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Hey - I've got an LS1 with hardened pushrods and dual valve springs, spec 3 clutch, stock t56, and a driveshaft + rear end that are both rated for over 1000 hp. I was on the highway today, and I ran the car most of the way through third, went to grab 4th, missed, hit second, dropped the clutch -- I don't know if I let it all the way out or not... but if so, it couldn't have been in gear for over a quarter second. Anyway, it scared the sh** out of me. The car drives fine. No weird noises from the valvetrain. Still feels like its running at full power, tranny feels totally fine. Would I know by now if the valvetrain was damaged? What else might be damaged, engine wise, by a split second of overrev?

Thanks!
 

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What do you consider overreving (WHAT RPM)... You would know by now if the valves kissed the piston or each other... That old sound of clack, clack and pop, pop and rattle, rattle would be heard.
 

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WOW no way it reved that high, if anything the valves floated and you got lucky.... Why don't you have a rev-limiter on it.
 

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It has a rev limiter on it, but that doesnt save you from downshifting overrevs does it? I mean, the engine wasn't firing at that speed, you could hear it cut out for that split second. You can still damage it just spinning at that speed.
 

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I'd pull the oil filter and cut it up. If you chunked anything in the mis-shift it will show up in your oil and filter. Good time to change the oil anyways just in case some gunk was broke loose.

I think you are fine thou, you would heard it if a piston kissed a valve. If you hear noise or find a lot of shavings you could always do a compression and leakdown test see if anything it out of wack.
 

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Then your all good, the rev-limiter did its job. Some times its hard to hear when the rev-limiter is shutting down. What is the rev-limiter set at.
 

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Then your all good, the rev-limiter did its job. Some times its hard to hear when the rev-limiter is shutting down. What is the rev-limiter set at.
I don't think you are understanding what happened.
He was near the redline in 3rd gear, meant to shift into 4th but got 2nd instead. If you let out the clutch in 2nd gear when the car is moving at top speed for 3rd gear, the engine can hit very high RPM's through mechanical forces.
No rev limiter is going to save you from that.
It's called the "Money Shift", and it usually causes instantaneous damage.
Sounds like Mitch caught it in time and saved the engine.
 

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Discussion Starter #9
I don't think you are understanding what happened.
He was near the redline in 3rd gear, meant to shift into 4th but got 2nd instead. If you let out the clutch in 2nd gear when the car is moving at top speed for 3rd gear, the engine can hit very high RPM's through mechanical forces.
No rev limiter is going to save you from that.
It's called the "Money Shift", and it usually causes instantaneous damage.
Sounds like Mitch caught it in time and saved the engine.
Exactly what happened. Ragtop, if there were damage, would it most likely be immediately noticable? I mean this is an all or nothing deal for the most part, right? I'd know if I f***ed my motor up?
 

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Exactly what happened. Ragtop, if there were damage, would it most likely be immediately noticable? I mean this is an all or nothing deal for the most part, right? I'd know if I f***ed my motor up?
With most motors the damage is immediate. I know with BMW's it usually takes the valves out right away. With LS motors, I don't know if there is any latent damage. Take it easy for a while and see if there is any funny noises or loss of power.
Thankfully you put the clutch in quick, here is what happens if you dont:
 

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Although not as high, I over revved my LS1 when I attempted to manually shift my A4 (I wasn't about to give it up to a 5.0 Fox body). It went to N and winged up there. Engine ran fine but I pulled the valve covers that weekend and discovered 3 bent pushrods. Not bent enough to not work but not straight either.

BTW, they were stock pushrods. I replaced them with a set of hardened Comp pushrods.
 

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It has a rev limiter on it, but that doesnt save you from downshifting overrevs does it? I mean, the engine wasn't firing at that speed, you could hear it cut out for that split second. You can still damage it just spinning at that speed.[/quote

Correct..even more so when you went from the crankshaft delivering power and then being unloaded and driven from the rear.Hopefully the powertrain is stout enough and you had some momentary rear tire slippage when the clutch attempted to engage on the downshift.I would not sweat it..sounds like you dodged a bullet..but rolling some pushrods on glass would add to your peace of mind.:yes:
 
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