Why? When I was in the test cell for Cummins, it was policy to get them up to operating temperature then do the break in procedures. Not saying you’re wrong, but why are you saying it’s a bad idea for break in?
You are talk'n about a total differant animal.
Most diesel engines have roller cams which require zero breakin. With any engine it is proper to bring it up to operating temp before applying load but it is not always the case. Look what they do to engines on the production line test, no warm up at all. I am also a Cummins Guy as I retired from Cummins Engine 10 years ago.
It takes very little run time to flatten a flat tappet cam.
It has always been my opinion that alot of flat tappet cam failures are caused by the tappet(s) not rotateing in the lifter bore properly and/or improper lubricant's.
