Series 60 12.7 best year to buy?

I like the DDEC IIII engines. More features available in the DDEC system increaaing driver comfort and fuel economy.

 

I'll second d deck 4

 

98 because it’s drilled for wrist pin oil squirters for cooling. It may already have them, or you can add them. The blocks are all drilled, some are capped off. Plus it’s a ddec lV. Same as ddec lll, I think the only difference is lV has a battery for saving stored codes when starting battery power is lost. I believe the even older ones didn’t have injector calibration ability. Also originally didn’t have waste gated turbos. You can rebuild it any way at you want. Original 2 piece trunk style rods and 15:1 pistons, or using a BK kit w the higher 16:5-1 compression pistons w/floating wrist pins instead of 2 piece rods if that’s what it currently has. You‘d need to buy new rods. Higher compression pistons eliminates the excessive smoke on start up. You can even upgrade to the newer drilled rods if you’re going to be buying them anyway. The older pistons are fine. Maybe even get better mpg. That’s my experience. Had a 98 PK and a 99 BK. I think the BK had better power. It’s hard to say. 98 had 6 hole injectors 99 has 9 hole injectors, maybe to combat smoke? Better atomization for higher compression pistons maybe? 99 seems to idle smoother. From what I’ve read the 6 hole injectors are more responsive. Just things I’ve read doing research on mine. They’re all good. Limited on max hp without oil squirters. It was very common to have a wrist pin come apart right about 750k. Half the time knocking a hole in the block, supposedly depending on direction of stroke when it failed. I once met an O/O that had that happened to both of his Trucks in the same week. Both had mid 700k miles. First I’d heard of it. He was a Diesel Mechanic himself. His son in law drove the other Truck. Both were stock, maintained and driven right. That’s all I know. Just repeating things I’ve learned, mostly on this sight. It’s all here to be found. Just my opinion, best rebuild would be with the newer 2000? and newer drilled rods, BK pistons, maybe 6 hole injectors for better pedal response. I don’t really know exactly what’s possible. There’s choices though. There’s hotter cam that requires a different gear maybe? The real expert here is @benjamin260_6 he can advise best on 12.7. Worth looking up his posts. You’ll learn a lot.

 

I'd get the '98 for sure. The other two, based on the year, are ddec ii. They would be OK in a mostly stock application but I wouldn't even bother with them, personally.

 

I heard once from Leon that 05-06-07 14l are best detroits...