From: Carl Byrns <oxygen1@concentric.net>
Newsgroups: rec.crafts.metalworking
Subject: Re: Balance engine flywheel.
Date: 16 Sep 2000 03:44:21 GMT

Karl Townsend wrote:
>
> "The Kid", my 17 year old, is rebuilding a vintage 'stang. He's putting a
> new high performance 302 Crate engine in it. Somewhere in the last 25 years,
> Ford changed the firing order and hence the proper counter balance for the
> flywheel. We found out the hard way that the new flywheel has 164 teeth and
> doesn't fit where a standard 157 tooth wheel was used. Ain't no such thing
> as a 157 tooth wheel balanced for a '2000 engine.
>
> Anyway, need to rebalance the old flywheel. My thoughts are to turn out a
> piece of scrap in the lathe to make a center mandrel, clamp an ice pick in
> the vice, place the new flywheel on top with the center mandrel, find out
> exactly how much weight it takes to make it set level. I'd then use this
> weight on the old flywheel as the counter balance and add weight until it
> sits level.
>
> Any suggestions or comments?
>
> Karl Townsend
> in Dassel MN
>
> P.S. After we do this, we found out standard headers don't fit. Get to make
> custom ones. Brackets for alternator, fan,  and power steering don't fit.
> Get to make custom ones. Radiator won't fit. Get to make custom one. I know
> there will be more.

Karl-
Here's a quote from Clutch and Flywheel Handbook by Tom Monroe (HP
Books):

<<ZERO BALANCE AND DETROIT BALANCE
The engine a flywheel is used with determines how it is balanced.
For instance, engines are either balanced internally or externally.
Flywheels used with internally balanced engines are zero balanced.

This means a flywheel and engine are in balance whether they are
together or not. It also means the zero-balanced flywheel can be indexed
on the crankshaft in any position without affecting the balance of the
whole assembly.

The Detroit-balanced flywheel is a different ball game altogether. It
mates up with the externally balanced engine to provide a balanced
engine assembly. When the two are apart they are both out of balance,
but together, they are in balance, providing the flywheel is indexed
correctly on the crankshaft. Externally balanced engines use dowel pins
with a companion hole in the flywheel to ensure proper indexing.>>

I would add that a Detroit-balanced flywheel might not be pinned. Ford
used an offset bolt pattern on the crankshaft instead of pinning.
Older small-block Fords are externally balanced. I'm not sure about the
later ones.
If your new engine is Detroit-balanced, then the only choice is to take
the crank and flexplate to a good balance shop.

I note that you intend to use a C5 with this engine. I would recommend
against it- the C5 is nothing more than a C4 with a lockup convertor. It
is a light duty box, used mostly with 4 and 6 cylinder engines.
I'd go with a four speed AOD (Automatic Over Drive) box instead. They're
cheap and hell for leather strong. They were used in late 1980's full
size cars- Crown Vic, Grand Marquis, and Lincoln Town Car, as well as
some pickups and vans.

Regards- Carl