Man you are brave. The Cat 7. 2 which is a 3126b is a terrible engine. They are plauged by injector tip problems. The last one I worked on the number 3 injector tip came off, slapped on the piston a lot, and then went on to frag the turbine wheel of the turbo. Cost the company $5000. 00 with a new piston, turbo, valves, and of course injector.