Beyond Redline
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Intermediate
Joined: Mar 2005
Posts: 28
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Beyond Redline
Here are 2 questions for an LS1 expert / engine build.
1) How is redline established and is it a little conservitive from the factory on stock engine?
2) I was told that these engines are pretty tough, here is the situation. I was accelerating pretty hard in 3rd getting around a car and somehow screwed up and went to 2nd instead of 4th (what was I thinking) upon releasing the clutch I discovered what I had done, instantly I pushed the clutch back in and as I did this I glanced at the tach and noticed it unwinding trough 6500rpm (redline 6000 turns). Obviously there was a lot of engine noise in regards to rpm do to rpm being driven by gearing to the crank and the rev limiter not having any effect, but that is all I heard, and nothing metallic. The car seems to run fine and idles at normal rpm smooth, no smoke and accelerates smoothly. Needless to say I feel like a real dumb A$$, but I’ll get over that. Here is the question; If I had done any damage to the engine would it already be apparent? My first concern was bent valves, connecting rod, or broken rings.
Karl
1) How is redline established and is it a little conservitive from the factory on stock engine?
2) I was told that these engines are pretty tough, here is the situation. I was accelerating pretty hard in 3rd getting around a car and somehow screwed up and went to 2nd instead of 4th (what was I thinking) upon releasing the clutch I discovered what I had done, instantly I pushed the clutch back in and as I did this I glanced at the tach and noticed it unwinding trough 6500rpm (redline 6000 turns). Obviously there was a lot of engine noise in regards to rpm do to rpm being driven by gearing to the crank and the rev limiter not having any effect, but that is all I heard, and nothing metallic. The car seems to run fine and idles at normal rpm smooth, no smoke and accelerates smoothly. Needless to say I feel like a real dumb A$$, but I’ll get over that. Here is the question; If I had done any damage to the engine would it already be apparent? My first concern was bent valves, connecting rod, or broken rings.
Karl
Safety Car
Joined: Dec 2000
Posts: 4,798
Likes: 2
From: Norman Oklahoma
Cruise-In III Veteran
St. Jude Contributor
If you had gone far enough to do anything I think you would have known it right then.
Down shifting is about the only way to over rev an LSx engine that still has a rev limiter.
.
Down shifting is about the only way to over rev an LSx engine that still has a rev limiter.
.
Burning Brakes
Joined: Jul 2004
Posts: 865
Likes: 5
From: Jensen Beach FL
Generally any damage would be readily apparent. The most common issue would be rough idle and loud ticking from the valve train due to bent push rods. It would be a good idea to pull the push rods out and check them just to be safe. Other than that you’re probably fine.
Also; do yourself a favor and install an aftermarket shifter. I’ve been driving/racing manual transmission cars for over 20 years, and I shifted into 2nd instead of 4th twice with my car. I have never done this in any other car. There is something about the stock shifter that makes this easy to do for some reason. It seems to be a fairly common issue for the C5. I installed a Hurst shifter, and I love it.
Also; do yourself a favor and install an aftermarket shifter. I’ve been driving/racing manual transmission cars for over 20 years, and I shifted into 2nd instead of 4th twice with my car. I have never done this in any other car. There is something about the stock shifter that makes this easy to do for some reason. It seems to be a fairly common issue for the C5. I installed a Hurst shifter, and I love it.
Thread Starter
Intermediate
Joined: Mar 2005
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Originally Posted by MGorman
Generally any damage would be readily apparent. The most common issue would be rough idle and loud ticking from the valve train due to bent push rods. It would be a good idea to pull the push rods out and check them just to be safe. Other than that you’re probably fine.
Also; do yourself a favor and install an aftermarket shifter. I’ve been driving/racing manual transmission cars for over 20 years, and I shifted into 2nd instead of 4th twice with my car. I have never done this in any other car. There is something about the stock shifter that makes this easy to do for some reason. It seems to be a fairly common issue for the C5. I installed a Hurst shifter, and I love it.
Also; do yourself a favor and install an aftermarket shifter. I’ve been driving/racing manual transmission cars for over 20 years, and I shifted into 2nd instead of 4th twice with my car. I have never done this in any other car. There is something about the stock shifter that makes this easy to do for some reason. It seems to be a fairly common issue for the C5. I installed a Hurst shifter, and I love it.
I agree with you on the shifter, seems like a narrow throw between 1,2 and 3,4 even though the spring is suppose to center the shifter in line w/ 3&4. Longggg throw between 1-2 and 3-4. Does the hurst shorten this up and make more positive shifting? Seems that I heard some negative things about after market shifters. What model hurst do you have?
Thank you all for your input.
Karl
Burning Brakes
Joined: Jul 2004
Posts: 865
Likes: 5
From: Jensen Beach FL
Originally Posted by klem
I agree with you on the shifter, seems like a narrow throw between 1,2 and 3,4 even though the spring is suppose to center the shifter in line w/ 3&4. Longggg throw between 1-2 and 3-4. Does the hurst shorten this up and make more positive shifting? Seems that I heard some negative things about after market shifters. What model hurst do you have?
Thank you all for your input.
Karl
Thank you all for your input.
Karl
I think there is only one model of Hurst shifter available for the C5.
I neglected to answer your first question in your original post. The factory redline is set mainly as a function of the operating range of the stock cam and valve springs. The rest of the motor is capable of living with 6700-7000 shift points.
Thread Starter
Intermediate
Joined: Mar 2005
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Thanks MGORMAN, for your input 
nasty felling when you screw the pooch.
On the Hurst shifter you said noise is not an issue when installed correctly. I've been wanting to do something about that shifter but was waiting for some positive input. On the install what did you mean when you said, "When installed correctly". If I follow instructions that come w/ the Hurst shifter will that be sufficient or is there something I should look for or do differently. And how difficult is the install. Can it all be done without getting under the car?
Thanks in advance.
Karl
nasty felling when you screw the pooch.On the Hurst shifter you said noise is not an issue when installed correctly. I've been wanting to do something about that shifter but was waiting for some positive input. On the install what did you mean when you said, "When installed correctly". If I follow instructions that come w/ the Hurst shifter will that be sufficient or is there something I should look for or do differently. And how difficult is the install. Can it all be done without getting under the car?
Thanks in advance.
Karl
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Joined: Aug 2001
Posts: 5,364
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From: King George VA
Agree that problems with the valve train would probably be apparent already, but other hidden area is the timing chain. The timing chain doesn't like high rpms. It tends to curl around the sprockets, putting a lot of stress on the links and eventually it will break. Most SCCA T1 teams raise the rev limit on the car and I did likewise. Early last year I lost a timing chain... ouch. Fortunately, the engine wasn't a total loss. I ended up having it rebuilt and all it needed was six new valves and a valve job (and new timing chain obviously), but everything else was fine.
I wouldn't lose too much sleep over this as T1 Vettes tend to spend a lot of time at redline, vice one shot, but keep it in mind. If you ever open your motor for some reason, put in a heavy duty chain.
I wouldn't lose too much sleep over this as T1 Vettes tend to spend a lot of time at redline, vice one shot, but keep it in mind. If you ever open your motor for some reason, put in a heavy duty chain.
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Burning Brakes
Joined: Aug 2000
Posts: 889
Likes: 0
From: DFW tx
I doubt you damaged anything. Stock parts should handle 6500 rpm's fine.
To avoid the same problem I would suggest putting in an aftermarket shifter. The stock shifter makes it easy to miss gears. It is very loose and has very little centering force. I put in the hurst shifter and have been very happy with it. It takes a little more effort to shift, but you get used to it fast. It comes with different springs to adjust the centering force. I have not missed a gear in a long time.
To avoid the same problem I would suggest putting in an aftermarket shifter. The stock shifter makes it easy to miss gears. It is very loose and has very little centering force. I put in the hurst shifter and have been very happy with it. It takes a little more effort to shift, but you get used to it fast. It comes with different springs to adjust the centering force. I have not missed a gear in a long time.
Pro
Joined: Jun 2005
Posts: 529
Likes: 0
From: North Carolina
Originally Posted by klem
I agree with you on the shifter, seems like a narrow throw between 1,2 and 3,4 even though the spring is suppose to center the shifter in line w/ 3&4. Longggg throw between 1-2 and 3-4. Does the hurst shorten this up and make more positive shifting? Seems that I heard some negative things about after market shifters. What model hurst do you have?
Thank you all for your input.
Karl
Thank you all for your input.
Karl
I jsut put one in a couple of weeks ago. I used the softest springs, but still my first impression was, "wow this is stiff". After about a week, I'm used to it and would NOT go back to the stock shifter!
