Camshaft replacement

oogah

Member
Original poster
Joined
Nov 12, 2022
Messages
49
Location
Kansas
I'm replacing the cam due to shredded oil pump/opda gear on the cam. I found the torque specs for the rocker arms (21 foot lbs) but I'm just a little confused on the process for it, do I torque with the cam lobe up or down on the rocker, also should I use break in oil and if so how should I break in the new cam, any help is appreciated, thanx in advance. Pic of new and old cam if your curious, I'm pretty sure it was the dorman opda that shredded it cause it was fine before I was just trying to do some prevention maintenance for down the road

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do I torque with the cam lobe up or down on the rocker

I'm confused. Are you talking about setting lash?

should I use break in oil and if so how should I break in the new cam

Yes. This is a flat tappet cam which requires proper break-in. Use a proper break in oil and watch a few youtube videos to see the process. Make sure you do not reuse the old lifters. Those were mated to the old cam.
 
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The thing is the motor has only around 8,000 on it, are the lobes on the old cam only polished cause of rubbing against the lifters or should it come polished
 
Are you talking about the "polished" lifter path on each lobe?
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Yeah and should replace the lifters and their rods or is just the lifters fine
 
Yes, those "polished" trails are the lifter paths. Cams lobes and corresponding lifters mate together during break in, which is why they have to be replaced together. (in a pinch you might get away with reuse, but you also might not) The push rods can be reused. Make sure they are straight and smooth on the ends, and clean.
 
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You need to go to the resources section of this forum and get the FSM for your Jeep. It details the cam break in procedures, lifter torque, etc.

But, you need assembly lube on the lobes, gears and bearings, you need new lifters, pushrods can be reused as long as they aren't bent or worn on the ends.

There is no lash setting on a 4.0, you simply torque the bolts to the spec.

You need to run break in oil with high ZDDP.
 
I'm wondering myself jkp, after looking at the fsm it makes since to just torque em since they just hold the rockers in place and not actually go on top of the lifters and the fsm does help a lot thanx
 
I'm having trouble find break in oil tho, all I seem to find is Lucas zinc additive
 
Go to summit racing, JEGS, etc. Comp cams, amsoil, etc make it. If you want to pay big $$$ go to Jeep dealer.

I don't know how it could have worn down that much. I have 140K mi on a Dorman OPDA. 255K on the engine.
 
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Honestly I have no idea either unless something I did while driving caused it but I haven't been riding it hard, far as offloading goes worse I done is drive through sand to get out to the shooting range, that's why I can't see nothing else but the dorman opda causing it. I know as of lately manufactures haven't been the best with quality control, I ran into it when rebuilding another vehicle not to long ago