Crab distrubtor ignition advance

[Rudolph]

The rotation of the points plate sets the initial advance of the ignition the same way as it dose with the pertronix moduel, if you slide the screw to the top of the slot it rerards the ignition and down is advance,

The problem with the pertronix is the plate is cast alloy and they take a bit of fettling to make to fit, and I stripped the screw for the advance adjustment as with the steel plate you can loosen the adjuster screw and push it with a screw driver.

I was talking to the agent who sells the Petronix kits and he sed he files the slot a bit for more adjustment in the advance, I moved the moduel slightly when I fitted it to the new plate, you can realy feel when your vacuum brake is working but the screw is too tight as under engine braking the exhaust note changes suddenly

 

[glennpm]

The rotation of the points plate sets the initial advance of the ignition the same way as it dose with the pertronix moduel, if you slide the screw to the top of the slot it rerards the ignition and down is advance,

The problem with the pertronix is the plate is cast alloy and they take a bit of fettling to make to fit, and I stripped the screw for the advance adjustment as with the steel plate you can loosen the adjuster screw and push it with a screw driver.

I was talking to the agent who sells the Petronix kits and he sed he files the slot a bit for more adjustment in the advance, I moved the moduel slightly when I fitted it to the new plate, you can realy feel when your vacuum brake is working but the screw is too tight as under engine braking the exhaust note changes suddenly

Thank you

 

[Rudolph]

I found a good way was to adjust the vacuum brake is at idol and when its at its happiest the idol will drop down, I cannot get the engine to ping adjusting it how the ford book says

 

[Rudolph]

I knocked back the timing by a cople degrees

 

[Rudolph]

I just put my distrubtor on the timing fixture to see how far off 4 degrees it was and where I have it set is bang on 4 degrees witch means the Petronix is set very retarded and it would need to be set to full advance to get 4 degrees on the sliding scale.

 

[glennpm]

I just put my distrubtor on the timing fixture to see how far off 4 degrees it was and where I have it set is bang on 4 degrees witch means the Petronix is set very retarded and it would need to be set too full advance to get 4 degrees on the sliding scale.

The Petronix is a Hall effect device. When the distributor lobe and correct gap to the Petronix has been set, the Petronix will open the circuit and the coil will discharge. The dwell set via a point system is part of the internal design of the Petronix.

You have mentioned a couple of times that the "Petronix is retarded". This is not part of the design. The initial 4° advance is static and based on the rotational position of the Petronix module on the points plate. If you couldn't advance the static position without lengthening the slot, the Petronix is rotated to far counter clockwise, CCW. The location on the plate should be set so the "Petronix switch" opens at 4° before TDC as the mid-point position on the distributor scale.