Quote:
Rick Ehrenberg says it was from the consolidation of the AMC engineers when Chrysler bought AMC/Jeep in the 80s. When the 5.2/5.9 magnum was being developed, the AMC guys insisted on the pedestal mount design.
in fact, the pedestal mount rocker arm and pedestal is a DIRECT CARRY OVER PART from the AMC 290-401 series engines....
haven't heard of too many AMC rocker failures, so I wouldn't be concerned with durability until you get into completely nutso solid roller cam spring pressures...
and it definitely could have been an assembly line issue--I could see how it would be very easy for the shaft mount rockers to be installed incorrectly, since the intake and exhaust rockers have unique offsets, and there really is no easy way to poka yoke the assembly to eliminate those errors. the intake and exhaust pedestal mount AMC rocker is the same part. no way to f that up....
and from an inventory standpoint, it's a bit of an advantage....you have V6 shaft, V8 shaft, LH offset rocker, RH offset rocker....with the magnum assembly you have pedestal, rocker, base/guide plate.....1 less part, and cheaper to manufacture parts--I'm assuming the shafts are precision parts, that have to have some sort of secondary op to grind to precise tolerance.....and have to have 2 different sized holes drilled in them, and plugs pressed into the end. also, I've never seen an OEM stamped shaft rocker new, only used, where the bearing surface looks polished....are they as stamped new, or do they have some secondary machining on the bearing surface to true them up and polish the bearing surface?
Last edited by patrick; 07/12/13 09:01 AM.
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