Farmall Super MD Spark Plug

[Boomer2431]

What spark plug would everybody recommended for my Super MD? I am fluent with the gas plugs but this is the first diesel I've owned. Thanks

 

[old]

An MD is a gas start then once warmed up a diesel so take out one of the old plugs and then use that number on it to go and buy new ones. Now days if it has say a champ or auto lite in it I find the NGK equal to them since now days the other two brands are junk

 

[Bob M]

Champion D89D is the OEM plug for the MD. It's a special design with an extreme extended tip.

Uncertain if other mfr's have a cross to the D89D - I've never found one. However some auto parts stores can still provide the D89D. Last time I looked they were $10 apiece online from O'Reilly's.

 

[Eddie V]

BOB,

The very original plugs were champion #49 Now known as the D89D #543 Champion Plug
The other original Was A AC #18A which I have some new old stock ones and took years to
find some.

 

[jim warehime]

Champion d89d, new number is champion 543. Ac delco is 18a. Also you can use autolite 388 plug. Have autolite in my super md, and 41 md. Have d89d in my 51 md. Champions are about $11 each, autolite were 3 dollars each. Personally I liked the autolite better. All are available at auto parts stores or on ebay. What year is your diesel? Jim.

 

[rustred]

it dont make one iota of a difference what brand of plugs are in your tractor. i have a bunch of these old gas starts.i would say 99 % of them have champions. the tractor is also only going to run a couple minutes on gas each start up. i also found an old unique set of AC plugs i put in my wd40. bet most of u have never seen plugs like that. i believe they are what came originally in it in 1939.
also if you are stuck for example like breaking a plug which is easily done on those tractors you can use a gas plug to get you going. i have even tryed champion D16 plugs in mine, as an experiment. the tractor is hard starting due to the short reach but it will start and run. just saying...

 

[jim warehime]

Agre 100% everyone says use d89 champions, tried the 388 autolite, tractor starts easy runs good and are 75% less money then champions.