The Ford Barn

Mark's 37 · 02-14-2016, 05:32 PM

Installed the stock 6 volt starter on the so-far unstarted rebuilt 221 today. Charged the battery and the engine is pretty tight so the starter is fignting to turn it over. Can I jump at 12 volt battery directly to the 6 volt starter to get some umph without damaging the starter? That is, one jumper cable end to the terminal lug on the starter and the other cable end to the engine block?

petehoovie · 02-14-2016, 05:37 PM

Yes....

Charlie Stephens · 02-14-2016, 06:26 PM

Are you using the correct cables designed for 6 volts or do you have cables designed for 12 volts. That could be your problem.

Charlie Stephens

47COE · 02-14-2016, 06:32 PM

Besides checking that you have 6 volt cables, it could also be paint on the freshly rebuilt engine block.

After my rebuild I had to scrape paint off of the block where the ground strap connected to it, and where the starter mates to the block.

Cranked over nicely after doing that.

Mark's 37 · 02-14-2016, 06:38 PM

Quote:

Originally Posted by 47COE

Besides checking that you have 6 volt cables, it could also be paint on the freshly rebuilt engine block.

After my rebuild I had to scrape paint off of the block where the ground strap connected to it, and where the starter mates to the block.

Cranked over nicely after doing that.

Have the correct gage cables, etc. All the connections, grounds have been cleaned to bare metal beforehand. Left it alone and let the battery charger work a little longer. Came in for some beverages and checked again. turns over now just using the 6 volt battery. Should be firing this one off in the next day or two when the final parts come. Thanks.

G.M. · 02-15-2016, 09:35 AM

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Mark here's what I would do. Remove the spark plugs and put about a 1/2
glass of MMO or thin oil in all of the cylinders. Screw a mechanical oil pressure
gauge in the pressure port on the left rear of the engine. Put a rag over the
plug holes so you don't have a big mess. Spin the engine with 12 volts hooked
up as you described. The pressure you see on the gauge will be what you will
see driving at 40 MPH. I want to see 45 lbs or slightly higher. The advantage is
you can adjust the oil pressure before installing the engine. If the pressure is
low I can instruct you on how to increase it. Most low oil pressure is due to
a weak or short spring in the front pressure bypass valve or in the oil pump
itself if it is a later style pump. If it has a later pump I screw the pressure
adjustment in so it opens at about 55 lbs leaving the front valve in the intake
manifold to make the adjustment. Leaving the front valve to do the pressure
release also dumps more oil on the timing gears and more oil to the water
pumps that are oil lubricated. G.M.

Bored&Stroked · 02-15-2016, 09:43 AM

When I recently fired up my 42 Merc engine, the old 6-volt starter just didn't have enough power to turn it over fast enough. So, I did as you mentioned . . . switched over to 12 volts, ran it with the plugs out - got good oil pressure, put the plugs back in and fired the engine.

I have a magneto, so I didn't need 6V at all. Once the engine was initially broken in, then I switched back to a 6V starter. I noticed that my starter just didn't turn the engine over that well (too slow), so I had the starter rebuilt by a reputable firm here in Columbus - now it turns over nicely and the engine has no problem starting. With a mag, you need some rpm to generate enough juice to fire the plugs efficiently . . . so this really helped.

Note: I used to run my flathead 6V starters on 12V for the long haul - I never had issues, but some folks have bendix problems due to the force at which 12V slams the bendix into the flywheel. Things like bendix springs breaking, etc.. Just something for others to think about . . .

02-14-2016, 05:32 PM	#1
Mark's 37 Senior Member Join Date: Jul 2015 Location: Aptos, Ca Posts: 355	12 volts to a 6 volt starter? Installed the stock 6 volt starter on the so-far unstarted rebuilt 221 today. Charged the battery and the engine is pretty tight so the starter is fignting to turn it over. Can I jump at 12 volt battery directly to the 6 volt starter to get some umph without damaging the starter? That is, one jumper cable end to the terminal lug on the starter and the other cable end to the engine block?

02-14-2016, 05:37 PM	#2
petehoovie Senior Member Join Date: May 2015 Posts: 8,149	Re: 12 volts to a 6 volt starter? Yes.... __________________ The only thing nice about being imperfect is the joy it brings to others.... *"Silver rings, your butt! Them's washers!"* "We shot our way out of that town for a dollar's worth of steel holes!" - from 'The Wild Bunch' - 1969 https://www.youtube.com/watch?v=7NReUd2_0u0

02-14-2016, 06:26 PM	#3
Charlie Stephens Senior Member Join Date: May 2010 Location: Southern California Posts: 7,032	Re: 12 volts to a 6 volt starter? Are you using the correct cables designed for 6 volts or do you have cables designed for 12 volts. That could be your problem. Charlie Stephens

02-14-2016, 06:32 PM	#4
47COE Senior Member Join Date: Apr 2011 Location: Oregon Posts: 220	Re: 12 volts to a 6 volt starter? Besides checking that you have 6 volt cables, it could also be paint on the freshly rebuilt engine block. After my rebuild I had to scrape paint off of the block where the ground strap connected to it, and where the starter mates to the block. Cranked over nicely after doing that.

02-15-2016, 09:35 AM	#6
G.M. Senior Member Join Date: May 2010 Location: Florida and Penna. Posts: 4,471	Re: 12 volts to a 6 volt starter? Sponsored Links (Register now to hide all advertisements) Mark here's what I would do. Remove the spark plugs and put about a 1/2 glass of MMO or thin oil in all of the cylinders. Screw a mechanical oil pressure gauge in the pressure port on the left rear of the engine. Put a rag over the plug holes so you don't have a big mess. Spin the engine with 12 volts hooked up as you described. The pressure you see on the gauge will be what you will see driving at 40 MPH. I want to see 45 lbs or slightly higher. The advantage is you can adjust the oil pressure before installing the engine. If the pressure is low I can instruct you on how to increase it. Most low oil pressure is due to a weak or short spring in the front pressure bypass valve or in the oil pump itself if it is a later style pump. If it has a later pump I screw the pressure adjustment in so it opens at about 55 lbs leaving the front valve in the intake manifold to make the adjustment. Leaving the front valve to do the pressure release also dumps more oil on the timing gears and more oil to the water pumps that are oil lubricated. G.M. __________________ www.fordcollector.com

02-15-2016, 09:43 AM	#7
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,068	Re: 12 volts to a 6 volt starter? When I recently fired up my 42 Merc engine, the old 6-volt starter just didn't have enough power to turn it over fast enough. So, I did as you mentioned . . . switched over to 12 volts, ran it with the plugs out - got good oil pressure, put the plugs back in and fired the engine. I have a magneto, so I didn't need 6V at all. Once the engine was initially broken in, then I switched back to a 6V starter. I noticed that my starter just didn't turn the engine over that well (too slow), so I had the starter rebuilt by a reputable firm here in Columbus - now it turns over nicely and the engine has no problem starting. With a mag, you need some rpm to generate enough juice to fire the plugs efficiently . . . so this really helped. Note: I used to run my flathead 6V starters on 12V for the long haul - I never had issues, but some folks have bendix problems due to the force at which 12V slams the bendix into the flywheel. Things like bendix springs breaking, etc.. Just something for others to think about . . .