Distributor gear

> I'm unable to get the holes for the split pins to line up with the holes
> in the distributor shaft.

If you do get them to line up it's just luck. The procedure is to drill
a new hole. Here are the Ford Motorsport distributor gear installation
instructions:

http://www.bacomatic.org/gallery/album24/FordInstShtM_12390_ABCDEFGH

Dimensions for gear placement:

http://www.bacomatic.org/gallery/album24/OHOnews18of38

> I've ordered 2 so far (One from Crane, one from Ford Motorsports)

Did the one from Ford have a hole drilled. Their instructions say
they come undrilled.

Dan Jones

Dan,
Thanks for the reply. I guess I'm just spoiled by plug and play technology. I noticed your instructions are for the M-12390 A-H gear. Mine is a M-12390 J. This gear was pre-drilled. Actually it has 2 sets of holes at different heights above the gear. Wouldn't drilling out the hole in the gear, essentially elongating it, allow the gear to rotate on the shaft? Would you go with a solid pin or drill it out for a larger roll pin?
I was reading through the instructions and on Step * it has you drill a new hole "through the gear and shaft 90 degrees from the original hole in the shaft". This seems peculiar. Why would they do this and not use the original hole or are they expecting the original hole wouldn't be usable?

Mark,

I used to recommend inserting a smaller roll pin inside the original roll pin. However I have been recently educated on the existance of a heavy duty "coiled" roll pin, this has become my new recommendation (see the picture below). You can find them at McMaster - Carr Supply Company. Their web site:

http://www.mcmaster.com

You'll find them in the fastening & sealing category, or do a search, McMaster refers to them as "coiled spring pins".

Locating the dizzy gear on the shaft is a fairly critical step necessary to properly positioin the moving parts inside the distributor in relation to the stationary parts. Due to the design of the drive gear cut on the camshaft and the mating gear on the distributor shaft, the distributor shaft pulls downward when the motor is running, trying to pull the shaft out through the bottom of the distributor. The gear rides downward and rests against the block casting where the distributor shaft guide hole is located, acting as a thrusting surface. If the gear is located too high or too low on the shaft, it can result in parts attached to the rotating shaft hitting stationary parts inside the distributor.

Since an aftermarket gear manufacturer has no control over whose distributor the gear will be mounted on, it is safer for them to leave the hole undrilled and to let the engine builder hand fit the parts.

cowboy from hell

George,
Thanks for the reply.
Since the engine is assembled and in my amateur hands, is there anything I can do? I have the instructions from Dan which gives dimensions for gear placement. Should this be enough?

Mark,

The Ford instructions are better than nothing. Follow the instructions, install the distributor, check the shaft for the presence of up and down play and freedom from binding, leave the cap off, turn the crank by hand 2 revolutions checking for any interference problems inside the distributor. If none found, crank the motor with the starter once again listening for the sounds of "destruction" coming from within the dizzy. So far so good, then put the cap on & start it up.

In other words,proceed cautiously.

cowboy from hell