amadeospike

iTrader: (1)

I have an 08 chevy silverado with full bolt-ons and cam. The truck has the displacement on demand system which has been disabled. A couple of weeks ago the truck started with a misfire on cylinder 7. Well i checked all the obvious like the wires, plugs, coil, but everything was good. I finally noticed that one of the lifters on that cylinder was bleeding out and consequently not opening the valve. Well i took the heads off and replaced the lifters with some ls7 lifters then i noticed that cam had been damaged on a couple of lobes. The damage was in the area where the lifter rollers hit the lobe. I also had to replace the cam. I turned the truck on yesterday and drove it around and it was working fine the only thing that i noticed is that the oil pressure is a very low but the scanner is showing a faulty oil pressure switch.

Tootall

iTrader: (79)

chewed up lobes and lifters - either the lobes were hit on the cam bearings when the cam was installed,
or not enough seat pressure for the lift of the cam, over reving the engine (high RPM)

How big is the cam, and what springs? How did the surface of the cam bearings look when it was taken out? Can you snap a pick of the chewed up lobes?

change the oil several times if the cam was chewed up that bad, there's bound to be a ton of shavings in the system.

amadeospike

iTrader: (1)

i'll post a pic of the cam lobes. Do you think the stock dod lifters may have been part of the issue. I don't know exactly how this system works but i've been told that they are activated through solenoids under the valley cover.
I'm going to remove the valley cover and remove all the solenoids then replace the cover with a regular non-dod ls2 cover.

amadeospike

iTrader: (1)

here are the pics of the damage on the cam and i also posted the lifters. The cam is a 222R with .581 lift and the springs are comp 918 new design.

eallanboggs

iTrader: (1)

They have special lifter that collapse(bleed down) when the computer tells the LOMA to deactivate the solenoids for the 4 DOD(AFM) cylinders. When that happens those lifers bleed down, but are able to refill with oil very quickly when the computer commands the solenoids to go active again. This is supposed to happen so fast that it is tranparent to the driver. Your #7 lifter should not have bled down. It did, but that still wouldn't explain the damage to the cam lobes. You need to find out why the lobes were damaged. Were the corresponding rollers damaged as well? Were the rollers free to turn smoothly? Did you disable DOD using a reflash?

amadeospike

iTrader: (1)

That's exactly what i thought. The corresponding rollers on the lifter had some damage on the edges but rolled freely. From what others have posted and have told me is that "this type of damage is caused by improper seat pressure or over reving." What im thinking is that those lifters may not be suited for high lift cams. I have replaced all the lifters then today i removed the dod system by replacing the valley cover with an ls2 valley cover without the solenoids and passages. This has corrected the low oil pressure readings.