[AT] Never Heard Such a Bang!

Ken Knierim ken.knierim at gmail.com
Fri Mar 1 05:57:22 PST 2013


2 weeks ago I fought with a buddy's Ford 3000 that had ignition issues.
The original coil had gone south and the replacement didn't work.

Here's the condensed version

the original coil was an external resistor type.
The harness did not have a resistor in it. (ran for years like this. not
sure how)
Original coil died. No spark output
replacement coil was also external resistor type.
Replacement points were installed.
Coil wouldn't fire until new points were filed and cleaned with alcohol
(thanks Neil Yerigan)
Engine ran weak and rough and died again, never to restart.
Noted resistance across points. Replaced with new Napa set.
spark again for a short period. Looked at everything again. Replaced coil
with internal resistor type.
Engine started. retuned carb since it had been tweaked to run with poor
spark.
Very happy all around. Took me about 5 hours of cussing and getting parts
to get it working.
My buddy had been fighting it off and on since November.

Many ignition problems are blamed on carbs. In this case we used starting
fluid injected into the intake manifolf to make sure we had fuel that would
ignite. After we got the first sneeze out of it, we knew we were headed in
the right direction.

We also got an el-cheapo adjustable-gap spark gap tester. This proved to be
very handy. When the tractor lost fire we would connect the coil to the
spark gap tester, roll the engine up to where we could move the distributor
rotor past point opening and listen for the snap of the spark. We knew it
was right when it was easily throwing 1/4" of spark. Early on it wouldn't
go 1/16"... this provided an adjustable metric that helped with
diagnostics.

Hope this helps.

Ken in AZ

On Thu, Feb 28, 2013 at 7:03 PM, John & Jan Paur <johnjanpaur2 at directcon.net
> wrote:

> Look for either moisture and/or cracks inside the distributer cap on the
> magneto.  JP
>
>
> ----- Original Message -----
> From: "charlie hill" <charliehill at embarqmail.com>
> To: "Antique tractor email discussion group" <at at lists.antique-tractor.com
> >
> Sent: Thursday, February 28, 2013 7:45 AM
> Subject: Re: [AT] Never Heard Such a Bang!
>
>
> > 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
> >>>
> >>> _______________________________________________
> >>> AT mailing list
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