Well, after those went out, glow plugs came in...and, as somebody else
already noted, there were also the pony engine starting systems as well.
That there were alternatives before them (glow plugs) doesn't negate the
But, technically, he's right. And since we must accept everything EXACTLY
as it is written, with no allowance for common sense, colloquialisms, or
brain farts, the correction is valid.
I just wish we could get back to a time when everything didn't have to be so
damn exact. And netnannyism wasn't so many people's hobby.
Oh? Never saw the older ones? International TD series had a full
gas system that they started on, carb, plugs, everything, using the
same engine. Cat used a gas pony engine. I spent enough hours
cranking them. Don't know how far they went before the glow plug
system came into use.
IH also used pony engines on at least some. We had a loaner for a while
one year while a major repair on the 560 was underway I remember that
was a real pita. The complication and starting difficulty in winter
(and the odor) were main reasons Dad never switched over from LP to
diesel until the 4000-series Deeres came out in the early/mid 60s. They
initially were glow plug. The oldest I have on the place now is the '85
(I think I recall that, at least it's close) 4440 and it is direct
start. Recollecting, I'd guess the transition to glow plugs began in
the early 60s, direct start pretty widespread in the late 70s/early 80s
for farm tractors, anyway. Would presume that to be roughly the same
The 955 is the Yanmar 3-cyl and it still uses glow plugs. The Cat 3208
in the '88 Ford chassis truck was an optional direct start.
But it did back then. Those were the early days and my statement,
'except for starting', was accurate. The ones I referred to were
built in the 30s and 40s. I don't know if the TD series continued
that wierd starting system into the 50s.
I _really_ learned about how high comprression was on diesels the
morning I grabbed the crank on the TD6 and almost drove my ankles into
the ground. It was like hitting a solid block of iron. The
decompression link had come adrift.
Diesels never have spark plugs. Some designs use glow plugs which are
actually just a little heating element to preheat the combustion chamber
. Some designs have a heating element in a box in the intake which warms
the air before starting.
Its the heat of compression that fires a diesel. If the weather is warm
or you had a sufficiently beefy starter you could start one without glow
Spark-converted diesels do. This is a diesel engine burning natural or
other fuel gas. The mixture is so lean it withstands the typical diesel
heat of compression and doesn't ignite until sparked. Or they can leave
the oil injection system in place and inject a small amount as a pilot to
trigger combustion. In the latter case such engines are often designed to
be able to up the amount of liquid fuel injected to normal levels while the
gaseous fuel is turned off in which case it's known as a dual fuel engine.
Purists will maintain that if a spark ignition system replaces the fuel
injection system then it's no longer a diesel. The problem with that is
that words mean what the majority says they mean. I can say that a single
"D" power cell is never by itself a "battery" but it's a lost cause.
Further, the definition of diesel as being an engine using the heat of
compression for ignition has not always been the case either. There was a
time when folks thought "Diesel" (it was usually capitalized in those days)
referred to an compression-ignition engine using high pressure air for
injection. Engines using "solid injection" as came to be standard were
known as "oil engines." You'll see pictures of some early Diesel
locomotives which say on their sides, "OIL ELECTRIC LOCOMOTIVE." Gradually
it was recognized that Dr. Diesel's big innovation was compression
ignition, not how fuel injection was done (or even what was injected...his
first experiment used coal dust!). My point here is simply that the
definition has been and is flexible. With that in mind, yes, sometimes
diesels have spark plugs.
You should have learned not to say 'always' or 'never'. Back in the
early days, the McCormick Deering (later International) all had spark
plugs for starting. They started on gas to warm up then changed over
to diesel. You can google International TD6 (for one) or Mc Deering
T20 for another. Those were in the 30s and 40s which is when I was
Yes, before you go off on a tangent, the plugs were in the same
cylinders. There was a compression release that had to be set as part
of the starting procedure.
Technology moved on using first glow plugs and then nothign at all in
Thanks a lot, guys. This time, I lived up to my screen name! Now I
feel better about running this engine. My previous experience was with
4 stroke engines and diesels (Onan DJE repair and Cummins L423D
Ignorant is just never having something explained to you. Stupid is having
it explained to you, and not listening to the explanation. That's how we
learn. We're born not knowing everything. Then, we're taught about this
and that. Being stupid is choosing not to heed instruction.
Now you know.
Now that you've seen how it works, it IS exquisitely simple, isn't it?
The first explanation I had of it had an animated moving parts diagram.
Since the fuel/air mixture is forced into the combustion chamber by the
downward travel of the piston, it achieves almost a supercharger effect,
forcing the air/gas mix rather than working on suction as a four stroke
2 strokes do a great job at high RPMs that is why racing motor cycles
and boat outboard motors used to always be 2 strokes.
The problems start at low RPMs. You are not moving enough fuel at an
economic throttle opening to lubricate the engine so they usually do
tricks with the timing and they end up smoking a lot.
These days guys like Evinrude are doing things with computers and
independent oiling systems to make a clean 2 stroke. The FICHT was
their first unsuccessful swing at it but the Etec is doing OK now.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.