091 coil

[Jack H.]

Re: 091 coil

Remember, the act of measuring/confirming primary and secondary winding resistance is a necessary but NOT sufficient test for coil operability.

All you do when you measure resistance is confirm the transformer's (an ignition coil is a transformer) primary and secondary windings are intact. That tells you NOTHING about the health of the transformer's core lamination(s) which are what transfers energy from the primary to secondary windings...

[Ted S.]

Re: 091 coil

Jack, so other than buying NOS how do you know you're not buying a piece of junk? With the price of 091s these days it could add up quickly.

[Dave S.]

Re: 091 coil

Jack, so other than buying NOS how do you know you're not buying a piece of junk? With the price of 091s these days it could add up quickly.

Ted,
In simple terms the only way to test a coil is to put it on a running car and let it heat up to operating temperature and run it for awhile. If it performs under those circumstances then the coil is good.

[John D.]

Re: 091 coil

63 Shop manual. Specifications 14-5.
091 Coil.
Application: All (???)
Primary Resistance-Ohms 1.02-1.13
Secondary Resistance-Ohms 8000-10,500
Ignition Resistor Ballast.
Resistance-Ohms of the IR = 1.4-1.62.
As typical the 63 shop manual has incomplete info and totally disregards the 087 coil and the D1110 BR.
I have been reading this 091 post the whole way thru. If it were my car I wouldn't be experimenting with oils in the fried coil. I would be putting a good SR coil on the car and putting the bad one on the shelf in hopes that some day it could be properly restored.
Temporarily I would install a nice NOS 087 or 202 which are readily available on ebay for about 125 or so and take the hit. Or a good used one. Ever see what the damage is when a coil explodes??? It's scary. My friend sent me a pic of his 57 engine compartment when an SR coil blew up. Hinckley know who I am talking about as the guy lives in his 'hood. JD