Wd runs on 2 cylinders
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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=56571
Printed Date: 06 Sep 2025 at 8:27am
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Topic: Wd runs on 2 cylinders
Posted By: ironac
Subject: Wd runs on 2 cylinders
Date Posted: 09 Sep 2012 at 2:30am
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For some reason my wd will only fire on 2 cylinders. I can unplug #1 and #4 wires to plugs and it doesn't do anthing. With them plugged in I get a very faint spark to 3/4 cylinders. But if I pull #1 and #4 wires out of the dcap and hold them over top the hole they go in the spark jumps out of the hole to the wire and all of a sudden it's fireing on all 4. I tried differnt caps and wires but I couldn't even get it to fire then. Anyone have a idea??
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Replies:
Posted By: Gerald J.
Date Posted: 09 Sep 2012 at 3:10am
Fowled or very worn plugs on those two cylinders. The added gaps causes much higher voltage to make the plugs fire. The higher voltage is hard on the coil and distributor insulation.
Gerald J.
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Posted By: jlogli
Date Posted: 09 Sep 2012 at 9:04am
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Change your plugs.
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1945 WC on full steel, WD wide front, WD45 power steering, 1966 D-17IVfactory 3 point.1967 D-17IV SC. 1973 rotobaler white top. orange top roto, model 90 combine,82S, four bottom plow.302 baler.
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Posted By: Ted in NE-OH
Date Posted: 09 Sep 2012 at 9:09am
Do you have the wires mixed up? Firing order is 1-2-4-3
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CA, WD, C, 3 Bs, 2 Gs, WC, I-400, 914
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Posted By: DaveKamp
Date Posted: 09 Sep 2012 at 9:27am
I've had engines that did that... even changing plugs didn't fix it. Sometimes going to a hotter plug solved it (oil-breathing engines), and sometimes replacing the condenser and/or coil cleared it up.
Question for you is... if you lift just ONE of the two offending plugs... 1 or 4, do you get one more cylinder firing, or do you get TWO?
There's only two things in common with 1 and 4 that aren't in common with 2/3... they're on the same plane, and they're opposite eachother in the distributor.
If the distributor shaft bushing is worn on that plane, it could be getting a lousy contact settling, which causes the firing of the 1/4 plane to be lousy in comparison to the 2/3... and lifting the wires is JUST enough to make it develop a higher voltage.
If you have a known-good distributor off another engine, I'd try a swap, or at very least, take the cap off both, and measure for slop. I would also not discount the possibility of the point cam being worn, or as weird as it may seem, even something in the mechanism being damaged or bent.
I would recommend, regardless, that you change out the coil and condenser regardless... my bet is that they 'don't owe you anything' now.
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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
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Posted By: ironac
Date Posted: 09 Sep 2012 at 3:06pm
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I will deffinalty make a trip onto town and see what I can pick up. The plugs are ac delco and I've had a lot of good luck with them but I guess u never know.
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Posted By: Gerald J.
Date Posted: 09 Sep 2012 at 5:39pm
Its certain that the bushing is worn. And if the shaft is worn ROUND that slop will affect all cylinders. However, if the shaft is worn oval it can have more slop in the direction where it skinnier and not open the points as well, which means longer dwell and more energy stored in the coil. But that presumes the point gap was set with the shaft in the position to open best.
Could be oil fowled plugs, and Champions tend to never clean up once dirtied and they can tak higher voltage to fire then especially under compression. Some lines of old tractor champions have a built in air gap to raise the spark voltage for oil burners, as if all old tractors are never rebuilt. Other brands seem to run better and longer.
Gerald J.
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