Ongoing problem 1946 v8
 

This has happened the last three times I have driven my 1939 truck. It has a 1946 v8 flathead engine. Each time I have the failure I replace another part.
I drive twenty miles, no issues - then motor starts to falter a little and maybe after about a mile of this, motor stops. I try to restart but battery is unable to turn motor over to have a chance to start. Call rollback! Change parts again!
Motor is 6 volt positive. Skip Haney coil. Tubman big brass condenser. New and gapped Auto lite 216 plugs. Rebuilt generator. Rebuilt starter. All new wiring. Crab distributor with new parts. Optima 6 volt battery. New battery cables with grounding spots checked and rechecked. New inside dash starting button. New voltage regulator. Can someone offer advice? Many Thanks from Tn.

Re: Ongoing problem 1946 v8
 

What you have not replaced is the ignition resistor as well as the ignition switch. Make sure wires are snug and terminals are clean. Take the ignition switch apart and clean it. also clean the ground cables and connections. Do you have to recharge the Optima battery is that why it doesn't crank or is the battery up to full charge??

Re: Ongoing problem 1946 v8
 

How old is the optima battery? That certainly not the answer to your problem but let's start (no pun intended ) there. I had a similar issue ended up being multiple things make sure your gas cap is venting correctly

Re: Ongoing problem 1946 v8
 

So you get it home and then what? Cools off and restarts?

Re: Ongoing problem 1946 v8
 

The first place I would start is "battery is unable to turn motor over to have a chance to start."

Re: Ongoing problem 1946 v8
 

small diameter battery cables off a 12 volt system will NOT carry the amperage required to start a hot 6 volt engine--not gonna do it!!

Re: Ongoing problem 1946 v8
 

Do this first. Check all the cables to the battery, and ground cables to the body and motor. Make sure all are clean and tight. if you have an old braided ground cable that shows signs of corrosion get a new proper sized ground cable. Next check the age of your battery. Optima's don't last forever. Also check the starter switch and cable. The problem could be somewhere in the charging system and you may be trying to run on a weak battery that is not being charged.

Re: Ongoing problem 1946 v8
 

X2 what TJ suggested.

Re: Ongoing problem 1946 v8
 

Does the ammeter show positive when you are driving? If you turn the headlights on does it stay on the positive/charging side? If not, generator and/or regulator are malfunctioning and the ignition will eventually drain the battery voltage down to where the engine dies and it will not crank.

Re: Ongoing problem 1946 v8
 

Voltage reg especially if it has/had a nice blue cover.
Charlie ny

Re: Ongoing problem 1946 v8
 

When it fails, carry a volt meter with you and take a look at the current battery charge to see if it's drained. If you are running a 12v battery (I didn't see that in your description) on a 6volt electrical motor system. Well I'm no help to de-dug the long list of things. Is it a 6v starter? Cables should not have a huge issue less you are cranking a ton. I use 00 welding cable on my 6v battery cables. Fairly easy to see if the battery is being charged with a volt meter.

How do you get it home? wait 30 minutes and then it works? Do you flatbed it home and charge the battery and all things are fine for 20 miles.

You still have fuel to consider so get out the check book. I'm just kidding. but...

Re: Ongoing problem 1946 v8
 

Thanks for the suggestions. I think I will start by installing a new set of battery cables and also taking off the starter and going over it and re-installing it. Any suggestions for best source for battery cables? I will let everyone know how it goes.

Re: Ongoing problem 1946 v8
 

Before you go through the time and expense, listen to Terry,OH.


Battery cables don't go bad, They can have loose and corroded connections or undersized.

Old cars are fussy, I carry a VOM with me for these reasons.

Re: Ongoing problem 1946 v8
 

Randy, where are you at in ET?

Re: Ongoing problem 1946 v8
 

Best to focus on your charging system before anything else. What does your ammeter show at fast idle?

Re: Ongoing problem 1946 v8
 

After going over the battery cables, I think now I will look into getting information on a Powermaster alternator made to look like an original generator. I still want to maintain 6 volt positive ground on my truck. Any experience out there on the Powermasters? Something is draining my battery over and over.

Re: Ongoing problem 1946 v8
 

There are many great diagnostic tips given here. I would go through each of those steps before I started buying and replacing "maybe" items. You can empty your wallet quickly and still miss the little wire connector that is the root of the problem. Don't ask how I know... Chap

Re: Ongoing problem 1946 v8
 

Thanks Chap. It sure has been frustrating dealing with my problem. I sure would be happy if I could find and understand the problem. I had been thinking about the generator to alternator switch for quite a while and thought maybe this would be an appropriate opportunity. We shall see. I will not give up on my truck. Many thanks for all of the suggestions.

Re: Ongoing problem 1946 v8
 

Randy, check the battery voltage before you start your truck. Then check it with the truck running. That should give you a good idea what the generator is doing. A fully charged battery should be close to 6.4V and running the battery should check over 7 volts (has to be above idle, say 1500 rpms or so).

Re: Ongoing problem 1946 v8
 

I have been running the stock generator/regulator set up on my '51 since I got it in 1987. I have never had a bit of trouble, and am even running some extra load on it in the form of a stereo, GPS, and back-up camera (running on a home made inverter/booster).

Like everything else, if properly maintained and in good shape, the stock systems on these old cars work just fine. I am running an Optima battery, because properly sized quality "normal" batteries are difficult to find.