Older Mack engines

[Dale smith]

I read many years ago that the reason the old Mack engines could be lugged at low speeds (highway speeds) was because the engines used "Rees" valves. Does any one know anything about this?

[tjc transport]

welcome to BMT.

by any chance did you mean Reed Valves? 

if so, no. Reed Valves were used in two stroke engines, not four stroke engines. 

[mrsmackpaul]

Welcome  Dale 

 

Sorry I have never heard of this, maybe the Lanova diesels had something different in the valves

I have heard plenty of stories were old blokes say they could count the revs they were reving that low, something I know nothing about

 

Paul

[Vladislav]

Lanova used common valves. At least factory description of the engine design doesn't describe anything extraordinar. There was a point on the material used for valve lifting rods which had about zero temperature expansion but I don't remember any valves especiality. Unfortunately no comments on"rees" valves too.

Welcome to the site!

[Phase 1]

Some early engines used rotary intake and exhaust valves instead of the more commonly used poppet valves. I have read about them but do not remember what kind of engine or vehicle used them, possibly it was Mack. Have found a reference to the Russell-Rees Rotary Valve Engine Corporation being incorporated in 1927 in Wilmington Delaware. Possibly Rees had earlier pioneered or manufactured that valve type and Mack had used it in early engines.

[JoeH]

My understanding is that it is high oil pressure. Most trucks regulate oil pressure around 45 psi, but our 1979 maxidyne runs about 90 psi. The higher your oil pressure the more it can withstand the downward pressures in the crankshaft journals before metal to metal contact. 

[JoeH]

Type of valves shouldn't matter, the slower an engine turns over the easier it is to keep valve train (pushrods, rockets, lifters, etc.) from floating.

Do t know what Rees valves are.

[Joey Mack]

I wonder if injection timing and duration of the spray is the reason? I am just asking.... I have driven a bunch of late 70's Mack's and they would work hard and pull at 1100 rpm's. I'm not a super trucker, just remember a few things from 20+ years ago..   I hope to learn something on this thread... jojo

[theakerstwo]

2 hours ago, JoeH said:

My understanding is that it is high oil pressure. Most trucks regulate oil pressure around 45 psi, but our 1979 maxidyne runs about 90 psi. The higher your oil pressure the more it can withstand the downward pressures in the crankshaft journals before metal to metal contact. 

If high oil pressure is good then cummins didnt get it right when the Big Cam 2 came out.Big Cam 2, 3, 4 all use 35 to 42 psi of oil pressure.

[Vladislav]

That oil pressure point makes sence to me. Actually what would you worry about lugging an engine? I think combustion process goes quite well at 1000RPM (sure not 100RPM). To me the trouble seems as insufficient oil pressure at low revs. There could be effect of high stess applied to cylinder walls or the crank group. But seems more a matter of the torque itself, not dependant to the revs.

If oil pressure have meaning there must be different capacity pumps used in Maxidyne engines or a different pump drive ratio. It's easy to recognize and I belive must be a well known fact. I just never concerned it so far.

[mrsmackpaul]

Hmmmm oil pressure should be reasonably high at the working rec range

 

As to how high ? I'm thinking at a minimum of say 40 psi for most motors of any brand 

Have never seen a motor run at 90 psi once it is warmed up and would be thinking something isnt right and a bypass spring or valve is sticking

To higher oil pressure in my mind would make it harder to contain the oil in the galleries etc 

That been said I am only thinking out allowed 

 

Paul

[theakerstwo]

On some of the older mack engines they use a pressure regulator valve in the oil filter mounting pad were the oil comes out straight from the oil pump which did not regulate the pressure at the pump.There was a port there i think it was 1/4 pipe that was on the pump side which has not been regulated yet.It was nothing to see more than 100 psi if you connected you gauge to it.The pressure gauge was to be connected to the other port which is reading the pressure after going thru the filter and against the regulator and will be in the 60s range.It takes alot of pressure from the pump to push oil thru the filter and before it is regulated.I have seen this happen before were some one is reading pressure from the wrong port.If i remember right mack came out with the gauge connected to me in the wrong place.When you have the gauge connected after the filters you can read pressure lost from a stopped up filter.

[Freightrain]

Had a 427 ford engine that had collapsed filter.  It read 60 psi before the filter.  Changed the oil and suddenly there was no oil pressure.  Reinstalled the old filter and 60 psi! 

Found out an oil galley plug had popped out, thus not much pressure at idle with such a large internal leak.  The old Fram filter had collapsed and was creating a false pressure reading. 

 

I think the pump relief had stuck shut, blowing the filter up, popping the welch plug, then relieved itself.  Leaving the engine with no real oil pressure.  We dont know how it survived all the driving it had on it til we found the problem.

This was in the red Willys that I was doing all the repair work on a few years back for a friend.

 

As for oil pressure.  It is there to keep the wedge of oil in the bearings so there is no metal contact.   

Lugging an engine has nothing to do with valvetrain.  The early Mack thermodyne engines could not be lugged.  It would pound the bearings out along with cracking the mains.  They were not designed for that until later on(maxidyne engines).

Edited January 4, 2022 by Freightrain

[Mark T]

All the work is done on top of the piston ( timing injection pressure , matching of turbo cam and fuel delivery ) and more important than any of it ?

Someone figured out how to do it for a reasonable amount of money .   Think many people realize one of those old constant torque Maxidynes were never anything bigger than what would be called an 11 liter today ? 

[theakerstwo]

And on the maxidyne block if you added too much fuel to it it would disturb the main brg aligment or crack main brg bore.

also Larry in cummins school years back they told us to never turn in a warrany claim if it had a Fram brand filter on it.Some of the 5.9 had problems with them collapsing and letting debris passing thru and stopping the flow thru piston cooler tubes.

[JoeH]

2 hours ago, Mark T said:

All the work is done on top of the piston ( timing injection pressure , matching of turbo cam and fuel delivery ) and more important than any of it ?

Someone figured out how to do it for a reasonable amount of money .   Think many people realize one of those old constant torque Maxidynes were never anything bigger than what would be called an 11 liter today ? 

I think this hits closer to the mark.  "Lugging" is trying to accelerate when you are too far below your power band.  There is a surging effect in power delivery that damages things.  Mack figured out how to make smooth power at a lower RPM, allowing them to start the power band lower and thus reduce the need for so many gears.  All this achieved by injection timing, fuel delivery, etc.  Mack, having engineering control over every vehicle component from engine to trans to rears allowed them to do what other brands like CAT and Cummins couldn't.  CAT and Cummins had to design their power delivery to match generic transmissions.  Not a chance in hell Eaton would have made a 5-6 speed transmission to pair as an option for one specific CAT motor with a wide power band motor.  Not enough sales market.  Eaton would be dependent on the end user spec'ing a KW or Pete with that motor and trans to sell the transmission.  Mack was able to build a 40+ year reputation on it. I don't know what kind of market share Mack had on OTR long haul trucking from the 60s to 2000, but I'm guessing not too much as truck stops don't seem to favor them.  I'd guess the Maxidyne setup earned them a huge share of local/regional market, where 55-60mph was all that was ever asked of a truck, but left the market open to CAT and Cummins for cross country trucking where the bigger liter engines moved along at 70+ mph.

[Mark T]

Fuller jumped in on the concept. A PowerTorque Cummins worked with a five speed Fuller. Husky Drives and TO 95ALLs were made just for that.  Of course that was years after Mack had a good foothold on the less shifting idea

[theakerstwo]

I remember this and the first cummins i saw with the 5 speed was in 1968.This did not catch on vert well.The engine wa a NHCT 270. Or something like that.It was a slow timed engine and some of them was nothing like a mack maxidyne.One i remember putting a 10 speed in it and retiming it so he had some power.I never knew of cat dont any thing like this.

 

[Brocky]

In the mid 60's into about the early 70's Brockway had what they called "Huskydrive" which used that Cummins 270 with a 5 speed behind it with a 2 speed rear that you only used in 5th to actually make it a 6 speed. A lot of the regional freight haulers who did not run heavy used this combo. Oldspwr , Tom Millard, can probably tell us how many were made??

[theakerstwo]

I was working for Freightliner then and some fleet had some of them here.I can not even remember the fleet now.

[Onyx610]

Not a maxidyne but mostly same concept while saving fuel…plus some cool info!

http://www.tyldenheritage.com.au/uploads/9/3/0/6/9306704/econodyneengines.pdf

 

Edited January 5, 2022 by Onyx610
Spelling

[Onyx610]

The maxidyne apparently had the “ability to increase both fuel charge and air supply when engine speed was decreasing” A little bit of info here.     

http://www.tyldenheritage.com.au/uploads/9/3/0/6/9306704/maxidyne.pdf

[Mark T]

Back to original question. Maxidynes didn't get their grunt from some mystery valves . 50 years ago, they engineered away lots of shifting, and now they do that with the M drive .

[theakerstwo]

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.

[Brocky]

Tom Millard posted the entire Brockway Huskydrive information in the Brockway section of Other Trucks in the Odds and Ends area.

Edited January 5, 2022 by Brocky