A retired diesel mechanic in Billings showed me a valve adjustment trick I'd never seen before

I was helping him rebuild an old Cummins 5.9 and he pulled out a thin feeler gauge that was bent at a 45 degree angle. He said it lets you get into tight spots without taking the whole valve cover off again. What weird tool modifications have you guys picked up from old timers?

2 comments

2 Comments

johnfoster1mo ago

My uncle ran a diesel shop in Omaha for 40 years and he'd lose his mind over that bent feeler gauge. He always said bending a precision tool like that throws off the measurement by at least a thousandth or two, especially on a used gauge that's already been flexed a bunch. I watched a guy jam a bent feeler into a JD 4045 valve gap once and the lash was way off after we checked it with a straight gauge. Maybe it works fine on some engines but I wouldn't trust it on a tight interference motor where a few thousandths can mean a burnt valve. What's the tolerance on that 5.9 anyway, 0.008 to 0.012?

mila_mitchell1mo ago

HOLD UP, are you telling me a bent feeler gauge can throw things off by TWO THOUSANDTHS? That's INSANE, I had no idea it was that sensitive. I just figured a little bend was no big deal, but hearing that story about the JD 4045 makes me want to throw all my old bent ones in the trash.