Hi
So out for a spin in the Corvette then had this loud noise from engine so advice please.
Now I have
• Changed Oil and filter cut in half nothing unusual found filtered oil through fine gauze again ok, used a strong magnet in oil nothing stuck.
• Checked headers no signs of blowing cracks.
• Removed roller rockers all look good
• No signs of spring snap or wear
• Removed push rods rolled on flat glass don’t seem bent no unusual wear on ends.
• Removed and reinserted all spark plugs no un normal marks or damage and all were tight.
• Oil pressure good.
2007 40000 miles
Don’t really want to run engine until found cause so next stop was to remove accessory belts and one more try before removing heads. Any other ideas things to check thinking maybe a lifter have quite a few mods listed below.
Lingenfelter: Cold Air Intake, GT11 cam 215/231 .631/.644 118.0 C5R timing chain. LPE Large valve ported heads. 2.055" / 1.57". Yella roller rockers. Manta pushrods. Ported throttle body and Fast 92mm intake. TB Spacer. 47 lbs. injectors. Kooks 1 3/4 headers with High Flow converters. Electric exhaust cutouts. Corsa Sport Mufflers. DTE HD differential with 3:90 gears. Bilstein Sport shocks.Z1 Sway Bars and end links, Dewitt’s radiator with large oil cooler, MGW short throw shifter, Dyno 465 RWHP 421 RWTQ

 

Your video doesn't work. Did you do a compression test in all the cylinders?

 

Hi no haven't yet done a compression test have re loaded video should work now.

 

sorry bud, gotta wait till I get home. But if all else fails I would start there. Knocking in the motor is not good at all. Chances are a CT might point you in the right direction.

 

Check to see if your harmonic balancer slid forward into the steering rack.

 

thats a good one too. I forgot about that

 

I got the video to work... that sounds exactly like rod knock. That is pretty much exactly what my STi sounded like when one of the rods failed. I HOPE completely wrong in this case.

 

Well, I hope it's not a rod. Good luck

 

and just to clarify I ment piston rods, not push rods.

 

yea hard to pin down first I fault it was a broken spring, have used a stethoscope but very hard to locate seems to be top end.
Will take a close look at the harmonic balancer tomorrow when I remove the belts.

 

Give us some back story on the car. Leading up to the problem, was the car driven daily, did this happen all of a sudden (last night was great, this morning its garbage) kinda something like that..... If you can please.

 

I have heard collapsed lifters that sound like that. Have you attempted to see if you can rock the rocker down towards the lifters? If this is your problem, one will be weaker and fairly easily depressed.

 

I'm with User Omega... especially if you reused the stock lifters on the cam swap.

 

No prior symptoms noises, low oil pressure or warning lights oil and filter changed every 3,000 miles or less nether used any fluids oil / water.
Car in regular daily use not winter

Heads were Lingenfelter machined and assembled large valves have been on the car since new. Springs and rockers changed 12,000 miles ago.

 

Sounds like a roller on a lifter has failed, and likely has wiped the cam out too. Tear it apart and have a look. My money is on a lifter failure.

Garry

 

Sounds like rod knock to me. But cell-phone audio isn't the greatest thing in the world to diagnose from.

 

Curious how this turns out... please continue to update us..

 

Just put mine in the shop it sounded just like that it was a bad lifter which wiped out the cam

 

Sounds too loud for valvetrain, too hi-pitched to be a rod.
Wonder what the plugs look like?

 

My guess, lifter, camshaft wiped out.
You could pull a wire on each cylinder, if the knocking goes silent, con rod bearing, but usually see particles in the filter.