E6 2 valve or e6 4 valve

[Jicaju]

I have a 1985 e6 2 valve  and  1987 e6  4 valve econodyne. Wanting to rebuild one or the other. Is one better than the other. Would like to put bigger turbo and injector. Would like to get 400 or 425 out of it.

[Jicaju]

2 valve is a maxidyne

[MACKS]

The four valve is not a maxidyne,I’m thinking it is and that’s the one I would put my money into..

[mrsmackpaul]

Thats a lotta power out of a small motor 

Maxidyne I think has extra webbing in the block, this might be handy for the extra horsepower 

 

Paul 

[Vladislav]

4 valve may be both Maxidyne and Econodyne. And E7 too. E6 versus EM6 and E7 vs EM7. Different settings in fuel pump and turbo (and I would really like to learn the particular differences).

Asking the original question - 4 valve is newer engine with better perspectives obtaining parts in the future. Just one of the aspects. 

[The Heinz]

If it makes any difference to anyone: along the same lines as Vlad being right about 4v parts availability, Impact handles those later E6's better, making it easier for the parts guy at the dealership. Again, should you actually use a dealership.

[Mark T]

22 hours ago, Jicaju said:

2 valve is a maxidyne

I don't think a 300+ was a Maxidyne 

[harrybarbon]

I have been looking to find a bit more information about the actual build/specifications difference between the Maxidyne and Econodyne motors. There is various information about the 2 engine performances, such as the powerbands for torque, Maxidyne is more suited to say construction type applications versus the Econodyne being more suited for hiway application. The motors were painted different colours. Externally both motors appear alike, both the Maxidyne and Econodynes had the intercooler over the motor, etc. I understand that the Econodyne E6 - 4 valve motor cannot have the intercooler over the motor, but the E6 2 valve can have the intercooler over the motor. I would appreciate any info - thanks.

[mrsmackpaul]

Dunno if there ever was a 2 valve Econodyne in Australia or if it ever was built

 

Paul 

[Mark T]

14 hours ago, harrybarbon said:

I have been looking to find a bit more information about the actual build/specifications difference between the Maxidyne and Econodyne motors. There is various information about the 2 engine performances, such as the powerbands for torque, Maxidyne is more suited to say construction type applications versus the Econodyne being more suited for hiway application. The motors were painted different colours. Externally both motors appear alike, both the Maxidyne and Econodynes had the intercooler over the motor, etc. I understand that the Econodyne E6 - 4 valve motor cannot have the intercooler over the motor, but the E6 2 valve can have the intercooler over the motor. I would appreciate any info - thanks.

I know mid '80s you could get a charge air cooler on a 2 valve. One I had here was a Maxidyne set up like that. (300 with a five speed road tractor)

[Vladislav]

I have a 1984 MH cabover with 2V E6 with chassis mounted aftercooler and T2090 9-speed tranny. So the engine's supposed to be Econodyne. I'm not almost sure all that is factory combo though. But more looks like that.

[Vladislav]

On 9/25/2024 at 10:05 AM, harrybarbon said:

I have been looking to find a bit more information about the actual build/specifications difference between the Maxidyne and Econodyne motors. There is various information about the 2 engine performances, such as the powerbands for torque, Maxidyne is more suited to say construction type applications versus the Econodyne being more suited for hiway application. The motors were painted different colours. Externally both motors appear alike, both the Maxidyne and Econodynes had the intercooler over the motor, etc. I understand that the Econodyne E6 - 4 valve motor cannot have the intercooler over the motor, but the E6 2 valve can have the intercooler over the motor. I would appreciate any info - thanks.

E6 2V could have the intercooler over the engine. But they could be both made as a Maxidyne (285hp) or Econodyne (300+). In the first case I would expect it to be called EM6-285. To me it seems like that model was a renamed (or slightly modifyed) earlier ENDT-676.

4V's were produced in two varitions (actually in more variations). But basically we would speak about well-known E6-350 Econodyne (...88 models such as R688, MR688 etc) and EM6-300 Maxidynes (..90 models such as R690, DM690). Virtually the engines are absolutely similar. And could be pained in the same gray color if produced in middle 80's. But had different performances. The only way to determine the difference known to me is the tag on the engine block or another one on the injection pump.

The basic idea the Maxidyne engines were developed providing a flat torque curve which allowed to minimize shiftings and use 5-speed transmissions. It's useful for driving in a city or other applications which require many starts/stops, accelerations etc. Looks like initially Mack has represented the Maxidyne concept for all applications. At the same time the original (Thermodyne-?) line of engines was offered anyway. Than later we can find out Mack begane offering two lines of engines: Maxidyne for recreational driving and Econodyne for on-highway applications. The reaon is although Maxidynes are simplier to drive they have a bit worse fuel economy. So under conditions when you cover high distances and haven't to do much shifting Econodyne's could be seen more suitable.

I didn't say Econodyne took place of Thermodyne because it didn't look almost correct. Originally Mack represented a new family of OHV engines in the late 30's (November of 1938) and called it "Thermodyne". When Maxidyne's took over the scene they formally could also be count as Thermodynes. And Econodynes too. So (seems to me like) two new families of Mack engines took place of the older line which became discontinued.

[Mark T]

I think I remember some of the 2 valves that required more than a five speed also had water running through the intercooler (heat exchanger mounted on the engine with a tip fan)  

[JoeH]

The 5/6 speed maxed out around 62mph screaming at 2100 RPMs.  The 2 stick 6 speed trans is a direct 1:1 ratio in top gear.  7 speed keeps the step ups reasonable and allowed an overdrive.

I think you're more or less right on some of the e6 CAC's using water, but I'm unfamiliar with that version.  My experience is with the endt676 version of the engine.

[cruiseliner64]

Hi all,im very interested in this topic as i'd like to know more about the engine in our Cruiseliner.we have the 2 valve EM6-300 engine and the engine number matches the build sheet.the truck was built in 1982.it has the 5/6 speed transmission and the intercooler is mounted in front of the rad.it does 60MPH at 1800 RPM.the engine is painted red and according to the first owner it was red from new.we are wondering how this fits in with whats already been said here.

Paul