ramaircjm

iTrader: (4)

I recently had my LS7 rebuilt and after running it at the track a couple of times I heard a faint but noticeable ticking sound starting right around 1500RPM. At idle you can't hear anything and beyond 2000RPM it goes away. The car doesn't feel like it's down on power as I ran a 10.72 with a very conservative tune in it last Wed night.

After just having fixed a similar sounding problem in my buddy's LS2 (which turned out to be from a lifter that got chewed up), I figured I was dealing with the same issue even though I had recently replaced all my lifters (which are stock).

I proceeded to tear it down this past weekend and was bummed to not find a smoking gun in the form of either a bad lifter or bent pushrod, both of which would have explained the cause of the ticking sound. What I did find however were that both the intake and exhaust valves in the #4 cylinder were noticeably damp with fuel as was the spark plug after only a few hundred miles.

At this point I'm stumped as to what's going on. I'm actually hoping that the ticking sound and wet valves are related because if not, I've got two problems to contend with.

All of the pushrods were fine and didn't show any signs of being bent and as for the lifters, none of the rollers were damaged or appeared to have any flat spots but I guess there could always be a plunger issue that won't be visible by just looking at them.

Things that I've tried and ruled out as possible causes are as follows:

- Injectors: I swapped the injectors over to my Z06 and drove it for several miles and the plug in the #4 cylinder was still dry so it's not a leaking injector
- Coil packs: I swapped the one bank and the plug remained dry after a similar driving test so I know it's firing correctly
- The valve springs in that cylinder don't appear to be broken
- I popped out both valves from that cylinder and spun them around in the guides and they appear to be completely straight
- Both valves also look like they're seating properly in the head
- All the rocker arms are brand new
- All the cam lobes appear to be in great shape as the cam is brand new

I am running a very high lift cam and have had a couple lifter problems in the past which is why I initially assumed that was the problem. Prior to this issue though I've had great success with only running stock LS7 lifters as I've made several hundred passes without having any problems whatsoever.

My best guess as to source of the issue is that I might have a collapsed plunger in one of the lifters but the problem with that is it'll take me a few hours to reinstall everything in addition to having to buy another set of head gaskets (which are not reusable) so I'd like to have a better idea of what might be wrong before I put everything back together and not have to find out I guessed wrong.

Has anybody has a similar experience to this? I'm open to any and all suggestions no matter how obscure they might be.

Thanks for reading.

Christopher