distributor plates

Charles E. McNelly III · Aug 1, 2009

Does anyone know which distributor plate was in the distributor on the 240 series farmall and the 340 series farmall tractors? I have seen a plate with 16L and another with 40L stamped on them. I understand that means total advance. Did IH make more then just these 2 plates? If your motor needed a total timing of 30 degrees, did IH use a 40L plate and limit the amount of total timing with heavy springs?
Thanks,
Charles

Janicholson · Aug 1, 2009

I'm not sure the advance was stamped on the plate, the advance is controlled by the weights and springs against pins on the shaft behind the plate. The total advance is determined by the maximum the rotor can turn in the advanced direction stretching the springs. It is 50% of the actual crankshaft motion, if measured directly with a protractor. thus 20 degrees of crank advance would be 10 degrees of distributor advance (measured at the distributor with a protractor. JimN

Jim Becker · Aug 1, 2009

The shaft (with the attached plate) determines the maximum advance. Changing springs alters how quickly (at what speed) it will advance. A 240 should have a type X distributor, with a 30L shaft. A 340 with flat top pistons uses the same. With Fire Crater pistons, the 340 uses an AE distributor, limited to 25 degrees. AE also uses different springs, but I don't know how different.

Charles E. McNelly III · Aug 1, 2009

Thanks for the replys, guys. I guess finding a 25 degree plate will be tough. I have a 16 degree plate that I can elongate the hole a little until I have what I'm looking for. Thanks for the info. and help.
Charles

Anonymous-0 · Aug 1, 2009

Ih used a 40 L , 30 L, 25 L, 22 L, 16 L, and a 8 R on farmall models, 8 R was for the diesels. Also had a R shaft for the W9 as the dist turned opposite way but don't know how many different ones . Umpteen different spring set for different rates of advance. I just measured up my M , it had a 22 degree L shaft in it , should have been 30 with flat head pistons, so I calculated how much longer to make the hole and by gosh I hit it real close first try. By the way, 16 was normally for LP gas.

NDS · Aug 2, 2009

The way the vast majority of 50 year+ old tractors are used any distribitor will work fine. Just set timing by ear and it will run fine. If you are looking for that last 1/2 HP then precision tuning may be in order. This is just my opinion but it is based on 60 years real world experience, Have swapped distributors from Ms to Hs to 400s to As and back to Super Ms and they would run good enough to suit me.

JakeE · Aug 2, 2009

if i remember right the stamping on the plate must be doubled up to get total advance,use a advance timing light to get your total advance at full RPM.s , i would try that at 36 to 40 and watch out for spark knock,as compresion goes up timing must move back down.

Anonymous-0 · Aug 2, 2009

No, the number on the plate it the total advance at the engine,ie a 40 plate will give you 40 degrees advance on the crank pulley. If you don't have a advance reading timing light, it is a simple matter to measure pulley diameter and calculate distance from tdc to any degree you want to make your mark. Back when these old tractors were doing the work on the farm no one even heard of an advance timing light so we marked pulleys accordingly. Put in a lot of fire crater pistons in M's and remember 22 degree advance that came with the kit and they even sent a template along to mark pulley l 7/16 degrees btdc. The springs they sent in the kit would rarely return timing to tdc at low idle even when weights and all were new, so you had to be certain to adjust timing while running full throttle.

distributor plates

Charles E. McNelly III

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Janicholson

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Jim Becker

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Charles E. McNelly III

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Anonymous-0

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NDS

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JakeE

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Anonymous-0

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