1922 DB electrical questions.

[Guest Hockeye]

Hi again, fellas. I have a 22 DB tourer which came from an old museum, and which had not run in many years. (Yes, a sucker IS born every minute.)

It did not have a battery, as one might expect, and being the cautious fellow I claim to be, I first found a 1922 dated DB manual, which, SURPRISE, said the car is supposed to be NEGATIVE GROUND!

So I got a strong 12v battery and installed it. After some fuel system and other routine work the old girl started and runs very nicely, but....

When the ignition is on the ammeter shows about 4v on the CHARGE side, and stays right about there when running. It is connected, and moves slightly when the starter is run, lights flipped on and off, etc.

OK, but when the battery is removed the ammeter stays in about the same place. It does not center.

Worse than that, after running it around the block a few times the battery is pretty much DOWN.

I talked with a couple of knowledgable DB guys, but they had never heard of a DB with a negative ground.

I thought about reversing the polarity, as one fellow suggested, but think I will ask you guys.

I have a meter, but do not know how to check for charging out of the generator/starter.

What do you suggest???? This is a nice car.

Steve

[nearchoclatetown]

Rule of thumb is, if the horn button is on the door it's negative ground. On the steering wheel it's positive, factory locations. Sounds like you have a charging problem. The only electric that should be used to "drive around the block" is for the ignition, not much. You have a drain somewhere.

[dwollam]

Hi, I have a 22 also, among others, and it was originally negative ground. The DB generator does not care which way you have the polarity. Nearchoclatown is correct in what he said. I currently have mine hooked up positive ground as that happened to be the way I hooked up the wires on the ammeter! Also I run a mag so coil polarity is not a factor. I have several ammeters that are flaky and don't always read or read correctly. Sounds like a problem in the system to me as well. Generator probably not charging, could also be in the cutout on the floor.

Dave

[Jan Arnett]

If you disconncet the battery and the amp meter does not move then you have a problem with the amp meter. The wiring on this car is very easy to replace and is the safest way to go and it will eliminate any shorts in the wire. If when you disconnected the the battery you didn't get a spark you probably do not have a dead short. A healthy twelve volt battery should give you a good spark. Did you check your fuse on the generator to make sure it is clean and not blown. You could also have a bad ground except you said that it starts easy which usually will not happen with a bad ground. Try bypassing the old wire if that does not solve the problem then it is probably in the cutout as mentioned earlier or the iginition switch. You can reverse the polarity and the only result will be the points depositing material on the wrong side of the point pad. Don't get discouraged as the Dodge is easy to work on and very forgiving.

[Guest imported_RAH]

Steve,

Welcome to owners of Good ole' DBs. The guys are right in that the earlier DBs are Negative ground and after late '22 (steering wheel horn button) they switched to Positive ground. As they also said regardless of which way the battery is connected as soon as you step on the starter switch the fields will polarize to that system and the starter/generator will continue to operate in that mode. You state the ammeter is hanging off center with the battery disconnected? That would indicate a physical problem with the ammeter. Probably at some time there was a short on the system that 'peggged the meter' and left it out of alignment. The N/E combination unit will nearly always operate as a starter but charging is a whole different subject. There are several things that may be at fault. The 'third brush' and/or its spring could be worn and not making good connection. OR, if at some time someone fired up the engine without the battery connected to the generator it would have caused the field fuse to blow. And, if someone replaced said fuse with a piece of copper tubing (Yes I have seen this) there would have been smoke. All of which may have happened before you got the car. As to the battery going down after "going around the block a few times" I might ask as to the condition of the said battery? The starting of the engine will take an immediate drain and if the charging system is not functioning to replace that on a weak battery could cause it to run down.

Checking for charging could be done with a volt meter connected to the hot terminal on the battery. 12v with all systems off. After starting the engine and revving up to somewhere approximating 10 mph

the relay should kick in and you should read somewhat greater voltage possibly 14v. Revving way up will drop off as over 30 mph the output from the generator will self cancel.

I hope this helps.

Rodger "Dodger" Hartley