I have a 06 that dropped a ring in #1. Had to rebuild it and bore it 20 over. What are the proper steps to break in 5.9? I don't ever want to have to do this again. Current mods on it are headstuds, 40 HP injectors, straight piped 4 in, edge with with attitude and an intake.

 

Sounds like a pricey ordeal to be sure. Break-in is one of those things that most have a difference of opinion. Ive heard "Drive it like ya stole it" ,"Drive it hard" , "Don't baby it" vs "Drive it gingerly for 500 miles, change the oil and filter, then drive it normally" , "Never rev past 2k for the first 1000 miles" , Drive it normal, but don't tow heavy for the first 1,500 miles" etc....
Personally Ive done the same method as a gas engine. Drive it normal for the first 500 miles keeping close eye on engine vitals ie: engine temp, oil pressure, fuel pressure, EGT etc. Accelerate hard in high gear numerous times (speeding up then slowing down) to help seat the rings during the 500-ish miles. Change the oil and filter, then just drive it normally as you always have for another 500- ish miles and change the oil again. After that, follow normal maintenence intervals. Other methods vary. Keep in mind though, Its known that the cummins isn't totally broken in until over 100k miles. If in doubt, research professional diesel engine builders and pick their brain.

 

The builders are where I'm getting some of the conflict. Some are saying pretty close to what you suggested. Others are saying break it in like a semi putting it under 70% load or more after the first 100 miles for at least 500 but suggest more than 1000 under load.

 

That sounds like a pretty good method to me, being that its a torque monster of a cummins. Most importantly, keep a close eye on the vitals, and change the oil in at least a couple of close intervals, looking for metal flake in the oil and inside the oil filters. If all goes well, it should last you pretty close to an eternity......unless you drop another ring.

 

I drove it home last night. Feels so much better. Got my 5th wheel installed and now I'm prepping to do a 600 mile road trip with my 11,500 LBS trailer. Fingers crossed. Mechanic said to get into a LITTLE on some of the hills and to very my RPMs while cruising.

 

It crushed the break in drive. More power than I've ever had in it. But now my 400 hp clutch can't hold the power (less than 20k on it). Now to start saving for a new dual disk.

 

Hahaha WHOOPS! Im glad to hear it went well...KUDOS to you bro. I told you that Cummins was a TORQUE MONSTER. That dual disk will be a great improvement. Cheers..