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851 SC 6v battery

  • Curt Schulze
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02 Aug 2022 16:46 #45789 by Curt Schulze
Replied by Curt Schulze on topic 851 SC 6v battery
John, I don't drill out the rivets in the endplate. Rather mount studs in the starter housing, cover the recessed heads with the dust cover. I have posted pix of this update previously.

The bitterness of poor quality remains long after the sweetness of low price is forgotten.
Be of Good Cheer
Curt

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  • johnmereness
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01 Aug 2022 22:13 #45777 by johnmereness
Replied by johnmereness on topic 851 SC 6v battery
Curt is correct - when restoring a car there is often too much paint - think metal to metal contact (ie paint everything together verses painting everything all apart so that for example your bell housing has metal to metal contact with the block and is just not grounding through bolts). Also, I have the bell housing cleaned of paint under the started face (and the stater was rebuilt thinking metal to metal contact as well). Also, Curt is correct that the brush holders in the starter are riveted and if you drill out the rivet you often will find rust on the end plate and/or rivet holder.

The one thing I will say though is that it does not take long to loose a great ground to get marginal grounds and then seems a while longer and you have no grounds (Andrew had to deal with grounding and battery issues on our car after it sat from ACD Meet 2019 to ACD meet 2021)

JMM

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  • johnmereness
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01 Aug 2022 22:03 #45776 by johnmereness
Replied by johnmereness on topic 851 SC 6v battery
Jim, I think Andrew just likes the security of the two batteries in parallel - it has run fine for eons (car was partially restored in 1959-ish). And I put the first Optima in it in 2006. They are wonderful batteries as they are so light weight and easy to handle, plus good longevity. And, I have bought literally I bet 100 to 125 of them over the past 15 years or so via Packard Museum 2009-2011, SignificantCars.com, friends, and .... - I have had pretty near faultless service other that miscalculating age on a few and not replacing them when I should (I think the shortest lived one also died at like 3 years, plus I have had a few museum stored cars where the car was started too much and never charged - not good for one and they are difficult and sometimes impossible to charge or revive when too far run down/abused).

JMM

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  • Curt Schulze
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30 Jul 2022 21:56 #45767 by Curt Schulze
Replied by Curt Schulze on topic 851 SC 6v battery
When they have two Optimas that have enough power to turn over a Cadillac V16 in 30 below weather but their Auburn still turns over slow the problem is the two grounding brushes in the starter endplate.

The bitterness of poor quality remains long after the sweetness of low price is forgotten.
Be of Good Cheer
Curt

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  • yorkgulch
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29 Jul 2022 19:28 #45763 by yorkgulch
Replied by yorkgulch on topic 851 SC 6v battery
Curt posted a great fix for the internal ground issue both here and on aaca I think. It worked great for me!

Auburn 851

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  • JIM.OBRIEN
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29 Jul 2022 19:22 #45762 by JIM.OBRIEN
Replied by JIM.OBRIEN on topic 851 SC 6v battery
Andrew, The rating system for batteries have changed from the 1930's to today so you cannot do a straight comparison of the numbers. a 600 to 800 amp battery is more then enough to start these old cars. If your electrical system is in good condition, your engine is tuned properly and you know to start your car(they all start differently) then they fire off on the first revolution.

I agree with Curt. It only takes a couple of ohms of resistance in the starting circuit to cause starting issues..

Wiring for 1600 amps is overkill. 4 ought cable is hard for the average person to get and is even harder to bend and run in these cars. If you ever have a short you are going to have major problems very quickly.

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  • Curt Schulze
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28 Jul 2022 13:22 #45757 by Curt Schulze
Replied by Curt Schulze on topic 851 SC 6v battery
If your car still turns over slow with the new optima, and all of the connections that you can see are whistle clean, you have a grounding problem in the starter.

The bitterness of poor quality remains long after the sweetness of low price is forgotten.
Be of Good Cheer
Curt
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27 Jul 2022 21:34 #45754 by [email protected]
The car will start fine with one battery. The old type of batteries used to be cranking at 1200 amps. The optima only do 800, so we decided to do two for that reason. The starter will only pull however many amps it needs to turn the engine over. We felt that there was no point in the battery or wiring being the limiting factor when it came to starting the car. We are not the only ones running this set up on our cars. We also didn't like how one battery sat in the holder. Many people carry two of them in there holder, we thought why not connect them.
Not sure what problem we would be masking up by doing this, if you have any ideas please let me know. We are always trying to have the car run the best it can.

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  • rlwardne
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26 Jul 2022 23:47 #45752 by rlwardne
Replied by rlwardne on topic 851 SC 6v battery
The guys are correct a single optima should be just fine, battery cables are ultimately important on every 6 V car. Your 12 V battery cables cannot handle the amperage required so you need to run at least double ought

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  • JIM.OBRIEN
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26 Jul 2022 23:37 #45751 by JIM.OBRIEN
Replied by JIM.OBRIEN on topic 851 SC 6v battery
Andrew If you need two batteries and 1600 amps to start the car you have other problems that you are masking. One battery is more then enough to start an Auburn.

The down side to the Optima batteries is they do some really funky stuff when they start failing. Several times I've worked on cars that were having strange electrical "ghosts" that I couldn't find. When I finally changed out the Optima battery all the "ghosts" problems disappeared.
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26 Jul 2022 16:52 #45750 by [email protected]
Andrew, great idea. This is tremendous help. Thank you so much for the advice. Woody

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26 Jul 2022 16:33 #45749 by [email protected]
These optima battery's are great. I strongly recommend running two of them in parallel. They fit in the normal battery holder and will not move around on you. We run this in a 851 sedan. It gives us 1600 cranking amps and we have not had a problem with it burning anything and it starts great every time. I would also suggest running bigger wire so that all the amps get to the starter. for 1600 cranking amps you need 0000 type wiring. It may not look the most correct but it will always start.
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25 Jul 2022 14:27 #45745 by [email protected]
Thank you so much Terry

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  • Terry Cockerell
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25 Jul 2022 03:33 #45738 by Terry Cockerell
Replied by Terry Cockerell on topic 851 SC 6v battery
I can highly recommend Optima 6 volt batterys. Plus you don't have to worry about fluid levels and they are considerably lighted than a conventional battery.
You can also get a mock up cover to make them look like a conventional battery.
They are rated at 800 CCA. Starts a Cord V8 easily.

T cockerell
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25 Jul 2022 01:26 #45737 by [email protected]
Any recommendations on 6v battery for a ‘35 851 SC Speedster? Would like as many cranking amps as possible. Thanks. Woody

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