400 d

tonastoy · Nov 19, 2009

i have a 400 diesel. i just fried the points and was noseing around to see why. there is no porcilen in line regulator going to the coil. do i need one . its set up for 12v but i thought you still needed the porcilen piece. next question . after i switch over to diesel are the points still working and if they are can i put a switch in line to help stop the points from arcing and wearing

Bob M · Nov 19, 2009

If your tractor still has it's original 12 volt coil, a ballast resistor (the "porcelain" you mention) is not required.

However if someone swapped it for a generic autmotive (externally ballasted) 12 volt coil a ballast resistor is necessary to limit coil current and prevent burning the points.

Regarding an ignition cutoff when running diesel, if memory serves there's a switch on the front end of the intake manifold to open the coil primary circuit when the starting lever is in "run" (diesel) position. Yours may be out of adjustment or bypassed.

M Diesel · Nov 19, 2009

And your memory is exactly right.

FYI, the switch may be configured to operate as a switch or a switch to ground for the tractors with a mag.

450D · Nov 19, 2009

My 450D bought new by my uncle is 12V and has a
ballast resister, so I would think your 400D should have one too.
Also there is a switch on the end of the intake manifold that shuts off the
spark when switched to diesel.

Dave

pete 23 · Nov 19, 2009

IH changed their minds many times on that 12 volt with or with out ballast on the diesel models. Latest was, 6 volt coil, no ballast as they felt you ran it such a short period of time the hotter spark outweighed the high current flow through the points. And yes, the manifold switch must be operating to shut off ign when on diesel cycle. Lot of them switchs failed so they were bypassed by hooking both wires to same terminal at the manifold switch. Then of course you had to be sure to shut off ign switch or points and coil would burn up. I would venture to say we replaced more coils on the diesel models than all the gas models combined in their hay day.

D Slater · Nov 19, 2009

Last half or so of 450D built used the resister, but also a wire from the starter switch to coil that bypassed the resister when starter was engaged. 400D and part of the 450D didn't use a resister or bypass circut. Later 450D used a distributor with no advance. Other 400 and 450 D used 8 degree advance units.
What pete 23 said about the rest.

400 d

tonastoy

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Bob M

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M Diesel

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450D

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pete 23

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D Slater

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