'72 D22 413 ~new ingition coil

[The_Handier_Man1]

From: mjswin  (Original Message)
Sent: 10/16/2006 6:52 AM

It seems the ignition coil in my 72 D22 has failed. I removed the coil wire from the distributor cap and turned the ingnition while I touched the wire to the metal rim lining the hole in the floor cut for the engine. This test produced intmittent spark which didn't appear strong to me. Since it was the first time I'd run this test I asked a friend to view it. My friend stated "that isn't much spark". Then he touched the coil housing and said, "wow, that's hot".

My questions:
1. Any other tests to make sure the coil is the problem?
2. When describing my 413 to a parts store, are there any more common vehicles I can mention beside Winnebago which would get me the right part.
3.Any tips, or big challenges I'll face, for installing a new coil in my D22.



From: denisondc
Sent: 10/16/2006 9:06 AM

You can tell the parts place that you have a 1972 dodge pickup truck with a 318 or a 440. I think they both take the same ignition coil. Most auto parts places wont have a listing for trucks of one ton and more capacity (which your motorhome chassis is). The 413-1 in your motorhome is the industrial version of the 413(no dash) that went into the Chryler/Dodge passenger cars in the mid to late 60s. The one in your motorhome has more water passages from the block to the engine head, better valves, a different water pump and larger water pump housing, a different thermostat from what the cars, pickups and vans took, a lower compression ratio and a camshaft suitable for a truck. (Lots of torque at moderate engine speeds). Also a different advance curve for the distributor.
To find parts for a 413-1 you will need to seek a place that supplies parts for light trucks, like delivery trucks, or to find a NAPA outlet that was willing to look in their hard copy listings, and not give up when parts for a scarce 34 year old truck chassis don’t appear in their computer.
It is possible your ignition coil is okay, and that someone has messed with the wiring that connects the ignition resistor in series with the coil The ignition resistor is at least as likely to fail as a coil. It is a white ceramic block about the size of a pack of chewing gum, with either two terminals, or if it’s a replacement, it might have 4 terminals of which you only need two with the ignition system that has points. The later ones that have electronic ignition use all 4 terminals of the ignition resistor.
It would be normal for a coil to be fairly warm, but it shouldn’t burn you when you touch it. And the ignition resistor should be warm too.
It would be a good idea to have a wiring diagram for the chassis, showing the wire sizes and color coding. It is in the dodge motor home service manual if you have one. This diagram only shows the wiring for the part of the RV that dodge made, not the wiring of the coach that Winnebago built on the chassis.
Dirty or pitted or badly adjusted ignition points will also result in a weak spark. Also a bad ignition condenser will result in weak spark. The ignition condenser is inside the distributor. There should be a wire from the swivel plate (where the ignition points mount) to the case of the distributor. This is to provide a good ground for the points â€" or you wont have much if any spark.
And a bad connection from the battery to the ignition switch will rob your spark of its health. You want to ensure your battery cables are not corroded, that the connection at the battery posts is clean (I use an exacto knife to scrape away the lead oxides on the post and the terminal). Also the ground cable connections are just as important as the positive cable connections. There needs to be a ground cable running from the frame to the case of the transmission â€" its an often overlooked cable, and often it is corroded or frayed.



From: denisondc
Sent: 10/16/2006 9:13 AM

A clarification. The ignition resistor should be warm if the engine has been running recently. It could get warm just by having the ignition on, but -Only If- the engine had stopped in a position where the points where closed. This varies from engine to engine.
After an engine is broken in it will always stop close to the same crankshaft position each time; but it wont be the same position as different engines stop in.



From: mjswin
Sent: 10/16/2006 11:07 AM

The list of items of other items to check to check was exactly what I was looking for. I would guess many of the items you mentioned are less expensive that a new coil. I'll let you know how it turns out, but it might be a couple weeks before I have an update as I have is stored in a yard I only visit on the weekends.

Thanks,



From: jbmhotmail
Sent: 10/20/2006 9:06 PM

Try http://www.mymopar.com/coiltest.htm for info on a coil test.