1982 Bobcat 630 vh4d running on 2 cylinders please help

[alexotoole]

so I post a lot on many forums to try to help and educate people in need so hopefully karma can kick some help back here. 1st time poster here and heres what I have going on. 82' bobcat 630 skid steer with a Wisconsin vh4d 4cyl gas engine that only has spark on 2 cylinders. I have replaced with new parts the coil, plugs, wires, ignitor(solid sate electrical ignition) cap and rotor with all oem quality parts. I even exchanged the coil to be safe with another new one to no luck. cylinders 2 and 4 have spark(right bank), 1 and 3 (left bank) none. I'm getting 11 + volts to coil but spark from coil seems like it once every .5 seconds not constant(not sure if it should be). I have re-grounded a new engine and chassis ground. In timing it with a gun, its spot on what should be #1 cylinder but I cant tell cuz it has no spark but btdc is spot on where marks on case align. I pulled the distributor and swapped it 180 degrees and it runs the same after switching dist wires around but runs on cylinder 1 and 3 (left bank). I tried to unplug regulator and rectifier one at a time while running to no gain. took apart dist to clean and inspect and see nothing out of the ordinary. I also swapped wires plugs etc with the working side to rule that out to no success as well. I even hooked up a charged jump pack to the positive side of the coil + and negative to chassis ground to see if the coil would fire different with higher voltage and nothing changed. one thing I can say is I pulled the monster flywheel off and the magneto or magnets inside were filthy one of which was shattered (maybe 8 or 10 total inside) and the stator filthy as well, cleaned them with wire wheel and still no luck. would the stator affect this? I always thought if you unplug it with a charged battery it would spark regardless. Again any help much appreciated as I'm in this with way too much time and money. sorry for the paragraph lol.

 

[mikebramel]

You bought it like this?

 

[alexotoole]

Prior to repairs yes

 

[repowerguy]

Are the points opening with the breaker cam on 1&3 ? A low lobe occasionally will happen and two is possible I suppose. If they look low, set the gap tighter then see if all four will spark.

 

[fast_st]

A good idea, if the cam is worn a few tenths more and everything is close, it might not spark. I suppose you could lay out all four wires and plugs and tie them down so you can observe the spark. We used to attach a bulbed test light to the coil ground wire on the points side of the coil and then ground it, it should blink as the points open and close

 

[alexotoole]

Are the points opening with the breaker cam on 1&3 ? A low lobe occasionally will happen and two is possible I suppose. If they look low, set the gap tighter then see if all four will spark.

No points as its an electronic ignitor setup

 

[alexotoole]

So thank you for all the responses. Turns out it was a rediculous fix. Apparently previous owner changed the rotor and cap and there is a small plastic peice that slides down the distributor shaft and has four tiny magnets in it. These magnets have a north and south polarity. If they are backwards that specific cylinder will not fire. Think of when you have 2 magnets facing each other they push away or stick together. Key is to take a small magnet and get them all to stick to it then install back. Who would have thought but i hope this helps others in the future on their wallet and headache/time invested

 

[xgiovannix12]

this had me scratching my head.I had no good response for the issue since you were pretty much in the right track Glad you fixed the issue.

 

[fast_st]

That's zany, good catch!!!

 

[kshansen]

So thank you for all the responses. Turns out it was a rediculous fix. Apparently previous owner changed the rotor and cap and there is a small plastic peice that slides down the distributor shaft and has four tiny magnets in it. These magnets have a north and south polarity. If they are backwards that specific cylinder will not fire. Think of when you have 2 magnets facing each other they push away or stick together. Key is to take a small magnet and get them all to stick to it then install back. Who would have thought but i hope this helps others in the future on their wallet and headache/time invested

I was thinking about this Wisconsin problem along the idea that some versions of those V-4 have an odd/uneven firing order two cylinders close together two further apart. If you look close at the cam in the distributer in the picture below you can see what I mean:


That can drive you crazy trying to get the firing timing right!

Then I did notice you mentioned the little magnets and it reminded me of a wood chipper I had to do some work on after borrowing it to get it to run and thought I was going to go crazy getting it to run right again. I did finally find some information on this ignition system and could send you it if it would be of interest. I also have a new in the box "pick up coil" that I would be willing to part with if there was any interest.

 

[Birken Vogt]

My uncle has a woodsplitter he shop built with one of those for power. He also posted on here once years ago but not about the woodsplitter, it was a tractor.

Thanks for reminding me about the silly firing timing. We use that splitter every year and it has no electrical system. Just a short little hand crank and impulse mag. When you are cranking it you never know when it is going to come up on another cylinder, very odd feeling.

Anyway I am amazed that you figured out the N/S magnet thing. Those are the things that waste days. Makes you feel good when you find it though.

 

[kshansen]

Not sure if the magneto engines had the same odd timing design. Seems like some of those V4 Wisconsins had evenly spaced firing orders and others like the distributor I posted above.

I know the first one I dealt with had me confused for a while. Think I finally had to figure it out by pulling all the plugs out and determining which piston came up on compression and when then matched that to the spacing on the cam in the distributor.

Also just be careful with that crank on the magneto engine. Sometimes when they fire they will kick the crank off and it will smack you between the eyes! Happened to both myself and dad on a water pump we had at the quarry many years ago!

 

[Birken Vogt]

I read it a very old book somewhere about all V-4 engines having odd fire. Makes sense to me unless you have 4 crank throws.

My dad puts a drop of oil from the dipstick on that shaft before cranking so the handle doesn't stick to the shaft. We always, always follow the old procedure of pulling up 1/4 turn at a time only, thumbs on the underside side of the crank same as fingers so that if it kicks backwards it just pulls your hands open and that's that.