regorih383

iTrader: (21)

I need a little help finding a loud ticking sound that happened after a buddy accidently dropped his C6 LS2 A6 from 3rd gear to 1st gear causing the motor to over rev fast to 7k rpms. I pulled the heads expecting to find a bend valve or some contact marks on the top of the pistons but they all looked normal and no evidence of piston to valve contact.

I also inspected all the lifter and they all looked normal too. Right before I tore the engine down the loud ticking sound was present and it would get louder as RPMs would increase.

Does anyone have any suggestions on where else to look? I’m hoping that the loud ticking sound isn’t coming from the short block.

Thanks,
Roger






*EDIT 8-3-15 I got the engine back together and the ticking sound is gone. I did h/c package with new lifter so I can only assume a lifter took a dump. Thanks for the comments*

Fraser588

Hows the oil pressure look?

redtan

iTrader: (5)

Could be a lot of things. How did the pushrods and rocker arms look?

If the valvetrain is ok then could be a spun bearing in the bottom end.

R6cowboy

iTrader: (3)

A quick 7,000 rpm likely won't hurt the bottom end, but definitely could have a spun bearing. How do the pushrods look? These are probably the most likely item to be damaged during an instance like this.

I did the same thing in my C5, 6 speed though. At the time it was 100% stock, I accidentally dropped it into 2nd at 90mph or so. Rpms jumped up to roughly 7500 resulting in extremely bent pushrods, valve contact with every piston and many bent valves.

Edit: I see the lifters are ramdomly placed in that box. It's good practice to place all valvetrain components in an organized fashion to identify which cylinder they went to.

regorih383

iTrader: (21)

Oil pressure was stable and normal @ 40psi at idle .
Ill have to go back and look at the push rods. It never occured to me untill y'all brought it up.

R6cowboy

iTrader: (3)

This could also easily damage the lifters, which may not be visible damage. I advise your friend to replace the lifters with at least stock replacement LS7 lifters (only about $130 for a set) for safe measure and peace of mind. Upgraded hardened pushrods (only $110 range) are also inexpensive and a good idea at this point.

R6cowboy

iTrader: (3)

Also, now is a good time to inspect the cam lobes and bearings while the heads are already removed.

regorih383

iTrader: (21)

Thanks,

I'm in the process of doing h/c on the car now that its appart.

ROger

jl sargent

I had a tick like noise once that ended up being a broken piston skirt. I later figured out that if I had made a little wire hook and fished the oil pan through the drain hole I could have pulled out some of that skirt before I took the first bolt out of that engine. Might be time for a little fishing expedition.

regorih383

iTrader: (21)

Pushrods look ok

CAMSTER

iTrader: (10)

Easiest way to find a ticking sound is to get as close as you can to it, this is done with a stethoscope which will eliminate areas where it is not present and will also help to determine whether is at top or the block.

Now that is not possible roll each push rod on a flat glass or mirror to eliminate the bend rod possibility.

To check for a collapsed lifter push on the rod seat to see if the spring is operable and check for play in the roller wheels.

If all above checks good next step is to turn the crank and stop to check any piston going down, and push the top of the piston at the center looking for a sly vertical play, there should be non, if you find a piston that dropped a few thousands mark it and go down check the rod bearing.

Hope this helps good luck.

06gtoLD

I agree with above..

regorih383

iTrader: (21)

Cars getting new lifters and pushrods as part of the heads and cam install. What I'm worried about is assembling the engine back and still have that ticking sounds. Pushrods and lifters look ok , guess it's time to look at the short block

MuhThugga

Just because the lifters look okay doesn't mean they are all still good to go.

Have you turned the bottom end by hand/with the starter?

SpankHiney

I would just drop the pan and start pulling each cap. First the rod caps . . .then each main. Why build up the top end? You could have a trashed engine...including a ruined crank.


Check cam bolts and timing chain. . .
Harmonic balancer could have spun. . .


You could try disconnecting one plug wire at a time to see if the sound would go away?


Another idea...drain the pan and temporarily fill the oil pan with 20-50 weight oil. Do not rev hard with this oil. If the sound disappears completely while the engine is cool. . . .you've got a serious bottom end problem.