[AT] Never Heard Such a Bang!

[Ben Wagner]

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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