Battery Question 6 or 8 volt

[frank]

I have a 1948 Plymouth Business Coupe with a 3.8L 230cid L6 95hp.  It's been running on a 6volt, but with the 6volt it’s very difficult to start it barley turns over.  Can I replace the 6volt battery with an 8volt, without damaging anything?  I need more cranking power.

[Plymouthy Adams]

you more than not need to determine first the low voltage or dragging condition that is causing your poor performance.  The engine starter motor needs a good clean supply of current and this can be impeded by such things as poor connections causing voltage drops and actual internal resistance of degraded cabling not visible to the naked eye.  Doing voltage drop tests will be you best method to detect these conditions.  Also the cabling should be no less than size 1 battery cable...0 and 00 are even better GIVEN your connects are again clean and tight.  Second is the starter dragging...you need to do a current draw test with a shunted meter to read this value...if you bust the current draw it will quickly heat up the starter and cabling and thus cause for even more current draw in what we call a thermal run away effect..test with a amp meter.  Most probably cause of higher current drain in a starter is dragging armature...this condition is usually corrected by replacing the elongated rear bushing with a new oilite bush..do not grease oilite..instead, soak in 10 weight oil prior to install..

 

going to 8 volt will require a tweak of the voltage regulator is nothing more than a bad aid to the real problem..

Edited May 31, 2014 by Plymouthy Adams

[Don Coatney]

First off has the engine in your car been changed? Plymouth did not have a 230CI engine in 1948. And talking liter's to this cubic inch crowd means nothing.

 

As Plymouthy stated adding 2 more volts will not fix anything. Six volts worked well when these cars were new and still works well today if the electrical system is healthy. Check and clean all connections including all ground connections. Pictures of your engine compartment (starter, generator, regulator, battery, etc.)will give a lot of clues as to why you are having this problem.

[greg g]

Also, when srarter bushings wear, they many times wear in an oval. This allows the armature to actaully drag against the field windings when they are energized, adding frictional drag into the equation. The most common fault is as mentioned the substitution of too thin 12 volt primary cables that will not flow enough current to satisfy the starters need.

Luckily the bushings are available and faily easy to repace.

Edited June 1, 2014 by greg g

[Plymouthy Adams]

is this maybe the same post on another forum??????

 

 

http://www.forbbodiesonly.com/moparforum/showthread.php?73472-Battery-Question-6-or-8-volt

[Don Coatney]

I did not know the B body guys were well versed in 6 volt stuff but I am glad he found the answer he was looking for.

[Plymouthy Adams]

ah..I see..that is why I found it over there...I also have a couple B-body Mopars in the wings....only reason it caught my eyes was so out of place..seems odd though even at that not to acknowledge the forum here as his log in shows he had read our replies on a forum dedicated specifically to the P15....live and learn I guess..

[greg g]

Perhaps he awaits confirmation from a higher authority? An intercedence from Mazda, as in the Persian minor god of lightening.

[48Dodger]

IDK.....The question was asked here first and answered here first. He got  multilple answers later in the day at B-Body (which I belong to as well) and said: "First, thank you so much for getting back to me again, B Body is no doubt the place to access for information" 

 

Oh well, win some lose some....lol.

 

I guess he must spend a lil more time there than here. No biggie, We'll get him back with his next question!

 

48D

[T120]

Barley influence?

[Dave72dt]

It may not have been posted here first.  It may make a difference what time zone the hosting site is located in .  For an example, as I post this it is 7:07 pm.  Now check the posting time for the post as it appears on the forum.

[Don Coatney]

It may not have been posted here first.  It may make a difference what time zone the hosting site is located in .  For an example, as I post this it is 7:07 pm.  Now check the posting time for the post as it appears on the forum.

8:07 for me

[Plymouthy Adams]

first reply 13 minutes, second reply 53 minutes..he was here again at least twice after his post and both earlier replies....I did not track him on the b-body..just thought it may have been the same guy...no big deal..some folks are more at home on some forums than others...

[Don Coatney]

Pasted below is the only other posting made by this thread starter. Interesting that he states his engine is a 217 in this thread. And he gets some good answers but does not respond. There is a photo of his car in this link.

 

http://p15-d24.com/topic/35372-best-oil-to-use/

[_shel_ny]

Better band-aid: 

12V jump pack anytime starting is desired.

 

Advantages:

Cheaper than a new 8V battery.

No VR adjustments required

Jump pack can be used for other things.

 

Or put an extra 12V battery in, connected only to the started. Charge periodically.

Edited June 2, 2014 by shel_ny

[SQ4MN]

I see that the guy asking these questions has the car for sale on EBAY right now. 

[Plymouthy Adams]

and what is the specification on the electrical system in the ad...?  6/8/12

[austinsailor]

You guys know that 8 volt chargers are non existent these days, don't know how you'd charge that high powered 8 volt.

[Plymouthy Adams]

6 volt will get it started..tweaked regulator will do the topping off....you do not want to know the actual voltage your starter is operating on under full load...try 3.8 volts..but man its heavy on current...285-312 depending on year model of starter for the 46-54..and by the way..the Chrysler starter spins faster than a Plymouth starter does...just a FYI

[Don Coatney]

I spotted this caddy equipped with an 8 volt alternator a few years back. Most likely he had the alternator converted to 8 volts unless someone is selling these conversions.

 

 

[Plymouthy Adams]

actually a good generator willput out 8 volts itself..the adjustment of the regulator is what determines the cut out...book specs are 8 however for bench testing specs...and it is know that an alternator will put out a tad higher voltage also over a generator and will meet demands of a running ignition system and usually put some reserve back to the battery on start up...

[Don Coatney]

Another issue with 8 volts is light bulb life. Six volt bulbs will work on 8 volts but not for as long.

[Plymouthy Adams]

this is true Don and the purpose of the regulator...just stating you must have potential/availability to be adjustable..8 volts is just a hat trick..this bainaide ahs been cussed and sicssed to no end here..but..it keeps rearing its ugly head..

 

of interest though, my Plymouth Acclaim headlamps were rated at 10 volts right on the bulb itself and I only recall having to change one in 226,000 miles..

[BigDaddyO]

I spotted this caddy equipped with an 8 volt alternator a few years back. Most likely he had the alternator converted to 8 volts unless someone is selling these conversions.

 

 

That's a rare double stack 16 volt alternator.

Edited October 8, 2014 by BigDaddyO