by loucrane » Thu May 17, 2007 10:44 am
John,
Fascinating for what you didn't say! Basically winging it, here;
If this is a manufactured 4-cyl, there should be some sort of distributor included. If, however, you've found or made a special, it will be up to you to create one, or its equivalent.
For an original, in either case, the engine has a 'firing order' - i.e., the sequence in which the cylinders fire. I'd presume that the ignition setting - "spark advance" - will be the same for all four.
If working from scratch, note down the firing order. Select one of the cylinders to call "#1" and count through them in a clear sequence. If it's a flat opposed four, you could go around them clockwise: - take the left front as #1, then the right front as #2, right rear as #3, etc. ...
Either with the valve cover off to observe the valves, or by some other certain method, rotate the engine to find when #1 is at Top Dead Center (TDC) with the valves closed, then further to find the next cylinder to reach TDC/valves closed, and on thru the others. Note down the sequence using the cylinder numbering you chose, e,g, 1-3-2-4.
If you have a distributor, connect the plug leads in that squence, making sure the points 'break' at a time suitable for #1 when #1 is coming up to TDC/valves closed, and the rotor rotation direction is correct.
If you have to generate some mechanical or electronic way to 'distribute' the sparks in the proper sequence, I'll leave that to you, or a trusted buddy, to figure out.
Unless, of course each cylinder has a separate point assembly. If that's the case, a pair of twin-cylinder coils might serve. Pair them to cylinders with more time between sparks - i.e. not to consecutive-firing cyls - I'd guess.
An intersting post; hope others add something more solid that my SWAG hereby offered.