locate the pics he posted.

John.

Originally Posted by Chris155

anyone seen a DMF explode?....

Have heard of it but never seen it or photo's of it happening..

Originally Posted by Chris155

but no-one's listening.....

No one ever does when it comes to Alfa's or indeed the car world in general

Too much secrecy, ego, and "i know everything" or plain denyal going on

Not to mention, vested interest!

Originally Posted by frozennorth

Not to mention, vested interest!

well there is that too

Have i disspelled the myth tho

Originally Posted by Pud237

Have heard of it but never seen it or photo's of it happening..

I can imagine it'd rip through the car like paper, I think I saw a picture on Pistonheads of the aftermath if this happening once.

Kinda like when a Grinding wheel goes bang, killer!!!