OC-4 will only run on wrong firing order?

[Grant Richie]

I bought an OC-4 with an IXB3 Hercules motor to push some dirt around.  It was not running when I picked it up and after replacing some spark plugs, wires, condensor, coil, and a few other things I was getting spark and fuel but still not running.  I have the manual and had turned the flywheel to the mark on the viewing hole, made sure the rotor was firing on the number one position on the distributor cap, etc and it still wouldn't run.  I checked compression and found between 100 and 110 psi on each cylinder.  Rotating the distributor back and forth I could get either loud backfires or a somewhat steady flame coming out of the exhaust manifold so I finally decided to move plug wires as it sure seemed like things were not right.  The firing order had been by the book (1,2,4,3) so for starters I swapped 4 and 3 so my firing order was 1,2,3,4.  The motor would halfways start and then die which was an improvement.  I then switched 4 and 1 so my firing order was 4,2,3,1 and the motor fired right up without hesitation and runs well.  I played with many other firing combinations just to make sure nothing else would work.  So my question is why in the world will it only start and run on 4,2,3,1 when the firing order should be 1,2,4,3?  Anyone else run into this sort of issue?

[oliverchris]

One problem, I have come across is the distributor gear being off by a tooth or two giving a rough running engine. When that was fixed, it ran perfectly. If your distributor gear is off, maybe that's the problem?

Secondly, and excuse me for asking - but you have #1 as the front cylinder, right?

Second could-be-silly question, when you say distributor you don't mean magneto, do you? I say that because 4 cylinder OC4s originally came with magnetos.

If its a magneto, I think I read somewhere that it is possible to have the rotor on backwards which would mess up the firing order, one would think.

[John Schwiebert]

There are only 2 firing orders for in line 4 cylinders. They are : 1 - 2 - 4 - 3 & 1 - 3 - 4- 2. Plug wires 1 & 4 will always be across from each other. @ & 3 will also be across from each other. You need to know which way the rotor in mag also rotate. Get @ 1 (front cylinder) on compression stroke. Take the spark plug out so you can fee the compression. Turn in the direction of engine rotation till the mag trips. Is the spark mark viseable on the flywheel. Turn the engine 1/2 turn (mark the front pulley with chalk) Then see where the rotor is pointing (to number 2 or 3) Change the wires around if you need to. More questions?

[Grant Richie]

Yes, it has a magneto not a distributor.  Notch on rotor and gear are lined up.  I double checked that many, many times.  Putting the rotor on 180 degrees off gets no response from the engine, while the original position of the rotor gets lots of backfiring through the exhaust (so no starting with either position).  I was calling #1 cylinder in the front near the radiator and #4 the cylinder nearest the driver seat. 

And I have read the same thing about there only being two firing orders for 4 cylinders, that is why I posted the question.  It doesn't make sense.  I read and reread the book many times, double checking everything trying to see what I was missing before I finally swapped plug wire configuration out of desperation. 

Is it really necessary to pull the plugs to feel for the compression stroke when the rotor can only be installed two ways that will have the notches lined up?  What I mean is that if it doesn't fire one way, pulling the cap off and installing the rotor 180 degrees would be the only other right way.  Or am I forgetting something here? 

[hotratz]

You mentioned the "mark" on the flywheel through the viewing hole. If I remember correctly there is a mark for TDC and also a mark for spark "S". You want fire at #1 when "S" shows up in the window. Referencing what John posted, rotating the engine through #1 compression stroke the mag should trip when "S" is viewed on the flywheel.

[Blake Malkamaki]

The impulse should trip several degrees after TDC. To set the points just opening at the S mark, you must turn it over past TDC on #1 cylinder until the mag trips. Then back it up just past the S mark (to take the lash out of the gears), then proceed ahead to the S mark. The points should be set to start to open at that point. My gramps always used cellophane from a cigarette wrapper between the points. When you could just start to pull it out, the points were just starting to open.

Blake

rotating the engine through #1 compression stroke the mag should trip when "S" is viewed on the flywheel.

[Grant Richie]

OK.  A few questions and observations:  First, when you say the "mag trips"  is that referring to the lobe on the shaft opening the points?  Second, my flywheel has a mark with the initials "D C" which I assume means Top Dead Center and just before that there is a mark with no letters which I am assuming is my "Spark" mark.  Third, I pulled all the spark plugs off and held my finger over the hole and with the notches on the cap and gear lined up I am getting the compression stroke when the cap is pointing to the last position (going clockwise) on the cap.  If I had the wires set-up for the by-the-book firing order it would be firing on #3 cylinder when the #1 cylinder was on the compression stroke.  

So here are my thoughts.  Is it possible someone took the governor off sometime in the past 50 years and didn't line up the marks on the two gears when reassembling?  And since that is a possibility, I should really say is it likely that someone did that?  The fact is the motor starts up quickly and runs smooth when put the plugs into a 4,2,3,1 firing order.  Is it worth tearing apart the governor to check those marks as well?  Or should I just put it back together with the odd firing order and get some work done?

[Jack in NB]

You get an A+ for detective work, Grant. Sorting out that firing order the hard way  - well done!

It sure sounds as if someone got the governor/mag drive gear off time. No problem - I've had to shift it at one time for a different impulse coupling. As long as the points open (using Blake's technique to trip the impulse and the cellophane tip) on that spark (advanced from TDC) mark you found you should be ok.

As a final check. you can use a timing light (or a poor man's replacement - a long spark plug lead, plugged into the correct turret on the dist cap or clipped to the appropriate spark plug, held carefully so it doesn't bite you, and aimed into the timing hole so it arcs on the flywheel) to verity your mag setting. It helps to highlight the spark line on the flywheel with chalk or a dab of white paint so it's more visible.

[Blake Malkamaki]

When I say the "impulse trips" I mean when the impulse snaps. The way they work is at very low rpm (like when cranking it by hand) the impulse part of the mag has a finger that catches and does not allow the rotor or cam to turn until there is enough tension on a spring. Then it lets it go all at once and the rotor and cam spin rabidly, creating a good hot spark for starting. In the process, it also fires at a very retarded point (past TDC) so that the engine does not kick back while cranking. Once the engine is running, the impulse is no longer functional and the timing reverts back to the place where you set it at the S mark.

First, when you say the "mag trips"  is that referring to the lobe on the shaft opening the points? 

[Grant Richie]

I hadn't heard about the impulse for hand cranking before.  I wonder why it doesn't mention anything in the manual about that or did I just miss it?  

I spent most of my day getting the clutch functional again.  Things were rusted together and frozen, not to mention a broken spring that wouldn't disengage the clutch even if you were able to move it.  Just got that all back together so I pulled the plugs once again and watched where the rotor was pointing on each cylinder's compression stroke.  The order was 2,4,3,1.  So I am a quarter turn out of normal, but at least the correct firing order now.  For fun I put the cap back on the magneto to see if it would start and how well it would run.  It started with barely a bump from the starter and ran even smoother now.  So I am guessing that things are NOT put together right somewhere between the magneto gear and governor, but it starts super easy and runs excellent now.  I really need to get some work done with it so is there any good reason to tear into it further at this point and time, or should I get my work done and this winter when I have more time I could disassemble to see where the magneto or governor gears were put in wrong?  I guess what I am asking is whether there is any risk of operating it this way, or is it just an annoyance that I can't put things together by the book?  And just to verify so I am sure I read the manual right: the number one position on the cap is the top right behind the viewing window?  Correct?  It seems someone assembled everything with number one being top left, one position before the viewing window.  

One last question: my only concern now is the driveline and U-joints.  I hadn't looked at them until I tore into the clutch pedal and one of the U-joints is shot and if I run it much that way it will probably ruin my knuckle.  Does anyone have any brands or part numbers to get U-joints from my local Napa store?  I stopped in and asked them today but they were having a hard time finding anything.  Thanks,

Grant  

   

[Paul Bianchi]

Is it possible that someone had the fly wheel off and put back on wrong?

[Doug424]

Dowel pins locate the flywheel on the crank so it should be in the right place. More likely someone didn't put the governor gear in right. As far as the U joints, Ford model A parts will work.

[hotratz]

You won't hurt anything by running it as is. Like you said, it is just an annoyance if you were to do any future trouble shooting by the book. Change it at your leasure.

[Blake Malkamaki]

Bring #1 cylinder up on TDC and use a white paint marker to make a new #1 position on the distributor on the mag. You can still go to the S mark on the flywheel and set your points. It doesn't care which cylinder the cam is on. But you do have to go past the impulse and back it up as I described below.
Blake

[Grant Richie]

I made the marks on the pulley to align with the marks on the flywheel when I was figuring out where everything was pointing.  I then turned it to the TDC mark, then reversed a half turn before I adjusted things so the points were opening up at the spark mark on the fly wheel.  So I think I have all that part of it done pretty well and like I said, it is running like a top with just a bump from the starter.

I took the driveshaft with U-joints into Carquest and Napa today and told them a Model A U-joint would fit.  After waiting for an hour at the Carquest they gave me a price of $320 for the pair.  At Napa, the salesman just acted exacerbated that I asked him to find a part that wasn't in his U-joint book.  I ended up just ordering one from a website called fordor.com http://www.fordor.com/search_results.cfm?startrow=1362&action=prev&search=&sort=price+asc

The whole assembly is $90.  So to do both sides you would be $180 plus shipping.  Does that sound similar to what others have found or has anyone found a better source?  

I also started draining all the oils so I could change the filters and put new oil in.  The engine oil was definitely well used, but when I drained the transmission I got more water than oil.  The boot that goes over the shifter is gone so I am assuming most of the water went in from there.  Does anyone have a good source for getting a new shifter boot so my transmission doesn't fill up with water again?  Right now someone has wrapped a piece of inner tube around the shaft and secured it with electrical tape.  That is better than nothing, but I would like something that seals a little better.