Flathead starter and 6V crap

Ok. Let me start off by saying that I am a newb/idiot with flatties, and never touched a 6V system in my life aside from my dad's old Ford tractor. So if you can get by that, read on.

Picked up a '51 Ford 'vert that has been sitting for about a dozen years. Engine was previously rebuilt and only has a couple hundred miles on it. So I dragged it in and cleaned out the fuel system, rebuilt the carb (Ford 94), and rebuilt the fuel pump. We got fuel. Pull the plugs, shoot some Marvel Mystery Oil down the cylinders, and install a new 6V battery. Use that to spin it over with the Marvel stuff to try to lube up the cylinders. Seems to spin over freely, and fairly decent so I thought for a 6V system. Mind you the plugs are out. So I clean up the points and put a plug on a wire, and low and behold there is spark. I'm happy. Put the plugs back in and try to fire 'er up. No dice. This 6V system can barely turn the thing over. And yes I've kept the battery fully charged. Cool thing is that the engine's got great compression.

So I hit it with ether. Nothing. Doesn't even try to start. It just seems like it can not turn it over fast enough to do anything. Hook the charger/booster to it and hit it with 12V for some extra kick. It's just a little faster spinning, but just doesn't seem like it can go quick enough to get 'er done. It doesn't even try to fire.

So where am I going with this? I remembered last night that this car was converted BACK to 6V right before it was parked (and did run back then with 6V). Dumb question - Could the starter still be a 12V unit, and if so if it was hit with 6V would it not turn over fast enough? Wondering if that might be what happened. We got fuel, we got spark, but she just won't turn over hardly at all. Gotta crawl under and check it out tomorrow night, but just sitting here at the computer thinking about it right now.

Any thoughts would be appreciated. Thanks for listening to me whine.

 

Still got them weenie 12 V battery cables on it??? 6V is current flow dependent and 12V battery cables don't have enough meat to flow the amount needed for a 6V starter to do its job. So if the skinnies are still on it, go get some 1 gauge and make sure all connections including grounds are clean and tight. Then do a static timing to and assure your wires are correct in the dizzy cap. If you got suck, and squeeze, and spark at the right time you should have bang and blow to go along and get your gettie up going. Remember these engines weren't far removed from starting with a crank, so speed is not as much of the essence as making sure, gas and spark arrive at the right time.

 

are you getting gas thrue the carb? pump it while looking down in it ?
then put a big dam 12 volt battery in it !

 

Dang you guys are quick - thanks.

Thing has big momma cables on it, seems way bigger than the weenie cables in my Mustangs. And yup, positive ground. Fuel through the carb also. I'm like "what the heck is up here", got fuel, spark, but doesn't try.

Good point on the wires and timing, though. I never checked firing order.....could be hosing me over. On the flatties, are the cylinders numbered like, say, later smallblock Fords?

This thing's gotta be close. Just probably the idiot turnin the key!

Thanks again.

 

Check your coil. If converted to 12V & de-modified to 6V, it's a long shot, but the 12V coil could still be in there & may even be wired backwards. None of that should prevent it from starting, but it will weaken spark a bit.

Since it's been sitting, it's also possible you've got a couple stuck valves that aren't helping. If you can get it to fire, run some ATF or MMO down the carb while revving the engine to help free them.

If it were me, I'd just drop a 12V battery in the thing & get it running with that - easier cranking, better spark, etc. Once you've got it running & tuned, if you really want to go back to 6V, you can...

 

I used to run 2x 6 volt batteries in series to give me extra cells thus more crankability,that was before I ran one big 12 volt.
Starter brushes and/or bearings may be worn out too,a big drag on the current like that will suck much needed power from the ignition. In that case,hook another battery to the coil and use that to keep a full 12 volts to the ignition to get it to fire. Even if valves are stuck you will get firing causing either intake or exhaust explosions.

 

Here are some tune-up specs, including firing order.

http://www.vanpeltsales.com/FH_web/flathead_tuneup49-53_239-255.htm

 

It was common for flatty starter armatures to drag on the coils when the bushings get a little worn, so people will turn them .050" under. Make sure the armature isn't shorted on some coils, good brushes, etc. It still won't crank as fast as a modern car.

Yes, the cylinder numbering is same as a 302 -- passenger side is #1 - #4, driver's side 5 - 8.

 

The original style battery is the worst enemy of 6volt systems.
They have something like 450 cca or worse.
If you decide to stick with the 6v,
get an OPTIMA battery they kick amps, I think its like 850/1000.
TP

 

you might want to check and see if the generator is good. if you have a bad gen the thing wont start. i couldnt get my flattie started til i got the gen rebuilt and replace the voltage regulator. also change the condenser in the distributor.

 

Make sure all your ground straps are clean on the ends and where they attach.A little crud can make a big difference.

 

I agree with lakes - sounds like bad connections if you can't get it to spin. Or does it just spin slower than your 12V stangs?

Fwiw, any time I start a vehicle that's been sitting for while I usually end up towing it up and down a gravel road in high gear, until it finally 'remembers' how it's supposed to run. Works for my flatheads and OHVs alike.

 

Thanks again guys.

I did pop in a new 6V coil just for grins. Gonna check grounds again, firing order on the wires from the dizzy, and maybe throw in a new condenser just for fun. And hook up the biggest 12V battery I can find. After that I'll pull down the starter and have a look at the armature.

Even with the 12V 100 amp boost it didn't spin as fast as one of my smallblock Mustangs. Maybe 1/2 to 2/3 speed (guessing) of what I'm used to in the 'stangs. That's what kind of caught me as odd. On just the 6V battery itself it might have been half of that.

Can't wait to hear 'er run.

Kevin

 

Well it is half the voltage.....6V does not spin as fast as 12V unless yer spinning it with 12V.

Here is where a tried and true trouble shooting technique will serve you well.

 

Or it could just be a bad starter. That's what it sounds like to me.

 

Sounds like the starter is dragging, I recently spoke to a guy in a gen. starter shop and he said that his rebuilder uses the same armature in 6 and 12 volt. You might try to ground to the block if not already doing so. I have used 6 volt starter with 6 volt battery on high compression Bangers and it works just fine. One thing to remember is that they used 6 volt until the late "50"'s. The 12 works better of course. If the 6 volt starter is okay 12 should spin it pretty fast. Just don't smoke it!

 

If your car was converted back to 6V correctly, better change all your lights to 12v before you install a 12v battery. Also, if you are using orignal dash guages and heater motor you will need voltage drop device(s) before going to 12v. Personally I'd go for GM alternator with internal voltage regulator (not 1 wire as they don't have enough out put at low rpm on older slow idling engines like flatheads). Need a 12v coil and lose any ballast resistor in the ignition system. Speedway Motors sells a good 12v conversion booklet for about $10. Highly recommended. They also sell a bracket to mount the alternator. If you buy a bracket, get the one that mounts the unit on top of engine where the generator was or you will have clearance problems with the battery tray.

 

If a flathead is anywhere close to being in tune, has fuel spark and compression, it don't require a zillion cranking rpm to start, our 8BA will start if barely bumped over.

 

News flash.....just back from the garage.....ANOTHER FLATHEAD LIVES.

Had roughly 15 minutes this evening to mess with the thing, so I checked the firing order, a couple grounds, and looked over those battery cables. All good, except I found the little wire that attaches to the distributor housing was not super tight, and the connection was somewhat corroded. Hmmmm. Disassemble/clean/reassemble. Noted also that the cable to the starter, as well as the negative side of the battery were the big 'ol 1 gagers, however, the positive ground side was 4 gage. Oh well, figured I'd crank again and see. Fired right up and purred.....smooth and quiet. And that was after barely spinning the crank over, just like I had done before. Cut 'er off after about 20 seconds 'cause I was filling the garage with Marvel oil smoke. Will roll it outside tomorrow and do it all over again.

No matter how many times you bring one back to life, it's always a great feeling. Thank you all again for the help.

Kevin

 

Congrats, Lightning.

As a fellow flathead owner, I read the thread with great interest. Mine is still 6v, and starts well, especially when I give the gas pedal a thump to the floor before cranking. Continued good luck with your car.

 

Well well well, just got some more time to mess with the thing, and learned what I think most of the problem was with the car. Stinking mice got up in the exhaust and plugged it all up!!!

What happened was that I decided that I wanted it to crank faster, so I put new 1 gauge battery cables on it, along with a new 1 gauge ground strap. Then rebuilt the starter. (It wasn't dragging, and the only thing I did was swap out brushes.....and they weren't too bad either.) That only helped a small amount, but now when I put the 12V booster to it, bam, it turned over real fast. And fired right up. It was backfiring through the carb and exhaust some, and was blowing big chunks of mouse nest out of the rusted out exhaust pipes (rusted out up near the floor boards). The more it blew out, the smoother and better it ran. No wonder the thing wouldn't start with good fuel, spark, and in time.....it couldn't breathe out!

Don't know why it ran ok there the other week for a short period of time. But I know today it really was corked up there for a while and not liking life.

So the moral of the story is check for bananas in your tailpipes. Eddie Murphy is probably smiling somewhere.

 

"Here is where a tried and true trouble shooting technique will serve you well."

LOL - I've sure never seen mice on a trouble shooting checklist!

 

Maybe not, but a cranking vacuum test could show a plugged up exhaust.

Stick to the basics.