Looking for details on Detroit 12.7 engine

I had the same setup in a 2000 pete. I got about 7 to 8mpg but I was pulling an MRI scanner which is skirted all the way to the ground and I ran alot of bobtail. I'd figure your in the 6.5 range with normal loaded running.
if the detroit was WELL cared for you will see a million miles. could got all the way down to half a million.
the other thing is that peterbilt won't work on it. They don't like to admit they ever built trucks with detroits. You'll need to find a freightliner shop to do motor work.

 

same setup in a volvo 610. 500 hp rtlo13 , 355 rears, with no air shield. pulling a transcraft with a vango curtainside. averaged 6.5 last quarter. loads vary from 8 to 48 k. mine has almost 500 k on the rebuild. have heard of these lasting a long time. parts are cheaper than a cat (can't afford that).i love mine. the motor blew at 500, previous owner. wrist pin i think it was. still these motors are hard to beat.

 

1 gallon of oil consumption every 10k. i currently have 78 k on the oil change. i run amsoil and a filtration solutions bypass filter. oil samples at 10 k. change the bypass filter. that's it. have seen mpg as high as 7.9 running flatbed light and low. look for oil leaks on the pan. i may be leaking from the pan or from above. tighening the bolts won't help because the have a spacer that keeps you from crushing things. so if you have leaks , chances are you will just have to replace a gasket, no big there. i typically cruise at 5 over the limit so i usually run around 70 on the interstates. mostly nc to new england, almost weekly. hope this helps. johnny

 

volvo is the same way about about det. course ,they are the same way about cat. guess the weren't happy till they put their own grenade under the hood.

 

What are you going to do with that BC?

 

I have a 98 FLD with 12.7 Detroit, 3:73 gears 13 spd and 24.5 tires. We are averaging with 80,000pounds around 6MPG.

We also have a 98 Century with 3:55 gears 13 spd and 24.5 tires. We average around 6.8 with 80,000 pound loads.