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MSD Ignition Conversion

PegCity

PegCity

New member
Has anyone installed one on a 1972 100 HP ? The 72 doesn't have points it has a Sensor #0385008. My Sierra Pulsar power pack/amplifier/pulse pack or whatever they are called, failed. Couldn't finmd one on ebay so researched the MSD solution and went with that. ( 100 bucks for MSD6AL and Blaster Power Pack /Coil - 16 bucks for MSD Ballast Resistor)


My problem is I need to find out if the sensor is an on/off type or just slight change in voltage. I read 5.2 Ohms across the sensor ( stationary ) which is within the 4 to 6 Ohms that was cited on a thread. I also read 5.1 to 5.2 changes as the Rotor Distributor Sensor #316459 cycled past the Sensor ( manual cranking ).

The MSD6AL and Blaster power pack ( coil ), complete with a Ballast resistor provides spark to coil when I short out the MSD magnetic pickup wires, which is a simple test.

The MSD pick up wires connect to Sensor #0385008 via 2 black white wires in the Distributor base plate. I confirmed that the MSD requires this output in order to fire the coil - which we proved by shorting out the MSD magnetic pick up wires .

My question is, does my problem lie with Sensor #0385008 and it's not functioning properly.

It is either a bad sensor not opening and closing , where I would read 5.2 and zero as the Distributor sensor cycles OR it is working properly and the slight variations of .1 ohm, was good enough for the OEM pulse packs but not for the MSD.



Some specs I gleaned while reading.

OEM - 220 V at amplifier to coil - 22000 V out of coil to spark.

MSD - 475 V at amplifier to coil - 45000 V MAX out of coil to spark.

Ballast resistor - should drop to 25000V out of coil to spark.




Issues I read about in similar conversions


Discrepancies and Confusion when reading Forums and others experiences - Some people use 2 coils and ground one of them to reduce voltage out of coil. Some people say the MSD unit will only put out based on engine configuration / compression, gaps etc and doesn't require a resistor or extra coil. ( which makes sense but I'll use the ballast resistor anyways. )

Reverse Cutoff Spring and Sensor caused a no spark situation when it was found the spring was touching the grounded distributor base plate.

One person went from magnetic pickup back to points and had success.

Thanks in advance. pictures and setup to follow.


NOTE - When shorting magnetic pick up cables to test MSD setup - DO NOT HOLD the Coil spark cable -------lol, good zap lesson.

Liv
 
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The setup I am using is fairly cheap and MSD parts are widely available. The only thing stock is the Distributor sensor and Sensor itself. I have read where others changed the sensor, can't recall the name, but they had to machine it to fit . Don't have that kind of equipment so if I can keep it stock I can still find those parts.
 
Was doing more reading and I think I just got what you said. I don't have to change anything on the distributor , I just add the HEI in the circuit and I should be able to change the square wave to a sine wave. I was thinking I had to get it in the distributor, lol, shaving it , machine it. I just hook it up to the existing sensor pickups + and - side.

Gonna give it a try.
 
kimcrwbr1 said:
http://www.marineengine.com/newparts/part_details.php?pnum=OMC0316459
OMC reluctor
http://www.ebay.com/itm/Ignition-Re...Parts_Accessories&hash=item462787521c&vxp=mtr
Ford reluctor. I am wondering if you can just file the OMC reluctor points narrower to achieve the proper signal for the MSD module. Possibly clean up the sine pulse going through the pickup coil. there is no posative or negative you can have the wires either way on the pickup coil in the distributor.
Click to expand...



The 72 Johnson 100ESL72 was only made with sensor and the rotor in your posted part. Problem is the sensor is outputting a square and the MSD is looking or a sine. Converting to points is an option but am being stubborn abut it
 
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