Ouch, over rev'ed today....
Thread Starter
Le Mans Master
Joined: Sep 2000
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From: DFW TX
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St. Jude Donor '07
Ouch, over rev'ed today....
Went for a cruise this afternoon and dropped down to first going to fast. That's the first time I have ever buried a tach. Motor sounds good with nothing bent (fingers crossed). Time to order that MSD 6AL.
Budman
[Modified by Budman78, 11:01 PM 10/6/2001]
Budman
[Modified by Budman78, 11:01 PM 10/6/2001]
Drifting
Joined: Mar 2001
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From: Indiana
Re: Ouch, over rev'ed today.... (Budman78)
:eek: :eek: :eek: I hear ya. Now with my solid cam, that is my biggest worry. Missing a shift with the Hyd cam is bad enough, but with a solid...... :smash: :eek: :smash: :eek: :smash: :eek: I think a rev limmiter is going to be a must have item. Hopefully, It will stay together until I have a chance to put one in.
Le Mans Master
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From: Westfield Indiana
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Re: Ouch, over rev'ed today.... (Budman78)
What happened when you did it? Float valves or anything? Or did you just rev it up real high and with no problems? I've over revved and floated valves before but luckily no damage.
Now my question. What would it take to install a rev limiter on my non-computer controlled 79? Or is that what the MSD does?
Now my question. What would it take to install a rev limiter on my non-computer controlled 79? Or is that what the MSD does?
Race Director
Joined: Nov 2000
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From: NC,USA
Re: Ouch, over rev'ed today.... (jsimpson)
i wonder how you could avoid doing that with a mechanical device?
I know you can make a plate that controls where you shift but dont think there is one for that kind of down shift? i wonder if you could make an electrical lock out? just a thought
ZD
I know you can make a plate that controls where you shift but dont think there is one for that kind of down shift? i wonder if you could make an electrical lock out? just a thought
ZD
Race Director
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From: Plano TX
Re: Ouch, over rev'ed today.... (Budman78)
Well, you already have a revlimiter in the ECM, don't you? The MSD box won't do anything for you that the TPI ECM doesn't. Some auto trannies are setup to prevent downshifts at too high of speeds. I know the 4L60E won't downshift. Dunno about the 200R4 or 700R4.
Thread Starter
Le Mans Master
Joined: Sep 2000
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From: DFW TX
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St. Jude Donor '07
Re: Ouch, over rev'ed today.... (zwede)
Yea, 6AL, sorry for the typo. :smash:
I thought I had a rev limiter built into the ECM too, but I guess not. I guess my 350 tranny does not have a fell safe for downshifting at high speeds. It has a shift kit installed, so that may be the difference.
Also note, while I was freshening up the motor, I did notice valve dents in the pistons. Looks like one of the prevous owners may have experienced the same issue.
Again, I'm glad I'm not breaking it down tonight. :cheers:
Budman
I thought I had a rev limiter built into the ECM too, but I guess not. I guess my 350 tranny does not have a fell safe for downshifting at high speeds. It has a shift kit installed, so that may be the difference.
Also note, while I was freshening up the motor, I did notice valve dents in the pistons. Looks like one of the prevous owners may have experienced the same issue.
Again, I'm glad I'm not breaking it down tonight. :cheers:
Budman
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Re: Ouch, over rev'ed today.... (Budman78)
Rev limiters will not do anything for downshifting and over reving. They will only cut the spark plugs from firing, but that will only prevent over reving when you are accelerating. While downshifting you could have the ignition turned off completely and that engine is still going to rev up......
Race Director
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From: Forked River NJ
Re: Ouch, over rev'ed today.... (BSeery)
I have the Crane HI6. It is good for missed shifts but will not do anything for a downshift. It has worked for me on missed shifts a few times. Worth the unit just the rev limiter.
Le Mans Master
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From: B'Ville NY
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St. Jude Donor '05
Re: Ouch, over rev'ed today.... (Budman78)
Glad to hear you didn't break anything 
Maybe you've learned your leason and it won't happen again ;) .
I have the 6AL and missed a shift on the strip going from 2nd to 3rd. Boy did the engine rev very quickly will the gas pedal floored :eek: ! Everything was fine when I did put it into 3rd :conehead .
Maybe you've learned your leason and it won't happen again ;) . I have the 6AL and missed a shift on the strip going from 2nd to 3rd. Boy did the engine rev very quickly will the gas pedal floored :eek: ! Everything was fine when I did put it into 3rd :conehead .
Racer
Joined: May 2000
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From: Daytona Beach, FL, USA
Re: Ouch, over rev'ed today.... (Budman78)
There isn't much you can do to prevent over revving an engine due to a accidental downshift. You're lucky you didn't lock the rear wheels up or throw a rod. Glad to hear the motor is alright. The early Corvette ECMs do not have a rev limiter. Also, the TH700R4 and TH350/400 will not allow you to shift back into a gear if it exceeds the factory shift point. However, you can hold them in gear to whatever shift point you would like. My TH700R4 shifts at 4800 rpm, and I have manually shifted it at 5300 rpm many times with spurts up to 6000 rpm in neutral.
