[AT] Never Heard Such a Bang!

charlie hill charliehill at embarqmail.com
Thu Feb 28 07:45:35 PST 2013


Ben,  from my experience a problem that develops quickly and is severe is a 
small thing.
Look for loose wires, bad grounds, etc.

I once had a mag on an old Fairbanks Morse stationary engine
that was dead.  The previous owner had bypassed the coil in the mag and 
wired an automotive coil external
to it.   I have to assume they tried to find the problem before they cut a 
hole in the Bakelite mag cap and ran
that wire in it.  When I tore into it I eventually found that the mag and 
the old coil were fine.  The kill wire
that goes to the kill lug on the side of the mag had rubbed on the mag case 
and was going direct to ground.
I don't remember if I replaced the wire or just taped it up but the last 
time I started that engine a year or two ago
it was still working.

Look for the simple stuff and as Farmer would tell you....Check the grounds!

Charlie

-----Original Message----- 
From: Ben Wagner
Sent: Thursday, February 28, 2013 10:13 AM
To: Antique tractor email discussion group ; Farmall/IHC mailing list
Subject: Re: [AT] Never Heard Such a Bang!

Thanks to everyone for their replies. I forgot to mention I was working
with an H4 mag.   It has fire at the plug at TDC.  But I've got a loose
H4 I'll try to drop in and see if that helps, just to rule out an issue.

I'm nearly 100% certain that the problem is either timing/valves or
spark.  After checking the valves, it's almost has to be the spark.  The
problem is that the H4 hasn't had 50 hours on it since it was
restored/rebuilt with a new coil, condenser, points, rotor, distributor
cap, coil cover, and wires.

Any other ideas, feel free to holler!  I'm planning to spend some time
on it today. I'll keep everyone in the loop as to what happens.

Ben W.

www.oldpathsequipment.com
Mt. Solon, Virginia
Antique Machinery Repair and Restoration

On 2/27/2013 9:38 PM, Spencer Yost wrote:
> The advance in your mag/distributor is misbehaving my guess. That would 
> explain the bang during hand starting and fouled plugs.
>
> Just a theory,
>
> Spencer
>
> Sent from my iPhone
>
> On Feb 27, 2013, at 21:19, Ben Wagner <supera1948 at gmail.com> wrote:
>
>> Hello,
>>
>> It's been awhile since I've had to ask a question on here. Incidentally,
>> the question is on the tractor I was always bothering everyone about a
>> few years ago, my 1948 Farmall Super A.  Since that restoration, I have
>> completed restoring/rebuilding everything from Gravely walk behinds, to
>> Clinton equipped lawn mowers, to Ford tractors, and now even John Deere
>> two cylinders.
>>
>> All of that to say is even after all of that antique repair work, I am
>> stumped on my Super A once again.  It's a long story: bear with me and
>> maybe I'll give the right information that will help someone diagnose
>> the problem.
>>
>> About a week ago, the Super A had been running for about 20 minutes.  I
>> had it pushing in a John Deere M that I was rebuilding. I stopped to
>> kick the block from under the Deere, while the Super A was running about
>> 3/4 throttle, with a snow blade, so there was load on the Touch
>> Control.  I got back on the A, and gave it a little throttle to push the
>> Deere.  From the three seconds I had gotten off and back on the Farmall,
>> it suddenly had no power.  As in nearly stalling while moving in first
>> gear down a slope.  I cut it off and replaced the D21 plugs with fresh.
>> It ran much better, well enough to push in the Deere (which was quite a
>> load) and even scurry down the road in high gear.  It was still
>> sputtering slightly, but it had power.
>>
>> I pulled the Farmall out a day ago to (once again) move a tractor. It
>> started immediately, I am hand cranking, but it had no power, once
>> again.  It died while I was trying to ease it into an area where I could
>> work on it.   It wouldn't start back up.
>>
>> I tried to start it today, cold, and all I got after four hand cranks
>> (choke at 1/2 like always) was one loud bang in the muffler/manifold.
>> Enough to loosen the muffler from the exhaust pipe!  No backfire, but
>> just one loud bang.  The engine didn't even try to start.
>>
>> I have checked timing.  Everything is in tip top shape.  All the valves
>> are free and adjusted properly.  The carburetor is spotless: good fuel
>> flow, no junk in the lines, clean jets.  It is a Zenith with no high
>> speed adjustments.
>>
>> So the question is, what does the problem seem to be?  I have worked on
>> quite a few engines (but not as many as the folks on this list) but I've
>> never heard such a bang without a hot engine and too much choke!
>>
>> Thanks in advance for your help!
>>
>> Ben Wagner
>>
>> -- 
>> www.oldpathsequipment.com
>> Mt. Solon, Virginia
>> Antique Machinery Repair and Restoration
>>
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