Charging/Starting

[37 Cab]

So I have been dealing with a problem getting my 37 to start when hot. It has a voltage regulator on the firewall. New battery last year. Checked my power and ground connections and ran an extra cable from engine block to battery.
Charging output at the regulator is 7 volts at 2500. 6.3 volts at idle. When checked at the battery it is 6.2 and 6.4 volts. Replaced starter today thinking it was the problem and wasted my time. Same results. It has Fenton cast iron headers and it is real close.. 1/8 inch from the battery cable connection. Think starter may be getting too hot?? Am I missing something? Should I be seeing more voltage at the battery??
Thanks in advance for any advise. Don`t know what I would do without you guys.

[30-9]

Sounds like coil.

[37 Cab]

Sorry.. Should have said it will not crank. Acts like dead battery or excess starter draw. I can put my shop battery charger on it and it will start if I turn the charger up.

[koates]

Hi there. Just because the battery is fairly new does not mean it is any good. Have you checked it with a hydrometer in each cell to establish its state of charge ? Or at rest with every thing off the voltage across the battery terminals should be 6.3 volts if it is good. You really then have to load test the battery by loading it with about 300-400 amps and reading the voltage under load. A battery load tester is required for this test. Establish if the battery is any good first before going on to check other components. Or swap the battery out for another known good 6 volt battery. Also with the engine revs up somewhat the voltage reading at your voltage regulator A or B terminal should be 7.5 to 7.8 volts not 7 volts which is to low. I presume your generator has been changed from the original 3 brush unit to a two brush with a three unit voltage regulator off a later car. Another simple test is to remove all the three battery filler caps and watch into each cell while you crank (or try to) the engine. If one cell is gassing or bubbling a lot then that cell is faulty. Wear safety glasses. You can also read the voltage across the battery terminals while trying to crank the engine. Voltage should hold at 4 or 5 volts, If it drops off lower then battery is faulty or flat. My guess is that your battery is faulty. Regards, Kevin.

[JSeery]

Good write up Kevin!

[37 Cab]

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Thanks Kevin.. I will check the battery as you stated. Don`t have a load tester but I do have a hydrometer. If that passes I will dig up a load tester. I thought the output was a little low but was not sure on a 6 volt system. I will tighten the belt a little and see if that helps there. It does have a two brush generator. Thank you very much. Will update tomorrow.

[koates]

JSeery, thanks for that. I must also state that your answers to electrical questions are always spot on. Trouble is many barners seem not to be interested in doing things the correct way and carry on with their back yard fixes. Anyway we do our best and that's all we can do from a distance. Best regards, Kevin.

[chap52]

Here in Arizona you can battery to O'Reillys or Auto Zone and they will load test it for you.

[ArcLighter]

Problem sounds very similar to my '53 V-8, would hardly turn over when hot. I "hangar" the car at my airport, and quizzed the airport starter/generator/alternator rebuilder. He said that 95% of all the aircraft he sees that start when cold, but won't start when hot are starter problems, needing rebuilding. I had him rebuild my starter, and it whizzes that engine over like a high torque starter. When I first took the starter to him, it only took him ten minutes to determine that only about 30% of the "juice" was getting to turning it over; needed rebuilding.

[37 Cab]

OK... Here is what I found today. Battery voltage is 6.3 with everything off. While cranking volts are 4.3. Tightened belt. Ran engine until hot and got 4.0-4.3 volts with slow crank. Crank speed increases once a cylinder fires and it cranks fast and starts. So I am thinking timing maybe?? It has a later crab style distributor and I have never dealt with one before. HELP PLEASE... I do not want to get into it as I would rather have Bubba do it. Right now the timing mark is lined up with the second mark down from the top. Sure would appreciate some more advice.

[37 Cab]

Forgot to add.. Charging volts are now 7.8V at the armature terminal of the regulator and 6.9-7.0V at the Battery terminal with a fully charged battery. 1500 RPM.

[JSeery]

Originally Posted by 37 Cab

Right now the timing mark is lined up with the second mark down from the top. Sure would appreciate some more advice.

Problem is the timing marks only help if the points are set correctly. Is that something you want to attempt or would you rather send it out? If you don't need the car daily I would send it to Babbas and get it cleaned up and set for the spring/summer/fall driving. You can always try moving the timing mark and see if it helps any.

VanPelts site has some information if you are interested in digging into it. http://www.vanpeltsales.com/FH_web/f...str-timing.htm

[37 Cab]

Thanks JSeery, If this is a timing issue it would be too far advanced causing my problem so I wanted to slow it a little. I am not equipped to set the dist up on a bench so, I agree with you and Bubba will get it soon, but I am committed to a show coming up and don`t want to disable it right now.
You make a good point though.. The marks mean squat if point gap is off. I did not take that into account when I looked at it.. Thanks again!!

[37 Cab]

Did some more checking.. Slowed the timing and no change. But then I tried to crank it with the switch off and still will barely crank. Can`t be timing then right? My battery like I said was new last year and seems to hold 3.9-4.0V when starter struggling to crank. Battery is a tractor supply 6 volt 650CCA- 750CA. Bigger battery? Don`t like the Optima battery for it`s looks.

[63tango]

Is your starter mounting flange clean. I had a rebuilt starter that was painted real nice but the problem was the paint on the flange made for a piss poor ground. It also cranked real slow.

[37 Cab]

That is a thought.. Thanks. I will check it. The Starter is new with new bolts but I can`t rule that out.

[37 Cab]

Update.. Went to O`reilly auto parts and had my battery load tested. It passed. They
had in stock a 6 volt commercial and fleet battery that is slightly bigger (actually fits better.. 1" wider) but more cranking amps. Problem solved. Cranks great hot or cold.
Here is what I got.. 830 cranking amps.
http://www.oreillyauto.com/site/c/de...0369&ppt=C0327

Thanks again for all the help and advise.

[JSeery]

Engines = can't beat cubic inches. Batteries = can't beat cranking amps!

[koates]

Well sounds like O Reilly did not load test your original battery hard enough. Some cheap load testers around today only load the batteries to about 100 amps which is way too low and the battery will pass at that rate. Need to load batteries to 300 to 400 amps or more for 10 to 15 seconds depending on the size of the battery. Your battery was faulty, that's why the new one worked OK. Many auto parts stores know only how to sell things, and don't know how things work or how to repair and test things. For auto electrical work you need an Auto Electrical repair shop. Regards, Kevin. Regards, Kevin.

[37 Cab]

How many amps do you think a starter draws? Why was my old battery maintaining 4.3 volts when trying to crank my engine and returning to 6+ volts when I let off the button? I did this multiple times with same result?
I am not arguing your point. The battery was at fault and thank you for your advise. You were spot on. Just trying to understand. Thank you very much.

[koates]

Well then why did the new battery fix your problem ? Starter current draw will vary according to conditions but ball park would be 250 to 350 amps for your 6 volt Ford. Check that your battery starter cables are very heavy like ones fitted to diesel trucks. Size O or OO B&S is required here. A 6 volt starter motor will draw double the amps of an equivalent 12 volt starter. Your old battery could not deliver that apparently. Most spare parts shops assistants, mechanics, back yard experts, don't know how to properly test a vehicle battery much less a 6 volt one. Pleased you have it fixed. Regards, Kevin.

[37 Cab]

My thought was the tractor supply batter just did not produce the advertised amperage. It never did crank the engine as well as the new one. Possibly defective from new?? My cables are correct for the 6 volt system and I cleaned all the connections well.
That is why I posted a link to the battery I used. I have heard the tractor supply battery mentioned here before and that is why I used one. Most auto parts guys here can`t even look up a part correctly or for that matter know the difference between one part and another, I cringe when I need to call. Again.. thank you for the sound advise. I am very pleased as well. I read all of your own as well as JSeery`s posts as your advise always seems to be spot on.

[40cpe]

For comparison, what is the voltage of the new battery while cranking?

[koates]

40cpe, Various factors could effect that voltage reading but I would like to see about 4.5 volts there at least. Maybe I will go out and check it on my 34 Ford V8 with its 6 volt optima battery when I get a chance. It cranks quite good. Regards, Kevin.

[37 Cab]

I am getting 4.6 on initial crank ramping up to 5.0 steady cranking.

[JSeery]

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Originally Posted by koates

40cpe, Various factors could effect that voltage reading but I would like to see about 4.5 volts there at least. Maybe I will go out and check it on my 34 Ford V8 with its 6 volt optima battery when I get a chance. It cranks quite good. Regards, Kevin.

I would be interested in what the static voltage is on the Optima as will as the cranking voltage. I have read that the Optima is higher than the lead/acid batteries.

"Fully-charged, our REDTOP batteries (and 34M BLUETOP) will measure about 12.6-12.8 volts and our YELLOWTOP and BLUETOP (except the 34M) batteries will measure about 13.0-13.2 volts. Each manufacturer will generally indicate a range or minimum voltage level for a fully-charged battery."

Not sure how that relates to the 6v.