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PSA: Found out I was torquing injector hold-downs dry for 6 months
I was doing a set of injectors on a 6.7 in my shop back in March and one of them started weeping fuel at the base three weeks later. Pulled it apart and the copper washer was crushed uneven. My old lead tech happened to stop by and asked if I was oiling the hold-down bolts. I said no, never have. He told me to look up the spec. Turns out the book calls for clean engine oil on those bolts, and dry torque gets you about 15% low on clamp load. Six months of jobs before that one, all done the same way. I got lucky none of the others let go. Now I keep a little cup of oil on the bench for them. So who here torques dry and who wets them, and has anyone actually seen a comeback from this or am I the only one who got bit?
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david5621mo ago
The 6.7 book actually lists 177 inch pounds on those hold down bolts with oil, and dry you are giving up right around that 15% like your lead tech said. I have been wet torquing injector bolts for 20 years and never had a comeback from a weep. The copper washer needs even crush or it will not seal, and low clamp load is exactly how you get uneven crush. Guys who torque dry are rolling the dice every single time. Keep that cup of oil on the bench, it is cheap insurance.
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