1952 M38 CDN coil question

Lyle · Post by **Lyle** » Fri Nov 01, 2019 2:19 pm

Im asking for help as I can’t locate the pages with information on how to test the ignition coil. Looking for values.

Thx.

Brumbach · Post by **Brumbach** » Fri Nov 01, 2019 7:07 pm

I believe it's 6.2 primary and 10k secondary.

Lyle · Post by **Lyle** » Fri Nov 01, 2019 7:22 pm

Primary with all disconnected - 12.3 ohms
+ term to high voltage - infinite
- term to high voltage - infinite
high voltage to case - infinite
+ term to case - infinite
- term to case - infinite

my guess its bad ...... anyone?

Post by **wesk** » Fri Nov 01, 2019 10:02 pm

These test should be conducted on both a cold and hot coil. I start with the cold check then using a heat gun or hair dryer on the coil until it is uncomfortable to touch then remeasure.

Keep in mind bad grounds, corroded connections can easily distort your test results.

There are official tests which do the needed checks by actually loading the coil. This needs the proper tester.

This page is from TM 9-1825B dated 1952.

The above photos are all in my photo album on the first page of Member's Albums. They are in my Ignition System sub-album on my 2nd page.

Below are testers & adapters you should acquire if you intend to service your electrical and ignition systems:

I havge to find my photo file for this tester. If not I'll take another set of photos in the morning.

All the above photos have their larger files and remaining photos in my albums.

Lyle · Post by **Lyle** » Thu Jan 30, 2020 8:59 pm

New coil is within spec. However i experienced misfire on every cylinder then engine died. Running MV 141a Pertronix. After calling Pertronix 2 tier support I found after zeroing the meter that while cold there was a a 0.2 ohm resistance between points plate and negative of battery; hot was 2.0 ohms. After running a separate ground from distributor cap screw to the battery negative no more resistance. Engine runs perfectly.

Post by **wesk** » Thu Jan 30, 2020 11:16 pm

Just a wild guess, are your two metal vent tubes connected to your distributor? Are you using the shielded water proof spark plug leads?

Lyle · Post by **Lyle** » Tue Mar 15, 2022 1:15 pm

Wes,

I’m using the complete 24 volt waterproof system. The complete Distributor is brand new Nos. And yes both ports are connected as per underwater venting instructions.