Just realized my old shop teacher was right about injector timing...

I spent 10 years setting injector timing by the book on 8.3 Cummins engines and never had an issue, but last month a job in Spokane where I needed 2 more horsepower convinced me his method of advancing it just a hair is actually better. Now I'm wondering if I've been over-torquing head bolts too after seeing a buddy snap one at 120 ft-lbs on a warm block. Has anyone else tried deviating from stock specs on older mechanical diesels and seen real gains?

2 comments

2 Comments

cora56215d ago

Are we really out here snapping bolts at 120 and calling it progress? I mean sure, that extra 30 ft-lbs might get you a tenth of a horsepower on a good day, but it also gets you a trip to the machine shop real quick. I get that factory specs are for lawyers not mechanics, but there's a difference between tweaking and just wrenching till it cries uncle. The warm block thing is a fun gamble too, like playing thermonuclear roulette with your threads. Guess I'll stick to my cold 90 and let the hot rod boys keep their spare block fund stocked up.

finleythomas16d ago

You never had issues with head bolts going to 120 on a warm block? I've always done 90 on a cold block and never looked back, that spec is there for a reason.