ALFAGTV6.COM

JJ,

You're reading me right.....its likely that all reciprocating parts were balanced by themselves to a predetermined (by testing) specification and then assembled at a later time.

Mats,

I have no idea why shrink is expressed the way it is. I do know that most patternmaking used to be (and still is) done with a "shrink rule" . Its a tool that looks like a standard ruler (or scale), but is graduated to take into account the specified shrink, ie. quarter inch per foot....the 24in shrink rule would measure 24.5in long, but would be numbered to 24in.

Looking at the Starrett catalog (I think the only company still making shrink rules) they offer 10 different shrinks on 12 and 24in rules.

Scott

Since this is related topic...

24v engine and 12v flywheel will be assembled in my Milano (3.0). I suppose I'll have to lighten 12v flywheel and balance it to 24v flywheel specs (24v flywheel is lighter)?

What to do with second (gearbox) flywheel, will it be in disbalance then?

I'm looking for cheaper solution, since I don't want to take engine apart.

Killaz-
The rear flywheel (gearbox flywheel) is a zero balanced unit. If you get your engine's lower end balanced, you shouldnt have any more problems. The gearbox would be fine as it is right now.
-James

I was talking to Dan Marvin of Norman Racing a few years ago about lightening my rear Alfetta flywheel. He said that he's seen premature donut failure when the rear flywheel is lightened without lightening the front. I don't know if the reverse is true.

So even though everything is balanced, there seems to be some problems if the rear and front have some weight discrepancies. Maybe if one end can speed up faster than the other? Or cause more of a drag to speeding up than the other?

I took the flywheel from my '83 GTV-6 and turned it on a brake lathe. I figured that by the time I was done I had easily removed 3-4 lbs from it. I had it checked and there wasn't any problem as I had removed the same amount all the way around. It was still balanced close enough for "government work". That 2.5 regularly saw at least 8 grand and I even ran it as far as 9400 rpm during an auto cross.(tell tale tach) The engine is still going strong after at least 10 years of VERY hard abusive running. The guy that bought it from the guy I sold it to says that she'll still run 140 mph with no problems. I would think that if the balance was that off it would have destroyed itself a long time ago.

Paul

Are you sure you had the 2.5 engine running up to 9400rpm on stock internals? Even once?

Those are metric RPMs, its about 5840 imperial RPM