magnet

I'm not sure, but I think you need to look at that magneto match again real careful like. My D7 is a 3T but I think the timing is the same.

Cat used a 180 degree crankshaft. That translates to 90 degrees of camshaft rotation, therefore you need a 90 degree magneto if runs at camshaft speed or a 180 if it runs at crankshaft speed. On the 3T the magneto runs at crankshaft speed but the rotor in the mag is driven at cam speed.

Just be real sure what you are dealing with there before you spend a bunch of money. I've been called out several times when the only problem was in the timing.

let us know how it goes.

Hi Jack,
No doubt the 3T is a 180 degree crank but later ponies also utilized a 360 degree crank (both throws had same indexing with a heavy bolt on counterweight) referred to as the even fire vs odd fire unit.

I'll be darned. I've never seen or heard of a 360 degree pony crank! Of course, I only tangled with a few of them that I and friends happen to have. There's been so much misunderstanding of the timing on the 180 crank engines I figured it best to be first sure of just what we have in hand.

I have a d7 magneto counterclock wise 7h6866

OM I don,t have parts book to check the mag numbers that were used but the 17A earlier ones and the D8s and D9s used the crank that did have the throws on the same side and then when they went to the odd firing on them the throws were 180 D. apart and that,s when they put the mag down front and not on top like earlier D7,8, & 9s in the 17A 14A & 15A and the D9s of that era along with other starting engines that were the same on some other engines.

hello ,this page may help you out with the info you need ,bruce oz

http://www.oldengine.org/members/diesel/MagnetoMisc/MagApps7.htm



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The 7H6866 is a Wico magneto that was used on the early 360 degree crank but it was for the crank driven vertical drive. Not sure if it will work "as is" on this conversion application.