Military Spark Plug Wire Timing Adapter Modification Info

[David Zelinski]

Good morning everyone,

For anyone using the OE Mil Spec Test Adapter Kit (4910-348-7600) with the OE shielded spark plug wires to set timing on their M-715, you will find that the adapter is too short to use a modern civilian timing light. The pick up clamp won't fit due to the close proximity of all the plug wires on the distributor tower.

Step 1- Desolder the flat end plates from both sides of the connections on the old adapter. Don't lose the tiny flat plates, you will need them. They are the contact points when installing.

Step 2- Get yer' self some 7mm COPPER CORE spark plug wire. I used new ACCEL. 7 mm is what you need. 8mm is a little too snug to slide the adapter shell ends over the plug wire jacketing.

IMPORTANT NOTE! COPPER CORE plug wire only. You can't solder to graphite, carbon or shielded spiral wound new fangled plug wires! It HAS to be pure copper core.

Step 3- Install all the adapter shells and "guts" in correct order on the new spark plug wire. You won't be able to install it all if you solder the flat discs on first.

Step 4- Cut the new UNSHIELDED copper core plug wire to required length and strip some jacketing exposing the copper core. Carefully thread the copper center core through the hole in the center of the small disk and then fan out the individual strands of wire. Solder the wire strands to the discs.

Step 5- Once the solder joints are cool to the touch (matter of seconds if you are a good solder tech. "The bigger the blob the better the job" is not what you are after here), trim off any over hanging individual strands of soldered wire from the contact discs and assemble the connectors.

Step 6- remove the 1/4-20 piercing test hook up screw. If you don't, you will knock yer'self on your buttocks if you touch it while the engine is running!!!!!

Step 7- replace the piecing test hook up screw with a small 1/4-20 round head screw. It has to be a round head in order for the connector to clear the other plug wire connectors when you install it. You need this screw to keep the wire correctly in the distributor tower. It just snuggly fits to the plug wire jacket to keep the connector and plug wire from moving, but NOT breaking the wire jacket.

Step 8- Test your solder connections by using a multimeter on ohms. Since you are using copper wire, you should read about 1 or less ohms. I don't own a Valhalla or a Wheatstone Bridge so I couldn't test down to milli or micro ohms accurately enough.

Step 9- Sit back, ogle your handiwork and celebrate by timing that 230 Tornado beast

Here is a picture of my contraption after modifying:



The full MIl Spec test kit info is:

Adapter Set
4910-348-7600
Dwg. # A7541281

Allen Electric and Equipment Co., Kalamazoo, MI.
Contract # DA-11-022-AMC-035502(W)

Test adapter in question is "High Tension Adapter" 4910-356-7504

Dave
(W4CPO)

[rboltz]

Never had problems with the original length. I'm confused. The kit was made for all the "M" series igniters and other electrical issues and seems OK.

[David Zelinski]

HHHmmmmmm. Maybe my kit adapter had a short length then? Someone cut it shorter to hide a issue? I dunno. Thanks for the great info on yours being all good.

Now I'm confused, amused and quizical

Dave-