coil testing
Fleet Owner
Joined: Sep 2005
Posts: 28,609
Likes: 18
From: Lake Tahoe, Nevada
OK, here is a primitive but effective coil test. All you need are a couple of test wires.
Disconnect the primary ignition wires. Using a clip wire, connect the +side of the coil to 12volts + Then ground your other clip wire. Ground the coil wire that normally goes into the distributor cap and pull it loose from the coil. Now, hold the coil wire about a half inch from the top of the coil where it plugs in. Then using the grounded clip wire, tap the -(minus) terminal of the coil. Repeat several times. If the coil is good you should be getting a spark jump from the coil to the grounded coil wire.
Do not connect the ground wire to the coil minus terminal, just tap. (If you leave it connected you can burn up the primary winding in the coil.)
There are a number of high output coils around. Any of the name brands like Mallory or Accel are great. (Parts houses usually have good ones that are a little cheaper.) Usually you won't get any real benefit from them unless you are turning ultra high rpms. Not likely from an older 351. If you do upgrade, get a set of tailored (Not the finish making them yourself kind,) high quality plug wires installed at the same time.
Disconnect the primary ignition wires. Using a clip wire, connect the +side of the coil to 12volts + Then ground your other clip wire. Ground the coil wire that normally goes into the distributor cap and pull it loose from the coil. Now, hold the coil wire about a half inch from the top of the coil where it plugs in. Then using the grounded clip wire, tap the -(minus) terminal of the coil. Repeat several times. If the coil is good you should be getting a spark jump from the coil to the grounded coil wire.
Do not connect the ground wire to the coil minus terminal, just tap. (If you leave it connected you can burn up the primary winding in the coil.)
There are a number of high output coils around. Any of the name brands like Mallory or Accel are great. (Parts houses usually have good ones that are a little cheaper.) Usually you won't get any real benefit from them unless you are turning ultra high rpms. Not likely from an older 351. If you do upgrade, get a set of tailored (Not the finish making them yourself kind,) high quality plug wires installed at the same time.
