Click Click Boom!!!!!

is this a Cummins if it’s got a auto tranny?

 

Seems paccar is now throwing more rods lately.

My Dad’s MX13 earlier this year is one.

 

Why are rods getting tossed? Are rpm’s getting to low and it is rattling them apart? I’m from old old school engine world where lugging is baaaaad. Makes grenades happen. Seems to be the norm with stuff now tho.

 

I am with you on this. I believe Paccar was advocating pulling the engines down to less than 1000 rpm, and I assume it is strictly to improve fuel mileage. The computer must take fuel away and adjust timing etc. to protect the engines, but personally I would prefer slightly poorer fuel mileage if the engine will hold together longer. Even on our C15 I don't pull hard much below 1400.

 

I know for the Cummins 5.9 and 6.7’s, the most common reason rods break is the 3 piece thrust bearing breaking apart and the crank slapping back and forth. Worse with manual transmissions. I’ve seen a lot of those over time.

Cummins cheaped out knowing full well those three piece thrust bearings are garbage. They save a few Pennies manufacturing, make a lot money for engine replacement after warranty. They actually stock updated one piece bearings for people that know to ask for them but won’t install them when making those engines.

All the 5.9 and 6.7 pickups etc have those 3 piece bearings ready to fail any day.

Other engines, the rods just fail. Gen sets, farm tractors, etc.

 

The problem with the 1000 rpm thing is that is idling to us old guys. So in my mind you might as well just take off from a dead stop in direct then put in od when you hit 2000. Drop back down to 1000 and ride it home the rest of the way like an old two speed power glide. Lol.

 

I wonder how much of that was Dodges influence on cost because them little engines never gave much problems like that in the class 7 Ford and FL trucks.

 

That very well could be the reason. Chrysler wanted cheap engines. Cummins actually doesn’t warranty those engines right from the factory because it’s not built according to their specs.

 

As one that learned in a 70 Pete with a 318 in which I would downshift when it got to down to 1800 or so, I hear you!