Overrev
02-13-2019, 04:41 PM
#41
Honestly I must not have fully releases the clutch because the tracer for the highest point you rev was at the 68-6900 point. If I was really in the 8k range, that tach should've shot hard to the right. Additionally, like I said, I wasn't redlining 2nd but rather at the higher end of it.
It goes to 7500 rpm. It stopped at 6900 rpm because that's about where the rpm maxed out.
If it went to 8 or 9k rpm the tach border would have maxed at 7500 rpm.
There is no evidence to suggest if it went to 8k it wouldn't have registered at least 7500 rpm.
In fact data logging suggest the Tach reads faster (samples faster) than the average data logger.
The tach signal operates at several thousand hertz therefore a 8k rpm spike regardless how brief will peg the tach marker at 7500 rpm.
Last edited by dar02081961; 02-13-2019 at 04:45 PM.
02-13-2019, 04:45 PM
#42
Intermediate
Honestly I must not have fully releases the clutch because the tracer for the highest point you rev was at the 68-6900 point. If I was really in the 8k range, that tach should've shot hard to the right. Additionally, like I said, I wasn't redlining 2nd but rather at the higher end of it.
Smart move!
02-13-2019, 04:58 PM
#43
Pro
Thread Starter
It's more so I'd rather keep the car and there doesnt appear to be any immediate damage. Also, selling like that would be pretty messed up.
02-13-2019, 05:06 PM
#44
Intermediate
Quoted below before he can deny saying it.
Last edited by Dwyer; 02-13-2019 at 05:14 PM.
02-13-2019, 05:17 PM
#45
Le Mans Master
i don’t abuse my cars and wouldn’t powershift 1st gear meaning to go to 3rd. I wouldn’t powershift the car period. So I wouldn’t have that issue of my conscience to deal with. I wouldn’t sell anything that was less then perfect. My goal is to leave things or pass them on better then I found them.
Last edited by Mr. Gizmo; 02-13-2019 at 05:20 PM.
02-13-2019, 05:24 PM
#46
Le Mans Master
OP, i wouldnt worry, because in over rev case, damages are immediate ! Sure changing valve springs could not hurt, but why!!?? Usually. springs will break fair and square! The odd of having a micro failure in a spring which will lead to a catastrophic motor failure isnt impossible, but unlikely! If i was racing like Jason does, i would change the springs, hell i would take both heads of to inspect them!
02-13-2019, 05:24 PM
#47
Intermediate
Gismo (the troll) vs Katech, hmmm whom should I believe?
Last edited by Dwyer; 02-13-2019 at 05:27 PM.
02-13-2019, 05:41 PM
#48
Pro
Thread Starter
i don’t abuse my cars and wouldn’t powershift 1st gear meaning to go to 3rd. I wouldn’t powershift the car period. So I wouldn’t have that issue of my conscience to deal with. I wouldn’t sell anything that was less then perfect. My goal is to leave things or pass them on better then I found them.
02-13-2019, 06:15 PM
#49
Intermediate
02-13-2019, 09:02 PM
#50
Race Director
This isn't necessarily true. Often, an over rev will cause a valvespring to lose tension causing valve float and loss of performance. In extreme cases, valve to piston contact can occur. In drag racing, springs are sometimes replaced after only a few runs depending on spring pressure and lift.
02-13-2019, 09:47 PM
#52
Le Mans Master
i read Katechs threads so that makes me qualified by reading. Maybe Katech can back their claim that things didn’t get jolted and gnashed with a 10 year 100k warranty to the OP.
02-13-2019, 09:56 PM
#53
02-13-2019, 09:59 PM
#54
Le Mans Master
1. Drive it and forget about. Car may still be under warranty.
2. Have a professional builder pull the engine
apart and check for damage
3. Sell it or trade with the disclaimer he power shifted 1st at near the top of second meaning to hit third.
If none of these are acceptable , he can continue to fret about it with all us arm chair tech experts telling him how it’s all going to be ok or Potentially not ok.
what would you do with all your smartness and expertise if you were in the OP’s situation?
Last edited by Mr. Gizmo; 02-13-2019 at 10:11 PM.
02-13-2019, 10:07 PM
#55
Gizmo is one strange dude....
02-13-2019, 10:11 PM
#56
Melting Slicks
Non interference means even at full valve lift the piston top will not contact the open valve. I have no idea if an LT 4 is this type of engine. This type of engine design is useful so that a valve train train drive failure like breaking a belt or chain does not destroy parts of the engine. It is usually difficult to obtain in a high compression, high valve lift design.
The following users liked this post:
timmyZ06 (02-15-2019)
02-13-2019, 10:34 PM
#57
Drifting
The LT4 is an interference design, meaning at full valve lift the valve enters the space in which the piston travels. In an extreme overrev the valve can float open and contact the piston...otherwise known as a money shift.
02-13-2019, 11:38 PM
#58
Non interference means even at full valve lift the piston top will not contact the open valve. I have no idea if an LT 4 is this type of engine. This type of engine design is useful so that a valve train train drive failure like breaking a belt or chain does not destroy parts of the engine. It is usually difficult to obtain in a high compression, high valve lift design.
However for the purposes of the OPs question unless the timing chain or a valve spring breaks, a 223 degree cam at .551 lift with flat top pistons and stock heads on a stock LT4 will not allow the valves to hit the pistons.
But to address the OP's original concern lets say for whatever reason the valves did hit the pistons.
This would be a mechanical catastrophe and as such would be immediately apparent.
So this is not a concern in the Op's case.
The following users liked this post:
timmyZ06 (02-15-2019)
02-14-2019, 04:09 PM
#59
Intermediate
the op has 3 choices :
1. Drive it and forget about. Car may still be under warranty.
2. Have a professional builder pull the engine
apart and check for damage
3. Sell it or trade with the disclaimer he power shifted 1st at near the top of second meaning to hit third.
If none of these are acceptable , he can continue to fret about it with all us arm chair tech experts telling him how it’s all going to be ok or Potentially not ok.
what would you do with all your smartness and expertise if you were in the OP’s situation?
1. Drive it and forget about. Car may still be under warranty.
2. Have a professional builder pull the engine
apart and check for damage
3. Sell it or trade with the disclaimer he power shifted 1st at near the top of second meaning to hit third.
If none of these are acceptable , he can continue to fret about it with all us arm chair tech experts telling him how it’s all going to be ok or Potentially not ok.
what would you do with all your smartness and expertise if you were in the OP’s situation?
02-14-2019, 04:37 PM
#60
Pro
Thread Starter
It has 8000 miles and I haven't taken it to the track yet