Mack E6, E7 vs their competition

[sodly]

I've always been curious about the torque output on the 80s/90s E6 and E7 versus their typical competitor engines like the ubiquitous 350/400 Cummins or 3406 Cat.  I know the Mack sixes are lower on displacement compared to almost all the other manufacturers (why is this?).  But people always talk about how a Mack engine will "pull".  Some say their numbers were taken at the rear wheels while their competitors measured power/torque at the flywheel (which I find hard to believe).  I'm curious, for example, how a 350 Mack stacks up to a 350 Cummins.  I've driven Detroit and Cummins powered trucks but never anything with a Mack engine.  Do Mack six cylinder diesels produce more torque?  Or just more torque relative to their displacement?  When you pull the big hood on a Superliner and see a 350 E6 sitting there it just, honestly, doesn't look all that impressive.  Yet, they were very popular/common in that model.  There must be a reason why. 

Another thing I've noticed over the years is that Mack engines sound different than others, at least at idle.  Does anyone else fixate on this?  Obviously, a two-stroke Detroit sounds like nothing else.  But can you discern a 350 Cummins at idle versus a 350 Mack?  It's hard to put in words but I've always thought Cummins motors (at idle) sound a little "hollow" and "knocky", if that makes any sense.  There's a hollowness to their idle sound.  Whereas Macks, to me, sound more "growly"... more "truckish".  Maybe a little louder?  But different.  How would you describe the sounds of Cummins, Cats and Macks... in general?  

[Timmyb]

I'm not 100% on this, but I think the Mack torque figures were close to that of cummins, but obviously out of a smaller engine. 

These are two charts from dw clutch. They say that the e6 350 put out more torque than the ntc400 cummins. Whether they are accurate or not I'm not sure, but it gives you an idea  

 

[Underdog]

In the days of mechanical engines, it was easy to tell just by the sound what type of engine any truck had. CAT, Cummins, Mack and of course 2-stroke Detroit each had their own distinctive sound. Nowadays, the Volvo/Mack is the only one I can tell just by the sound.

[Lmackattack]

My opinion was that the old E6 / E7 Mechanical 300s were just a very solid engine used for the job they did. they were not a powerhouse for over the road use but the little 676 cube 6cyl would hold its own against engines of 855 cube inch.  A 300 mack would run with a 350 cummins.  A 350 mack would run with a 400 cummins.  The macks had slight torque advantage even with a smaller bore/cube engine.

Gearing also has alot to do with it as Mack had widely used double reduction diffs and direct final drive transmissions.  Macks could put more HP/TQ to the wheels with their common gearing in use with Macks own drive train. 

That being said the old saying "There is no replacement for displacement" still holds true. In my opinion the cummins would pull long hills better. They had the displacement advantage to hold the Hp where the Macks would start to struggle and louse speed faster.

 I feel Mack lost the edge in the HP wars when they did not advance 6cyl engine engine options by raising their HP and Displacemet. Mack continued to push their 300 or 350HP small bore 6cyl diesel when all others 6cyl engine mfg were pushing their 400+ HP big bores...

 

just my .02

 

 

[james j neiweem]

Also I believe the E9 didn't catch on as well as it could have because of less than stellar performance of the earlier Mack V8's. Also V-8's in general are a little shy on torque and rely on HP(RPM) to get the job done. If Mack had made an 900 plus cubic inch six cylinder engine using the Maxidyne principal things may have turned out differently. They would have been well suited to todays 1000-1500 operating range.

[41chevy]

2 hours ago, james j neiweem said:

Also I believe the E 9 didn't catch on as well as it could have because of less than stellar performance of the earlier Mack V8's. Also V-8's in general are a little shy on torque and rely on HP(RPM) to get the job done. If Mack had made an 900 plus cubic inch six cylinder engine using the Maxidyne principal things may have turned out differently. They would have been well suited to todays 1000-1500 operating range.

Still born

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[sodly]

Great chart, Timmyb.  Just what I was looking for.  Does your chart include the E7400 (did it get cut off)?  Or any other makes of engine to compare to?  Very interesting that the E6 350 and the E7 350 appear to have identical torque ratings.  Although it appears that there was also a version with a higher rating, just cut off at the bottom of the chart.  

Where is the line between a "small bore" and a "big bore" engine?  Is the E7 still considered a small bore?  

 

[james j neiweem]

That big six looked like it was ready to go. I wonder who killed that (Renault)? I wonder if that was in the same time frame as the intro of the E-7. I know the E-7 got off to a rocky start(pistons rings) as I recall. This was about the same time Mack went to South Carolina. Was the E-7 a Renault design motor as some have suggested. That might help explain the big six never went into production. Too bad if so.

[6368]

I attribute some of the cummins hollow/knocky sound at idle to their weird single piston air compressor. 

[Timmyb]

3 hours ago, sodly said:

Great chart, Timmyb.  Just what I was looking for.  Does your chart include the E7400 (did it get cut off)?  Or any other makes of engine to compare to?  Very interesting that the E6 350 and the E7 350 appear to have identical torque ratings.  Although it appears that there was also a version with a higher rating, just cut off at the bottom of the chart.  

Where is the line between a "small bore" and a "big bore" engine?  Is the E7 still considered a small bore?  

 

Click away my friend. Also if your handy with a google machine you can google dw clutch chart and put cummins, cat, Detroit, Mack, international and they will have a chart for you. 

http://www.dwclutch.com/D&W/D&W Clutch & Brake 2/MACK TORQUE.pdf

[Lmackattack]

I forgot about the "Big 6" That could have done wonders if it was as good as it looked. 

[sodly]

So do all E6s have the same bottom end?  And all E7s?  It's just a matter of pump and turbo differences?  Interesting that E6 torque ratings range from 750 to 1277.  E7 torque ratings range from 1083 to 1660.  Quite a wide range on the same bottom ends, if that's the case.  

[Bullheaded]

After seeing these numbers I'm wondering how I ever pulled 140,000 pounds up and down constant 8,10 and 12% hills here for all those years, with my little E6 350.

We even did a test on a 300 mile trip. And the E6 350 took less than 30 minutes more compared to a C15 475/1850.

This one is an 88, 4 valve and the odo has rolled over zero twice.

Edited January 17, 2017 by Bullheaded

[kscarbel2]

The 11 liter (11.01 liter/672 cu.in.) Mack E6 and 12-liter (11.9 liter/728 cu.in.) E7 were able to meet 95 percent of customer applications, offering impressive power, torque and class-leading fuel economy combined with light weight and lower operating costs.

For those needing a larger powerplant, we offered the legendary E9 V-8, rather than a large six like Cummins.

Fast forward to year 2017, owing to new technologies, we're able to "reliably" get more horsepower out of 11 liters than we were able to in 1985 when we launched the superb E6 4V.

The four valve head E6-350 with an American Bosch pump remains one of my favorite engines.

I love selling V-8s. And our customers love driving them. But for most operators, a 420hp 11-liter will make their accountants smile the most, the same way the accountants at Chemical Leamon, Matlack and Overnite used to smile.

[Underdog]

1 hour ago, Bullheaded said:

After seeing these numbers I'm wondering how I ever pulled 140,000 pounds up and down constant 8,10 and 12% hills here for all those years, with my little E6 350.
We even did a test on a 300 mile trip. And the E6 350 took less than 30 minutes more compared to a C15 475/1850.
This one is an 88, 4 valve and the odo has rolled over zero twice.

And I bet you used less fuel than the CAT every day. Sometimes faster doesn't win the race.

[Underdog]

The 11 liter (11.01 liter/672 cu.in.) Mack E6 and 12-liter (11.9 liter/728 cu.in.) E7 were able to meet 95 percent of customer applications, offering impressive power and performance combined with light weight and lower cost.
For those needing a larger powerplant, we offered the legendary E9 V-8, rather than a large six like Cummins.
Fast forward to year 2017, owing to new technologies, we're able to "reliably" get more horsepower out of 11 liters than we were able to in 1985 when we launched the superb E6 4V.
The four valve head E6-350 with an American Bosch pump remains one of my favorite engines.
I love selling V-8s. And our customers love driving them. But for most operators, a 420hp 11-liter will make their accountants smile the most, the same way the accountants at Chemical Leamon, Matlack and Overnite used to smile.

It's all in the gearing. A properly spec'ed driveline gets the work done. Think about all the heavy loads moved when we all had 200hp, when the Maxidyne 300 was a "large car"...

[Underdog]

The 11 liter (11.01 liter/672 cu.in.) Mack E6 and 12-liter (11.9 liter/728 cu.in.) E7 were able to meet 95 percent of customer applications, offering impressive power and performance combined with light weight and lower cost.
For those needing a larger powerplant, we offered the legendary E9 V-8, rather than a large six like Cummins.
Fast forward to year 2017, owing to new technologies, we're able to "reliably" get more horsepower out of 11 liters than we were able to in 1985 when we launched the superb E6 4V.
The four valve head E6-350 with an American Bosch pump remains one of my favorite engines.
I love selling V-8s. And our customers love driving them. But for most operators, a 420hp 11-liter will make their accountants smile the most, the same way the accountants at Chemical Leamon, Matlack and Overnite used to smile.

KS, I appreciate your historical viewpoint on Mack engineering. I can't wait to put my MH 4v-350 to work this year.

[kscarbel2]

22 minutes ago, Underdog said:

KS, I appreciate your historical viewpoint on Mack engineering. I can't wait to put my MH 4v-350 to work this year.

An MH Ultra-Liner powered by an E6-350 (4VH) ties with the Value-Liner as being my favorite Mack trucks of all time.

[Timmyb]

1 hour ago, Underdog said:

And I bet you used less fuel than the CAT every day. Sometimes faster doesn't win the race.

Back in the mid 90's my dad ran a 76 Kenworth with an 8v92 detroit. He upgraded to a 91 Mack with an e7 400. He saved $700 a week in fuel. Truck repayments were $2000 a month. It was a free truck!

[sodly]

Speaking of the E6/E7 and E9.... 

Would you recommend an E9 as an engine in a hobby truck?  One that just hauled light loads or ran empty frequently?  Like most folks, I think a V8 is cool but I constantly hear horror stories about how scarce parts are getting to be.  If something went wrong, sounds like I'd be sunk.  I've never been around an E9 but wouldn't want to get a motor that is so obsolete that parts are unobtainable.  Sounds like that's not such a concern with the 6 cylinders.  

Also, what kind of MPG difference would there be between a small-bore 6 and a V8 under these light-load conditions?  

[Timmyb]

On 7/14/2017 at 6:54 AM, sodly said:

Speaking of the E6/E7 and E9.... 

Would you recommend an E9 as an engine in a hobby truck?  One that just hauled light loads or ran empty frequently?  Like most folks, I think a V8 is cool but I constantly hear horror stories about how scarce parts are getting to be.  If something went wrong, sounds like I'd be sunk.  I've never been around an E9 but wouldn't want to get a motor that is so obsolete that parts are unobtainable.  Sounds like that's not such a concern with the 6 cylinders.  

Also, what kind of MPG difference would there be between a small-bore 6 and a V8 under these light-load conditions?  

Based on what you said, I'd recommend an E6. 

Just about any engine could do what your asking of it, including an e9 but it wouldn't be my first recommendation. 

[mackdaddy]

The start of the E7 was a rough time for Mack due to the move to SC and trying to go non union. As I understand many unions in supplier shops purposely sabotaged Mack parts. The Big in line 6 that is displayed at the museum was something from the 70's I thought? And I remember one of the folks there telling me that weight, cost, power, fuel consumption, etc it was just not going to work for Mack. I remember seeing a picture of a truck in Canada that was running the test motor.

 

[Underdog]

My E6-350 did a kickass job this week. For power and MPG I would put it up against my old E-tech 427 any day.

[Jamaican Bulldog]

On 1/14/2017 at 11:01 PM, sodly said:

Whereas Macks, to me, sound more "growly"... more "truckish".  Maybe a little louder?  But different.  How would you describe the sounds of Cummins, Cats and Macks... in general?  

As a kid I used to be fond of being able to tell different engines based on their sounds from even far away. Even some trucks with the same engine types had distinct sounds due to their individual exhausts etc. which allowed me to identify the owner.

What used get me strange looks after they already had passed by a few moments before, was  when I could identify the engines and particular truck due to the smell of their exhaust fumes

 

[Jamaican Bulldog]

On 1/14/2017 at 11:01 PM, sodly said:

I've always been curious about the torque output on the 80s/90s E6 and E7 versus their typical competitor engines like the ubiquitous 350/400 Cummins or 3406 Cat.  I know the Mack sixes are lower on displacement compared to almost all the other manufacturers (why is this?).  But people always talk about how a Mack engine will "pull".  Some say their numbers were taken at the rear wheels while their competitors measured power/torque at the flywheel (which I find hard to believe).  I'm curious, for example, how a 350 Mack stacks up to a 350 Cummins.  I've driven Detroit and Cummins powered trucks but never anything with a Mack engine.  Do Mack six cylinder diesels produce more torque?  Or just more torque relative to their displacement?  When you pull the big hood on a Superliner and see a 350 E6 sitting there it just, honestly, doesn't look all that impressive.  Yet, they were very popular/common in that model.  There must be a reason why. 

Another thing I've noticed over the years is that Mack engines sound different than others, at least at idle.  Does anyone else fixate on this?  Obviously, a two-stroke Detroit sounds like nothing else.  But can you discern a 350 Cummins at idle versus a 350 Mack?  It's hard to put in words but I've always thought Cummins motors (at idle) sound a little "hollow" and "knocky", if that makes any sense.  There's a hollowness to their idle sound.  Whereas Macks, to me, sound more "growly"... more "truckish".  Maybe a little louder?  But different.  How would you describe the sounds of Cummins, Cats and Macks... in general?  

Sodly, thanks for asking these questions as I have wondered the same before. I have also wondered what were these Macks engine longevity compared to the bigger hp competition at the time?

My uncle in very mountainous Jamaica still has 74 Mack DM600 with a 237 engine, twin stick 5sp and 38k Mack rears that still works everyday with the original powertrain. Even though the engine has been overhauled it is still the original, and  the transmission has never been opened. Many trucks have come and gone since this Mack and the few other makes of the same vintage or from the 80s that have survived have had their engines replaced and other powertrain components. Everyone around there with a truck knows everyone else with one, so this truck and Macks in particular have this kind of reputation especially since there are not many Macks in that area.

I remember the bigger horsepower Cummins or CAT powered trucks being faster especially on the flats than even the 300hp plus Macks but the Macks even with their smaller displacement excelled on the steep or unpaved grades and other tough conditions fully loaded while 'screaming' less under pressure.