32V wiring questions

[Fineline]

Hello all can someone please.give me some information on what side of the coil is positive and witch one of neg . Also new spark plug wires
Do you have to peal back the rubber and expose the center to the side. And one more what cylinder gets what coil spark plug wire. I no these are some what simple question but I have to ask thanks again

[Sargehere]

Some say it makes no difference. Here, read: http://www.caimag.com/forum/showthre...uot-coils-Fail

[Fineline]

Thank you that information clears up alot for me to more forward . Real cool

[Tommo]

I was taught that if the system was positive earth the coil positive went to the contact points.
Negative earth and the coil negative went to the contact points.
If you got it wrong instead of jumping from the spark plug centre electrode to the earth point the spark jumped the other way.
Yes it will work but it is not as it was designed to work and generally speaking the spark plug gets a very hard time of it.
If you have access to a dyno try reversing the coil polarity either way and see what results you get.
Don't take my word for it, try it for yourself and you might be surprised with the results you get.

[HDSmitty]

On a related note......can it somehow be determined which is + or - on a coil that is not marked or installed ? (To facilitate installing as per Tommo) Thanks, Smitty

[Tommo]

Someone better than me may be able to answer that question but it is something I've never looked into.
If you're talking about the HD coil from 1930 on a careful look at the wiring diagram gives you your answer.
All HD's of this period are a negative earth electrical system and every wiring diagram I've seen shows the right hand side terminal on the coil going to the contact breaker.
Although the coil is generally not marked positive or negative on the terminals it is reasonable to presume that the right hand side terminal is the negative one.
I'm calling the right hand terminal the one that is towards the rear of the bike when the coil is mounted on the bike.
Hope this helps.

[HDSmitty]

Thank you Tommo. Smitty

[Sargehere]

Fineline, To help answer your original inquiry, here is a piece of our discussion on coil polarity:
Perform the "lead pencil test" described above,
(http://www.caimag.com/forum/showthre...uot-coils-Fail)
in the third reference, the "International Harvester Manual," and shown on "Next Page: Condensers" at its top right. Do it under low light, and you can check your current polarity at the plugs. On a UL, you can use a tiny c-clamp to hold a wooden pencil alongside the adjacent cooling fin and the pencil's lead point will be in the perfect position for the test, right next to the top of the rear plug
Here it is
TRUCK SERVICE MANUAL TM 5-4210-230-14&P-1 ELECTRICAL Fig. 5 Chart Showing Extra Voltage Required When Polarity Is Reversed For a time, the engine may run fine with coil polarity reversed--until the spark plugs have been in use for some time. Then, the driver may encounter hard starting or misfiring under load, as the amount of voltage required to fire the spark plugs under these conditions is higher than at any other time. In view of the above, it is very important that coil polarity should always be such that negative current is supplied to the spark plug terminals. CHECKING FOR REVERSED POLARITY A quick and easy method in checking for reversed polarity is the use of an ordinary wooden pencil, Fig. 6. Using the wooden pencil-check method, remove an ignition cable from any one of the spark plugs. Then, place the graphite tip of the pencil between the spark plug terminal and the cable and observe the spark as it jumps across the gap. If you notice the spark flaring or having an orange tinge on the spark plug side of the pencil, polarity is correct. If it flares or has a tinge on the cable side, polarity is reversed (be sure to use a wooden pencil when making this check or an uncomfortable shock may be received from the spark plugs). NOTE: The above check is used particularly on those coils not having any markings on the coil terminals. All coils recommended and used by the International Harvester Company are properly marked. NOTE: When checking for reversed polarity, always be certain that the spark plugs are correctly gapped and in good condition.

With the rear plug wire removed and placed right on the opposite side of the pencil. The spark should appear between the plug wire and the pencil, and the 'flash' of an orangish color, between the pencil and the terminal on top of the plug. Look quick, for the spark on one side and the "flash" on the other side. It's quick. You can snap "closed" points if you're using them. I had to kick over my electronic ignition and make it turn to fire off the coil.
--Last edited by Sarge; 03-31-2012 at 11:30 AM.