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#1CutlassSupreme · 05-09-2008, 11:37 AM

Okay, so I'm easily spooked by what I read...and I’ve read a few horror stories about hydraulic lifter cams.

I'm getting closer to turning the key for the first time since rebuild on my 72' Cutlass 350 and I want to make sure I don’t kill the beast. I took the engine out to a machine shop to have it rebuilt and had the machinist install a Crane Powermax Cam with Hydraulic flat tappet lifters. The instructions with the Cam says that it needs a pre-load between .030 - .060. BUT the break in procedure from the shop says to have 0 preload. (I'm sure he's assuming that most stock rebuilds are solid lifters.)

I noticed that stock Olds rocker arms aren’t adjustable and it looks they just tighten down straight to the head. SO…do I have anything to worry about with the lifter preload or is there a way I can make sure that I’m within spec on this? .030 - .060 doesn’t leave a lot of room for error.

I've read that I could basically ruin the cam or bend the rods if there is too much pre-load. And if there isn’t enough pre-load I wouldn’t get enough oil up to the top of the rod and have some serious problems in the valve train.

Any ideas/suggestions/tricks to make sure I'm good on my pre-load?

05-09-2008, 11:37 AM	#1 (permalink)
#1CutlassSupreme Member Join Date: Apr 2008 Posts: 52	Hydraulic Lifter Preload on a 350 Okay, so I'm easily spooked by what I read...and I’ve read a few horror stories about hydraulic lifter cams. I'm getting closer to turning the key for the first time since rebuild on my 72' Cutlass 350 and I want to make sure I don’t kill the beast. I took the engine out to a machine shop to have it rebuilt and had the machinist install a Crane Powermax Cam with Hydraulic flat tappet lifters. The instructions with the Cam says that it needs a pre-load between .030 - .060. BUT the break in procedure from the shop says to have 0 preload. (I'm sure he's assuming that most stock rebuilds are solid lifters.) I noticed that stock Olds rocker arms aren’t adjustable and it looks they just tighten down straight to the head. SO…do I have anything to worry about with the lifter preload or is there a way I can make sure that I’m within spec on this? .030 - .060 doesn’t leave a lot of room for error. I've read that I could basically ruin the cam or bend the rods if there is too much pre-load. And if there isn’t enough pre-load I wouldn’t get enough oil up to the top of the rod and have some serious problems in the valve train. Any ideas/suggestions/tricks to make sure I'm good on my pre-load?