300+ rebuild

[fjh]

27 minutes ago, Joey Mack said:

I was taught the same thing.  Mack would only cut the journal that needed cutting. To this day i look at all the counter weights, and bearing numbers.. i dont assume. And Mack bearing kits are not always packed in the correct order.  I was blessed to have a cranky old Man take me under his wing... Earl Harnden was his name.   Maine Mack, 299 Warren ave. ,Portland M.E.   

I had to post his name.. He went home a couple years ago..  

RIP 🙏to him Joey ! Bless some of these guys we worked under !  Grumpy  or not  For their knowledge! Best we can  do is pass it on here! What goes around comes around! Grumpy is sometimes a good way to learn shit ! Sometimes there’s a reason! The biggest takeaway is PAY Attention ! None of this is written in books!

[Joey Mack]

Amen.. 

[BOBWhite]

On 7/12/2025 at 12:34 PM, Geoff Weeks said:

The tip turbine and Low Flow cooling were both attempts to better charge cooling without have to re design the front of the truck for enough room for an CAC cooling radiator (Air to air).

once trucks were being redesigned anyway, the reasons for the tip turbine and low flow systems went away. Having the charge cooler in front of the radiator give the best cooling, and what has become the std today. 

At the time, Mack tip turbine was revolutionary, both Cat and Cummins were still using water cooled aftercoolers, and low thermostat temps, to walk the fine line between good block temp and enough cooling for the charge air. 

 After Macks success, Cummins used the low flow system to run the "super cooled" multi-pass radiator coolant through the aftercooler, before sending it the engine. Cat never did and opted for the cooler in front of the radiator, which meant that their engines above 400 hp could not be fitted to many trucks. Cat engines below 400 hp still had the old water cooled aftercooler.

I didn't know that about the Cummins low flow engines. I know that they were mostly hated around here in tractors, they seemed to go through fan belts frequently and you'd have to keep the radiators sterile to keep them cool. The weird oil thermostats they put on Cummins later weren't much liked either