oldhousehugger
Member
Serial # 528936
Zenith carb. # L-48-0034-E
Magneto # WICO XH1343
Oil filter # Allis Chalmers 240912
Spark plug # UD-16
A guy on one of the other forums asked me to insert this article in the Stationary engine forum so here it is. I recently resurrected a 1945 Wisconsin VE4, which had been in storage for 35 years. I got it off a hay baler in Walpole NH in 1975 and put it on a cordwood saw, which needed to be built. It ran OK back then as I remembered but I wasn’t able to take it with me on my travels and so since then it sat in a barn in Connecticut and waiting for me to get around to hauling it down here to Texas. And no I don’t need to be reminded it was a waste of gas because it has deep person meaning to me and it needed to be out of the barn.
After soaking the cast iron Zenith carb in a gallon of OSPHO to get rid of rust and varnish, it cleaned up quite nicely. The fuel pump was toast so I replaced it with a plate to cover the hole in the block. I used a small gas tank off a lawn mower and rigged it so it gravity fed. The engine had zero compression when I checked it so I pulled the heads and lapped the valves and honed the cylinder bores to remove rust and glaze. The magneto was full of spider webs etc so I took it apart and cleaned everything real well. I used a .005 brass shim stock to maintain clearance between the field and the rotor on reassembly. If it rubs it won’t work. I also replaced the old stripped out slot head screws with new Philips head ones which will last at least as long as the originals. After the mag was all put back together it had only a little fire so I broke down and bought a new condenser from P.A.Ross Company here in Dallas. They also had valve spring seat locks to replace the one I shot across the yard and could not find in the scrap iron pile where I heard it land. Up till that point I was operating on common sense, nostalgia and logic.
After valve lapping and resetting the tappets I had compression of about 60 psi in all 4 cylinders, I had gas getting to the engine but I had no idea how to time the magneto, what the firing order was or how on earth the mag cap terminals were marked 1-4-3-2 and the supposed firing order was 1-3-4-2. I read what I could find here in the archives but there was a lot of conflicting information.
Turns out the VE4 had an engine speed magneto, which turned the same direction and speed as the crank. I’ve worked on a bunch of old magneto-fired engines but never a 4 cylinder. Whenever I have worked on an engine with a distributor it ran off the camshaft at ½ engine speed. Not this particular one though.
So here’s a bit of what I had to learn in order to make it run. I got some of the info from the archives here but the repair manual at the dealer had the best explanation by far. They were good enough to make copies of those 2 pages for me.
Cylinder numbers
This is a paraphrase of the Wisconsin repair manual discussion of the firing order for the VE4 and VF4 with the engine speed Wico magneto. The layout of the numbered cylinders is as follows. Standing facing the flywheel end of the engine, the cylinder closest to you on the left side bank is number 1 and the one behind it is number 3. The cylinder closest to you on the right hand bank is number 2 and the one behind it is number 4.
Firing order is definitely 1-3-4-2
The Wico magneto on this model engine has terminals marked on the cap as viewed from the output shaft end of the engine as follows. Number 1 terminal is at the upper right, number 4 upper left, number 3 lower left, and number 2 lower right. DO NOT BE DECIEVED, THE ROTATIONAL SEQUENCE OF THE CAP IS NOT THE FIRING ORDER OF THE ENGINE. The logic of the firing order of 1-3-4-2 is as follows. First of all you must view the entire process as referenced by number 1 cylinder. The engine is a 4 cycle so the entire 4 cycles power, exhaust, intake and compression require 2 revolutions of the crankshaft. That is equivalent to 2 times 360 degrees or 720 degrees. The power stroke of number 3 is 180 degrees (1/2 revolution) of crank rotation behind number 1, number 4 is 270 degrees (3/4 revolution) behind number 3 and number 2 is 180 degrees (1/2 revolution) behind number 4.
Since the Wico magneto on this model engine turns in a COUNTER CLOCKWISE direction and at the same rotational speed as the crankshaft, number 3 cylinder must receive spark at 180 degrees after number 1. Since terminal number 3 is opposite number 1, it is 180 degrees of rotation away from number 1. Therefore, even though number 4 cylinder gets a spark at 90 degrees past number 1 on it’s trip over to number 3, it sparks on number 4’s exhaust stroke so it does no harm. Another thing to realize is that the right bank, 2 and 4 are 90 degrees out of phase with 1 and 3. This works out because number 4’s power stroke is ¾ of a revolution behind 3. So, the magneto distributor head sparks terminals 2 and 1 harmlessly on the way by, (hitting at the top of their exhaust strokes) to provide a spark for number 4 at 270 degrees past number 3. Number 2 fires at 180 degrees (1/2 revolution ) past number 4 so it’s the same logic as from number 1 to number 3. Number 3 gets a harmless spark at the top of its exhaust stroke.
So to recap, ILLOGICAL AS IT MAY SEEM, the sparkplug wire from the numbered terminal on the VE4 Wico magneto goes to the corresponding same numbered cylinder.
The repair manual stresses that even though the wires may have been switched around in the field because it is so hard to visualize the firing order, given the order of terminals on the cap, it is imperative that the wires be placed on the correct cylinders and magneto terminals to avoid accidental kickbacks and the broken bones they can cause.
Installing the Wico Magneto on the engine.
First, the gear on the magneto driven by the idler gear is the same size as the gear on the crankshaft, which drives the idler gear. Therefore, the magneto shaft turns the same speed as the crankshaft in the same direction. Looking from the rear of the engine at the magneto cap, the rotor turns in a counterclockwise direction.
To properly install the magneto on the engine, turn the crank until the leading edge of the vane with the DC cast next to it on the flywheel lines up with the vertical mark on the cooling shroud at the center top of the opening. With the crank held in this position fit the magneto so that the “X” marked on the tooth of the magneto drive gear is visible in the lower half of the inspection hole in the magneto gear housing. With the cap off, the rotor should be pointing just past vertical over towards number 4 terminal. It does not matter whether you are on the first or second revolution of number one cylinders combustion cycle because if it’s the second half it is harmlessly in the exhaust stroke. Once you are sure the magneto is properly timed, it fires every ¼ revolution of the crank and the correct plug gets fire at the correct time for power and harmlessly on the exhaust stroke one revolution later.
To check that you have timed the magneto correctly, turn the engine over very slowly by hand and listen for the magneto to snap when the “DC” vane on the flywheel lines up with centerline of the 1 and 3 bank of cylinders and then the 2 and 4 centerline of cylinders.
Spark advance
The automatic advance is built into the mechanism of the magneto and occurs progressively from 0 to 27 degrees as the engine increases in speed. At rest, (starting for instance) spark should occur slightly after TDC of the firing cylinder so that kickback does not occur.
I have included a schematic of the sine wave (up-down of the piston over time) for each cylinder in relation to the others as a way to visualize the firing order. If you want it straight from the horses mouth, get in touch and I’ll send you a copy of what I got from the dealer.
John
