i posted this in my build thread but felt it was appropriate to post here more since it is the motor. im trying to figure out what caused this problem so i can fix it. the truck is turbo'd with a pt7675 turbo motor is a l33 5.3 with head studs and ls9 gaskets. the rest of the parts are below that i was using for the valvetrain. somebody with some input chime in please

SOOOOOO pulled the motor apart yesterday and found didnt find a spun bearing.... i found metal in the pan then saw my cam gear chain hanging in front. i then took the timing cover off and saw this



not sure how this happened all the bolts were broken off in the cam including the dowel pin on the cam. i torqued everything down properly so i cant see that being the cause. i then went to pull the heads cause i figured the cam was FUBAR'ed got the heads off and were in good condition nothing wrong with rockers, pushrods, valves, or valve springs. no metal in the valves or anything so that was a plus. then started to pull the lifters. about 5 lifters were messed up and the front 2 are still in the motor. i think those 2 are the worst i can pull them out, and the cam is also f*%ked , so now im trying to figure out what caused this. the cam is a speed in Tu0 cam with prc .650" double spring kit, 7.40 comp cam push rods, stock rockers and stock lifters, ls2 chain. if anyone has any input on why this might have happend please let me know so i can fix it. i had everything tq'd to spec so i dont see that being the problem. please chime in

 

Wow, I've never seen or heard of that. Can you post pics of the lifters? I can't imagine all the bolts breaking without something causing the cam to bind.

 

How long was it running with those parts before this happened?

 

yea i can just not today. it will be tomorrow. and thats what i thought i've tried searching for similar problems. i thought it might have been the valve springs having to much lift for the cam but im not exactly sure, and maybe im spinning the motor just to high for the lifters. which its around 6500.

 

about 300 miles. about 60 from tuning.

 

Looks like the cam seized up somehow. Any odd noises before it happened? Did you check your lifter preload? Oil pressure?

 

i started to sound like i spun a bearing, then there were a couple loud like chirps then just turned off. oil pressure was good. then im sure as it did this the pressure was going down never got a accurate reading while it was chirping. i didn't check the lifter preload no.

 

Can you pull the cam out?

 

Yea i had trouble with it but it did come out and it wasn't pretty... i just dont know what would have caused this kind of damaged. i keep going back to my springs since there dual springs. maybe too strong for the lift the cam was pushing??? the front cam bearing is done for also but the rest look good as much as i can see.

 

How hard was the cam to install?

I really doubt its springs.