Paccar MX-13 tuning

[Texasdude74]

I've heard that he can tune them. 530-550 horsepower and 1850-1950 torque seem to be the highest recommended power levels. So far so good, it looks like a well built and durable 'lil engine. The only unreliable parts surprise, surprise seem to be the Cummins after treatment bits. But there's an easy solution for that.

I never would have believed a 13 liter engine would hold up well in a car carrier over a 15 liter. But, I do know of a stock MX with over 400k at the moment with no issues. For comparison, the C13's in their day only seemed to last 5-600k miles at best. I only know of one ISX that has gone over 400k and it's a '13 tuned by Gearhead at 230k. It currently has 510k and is still running just fine and has never been apart, although no one will believe him.

The biggest complaints with the MX are that if you run them out of fuel they are a real bitch to get started again. Heard of smoking starters and emptied ether cans! Pete 389's are notorious for sucking one fuel tank dry with 40+ gallons on the other side. (A mandate removal seems to fix this fuel balance problem somehow)
Also the jake brake isn't nearly as strong as the ISX.
Not every shop or road truck has the correct software, DAVIE to trouble shoot and clear codes. Which are almost exclusively after treatment related.
Most of the independent diesel shops aren't very familiar with them.
Guys say they completely run out of steam above 1700 rpm.
If you have to replace the camshaft the engine has to come out of the truck because it comes out the rear of the engine, they're in the block instead of the head. The cams are steel instead of cast iron and are supposed to be much tougher. Time will tell. There was a cam recall already for some of them.

On the plus side, most everyone is reporting mileage gains of .7-1.0 mpg. They seem to get best mileage at cruise rpm of 1350 vs 1450 for 2250/2350 ISX. So 3.08 vs 3.25 with 255/70/22.5 drives.
They are said to be about 380lbs lighter than ISX and the '17 models are supposed to be 50lbs lighter still. The extra was taken off the accessories.
Most importantly, I don't know anyone that's thrown a rod yet. Or blown a head gasket or had a liner sink. Or worst of all had a fuel pump (these have two) turn an entire engine into a boat anchor.