I was overtorquing injector hold-down clamps for years without knowing it

2 months back I pulled a head on a 6.7 Cummins at the shop in Phoenix. When I went to torque the injectors back down I just went to 89 ft-lb like always. My lead mechanic walked over and asked why I wasn't using the updated spec from the 2019 service bulletin. Turns out I'd been overtorquing them by 15 ft-lb on every single rebuild for almost 4 years. The injector cups were probably getting hairline cracks the whole time. Anyone else ever find out they've been doing a basic step wrong for years because nobody told you about a bulletin update?

2 comments

2 Comments

the_sam3d ago

Hold up, 89 ft-lb on a 6.7 injector clamp? Dude that's crazy. I remember when that bulletin dropped and a few guys at our shop were still using the old spec until someone got a call from Cummins about a warranty claim. The fact that you went four years without anyone catching it is wild but honestly super common. I bet you're not the only one who missed that update, especially since they didn't make a huge noise about it. Good thing you caught it now before those hairline cracks turned into a bigger headache down the road.

patricianguyen3d ago

Notices how little things like that slip through the cracks everywhere, not just in shops...