Staghound ignition coils and ballast resistors
 

We have a Staghound on loan. One ignition coil is bad. Probably because the coil has only 2.4 ohms primary resistance and no ballast resistor in series so it was drawing 10 amps from the 24V supply when the points were closed. This causes the coil to run really hot and the points to pit badly. These coils must have originally had a ballast resistor or high internal resistance to reduce coil primary current to 3 or 4 amps. But the manual I have (TM 9-741) makes no reference to a resistor in series with the coil. Can anyone tell me what coils and resistors they are running in their Staghounds?
Thanks,
Malcolm

the G122 parts book refers to "coil, with resistor unit and terminal screw" but no illustration. The coil number is DR 1115280, B244231. That is all I can add.

Hi, Brian,
Yes, the coil that went bad was a 1115280. But it does not have the integral ballast resistor unit described in the description you gave, or any means of attaching that unit.
I have temporarily borrowed one of the coils off our Chaffee which looks identical except it has a 6 ohm ballast resistor and heat shield bolted to the bottom of the coil, which sounds like what the 1115280 should have had. Anyway, it's exactly what I need to get the primary current down to a reasonable level.

Just to confuse me, I noticed the Chaffee coil was a 115821. So I was a bit surprised to find the coil spec'd for the Chaffee is a 1115282.

As an aside, I was puzzled by these coils. Unlike every other coil I have tested, where the secondary coil grounds to the negative primary terminal, these coils ground to the case. While searching the 1115280 number, I found an old army bulletin explaining that Delco Remy grounded the secondary coil to the case in a few coils, including this one, because they figured it reduced radio interference. Live and learn.
Malcolm
PS if you have any Chaffee coils please email me. :)

Stag' fixes
 

An earlier reanimation project on that vehicle was conducted by Len ???? at Lentech Automatics, auto repair shop in Richmond, Ontario. Phone (613) 838-5390

I only know this because about 12-15 yrs ago, I met some Dragoons at his shop who were working on their vehicle with Len and his mechanics.

The mystery is explained by the photo below Reg Hodgson sent me of his restored Staghound. The ballast resistor is mounted on the +ve terminal stud of the coil as shown and could easily go missing during maintenance/restoration like it did in our case, whereas the Chaffee resistor is permanently mounted on the bottom of the coil.

Attachment 105518

we have actually found 6 volt coils (marked on the box with wax-wrapped coil inside)in our stock and 24v coils with the round resister drop for the 24 supply to the coils. Coil resistances are different. We are making the screw-in 10-32 brass fitting for the coil wire to insert into the top of the coil.

Stag coils
 

I believe I have some NOS staghound coils with the ballast resistor attached in stock. May also have some takeoffs. Tons of GMC 270 engine parts.
Los of parts left over from a juts about complete T17E1 we are finishing up....
most of the drive line parts and kits and seals, some hull parts, some interior electrical boxes and spares boxes, lots of braided brass electrical conduit and all the Amphenol connectos for the internal wiring. 505-269-2056