girlys2k

hello guys!

I have a question for you.

What part usually goes bad when you mis-shift and over-rev?

My car is in the dealer, because there was a problem with the engine.
I know I did NOT mis-shift, but I just want to find out what happens to the engine if I did.
Just in case the dealer tries not to fix my car under warranty saying 'you probably mis shited your car.'

Thanks!

fenixv8

valves get bent

andrewboro

Just had this happen to me, I didn't over-rev my engine, but the dealership was telling me I had. Do your research and know the difference between bent valves and burned valves. The only way to bend valves is by over-revving your engine. Basically your piston collides with your valve (bad) and bends it. If they run a compression check and find low compression it could be a bent valve, burned valve, piston ring etc. In my case it was most convenient for them to say low compression was caused by a bent valve because that would have been my fault and would not have been covered under warranty. If you suspect you may have a problem you should run a compression check and a leak down test. It also wouldn't hurt to remove the valve cover and look at valve clearances. If you over-revved your engine the ecu should log this event and the mechanic will be able to see an engine code telling him there was an over-rev. At 12000 RPM you are doing 200 rotations a second its likely that you will see damage to more than one valve on more than one cylinder. If you do a leak down test and find a problem with only one valve it is probably not a bent valve.

Enthralled

your engine is toast.



have a nice day.

madkimchi

whinnnnnnnnnnneeeeeeeeeee... KABOOOOOM!

Blue_S2

I take it your are talking about a mis shift such as going from 5th to 2nd?

jdmgpw04

do you have an ap1 or ap2?

__redruM

I believe that you can crack the valve spring retainers as well. But that brings up an interesting point. If the valve spring retainer is defective and comes apart at a high RPM that is below the redline, you could get a single bent valve without an overrev. But bent Valves (plural) would almost have to be an overrev, or a broken timing chain

A broken or possibly a streched timing chain can also bend valves. But it's pretty rare. I worked a few years as a mechanic and only once saw a bad timing chain. Plenty of bad timing belts, but only one bad chain.

Also another question. Is there a way to clear an overrev from the ECU? Would pulling the fuse help?

RACER

girlys2k

something like that.
but I was thinking more like 5th to 4th not 2nd...