The valve adjustment chart that proved my last 2 years wrong

I got a kickback from a customer who had a manual for a 2006 Cummins ISX. The chart said intake valves should be 0.014 and exhaust 0.027. I'd been running 0.018 and 0.031 for two years because that's what my old boss swore by. Pulled a head off a 400k mile engine last week and found the rocker wear pattern was off on all six cylinders. Checked three other trucks I'd done the same way and two were already starting to tap. That manual is now sitting in my toolbox and I'm redoing every job I touch until I match it. Anyone else find out their go-to spec was wrong after years of trusting it?

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parkerh3812d ago

Ha, yeah I had the same thing happen with a Ford 6.0 years back, but heres the catch: your old boss might not have been totally wrong, those bigger gaps can be a hot rod trick for high EGTs, it just wrecks the valvetrain on a daily driver. Shop manual is king though, good on you for biting the bullet and redoing them.

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