roper2

what does happen when you over rev. your engine past 6500 R.P.M. had this happen 1 time sort of sacred me was not paying attention mother just shut down .

occar

Anything from absolutely nothing to catastrophic engine failure.

roper2

Still running very well

jdmdohcpower

it depends, if you miss a shift and hit the rev limiter "over revving", nothing should happen. If you hit second gear when you were trying to go hard from 3rd to 4th "mechanically over revving"... all kinds of $hit will happen. Its one of those things where you will know if you broke it

RandomTask

Happened to me. Going for 3rd, went right back into 1st. Motor screamed. Its un-nerving, but as long as nothing let loose, you should be alright. If it did suffer a catastrophic failure, GM would probably tell you to pound sand for a warranty. Since it didn’t, no harm no foul, just make sure to not let it happen again.

RJ-92

It has a rev limiter, you're like fine. Unless you grabbed second instead of 4th and engaged the clutch you'll be A-ok.

I missed a shift once and did exactly that in my old Taurus SHO, spun the motor to like 10500 and never had an issue. That was an OHC motor, OHV motors will sometimes bend a push rod.

roper2

It is a A 8 zo 6/7

Karanx7

If you get lucky, the piston won't hit the valve so no damage.

If you're not lucky, you will know the piston hit the valve. Even slight damage will create obvious symptoms, if the engine still runs.

roper2

going from 1st to 2nd

NSC5

With the A8 you couldn't have created a serious over-rev via a missed shift It won't allow a paddle shift into too low a gear, you will get a shift denied message if you try to shift into a range that will result in excessive RPM and the same is true if you try to select a range that results in RPM being too low. If you neglect to shift while accelerating the rev limiter will simply prevent you from going faster.

I am not sure what the transmission will do if you are on a very steep downgrade and have manually selected a range where the engine will exceed safe RPM if you don't use the brakes to keep speed in check. That is a programming choice and I would not advise testing how it behaves

With the A8 you haven't hurt anything except maybe your pride if you were racing and didn't shift quickly enough and lost.

Poor-sha

Sounds like a non-issue for the OP since it was an upshift in an A8. However, I have had the experience of "upshifting" from 4th in to 3rd instead of 5th on the back straight at Road Atlanta. This was in my C6Z and the data showed I hit 8200 RPM. Nothing broke but I was smart enough to park the car after that.

I called Katech and Jason told me to change the valve springs as they were likely weakened from the overrev. I did and you could tell that some of them were because they were special pains to get out. If you keep running the motor the odds are the spring will fail, you will drop a valve, and then it gets expensive. In my case it was an easy fix because I didn't just keep going.

Just a word of warning should it happen to someone else.

occar

A8? Err.... You can't overrev that unless you're pushing or pulling it or something...

Over-Rev

You rang?

It could seriously harm your engine though, especially if you downshift into a really low gear at high speeds.

Thomasmoto

I really doubt that you hurt anything. I went from top of 2nd at 6500 looking for 3rd and went right into 1st rear tires squalled like hell and the car's rear end went all over the track, but I saved it and it didn't hurt a thing.

AZDoug

If nothing broke, then nothing happened. You would know.

I missed a shift in my 308 once, which has a 7500 redline motor; I watched in horror as that tach finally peaked at about 10,500-10,800, and started coming back down. Time seemed to in be slow motion.

Nothing was hurt.

Doug

Poor-sha

I disagree. An overrev will weaken springs. They may not fail immediately but if sufficiently weakened they will fail.

Somewhere around here there's a thread where JD dropped a valve at VIR. Jason went back and looked at his video from a previous session and found where he overreved on an early downshift.

All I'm saying is just because it seems fine I would take the precaution of swapping the valve springs and make sure everything else looks ok. It's not a big job.

RedZ4me

It's the other way around, the piston always moves the same length during the crank rotation, it's the valve that can hit the piston should it break, or the valve spring break, keepers let go etc.....

Boiler_81

No issue, you just hit the rev limiter. The car is programed to keep you from over reving it. Even on downshifts, the automatic will not let you go to a lower gear if it would result in the engine over reving.

The only way to over rev a Corvette engine is with a manual transmission car. It will not over rev via the throttle as it is also rev limited. The danger is shifting into a lower gear and over reving.

roper2

I was in track mode drive and decided to shift down to 1 st. and punch it I thought it would shift automatically to the rest of the gears but it didn't

occar

You were lucky, unless the LT4 has lighter valves and better springs than the LT1.