48 farmall cub cranking help

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Matt in nc
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48 farmall cub cranking help

Postby Matt in nc » Wed Aug 05, 2015 8:28 pm

OK so I'm sure you guys get tired of hearing the same old thing, but I have researched and read over hundreds of threads only just to get back to square one. So I finally joined and just decided to ask for myself.

I have a 48 cub and i have completely restored it from the corks, to the bolts, gears, everything there is not one thing on this tractor original other than the casting. Way more in it than its worth but sentimental value is priceless.

OK so I had the engine bored .60 over and bought dome top pistons, had the machine shop do the valve job while I re built the engine afterwards. Timed and torqued everything to manufactors specs. Put the new clutch on and put it back together, primed the oil pump by taking the Allen head screw out and squirting oil in there. Have new points, new distributer, good gas flow, good spark, and good suction. Converted the tractor from 6v to 12v left the 6v starter on and put in a regulator.

After I check over everything a dozen times when I pull the start lever it acts like it wants to start it just wont. I will hit and run for about a second but wont crank. I also have noticed all the times I've tried to crank it my oil pressure gauge has not moved not one bit.

Any help on why it won't crank throw some stuff at me I'll try it from day to day when I get off work and hopefully we can get this thing started for the first time in 25 years

muleboss
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Re: 48 farmall cub cranking help

Postby muleboss » Wed Aug 05, 2015 8:45 pm

What do you mean by :put in a new regulator: ?

Matt in nc
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Re: 48 farmall cub cranking help

Postby Matt in nc » Wed Aug 05, 2015 8:52 pm

There may be another name for it but it breaks down 12v volt to a lower voltage so the 6v starter doesnt burn up from being spun so fast on 12volts

Matt in nc
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Re: 48 farmall cub cranking help

Postby Matt in nc » Wed Aug 05, 2015 8:53 pm

It's an inline regulator only wire it's hooked to is the starter

Eugene
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Re: 48 farmall cub cranking help

Postby Eugene » Wed Aug 05, 2015 9:20 pm

Most of us who have converted a 6 volt Cub to 12 volts operate the starter on 12 volts or purchase a 12 volt starter.

I don't know of a DC "regulator" (voltage drop, ballast resistor) capable of handling the 100 to 150 amps required to operate a starter. Suppose there are some. Photo please.

You need a voltage drop (ballast resistor) dropping the voltage to the coil and points. Or a coil with internal resistor.

What type ignition system does the tractor have; magneto, battery powered, or magneto converted to external coil?
I have an excuse. CRS.

staninlowerAL
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Re: 48 farmall cub cranking help

Postby staninlowerAL » Thu Aug 06, 2015 8:36 am

Have you rechecked the firing order? Your post indicates new distributor on a 48 Cub, is this still a mag dist or a battery ignition conversion? Your statement of "Have new points, new distributer, good gas flow, good spark, and good suction" leads me to believe that there is a timing issue.

Clip
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Re: 48 farmall cub cranking help

Postby Clip » Thu Aug 06, 2015 8:39 am

I'd tend to agree with Stan, if your coil/points/distributor cap/spark plugs and wires have been replaced and you're getting fuel. Check timing (make sure it's not 180° out) and firing order.

staninlowerAL
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Re: 48 farmall cub cranking help

Postby staninlowerAL » Thu Aug 06, 2015 8:45 am

Also a quick compression check of all cylinders will tell you if the valves are sealing.

Matt in nc
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Re: 48 farmall cub cranking help

Postby Matt in nc » Thu Aug 06, 2015 10:05 am

Clip what do you mean 180 degrees out. What should the compression be

Matt in nc
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Re: 48 farmall cub cranking help

Postby Matt in nc » Thu Aug 06, 2015 10:09 am

I can't take a picture of the anything hut the harness a guy out of Virginia custom built me the harness and put the regulator in the harness. I couldn't imagine that would have anything to do with it not cranking but I could be wrong. I spent 700 bucks on the harness, I had I built inside a stainless steel tube so no wires are visable anywhere on the tractor except the wires attach to their point of contacts.

Clip
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Re: 48 farmall cub cranking help

Postby Clip » Thu Aug 06, 2015 11:31 am

hlchauvin.php#Won't Start - Electrical Phase 2

staninlowerAL
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Re: 48 farmall cub cranking help

Postby staninlowerAL » Thu Aug 06, 2015 11:39 am

Matt in nc wrote:Clip what do you mean 180 degrees out. What should the compression be

What Clip is saying is the engine may not be firing at the right time, i.e. #1 at TDC on compression stroke but another piston is firing at that moment. IMHO, Compression on a newly rebuilt engine should be greater than 100 psi on all cylinders if done correctly. As far as oil pressure is concerned, you are not likely to see any change on the pressure gauge until it is running. It might take up to 20-30 seconds of running time for that to happen.

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Re: 48 farmall cub cranking help

Postby Matt Kirsch » Thu Aug 06, 2015 11:55 am

First thing, get rid of that "regulator." It's not necessary. The 6V starter can handle 12V for ~30 seconds at a time without damage. If your tractor doesn't start in 30 seconds of cranking, you've got other problems.

Next let's get some terminology straight so we are all speaking the same language:

"Crank" is the action of physically cranking the engine with the crank, or with the starter.
"Turn over" is generally used to describe the action of cranking the engine with the starter.
"Fire" is the action of one or more cylinders experiencing internal combustion.
"Run" is the action of the cylinders firing repeatedly in sequence, for a length of time.
"Start" is the sequence of events that cause an engine to go from a non-running to a running state.

I think if you simply remove that "regulator" thing, the tractor will crank, fire, and start. At least it will remove one variable from the mix and make troubleshooting easier.

Eugene
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Re: 48 farmall cub cranking help

Postby Eugene » Thu Aug 06, 2015 12:09 pm

As I understand, the "regulator" is hard wired in the harness and the entire harness has been installed inside a stainless steel tube.

Post a copy of the harness wiring diagram.

Photo of the $700- wiring harness/stainless steel tube?
I have an excuse. CRS.

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John *.?-!.* cub owner
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Re: 48 farmall cub cranking help

Postby John *.?-!.* cub owner » Thu Aug 06, 2015 12:23 pm

First thing I think is we need to define a couple of terms. Won't crank to most of us means the engine will NOT turn over when you hit the starter, if that is your problem I would suspect the "regulator" or voltage reducer which is what I would call it. If you mean the starter will spin for a second then stop, again I would suspect the "regulator". If you mean it runs for a second and stops, then I would suspect ignition wiring or fuel blockage.
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