When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Well, that is interesting. I looked in an auto electrical book and it said 20k on primariy coils then I measured a brand new 6v coil from autozone (oil filled) and it measured 20k also. Old coils must be lower on the primary. I wanted to keep it because it looks cool, kinda like a tin can.
Now I'm interested. I just checked the ancient 6V coil on my 50. I do not know the exact age but it is a metal can with BATT and DIST on top. The secondary was at 4.38K.
Checked a replacement (new) Standard UC 14 - 6 volt replacement coil and got about 9.3K.
All I can say for sure is that the coil with 4.38K in the secondary is working fine on the truck.
Both were at about 1.1 ohms (not K) in the primary at about 60 degrees.
Last edited by jb50F1; Oct 21, 2011 at 04:01 PM.
Reason: add primary readings
The old coils were oil filled....with PCB oil (poly-chlorinated-biphenyl). That stuff is considered pretty toxic, but it has the right dielectric properties between the primary and secondary windings. Wash your hands after handling coils!
I'm not sure if the newer coils use something that is more politically correct.
If the resistance measurements are out of limits, I'd consider getting another. Just to be sure...the primary measurement is between the two threaded terminals (marked "batt" and "dist"), and the secondary measurement is between the center high tension lead connection and the threaded terminal marked "dist". Sometimes there is corrosion in the center high tension connection, so clean that up before measuring.
My new 6v coil sounds like it is full of a thin liquid, not the vis. of engine motor oil. Old coil makes no shound when shaken but is in spec 5K on the secondary. New coil is 20K(like most modern cars) on secondary. Wish I could find an exact replacement.
I'd take a close look at the parts that start with "IC" for ignition coil. IC7 seems like a good fit. I couldn't find the specs on it, but it is somewhat application specific for the year model.
You can use the Napa website to try by application (year, make, model), then use the pdf to see a picture of the part once you know the number. The layout doesn't lend itself to a keyword search.
You can also just flip through the pictures by section to zero on on what you need. The items are grouped by category and most of the part numbers have a prefix (like "IC" for ignition coil) that actually means something. The coil was pretty easy to find because their applications also are grouped by year...oldest first, so the old 6V coils were right up front in the coil section.