[RUQWIKR]

Originally Posted by TrackClub

Just some food for thought: you could be fine, or some parts, springs especially, could have gotten fatigued.
Nobody can tell you one way or another, not even if they are a Grand Master Mechanic, or a BB poster
The fact you dont hear anything is a sign nothing broke immediately, but not that something wont break next time you reach red line, if it has weakened. Metal fatigue is not a binary type of proposition a la: it works today so it will work just fine tomorrow. I know semi pro circle track guys who change springs for every race, as a cheap insurance. Usually, 4th to 2nd will grenade a motor in an instant, but perhaps your shift was a lazy one, allowing rpms to drop quite a bit. Regardless,
I wouldn't say you're risk free longer term. My 2 cents.
Then again, you are covered by GM power train warranty, so there is that Cheers!

If the warranty folks see a mechanical over rev, the claim should get denied as max rpm seen by the cam and crank position sensors are recorded. Not sure how long it stays in memory or is permanent, but, I know of instances that nuked motors had warranty claims denied as a result of that.

[EV2DEMON]

Send a sample to blackstone and tell them you money shifted it. If there is metal in the oil, they’ll tell you.

Except that fatigued valve springs will never show any signs of metal in the oil.

[Stephen12ZL1]

the valve spring thing is not much of worry IMHO unless the "over-rev" rpm was extreme for a longer period of time. The higher than redline rpm didn't make the camshaft valve lift increase during the described incident. No doubt they were stressed. The events were occurring more rapidly but at stock valve lift you should be OK. With a high lift longer duration cam (with more overlap), this incident would have been potentially worse. Piston to valve clearance could have caused contact. Get an oil analysis and inspect the filter.

[s346k]

i thought some dude on here posted his experience with a money shift gone wrong and getting the engine repaired under warranty...? at least i recall seeing the vid on youtube.

[TrackClub]

Originally Posted by Stephen12ZL1

the valve spring thing is not much of worry IMHO unless the "over-rev" rpm was extreme for a longer period of time. The higher than redline rpm didn't make the camshaft valve lift increase during the described incident. No doubt they were stressed. The events were occurring more rapidly but at stock valve lift you should be OK. With a high lift longer duration cam (with more overlap), this incident would have been potentially worse. Piston to valve clearance could have caused contact. Get an oil analysis and inspect the filter.

Good thoughts, but i did brake a spring on LS6 with oem cam which doesnt have high lift at all without a single over rev. Not to mention high lift cams call for double springs for a very good reason. If there was a metal to metal contact then this would likely result in bigger metal particles likely captured by a plug (if not aluminum) and/or filter, such as during break in period. If microscopic then oil analysis will show it. But...what then? Pay to rebuild the motor?
Trade her in? (Not very ethical imo but i am sure this woudnt be the first, or a last time somebody punts trouble away.)
The reason i have mentioned springs is that they are easy to change, not hugely expensive and - often enough - the cause of push rod motors going boom. Even if oil anaysis were perfect and no chunks seen anywhere at oil change i would change the springs for exactly the reason of piece of mind. But as i often say: that's me
Cheers and best of luck to the OP!

[TrackClub]

Originally Posted by s346k

i thought some dude on here posted his experience with a money shift gone wrong and getting the engine repaired under warranty...? at least i recall seeing the vid on youtube.

Yes, there were more than one vids posted by folks who routinely over revved on downshifts. And got motors replaced regardless. Whether GM continues "no questions asked" attitude when honoring motor warranties is to be seen. As mentioned above, it would be easy for them to deny it based on over revs. Red line is there for a reason. Unfortunately manual tranny cant protect it on downshifts.

[RUQWIKR]

Remember, these engines have the AFM / shifting lifters on cylinders 1, 4, 6, & 7. Even though AFM is not active on any ZL1 nor manual SS's, the hardware for AFM is all there. The AFM lifters do not take high rpm's as well as the regular lifters and are more prone to internal damage on over rev's. That's why they are replaced, typically, when aftermarket camshafts are put in because of the lobe profile differences along with the typical increase in fuel cutoff rpm put in aftermarket tunes.

Either way, over rev's causes valve bounce, valve spring bind & rotation, lifter over travel, etc. As TrackClub and others have pointed out, a single over rev can cause component failure - or not. Multiple over rev events can cause a component failure - or not. Any way you cut it, try not to over rev on up or down shifts.

[Jaxcam02]

Originally Posted by RUQWIKR

Remember, these engines have the AFM / shifting lifters on cylinders 1, 4, 6, & 7. Even though AFM is not active on any ZL1 nor manual SS's, the hardware for AFM is all there. The AFM lifters do not take high rpm's as well as the regular lifters and are more prone to internal damage on over rev's. That's why they are replaced, typically, when aftermarket camshafts are put in because of the lobe profile differences along with the typical increase in fuel cutoff rpm put in aftermarket tunes.

Either way, over rev's causes valve bounce, valve spring bind & rotation, lifter over travel, etc. As TrackClub and others have pointed out, a single over rev can cause component failure - or not. Multiple over rev events can cause a component failure - or not. Any way you cut it, try not to over rev on up or down shifts.

shit really, I thought I wasn't going to have to worry about AFM on this manual and leave it stock. Now I have to get a camshaft just to get rid of those lifters.

[TrackClub]

Originally Posted by RUQWIKR

Remember, these engines have the AFM / shifting lifters on cylinders 1, 4, 6, & 7. Even though AFM is not active on any ZL1 nor manual SS's, the hardware for AFM is all there. The AFM lifters do not take high rpm's as well as the regular lifters and are more prone to internal damage on over rev's. That's why they are replaced, typically, when aftermarket camshafts are put in because of the lobe profile differences along with the typical increase in fuel cutoff rpm put in aftermarket tunes.

Either way, over rev's causes valve bounce, valve spring bind & rotation, lifter over travel, etc. As TrackClub and others have pointed out, a single over rev can cause component failure - or not. Multiple over rev events can cause a component failure - or not. Any way you cut it, try not to over rev on up or down shifts.

Words of wisdom! And ya, i forgot about AFM as another weak point. Regardless, failures can happen immediately due to a catastrophic event, or due to fatigue over time.
Tons of examples not only motor wise, but also other components. Run slicks on a street car long enough and one will be replacing hubs and control arms - guaranteed. Rotors and wheels can crack due to metal fatigue over time, etc. Bottom line: the fact nothing let loose is no guarantee it won't in a near future if it has been stressed beyond its operating specs.
So the OP can get lucky, or his luck could run out at a next track event. Or one after that. Or whatever.
In any case, i would caution against proclaiming everything is peachy, because that would be way premature a verdict imo and for whatever it is worth.

[RUQWIKR]

Heck - its' hard on valve springs just sitting with the key off! All sixteen of ours are under various static loads depending on where the cam lobe is for each.

[TrackClub]

Originally Posted by RUQWIKR

Heck - its' hard on valve springs just sitting with the key off! All sixteen of ours are under various static loads depending on where the cam lobe is for each.

Very true. That's why those are first to get replaced especially on race motors that sit idle for a long time.

[Tango1LE]

Originally Posted by Jonnydz

Thanks for all the info. Engine is running fine with no lose of power, smoke, or ticking. I am going to change the oil this weekend. Tango I am a no go for the 17th. Going out to auto club speedway (cally) for a hpde in a c7 grandsport. Cant wait to compare to our car. Hopefully Jan we can meet up again

Sounds good Jonny. Have fun in the C7GS.. See you at WinterFest in January..

TC

[Dads1le]

Reading all this has me thinking about my recent smoking/oil burner. At my second track day with built heads cam motor that has ls7 lifters... engine started smoking coming out of corners at Grattan raceway Checked oil at event and by the time I got home after 160 mile drive I was down 1/2 quart. Have done several auto x events and only two tack events and never used oil or had visible smoke. I did miss shift once from 4 to 3 instead of 4 to 5 but didn’t catch on pdr. That was during first track event and didn’t smoke at all then. Going into builder in next few weeks to diagnose. After first track event car went in for new injectors and was a down a little on peak hp I’m no engine expert so appreciate any input on what I should be asking.

[RUQWIKR]

Originally Posted by Dads1le

Reading all this has me thinking about my recent smoking/oil burner. At my second track day with built heads cam motor that has ls7 lifters... engine started smoking coming out of corners at Grattan raceway Checked oil at event and by the time I got home after 160 mile drive I was down 1/2 quart. Have done several auto x events and only two tack events and never used oil or had visible smoke. I did miss shift once from 4 to 3 instead of 4 to 5 but didn’t catch on pdr. That was during first track event and didn’t smoke at all then. Going into builder in next few weeks to diagnose. After first track event car went in for new injectors and was a down a little on peak hp I’m no engine expert so appreciate any input on what I should be asking.

Pull the spark plugs and look for oil and any signs of aluminum as well. Do a compression and leak down check on each cylinder, too.