Mailing List flyrotary@lancaironline.net Message #38613
From: <Lehanover@aol.com>
Subject: Crank triggered ignition systems.
Date: Sat, 21 Jul 2007 10:54:52 EDT
To: <flyrotary@lancaironline.net>
I found the old front pulley with the crank trigger reluctor and degree wheel. The pulley is from a twin distributor engine. It has two sheaves if you want to use them. It has 4 bosses on the front drilled and tapped to mount a bigger set of sheet metal pulleys in the car.
 
The aluminum disc started slightly larger than the degree wheel. I lied about the nail for the reluctor. It is a 1/4" bolt. The nail was from a similar disc on the front of my Fiat race car. It worked great also.
 
NAPA used to sell replacement pickups without the advance plate attached for about $4.00.
 
I drilled out the brass rivets and moved the magnet and coil to the back side of the mounting bracket.
 
Use brass screws and nuts from the hobby shop to prevent shorting the flux field. I TIGed the mounting bracket to a plate with oversized mounting holes and big washers so I could move the pickup a bit to control timing and air gap to the reluctor wheel.
 
There were at least three control modules. Early 5 pin. Later they discovered that since it was bolted to the chassis, they could do away with one pin, because it was only a ground. So then it had 4 pins.
 
You cannot fool Chrysler engineers for very long.
 
 Then in 74 or 75 (fuel crisis) they made the module a multi spark unit,
and called it the "lean burn unit". They jetted the carbs so lean they would not start without this unit in place.
 
Motors manuals at the library have the wiring diagrams for all modules. The early module requires a two sided resister be included in the circuit. The later modules us just one resister. I used both the stock connector that is held into the module with a sheet metal screw, and individual push on round wire ends.
 
If you get this out of a junk car you can get it all for real cheap. You will be the only one looking at this old stuff. Buy it cheap, and play with it for a while, and if you like it, build one up with new parts.
 
Any way, you mount one pickup on each side of the disc. Each pickup runs on module (you need two). Each module powers one double ended coil with wires to both plugs in one housing. Both plugs fire at once, and no distributor is required.
 
You have to set the timing for both front and rear housings. So, for the rear housing, the timing light will be flashing at say 20 degrees before BBDC ( if your head is hurting, it really isn't BBDC in the rear housing. It is BTDC) and the front housing will flash at 20 degree BTDC.
 
For injection you will still have to mount your stock sensor wheel on the front of this rig, or run off of the gizmo in the distributor hole. (I forgot the name of that thing). Gap the plugs at .012". Good for 9,000 RPM  
 
There are two marks (grooves with black paint in them) one is TDC, one is at 20 degrees BTDC.
 
Lynn E. Hanover




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