TurnerJ

Hi everyone,

I haven't driven my car a whole lot since its top end rebuild as it still has an annoying hanging idle. I don't necessarily remember this knocking noise from the beginning but maybe it has always been there and just slowly got louder. Pretty positive this noise was not there before rebuild though. I'll admit this was my first time working inside an engine and it seemed too simple, I probably missed something. Like anything specific to do when assembling the valvetrain? I don't know if it goes away when warm but next time I start it I want to know what to look for ahead of time!

ls6 heads professional rebuild
mild cam with recommended push rods
ls7(?) lifters were already in there
new lifter trays
didn't touch bottom end

Here's the video! I'd really appreciate any ideas!

(Let me know if the attached videos don't show well, I could try uploading to youtube)

Thank you all!

unit

No way of knowing from your vids. You can by an automotive stethoscope at most autopart stores for less than $15.00. Use the scope to probe and pinpoint the location of the noise. You can do the same thing with your ear to the handle of a long handled screwdriver but the stethoscope works far better. Could be tappet noise, a rod bearing or something else. Good luck with it.

TurnerJ

Thanks will do!
Only other piece of information I have is that it is directly related to rpm.

How fast can this get worse if, say, it was a bearing? Would driving it be a bad idea? Or would the crank already be out of round anyway (I think that's the terminology).

JeepinJeremy

iTrader: (11)

To me it sound like lifter tap and an exhaust leak. Did you pre-lube everything prior to assemble? Did you torque your rockers when both valve were closed? How much was milled off your heads and did you install the correct head gaskets for good piston to valve clearance?

TurnerJ

Yes thank you for that response! I think your diagnosis is very probable. I will double check for exhaust leaks as I wouldn't be surprised. I didn't have a lot of room to work with the headers.

I was not informed of any milling so I believe the least amount possible to ensure flatness. I used stock head gaskets.

Now for the rockers. I knew it couldn't be so simple.. It was a year ago when I did it but I don't recall having both valves on a cylinder closed as I torque the two. And considering the hydraulic lifters, this means I don't have to worry about valve lash and stuff right? Just torque them down with valves closed?

So at this point I'm best of driving it to my garage, popping off the valve covers, and wiggling things looking for play in the valvetrain