Barry / Dave -
BN2s don't have a harmonic balancer, they just have a
pulley. Part of the reason the cranks break at the
2nd bearing from time to time.
Late BJ8s are the only healey that has the harmonic
balancer attached to a rim which is a cast part of the
pulley... this means the round dimple, which is
drilled into the face of the harmonic balancer (not
the pulley), and sometimes on the edge of the
balancer, can in fact shift position over time because
it is attached to the pulley with a rubber vibration
ring. To be honest you don't ever want to be taking a
timing measure off of this round dimple.
There should be a little notch cut into the edge of
the pulley itself, that should be the only thing you
take a timing measure from. It is hard to see, but
with enough light and patience you will find it.
I hope that is clear. Please write back if you have
more questions.
Regards,
Alan
'53 BN1 '64 BJ8
--- Dave & Marlene <rusd@velocitus.net> wrote:
> Hi Guys,
>
> My front pulley also has a small dimple to indicate
> TDC.
>
> I can't imagine that a "small round dimple" would
> have much effect on
> balance. It would weigh about .026 gm. At a radius
> of three inches this
> would be about .0023 oz/inches. The balance
> tolerance for very serious race
> engines turning 9,000 rpm is only .02 oz/inches. The
> effect of the
> dimple would only be about 1/9 of what the balancer
> could detect.
>
> Dave Russell
> BN2
>
>
> Blue One Hundred wrote:
> > Barry -
> >
> > That round dimple is what the machinist does to
> the harmonic balancer
> > to balance it. It has no relation to TDC.
> >
> > I am very suprised that your pulley does not have
> a notch in it. It
> > is very small and hard to see... try looking for
> it with ALOT of
> > light in the engine compartment, rotating the
> motor either with a big
> > wrench on the dog nut, or putting the car in 3rd
> or 4th gear and
> > rolling it on the floor bit by bit... which
> should rotate the motor
> > till you see the notch.
> >
> > I'm sure the notch is there... it's just hard to
> see. Mark it with
> > paint when you find it.
> >
> > Regards,
> >
> > Alan
> >
> > '53 BN1 '64 BJ8
|