all the engines are ok, however they have issues, they are all built by humans and accountants.
the cummins is based off an industrial engine. the GM/Isuzu and Ford/Navistar engines were designed to be light duty engines. The new Ford engines..... well enough said.
John, I agree with the poor RH47 transmissions behind the 12 valve. That is why Cummins had to detune the engines for the dodge trucks. however a titanium planet carrier and kevlar clutches will make the trans bullet proof, then you can go with a TST Fuel plate and pull 275hp all day long. much more if you change the governor springs and injectors.
Ford/Navistars suffered from broken rockers for many years, then when the new engines came out in 2006, they would start on fire when they went to regen. I dont have enough exposure to the 2010 and newer Ford designed engines to know all their shortcomings.
the GM/Isuzu engines mounted the electronics to the fuel pump in the valley. at about 140k it will fail. also, the oiling system is a bit on the weak side.
I myself am partial to the Cummins.
