shannon8650

After i installed my crane stage 3 cams and beehive valve springs I keep breaking exhaust valve rocker arms/cams followers. only does it on start up. may start up 5-10 times ok then next time it breaks one or two. they all break in the same place. I haven't seen or heard of this happening thought i'd run it by you guys
thanks

steelcomp

Sounds like you have some valve piston contact going on. Are you sure you got the cam timing right, and the gears back on correctly? I think after the first one I'd have found out why.

shannon8650

well like i said only on start up, i drove it around all day it saw 6800 a couple times no problems. i have never seen a valve hit a piston and not bend, let alone break a rocker arm, not saying it isn't possible. i just haven't seen it. as you might know the cam pulley only goes on one way it has only one groove. i had everything marked when i swapped cams nothing changed.

Dex

only way that would happen is timing. how else would it break?

flounderlipps

Well if it's not a timing issue.
Try these
http://www.jeselonline.com/v2/index.php?categoryid=43

sleeper2

Shannon, did you/do you have to do anything with the variable camshaft timing when you swap cams on these engines? (I'm asking because I don't know what the solenoid does in startup/open loop.) I wonder if the PCM is changing the the valve timing on startup in a way your new setup doesn't like.

Sleeper2

shannon8650

well i wasthinking the same thing with the vct, but the thing is i left it unhooked on both cams so it won't do something bad before i got my tune, but i think it might be doing something stupidwith it unhooked on start up likemoving the cam timing around which is causing it. the first time i broke one my springshadn't came in yet so i just thought coil bind was the reason but i installed the springs and it didn'y help.

steelcomp

I know there can be as much as 150psi oil pressure at start up, I also know that the mechanism inside the cam gears is very fragile and dosen't like much more than stock spring pressure. They typically self destruct when heavy springs are installed and that usually looks like a nuclear explosion under the valve cover. You may have some problems inside the cam gears that aren't completely obvious..except on occasional start ups.

steelcomp

any more on this one??