Older Mack engines

[fjh]

1 hour ago, theakerstwo said:

The maxidyne was the first mack engine to use the fire ring for sealing compression in the head gasket.Also the governor was different from the ENDT 673 B and C engine so it would be able to fuel more at 1200 than it was at 2100 so the torque rise was more that the early engine.No the valves and heads was same as the ENDT 673 but had the fire ring grove cut in the surface for the fire ring.Later engines in the ENDT673 started to use same head and gaskets.Same block.

When the E9 was introduced I was offered in a 400 hp maxidyne Version there was no change in oil pressure no physical changes to  the engine other than the fuel pump and turbo! These would pull there asses off right down to 1000 RPM you could use a 9 speed transmission  behind them ! I believe that they did away with this concept for emission reasons due to the smoke! (opinion)  If they had VGT back in the day imagine the power and fuel efficiency if they were able to dial up the air to burn that extra fuel properly !  As soon as they dropped the use of maxidyne they increased the RPM and HP to 440 then 450 then 500 all had a far less rpm  range and had to have a multi speed trans to keep them in the zone for power and efficiency! That said The maxidyne  theroy only worked for a bit longer In the E6 Lineup for a few years after this before they converted to  econodyne  again the engine needed  the multi  speed Trans and the higher RPMs because of the smaller working range ! All of these changes were all gifted to us By the What is now Known as the EPA !

just a mix of observation and opinion!

[Mark T]

Multi speed transmissions gained popularity as axle ratios became faster.  A truck with a 3.7 axle grossing 80K would have a hard time starting out on black top even with a 6 to 1 first gear in the transmission. Newer engines all made much more torque than engines common in the mid '60s

[james j neiweem]

This was a time when Mack Engineeres were allowed to be engineers. Not Volvo string puppets.😟

[Freightrain]

The early v8s(865,866), was it just owners over fueling them that caused failures?  Or just not a strong enough platform to live long?

[theakerstwo]

I like the way the old 864 and 865 was built for as the weep hole that was in the block near the liner o/rings.There was a weep hole between the top o/ring and next o/ring to drain any leakage pass the top o/ring.This would drain coolant to the outside of the block.

[Mark T]

7 hours ago, fjh said:

When the E9 was introduced I was offered in a 400 hp maxidyne Version there was no change in oil pressure no physical changes to  the engine other than the fuel pump and turbo! These would pull there asses off right down to 1000 RPM you could use a 9 speed transmission  behind them ! I believe that they did away with this concept for emission reasons due to the smoke! (opinion)  If they had VGT back in the day imagine the power and fuel efficiency if they were able to dial up the air to burn that extra fuel properly !  As soon as they dropped the use of maxidyne they increased the RPM and HP to 440 then 450 then 500 all had a far less rpm  range and had to have a multi speed trans to keep them in the zone for power and efficiency! That said The maxidyne  theroy only worked for a bit longer In the E6 Lineup for a few years after this before they converted to  econodyne  again the engine needed  the multi  speed Trans and the higher RPMs because of the smaller working range ! All of these changes were all gifted to us By the What is now Known as the EPA !

just a mix of observation and opinion!

I had 2 MP7s   one was a Maxidyne and one Econodyne.  Far as I know it was only a software difference One was a 395 and the other a 405.  Those little engines were sorta like you suggested about the V8 using everything for power. In my opinion ???? cubic inch for cubic inch ...not many run like them. (and yes I know they don't leave a trail of fire, but they're a tiny engine compared to even a 13 liter) and they're actually fairly close to the same displacement as a 237

[Joey Mack]

the E-6 is 672 c.i.d. and the E-7 is 728 c.i.d.  i think its just under 11 litre's..  Pretty impressive when compared to newer/larger engines. 'Slow and deliberate'   

Edited January 5, 2022 by Joey Mack
Poor spelling

[Mark T]

659  

[doubleclutchinweasel]

I've been following this one for a while, but have said nothing.  It has been fun watching the comments on here.  Like on so many of these, there is more discussion happening than just what relates to the original question.  Guess that's why I like it here so much!

When Mack brought out the "673" series Thermodyne (still 672 cu in), they made a point of differentiating it from the earlier Lanova engines by referring to it as a "high speed" engine.  I am guessing the piston, head, and fuel delivery were system were the primary reason for the higher RPM range.  In fact, I think Lanova was the name of the combustion chamber design patent those earlier engines used.

Really like re-living the old Maxidyne/Maxitorque era!  I remember when those first started showing up.  Personally, I never got used to the 5- and 6-speed transmissions.  Just hated the RPM drop between gears.  Too much time behind a Quadruplex, I guess!  But, the Maxi engines were definitely revolutionary for their time.  Still cool to read the old brochures.  Takes me back to when I read them for the first time.  That whole Idea of "high torque rise" and "constant HP" was so different from anything else out there.

Somebody mentioned earlier about Mack having engineering power back then.  Yes!  I am an engineer myself now, and can really appreciate what Mack did then, taking a step out of line and doing something so different.  Took guts.

And, as somebody else already mentioned, I think constantly tightening emission regulations were the downfall of the Maxi setup.  Easier to run clean if the engine stays in a more-or-less constant RPM range.  Same thing is still happening today, with cars and pickups getting more and more gears.  The most efficient, and least polluting engine is one that runs at a constant RPM, right in the "sweet spot".

Anyway, just thought I would chime in here with my 2 cents!  Hope everybody had a great Christmas and a happy new year.

[theakerstwo]

 Same thing is still happening today, with cars and pickups getting more and more gears.  The most efficient, and least polluting engine is one that runs at a constant RPM, right in the "sweet spot".

I have never stop to think about this but is so true.My wifes ford and its a light weight car has a 6 speed trans in it.

[Vladislav]

The thread turned out as an interesting discussion and I heave read it whole to this point but still don't see the answer to the matter of ability realizing the Maxidyne concept.

I understand the lower RPM torque rise was done by fuel and turbo settings. That's fine, Ok, the engine would pull at 1000RPM. But to me it's nothing else but extreme lugging. You add fuel and add air to burn it out and the engine pulls. But I can't figure out how the crank and the block withstanded those high stresses and a similar made Thermodyne could not? Or Mack engeneers just used the actual sturdiness of the components which could work for Maxidyne but just were not stressed up really much in Thermodyne version?

[theakerstwo]

When you say Thermodyne then the old thermodyne which was 673T that had a different crank and also did not have piston coolers then no it could not take the load that the maxidyne did.Two different engines.But thermodyne also was into the later ENDT 673 which was same block and pistons with a big boy crank and rods with piston cooler and more and bigger head bolt.This engine would take the torque if it had the fire ring head gasket and the maxjdyne governor.The older thermodyne would brake a crank if you pulled them down to 1100 if they had the pump to fuel like a maxidyne.Their timing was much faster that a maxidyne also.The ENDT 673 B and C and the maxidyne also had a larger wrist pin.The rods were much thicker. 

[Vladislav]

2 hours ago, doubleclutchinweasel said:

When Mack brought out the "673" series Thermodyne (still 672 cu in), they made a point of differentiating it from the earlier Lanova engines by referring to it as a "high speed" engine.  I am guessing the piston, head, and fuel delivery were system were the primary reason for the higher RPM range.  In fact, I think Lanova was the name of the combustion chamber design patent those earlier engines used.

 

This is interesting to read nowadays since Lanova (at least ED519) had the top revs of 2100 and 2000 when under maximum load. Doesn't look notably (or at all) lower than END-673. The 2nd point END-672 which was still Lanova had an outcome of 160 or so HP. The same figure than the next generation END-673 engine produced using similar displacement.

My understanding is the jump from Lanova to Thermodyne (worth to admitt Lanova was also Thermodyne having overhead valves) was more a go from pre-chamber to the single chamber design. The most early automotive diesels utilized pre-chambers. The reason was to make the combustion process "softer" to decrease momental stresses to the engine parts. When the fuel injected into the engine first burns in the pre-chamber and than spreads out into the main chamber (cylinder) the pressure rises slower than if a single "blast" takes place. And seems like early diesels could not withstand hard burning and pre-chamber design prevailed. It also did that in cars up to the recent times. There's another matter (but with the same origin) - pre-chamber allowed a diesel to operate at high RPM's what is actual to a car.

At the same time pre-chamber style has its specific disadvantages. First of all it's less fuel efficiency than a single chamber style. The reason is pre-chamber needs extensive cooling being a combustion area. So made sorrounded by cooling passages in the head body. More cooling means more heat remove i.e. energy losses and less fuel efficiency as a follow. The same matter determines difficult cold start. The most pre-chamber diesels had glow plugs. And single chamber ones don't need them. Also there's a tendency of the cylinder head to get heat cracks. It's also a generic problem. One of the main principals of designing a heat stressed part is shape symmetry. When the material expands it gets symmetrical stresses being symmetricaly shaped. And the very existance of a pre-chamber in a cylinder head makes it asymmetrical. As a result about every head off a Lanova is cracked. And quite a seldom case for END or Maxidyne/Econodyne.

[theakerstwo]

When the N14 cummins came out drivers could not let their self pull the rpm down on that engine like should have been untill you tear one down and show them the difference between a N14 and NTC.Then they understand how they can take lower rpms.The crank and rods and wrist pins are so much robust than a NTC.Plus the timing is jerked down slower at that condistion.

[Vladislav]

9 minutes ago, theakerstwo said:

When you say Thermodyne then the old thermodyne which was 673T that had a different crank and also did not have piston coolers then no it could not take the load that the maxidyne did.Two different engines.But thermodyne also was into the later ENDT 673 which was same block and pistons with a big boy crank and rods with piston cooler and more and bigger head bolt.This engine would take the torque if it had the fire ring head gasket and the maxjdyne governor.The older thermodyne would brake a crank if you pulled them down to 1100 if they had the pump to fuel like a maxidyne.Their timing was much faster that a maxidyne also.The ENDT 673 B and C and the maxidyne also had a larger wrist pin.The rods were much thicker. 

Thanks for clearing me up, Glenn.

I knew Mack went to much more massive crank and rods (and other parts) in a inline block but I thought it was when END-673 was made. If it was for Maxidyne it put the ducks in order.

[theakerstwo]

And the very existance of a pre-chamber in a cylinder head makes it asymmetrical. As a result about every head off a Lanova is cracked. And quite a seldom case for END or Maxidyne/Econodyne.

Newer designs and better metal may play into that also.I have seen a Lanova engine maybe in 1965 here but i did no work on it.If you was around early cat engines you know they had alot of crack head on the 1693 which was a per combustion design.My thinking was there was alot of fire in the chamber before it was exhasted and some of it was in the prechamber not producting downward energy.A pryometer may have gone off it scale from the heat were as on a single chamber the moment the fire starts it turned into doward movement of energy.

[doubleclutchinweasel]

34 minutes ago, Vladislav said:

This is interesting to read nowadays since Lanova (at least ED519) had the top revs of 2100 and 2000 when under maximum load. Doesn't look notably (or at all) lower than END-673. The 2nd point END-672 which was still Lanova had an outcome of 160 or so HP. The same figure than the next generation END-673 engine produced using similar displacement.

 

I'll take your word on the Lanova RPM range!  I'm just saying that Mack referred to the 673 as a "high speed Thermodyne".  Might mean about as much as the "wide track Pontiac" from the '60's...which had the same track width as its Chevy or Olds cousins!  LOL!

Edited January 6, 2022 by doubleclutchinweasel
Sloppy formatting!

[tjc transport]

1 hour ago, theakerstwo said:

 Same thing is still happening today, with cars and pickups getting more and more gears.  The most efficient, and least polluting engine is one that runs at a constant RPM, right in the "sweet spot".

I have never stop to think about this but is so true.My wifes ford and its a light weight car has a 6 speed trans in it.

so true. i have a 2014 F250 4X4 6.2 gas engine and 6 speed trans. it gets around 8-9 mpg around town and 14-15 out on the highway. 

while in the body shop after getting run over they gave me a 2020 loaner. 4X4 5.0 10 speed. it got 20 around town and 28 on the highway. 

[Mark T]

4 hours ago, Vladislav said:

The thread turned out as an interesting discussion and I heave read it whole to this point but still don't see the answer to the matter of ability realizing the Maxidyne concept.

I understand the lower RPM torque rise was done by fuel and turbo settings. That's fine, Ok, the engine would pull at 1000RPM. But to me it's nothing else but extreme lugging. You add fuel and add air to burn it out and the engine pulls. But I can't figure out how the crank and the block withstanded those high stresses and a similar made Thermodyne could not? Or Mack engeneers just used the actual sturdiness of the components which could work for Maxidyne but just were not stressed up really much in Thermodyne version?

I could be wrong on this, but I think some of the old Thermodynes had hollow crank throws. (along with no oilers)  As the Maxidyne evolved and horsepower went up there was some kind of update that added bracing from main cap to main cap.  So much got better and better over time. Another thing that was huge in accomplishing all this was higher injection pressure (made by a pump that could have a life)