start with 12V, run on 6V

[DutchEdwin]

I still have my starting problems with my 1955 Plymouth V8.

See.

Trying befor winter I found that starting with aspraying starter flued in the carb does not work, so the problem is the starter motor does not have enough power to turn a hot engine. (pistons have heated up, making the enging harder to turn by the starter).

 

I would like to solve this issue this summer but unfortunatly over winter the battery died.

So a new battery is needed. Original: 6V 140Ah 720 CCA

I have a few options I would like to discuss.

1) I keep running on 6V. Installing a 50Ah 850 CCA/6 volt 10x3.5x8 Optima battery. Changing the battery cables to new very thick ones. 

The advantage of this battery is very low self-discharge and very quick high amps for starting.

Question: does anyone have experience unig this battery?

2) If this does not work I can take a second 850 CCA/6 volt 10x3.5x8 Optima battery. Using them in series for 12V for the starter, and 6V parallel for the car systems.

The question is, does anyone know how to wire this so both batteries are charged by the generator on 6V.

 

2) I can use a 6V/12V battery  ( http://antiqueautobattery.com/accessories.html )

This way the car starts on 12V, system runs on 6V.

For me living in The Netherlands, is very high transportation costs + taxes.

Does anyone have experience with this?
 

 

[Plymouthy Adams]

you are having issues but how much is this guess compared to proven problems.  Have you done a voltage drop test, have you tested to see if for some reason (usually a worn rear bushing) that the starter is NOT drawing excessive amperage starving the ignition of the current it needs.  The Optima 850 CCA 6 volt battery is an excellent source of power.  Your cables should be 0 or 00 for ability to sustain current draw without heating up...remember, the more heat the more loss and soon you have a thermal runaway effect.  If you hae the repair manual, troubleshoot each subsystem, going straight to the battery is 'grouping' and defines very little.

[DutchEdwin]

I do not know the test "voltage drop test", is this a test to see the battery is still good?

As for the starter, I did a complete overhaul. The rear and front bushings are good, and lubricated with oil.

I have a new 00 cable to the starter solenoid, but an old one from the solenoid to the starter. Going to replace that one with a new one.

As for the current 140Ah 720CCA battery, it did not survive the winter for sure. Not even two turns on a cold engine now after recharging for 48 hours, but no complaint as it lasted  8 years.

 

 

[Plymouthy Adams]

on the suggestions I threw out, you got a handle on a few of them. as not to type out a page of instructions, google (or other favorite search engine) the procedure for doing a voltage drop test.....it goes a long way in assuring your cables and connection are up to the task...it is not complicated.  

[soth122003]

If you got 8 years out of that battery, you did real good. Have you had the hot start problem for awhile or is it recent? Mine does the same thing. I believe the shop manual says when starting a hot engine to hold the accelerator pedal down at the 3/4 mark. Like I said mine has been doing the same thing recently so I redid all my grounding points. cleaned them up and reconnected  them and the car turns over a lot better now. Also, instead of installing another battery, you might want to get a jump pack with a switch. Turn key on, connect pos to pos and Neg to the Starter or at the cable past the starter solenoid, Turn jump pack on until eng starts then switch off jump pack. Cheaper than installing another battery and wiring.

 

Joe

[HotRodTractor]

How is your timing? A bit too advanced can make the engine hard to turn over - especially when hot.

[sser2]

It is not a starter/battery problem. Engine is easier to turn when hot than when cold. The problem could be something that malfunctions upon warming-up, like ignition coil or vapor lock in the fuel system.

[DutchEdwin]

1 month ago I charged my battery for 48 hours. Today I did try to start my car , battery reading 6,20V. After 1/2 turn of the engine it stopped. After that, battery reads voltage 6,01 volts. So I think it is dead. My guess is that last year the battery wasn´t in a good conditioning, not able to deliver 500 amps.

 

To Soth I got these problems last year. I cleaned all terminals, overhauled the starter. After that the car started better when cold ) engine speed by the starter was a little faster. However when hot still a problem. Putting the pedal 1/2, 3/4 or to the floor did not matter. Waiting for it to cool down 0,5 hour did.

 

To SSER2: I have no vapor lock. Even spraying starter fluid into the carb does not work.

 

My timing according to the manual should be at 4 deg. But I set it at 8 deg advance. Even then the vacuum pressure is only 18 inch, should be 21 inch. I´m affraid to do more advancing because of getting a knock in the engine. 

 

3 years ago I replaced all electrical for the ignition like spark plug wires, coil, points, condensor etc.

 

To be shure, I´m taking out the two old cables that run from the battery to the engine and battery to the solenoid and replace them by new 00 cables. After that I´ll do the voltage drop test.

(when having a new battery).

 

I'm thinking to use the Optima 6V battery. (two of them fit in the same space as my current batter).  In case this does not work I would still like to know how to connect 2 6V batteries is a system tat allows me to start at 12V and use both batteries in the 6V system of the car and have them charged with the generator.

Anyone knows how to do that?

 

 

Edited July 19, 2018 by DutchEdwin

[Plymouthy Adams]

your extra advance could be your dragging at temp.....

[DrDoctor]

DutchEdwin,

   I remember seeing a photo of 2 6v red Optima batteries in a car connected in series in the engine compartment of a vintage Plymouth/Dodge/?????, but cannot, for the life of me, find it again. I’d think someone who visits here frequently would be able to point you in that direction, and perhaps that’d answer your question. Sorry I couldn’t be of more help. Regards to you . . .

[Silverdome]

1 hour ago, DrDoctor said:

DutchEdwin,

   I remember seeing a photo of 2 6v red Optima batteries in a car connected in series in the engine compartment of a vintage Plymouth/Dodge/?????, but cannot, for the life of me, find it again. I’d think someone who visits here frequently would be able to point you in that direction, and perhaps that’d answer your question. Sorry I couldn’t be of more help. Regards to you . . .

 

I believe you're talking about John Edge's 52 Plymouth Suburban.

[DonaldSmith]

That's not series, that's parallel.  Still 6 volts, but double the amps. 

[Silverdome]

1 hour ago, DonaldSmith said:

That's not series, that's parallel.  Still 6 volts, but double the amps. 

You are correct.

I think this should give him the cranking power he's looking for and still use the generator for charging. Because it's basically like having a jump start battery hooked up all the time.

[greg g]

Is the starter close to the exhaust manifold?  Is the heat riser for the intake on the starter side? I had a VW Rabbit (Golf) with a similar problem, l made a sheet metal heat shield that fit between manifold and starter.  In addition, l got some metal 3 inch clothes dryer ducting and rigged it up to provide ambient airflow from behind the grill directed toward the starter.  This solved the problem.  Wonder if you might have some armater sections that are bad ?  You said you had put new bushings, did you test the armature?  You might want to pull the starter and take it to a shop for a thorough test.  

[dale]

On 7/18/2018 at 1:40 PM, DutchEdwin said:

I still have my starting problems with my 1955 Plymouth V8.

See.

Trying befor winter I found that starting with aspraying starter flued in the carb does not work, so the problem is the starter motor does not have enough power to turn a hot engine. (pistons have heated up, making the enging harder to turn by the starter).

 

I would like to solve this issue this summer but unfortunatly over winter the battery died.

So a new battery is needed. Original: 6V 140Ah 720 CCA

I have a few options I would like to discuss.

1) I keep running on 6V. Installing a 50Ah 850 CCA/6 volt 10x3.5x8 Optima battery. Changing the battery cables to new very thick ones. 

The advantage of this battery is very low self-discharge and very quick high amps for starting.

Question: does anyone have experience unig this battery?

2) If this does not work I can take a second 850 CCA/6 volt 10x3.5x8 Optima battery. Using them in series for 12V for the starter, and 6V parallel for the car systems.

The question is, does anyone know how to wire this so both batteries are charged by the generator on 6V.

 

2) I can use a 6V/12V battery  ( http://antiqueautobattery.com/accessories.html )

This way the car starts on 12V, system runs on 6V.

For me living in The Netherlands, is very high transportation costs + taxes.

Does anyone have experience with this?
 

 

 

[dale]

If the system isnt too much money it sounds like a great product.  You can still use the 6 volt starter if you dont crank it too long.  12 volts makes it really turn over.

[DutchEdwin]

Greg, The starter is located next to the sump. I did the same like you did, put a heat sheald from reflection aluminum around the starter with an air gap of 0,5 inch. It helped a little.

Taking the starter to a shop for testing is something I didn't think of before because it funtions great when the engine is cold. I'll try looking for a shop that does that. Hope there is one for 6V.

 

The pictures from John Edge's car are great, I want to do the same..... but with the posibility to start on 12V.

[NickPickToo]

On 7/20/2018 at 10:12 AM, DonaldSmith said:

That's not series, that's parallel.  Still 6 volts, but double the amps. 

 

Here is a good piece on difference.  

https://www.batterystuff.com/kb/articles/battery-articles/battery-bank-tutorial.html

[plyroadking]

I did it with my '41 Buick to get the straight 8 turning over quicker. I used two Optima 6 volt batteries wired in series. I use a 12 alternator to charge the positive side of the 2nd battery. Negative on the first goes to ground. I pull my 6 volts off of the cable that goes from the negative on the 2nd to positive on the 1st. Ground is the same for both voltages. I went a little further and just use the 6 volts for the radio, heater blower motors, and the fuel gauge. Its been several years with out any problems.

[nonstop]

May I suggest, you addressed replacing cable from battery to ground and battery to solenoid.  What about the cable from the solenoid to the starter? Your system will only be as good as the worst cable. Next, I would do one new regular 6 volt battery. I may be wrong, but I thought Optimas needed a special charger and such.

 

It sounds simpler to bring the system up to snuff and then continue from there. Who knows, as mentioned above it might not even be starter related.

[JOHN EDGE]

I've had no problems with starting or cranking speed. I do run a 6 volt posi ground  alternator and 00 welding cable for both the starter and ground (posi) side. The dual optima' fit perfectly in the factory  battery box.

[mmcdowel]

I agree.  If the 6V was strong enough to start the car when it was new......it should still start it fine now.  I'm betting the starter has a burnt armature as mine did (had a similar issue with my generator too....stopped charging after the engine warmed it up).

[9 foot box]

When I got my car it had a 12 volt battery in the trunk. Neg. ground with a cable run forward to an additional solenoid also going to the starter. It has push button under the dash that starts the car on 12 volt neg. and is isolated from the 6 volt system by the other solenoid. Just don't use both at once,Duh! It's also handy for tunes, phone,etc. by having a 12volt neg.power source and also to the lighter. I was thinking of adding a solar charger in the back window. I used it the other day in a no start hot situation  and had to employ a full throttle start.The six volts didn't cut it. It gets hot under that hood. Or get a 6/12volt series parallel switch from Texas Industrial Electric Co.,  no.111984-6v

[DutchEdwin]

To give you an update.

I learned from an old engineer that when looking for a problem... do not stop before you find at least 3 faults.

No I have found two.

The wire from the battery to the starter soleniod and from the battery to ground were green under the isolation. Replaced those two. The wire from the solenoid to the starter is ok.

The battery is dead. I charged it for 4 days with 4 amps. When starting the voltage dropped to 3V!.

Now I will order a 6V red top Optima battery. See what that will bring.

After that I´ll do a voltage drop test to see it there are bad connections.

I´ll keep you updated on that.

 

There is also the solenoid. How can you find out that the connections inside are still good enough let the high current pass?

 

When the above are all solved I'll dive into the starter, generator and regulator.

 

To John Edge, Why do you use two 6V Optima instead of 1?

I called Optima in the Netherlands. They told me that there is no need for two batteries. For the lead plate batteries, to get 720CCA you must have a big battery, thus getting a 140Ah.

For the Optima Red Top can give 815CCA (1000 at 0 deg celcius) with a 50Ah battery there is no need for taking two, if there are no electrical equipment running when the car is not used, like a clock.

Edited August 7, 2018 by DutchEdwin

[DutchEdwin]

Update on the battery.

 

I managed to get in touch with an adviser from Optima.

He advised to put a Yellow Top 6V motor start/deep cycle battery instead of the Red Top starter battery

The reason is as follows,

- The car is not used for long periods. The Yellow Top can withstand the period of not being used better, thus givving a longer battery life.

- Most important, the Yellow Top will give higher voltage compaired to the Red Top when high amps are drawn, about 0,3 volts. On a 6V car this means a lot for the starter.

- The little lower CCA of 765A to 815A will be of no meaning for this use.

- The Red Top can be drained for 30%, but the Yellow Top to 70% without damaging the battery.

He stated that both batteries are performing much better than normal lead-acid batteries. Also on higher under the hood temperatures, where lead-acid batteries will perform less at these temp.

For maintenance, you must use a charger with tickle charge function suitable for AGM batteries, 

 

So I ordered a Yellow Top today.

 

Edited August 7, 2018 by DutchEdwin