Difference between "E" and "EM" series Mack engines

[Mr Black]

Hi, trying to clear up what the “M” stands for in an “EM” series engine.

I have an “EM6” in a 1985 R Model. It is the original engine from the factory (truck assembled in Brisbane, Australia).

I have been told that it may be a Maxidyne but I can’t find anything official to support that theory.

It’s our first Mack so I can only compare it to other brands but the engine is unbelievable for its age and relatively low HP (it's an EM300). I thought I would be re-powering for something with more HP but am now keen to keep it and would like to understand exactly what it is.

Can anyone educate me on this?

Thanks

[j_martell]

as far as i know, EM indicates a Maxidyne torque curve engine....pulls from around 1000rpm...what transmission is in the truck? A straight 5 or 6 speed would also back this up

[Superdog]

M is for Maxidyne

[Mr Black]

as far as i know, EM indicates a Maxidyne torque curve engine....pulls from around 1000rpm...what transmission is in the truck? A straight 5 or 6 speed would also back this up

M is for Maxidyne

Thanks guys, that is good to know. Makes sense as this thing will let you lug right down and will pick up again.

It was fitted from new with a T2090, but my understanding is that 5 and 6 speeds where not really used much in Australia at that time (if at all). Someone from my side of the world may want to jump in and correct me but I have only seen older models with 5/6 speeds here.

The T2090 has been a source of grief so I bought an Eaton 18 Speed for this truck. However, I would prefer to go all Mack again so am looking for a 12 speed. The only ones I can find are the early 2 stick versions, which I am of 2 minds about. Will probably post a thread for a transmission opinion next.