Rotor

Hi Ron. your 1919 5 Ton Truck ought to have a ‘Dual Delco’ distributor unit that has two 6cylinder distributor caps. What you described sounds like the 1927-28 Series 36 distributor with a large distributor cap with 12 spark plug wire sockets and two coil wire sockets.

On the dual point distributor, one set of points is fastened to the point mounting plate and can only be adjusted to change the point gap. The other set of points is mounted on a moveable plate that is then fastened to the main mounting plate.

The method is to locate TDC [top dead center] on #1 cylinder, then look at the rotor, it should be pointing at the #1 plug wire contact inside the distributor cap. Both sets of points should be just opening.

This is set with the timing retarded..

On my 1919 Series 31, which has the original Dual Delco with two distributor caps. The operator’s manual states that one set of points is to be set to open 1*-2* later than the first set.. i can see no reason for any split in spark timing, and asking people with decades of experience with the T-head engines with dual spark plugs. They all say that i should just set them to fire together, at the same time..

Do you have an owners / operator’s manual for your truck? These manuals give a lot of info, such as adjusting brakes, setting timing, adjusting the clutch, etc..

Hope this helps..

Greg Long

Ron,

I have some info on setting the points in the Series 36 dual point, 12 wire distributor that I will e-mail to you (to the address you have listed in the roster) along with a photo of a Series 36 distributor to see if that in fact is what you have. The info I have says the points that fire the plugs over the exhaust valve should open 3-9 degrees prior to the set that fire the plugs over the intake valves. Dave