Jim,
Yes, Tom Hall is the tach coordinator.. Us Electrical
Engineers have the design completed, we are just waiting
for the Mechanical Engineers to finish the printed
circuit board! ;-) TOM!!!
For your MOMA problem you might try these ideas:
DISCLAIMER: I have never seen a MOMA and can only guess
as to what is wrong, there is a small possiblity this
may blow their circuitry, use at your own risk.
1. Try a capacitor in series with the pickup lead that
goes to the coil. I would try a .1uf or if that
doesn't do it, try 1uf.
2. Since you have (I hope) an insulating wood dasboard,
you could put a diode in series with the black ground
wire. I would use a silicon diode 1N914 or 1N4001 type.
They are polorized, the marked end would go to the black
wire, the other end to the tach case. Make sure there
are no other grounds going to the tach case.
3. You may be able to fix it by just providing better
grounding to the distributor. Maybe run a separate
ground wire from the distributer to the tach case.
OR, you could go back to points and see if that will fix
it (temporary only, to give me more data).
I think the problem is that the Pertronix doesn't go as
close to ground (has higher resistance) and the MOMA
circuit is too sensitive to this (it's trigger voltage
is too close to ground). MOMA should fix their
circuitry.
Failing to fix it with any of these ideas, you could
wait for our new improved circuit. It will allow you to
go back to current triggered so you don't need that
extra wire to the coil. I works great with my Pertronix
in my stock car.. as well as voltage triggered by my MSD
in my other car.
Gary
> To refresh everybody's' memory, here is my problem (which I believe several
> others also have): I have a tach built by MOMA. It does not use the white
> loop wire of the stock tach, but rather has a single wire which attaches to
> one side of the coil. (I must confess I'm rather ignorant on how exactly it
> works.) I use the Pertronix Igniter on an otherwise stock single-point
> setup. The tach works fine to about 3000 rpm. Above 3000 rpm, the needle
> starts to fall back to zero. It continues to fall until the actual revs
> fall back below 3000. I have returned the tach to MOMA, who checked it over
> and claim it works fine. They included some resistors to add in series
> between the tach and coil, but the tach doesn't work at all with this
> arrangement.
>
> Some time back, I thought a group was working on a modern accurate tach
> innards for a stock tach. I wondered if any progress has been made.
>
> Has anybody else encountered and solved this problem?
>
> Jim Pickard
>
> -----Original Message-----
> From: Sjhcobra1@cs.com [mailto:Sjhcobra1@cs.com]
> Sent: Wednesday, February 20, 2002 8:40 PM
> To: geowiz@cox-internet.com
> Subject: Re: tach
>
>
> What problems did you have? I've had Pertronix in my stock 260 Mk1A for
> about 3 years and 10,000 miles with no issues.
>
> Steve Halbrook
> B382001208
> B382100572
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