I would check out the injectors first (always check the simple stuff first) but I would agree with ronm. If when you start the engine cold in the morning and notice more white smoke than what the engine would normally have that is an indication of low compression. Low compression would indicate the probability of a scored cylinder. I had some experience with Long 1100 tractors (these models were Ursus tractors with Zetor engines) years ago. The non-turbo 900's were fine but the 1100's were fitted too tight to allow for the higher horsepower of the turbo version. Under an extremely heavy pull, especially when brand new, they would lock up tight right in the field. Let them cool down and they would start and run just fine again but with fairly high oil comsumption compared to no oil use before. I have actually ran one a year or so this way and the power was fine, just had to add oil. During overhaul it was evident the pistons swelled up too big for the hole and that is what locked the engine up. The cylinder walls were scored on one or more holes on two sides about an inch wide, causing the oil comsumption. The remedy was to put "A" size pistons in "B" holes for a little more clearance and no more problems - engines were just fitted too tight for the power level.

My best guess is scored piston/liner(s) because of the excess heat swelling the aluminum piston more/quicker than the steel liner.

Run a compression check when you pull the injectors to check them - it will tell the tale.

John