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UPDATED:..Supercharged Engine started tapping after spirited run.
Found what was making the tapping noise. I was a peice of ceramic off the plug. I guessing detonation on cylender 7 destroyed the plug. Car runs fine with new plugs and the tapping is gone. What the next step to check? Did I ruin my block?
Took the Vette out for a drive today. Got about 1/2 mile from the garage and this happened. When shifting in to second and accelerating at 75% throttle the engine sputtered, check engine light came on for just a few seconds. I let off the throttle and heard a tapping. See video. After this video was taken the tapping when away. I let the car sit for a few minuets while checking the codes. No codes, no check engine light. The car has good oil pressure, seems to idle ok while sitting. Have not attempted to drive it. Any ideas or info would be appreciated. The ls3 has a Mild blower grind cam, HD Double Valve Springs, Retainers & Hardened 1 piece push Rods, Procharger with meth injection. The corvette has 11,500 miles and around 7000 miles on engine after supercharger install.
I'd tow it in if not the gasket. Don't run it, tow it. My rocker arm broke and lifter failed. I had to replace the block because I was a ways from work and drove it in. Be safe, or it will cost u more in the long run....
Good oil pressure ... and now the noise went away ... hum.
My first guess was lifter as well. Hydraulic lifters have springs, *****, clips, etc. parts that
can fail or get clogged. The lifter may not bleed down or pump up properly and when it doesn't do this it functions in a less than ideal state of "load" (preload ...) between the cam and the pushrod and can make noise. Did you let the oil temperature come up above 170* before the 75% burst ? Is the oil clean ?
I think header gasket is a great place to start as well. While in there I'd at the very least pull the valve covers and look for a broken rocker arm, broken valve spring, bent push rod, etc.
Also, check to see that your intake manifold didn't shake loose. On my ls7 it got loose at one point and I heard a similar noise in my wheel wells and below the car (weird). Hope you find what it is !! Tom
No, I just thought the noise went away. Started it up the next morning and it was still there. Maybe it went away as the engine oil heated up. Going to check for blown header gasket and loose spark plug. Thanks for all the info.
Originally Posted by 2StrikeHtr
Good oil pressure ... and now the noise went away ... hum.
My first guess was lifter as well. Hydraulic lifters have springs, *****, clips, etc. parts that
can fail or get clogged. The lifter may not bleed down or pump up properly and when it doesn't do this it functions in a less than ideal state of "load" (preload ...) between the cam and the pushrod and can make noise. Did you let the oil temperature come up above 170* before the 75% burst ? Is the oil clean ?
I think header gasket is a great place to start as well. While in there I'd at the very least pull the valve covers and look for a broken rocker arm, broken valve spring, bent push rod, etc.
Also, check to see that your intake manifold didn't shake loose. On my ls7 it got loose at one point and I heard a similar noise in my wheel wells and below the car (weird). Hope you find what it is !! Tom
Its your lifter when its cold it will do it I bet then it will go away I bet it broke drain oil then pull cover.. I bet its loose or just went bad just don't start it till u pull covers. Good luck. Its not the engine internally thank goodness. Also I assume you are running a 20w oil.
Its your lifter when its cold it will do it I bet then it will go away I bet it broke drain oil then pull cover.. I bet its loose or just went bad just don't start it till u pull covers. Good luck. Its not the engine internally thank goodness. Also I assume you are running a 20w oil.
Why would he be running a 20w oil? Doesn't the General request you to run 5w30?
I agree with pulling the valve covers and having a good look before running it again. Hope it's as simple as a rocker arm or valve spring. Best of luck to you
◦Often, 30W motor oils contain a slightly higher quantity of viscosity-improving additives to create a thinner texture. These additives have their drawbacks. In high temperatures and pressures they "shear" or break apart, and can create a detrimental sludge, which reduces the engine's performance. Once the oil has begun this process of degrading, the rating changes from a 30W oil to a 20W or 10W oil. Quoted....usually all my buddies a&a charger they use 20w 40w after it breaks down ur good to go.. Why use 0w or 5w on such a high horsepower setup, you need all the protection from the start....then you get to 170 180 operating temps...
I have a similar setup on my 13 gs with meth and same hp. Had a noise that I first thought was a pulley bearing or timing chain tensioner. .. the shop pulled the front engine cover off after stethoscope testing indicated that the noise was from in the block. Noise was not from pulleys or tensioner. .. it was from the center of the bottom of the block and a Shiney spot could be seen on a spot on the crankshaft. We are thinking a bearing may have gone bad and is causing contact on the crank. The engine was running just fine and still made power. ..it just squeaked. I even drove it to the shop. I decided to forge the motor since I run my car on road courses regularly (and I was planning a motor build next year anyway). I'll know for sure what failed in a week or 2 once the shop starts disassembling the motor. Just wanted to share my experience. I definitely agree with other's advice on towing the car if you are taking it to a shop. It's all speculation right now until someone looks over the motor and starts locating the exact origin of the noise and investigating possible causes. Best of luck to you
Sounds like a knock in the bottom end to me. It was quite clear when you put the camera underneath behind the front tire. You said all the springs and rockers we're good on the visual inspection. Doesn't really sound like a bad lifter, that's more of a taping sound. That leaves moving accessories, rod and main bearings. I've heard the leaking gasket thing before and that's not how I remember it. I hope it works out for you and it's just something simple.
10-12-2014, 10:58 PM
UPDATED:..Supercharged Engine started tapping after spirited run.
Sounds like a lifter to me too
