Why do I keep breaking rocker arms?
So I finally took my rebuilt 225 (1700 miles on rebuild) with its 3-speed manual transmission and big cam in to my mechanic to have it set up with one of
@halifaxhops' hotrod distributors and during the tuneup something sounded off and when they checked the valves they found a broken rocker arm, the second since the rebuild (the first happened during the break-in). Mechanic says I must be revving too hard. I've got a tach so I know I tend to cruise all three gears in the high 2000s and usually shift up in 3000-4000 zone depending on conditions and level of friskiness. I thought slants could take a pounding. Am I doing something wrong? I s my mechanic full of ****?
Full of ****.
1) Valve guides weren't cut down for sufficient retainer clearance at the increased lift.
2) Valve springs are going solid because they're not correct or improperly installed/set-up.
3) If they're not getting oil due to plugged passage/wrong or installed wrong shaft etc., they could heat up & try to seize, which may take the temper out of them & allow failure.
(You didn't allude to symtoms of no oil, so this would be unlikely, & be multiple rockers damaged/failed.)
4) The pushrod cups are touching the rocker, suddenly over-lifting the valve near peak lift.
5) Ain't no chance You're "over-revving" any 225, but if the springs aren't anywhere near strong enough for the cam, it could be floating/bouncing enough to try dropping the pushrod with the same consequence as #4 above.
6) The Slanty pushrods are not "on axis" with the lifters, and are just short of 10" stock, at only 5/16" diameter they should've bent if they actually broke a rocker arm.
Looking forward to more details & pics, peace!!
