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...failure to communicate
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Discussion Starter · #1 ·
Last night, I was crossing the traps at 120 mph in 3rd gear in my C4 - should be right around 6000 rpm or so (4.10 gears, 28" slicks). I reached over for the chute release to test it. I missed it and my forearm knocked the shifter forward (reverse pattern manual valvebody) while still at WOT.

The rpms skyrocketed (duh) and I didn't feel the chute hit. At the same time, the back end of the car washed out like I ran over something slippery. It was fishtailing around at least a half dozen times. I got off the throttle and one I got it straightened out I killed the ignition and fuel pump and got on the brakes. It was stilling screaming rpms. Got it stopped right in front of the turnoff and safety crew and noticed the chute lever hadn't moved and realized i must have hit the shifter (stupid!!) Unfortunately I didn't pay attention to what gear it was in.

I let it sit to check everything over and saw no leaks or anything dripping. Started it up and it ran and drove just fine back to the pits. They checked the track and didn't clean anything up, so hopefully that means they didn't see any fluids.


QUESTIONS:

Do you think maybe just the tires locked up from zooming the engine and that's why the back end broke loose?

What will a reverse manual C4 do when knocked into 2nd or 1st from those speeds/rpm? Will it go into that gear or will it kind of freewheel at some point? Anything to govern it so I can see how high the rpms may have been? (When I stopped I hit the shutoff so I lost the peak recall on the tach) Based on sound, it sounded a lot like 8-9000 rpm but depending on what the tranny does, I know it should be higher. If it only drops to 2nd, 9K rpms at 120 sounds about right with my tires and gears

FWIW, I have an 8000 rpm chip in the MSD and usually turn the car 7400-7700 or so. I never heard the rev limiter hit, I must have gotten off the throttle before it hit 8K rpm.



Trying to figure out exactly what I did, but also what may need to be checked.

gonna check all the fluid overflows tonight and going to do a leakdown and compression check and check all the valves and rockers (solid roller) to make sure nothing got bent or cracked.
 

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Actually I had the same thing happen to me a while back.I was coasting in the shut down area in my Mustang and accidentally put it in 2nd instead of neutral on my C4. The revs jumped to the moon but lucky for me there was no damage to the trans.It was when I was running 11.60's and making 500 hp. You seem to have a lot more car than I did so I hope nothing is hurt by your mishap.:cool:
 

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You should feel extremely lucky (you are) that you did not wreck your car irregardless if there is any transmission damage. I would also check the engine over real good as well. When you mechanicaly over rev an engine a rev limiter does no good. Do a leakdown, check the valve lash and springs to determine if anything bad happened there as well.
 

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Put the chute handle up top.
 

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c4's are pretty strong when it come to accidents lol ive seen some things that would blow anything else yet not even phase a c4. as for the reason you got loose, its because you caused the car to unload real fast and hit the tires hard, and at that speed yeah itll get reall scary. its the same as if you were driving down the street and slammed on the brakes to avoid that damn squirrel lol. if you didnt hit the limiter then you didnt get past 8000 but like said a sudden shock of rpm can hurt things so check things good including the flexplate, i learned that the hard way although that was an art carr peice o crap. if that happens again you may want to pull the chute, it can straighten you out sometimes or depending on the situation, stab the throttle a bit to get the weight transfer and hook. obviously these tips dont fit every situation so you have to know when to use them. as for what a c4 does, it will go into gear at 2nd but 1st is usually just like neutral.
 

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...failure to communicate
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Discussion Starter · #6 ·
c4's are pretty strong when it come to accidents lol ive seen some things that would blow anything else yet not even phase a c4. as for the reason you got loose, its because you caused the car to unload real fast and hit the tires hard, and at that speed yeah itll get reall scary. its the same as if you were driving down the street and slammed on the brakes to avoid that damn squirrel lol. if you didnt hit the limiter then you didnt get past 8000 but like said a sudden shock of rpm can hurt things so check things good including the flexplate, i learned that the hard way although that was an art carr peice o crap. if that happens again you may want to pull the chute, it can straighten you out sometimes or depending on the situation, stab the throttle a bit to get the weight transfer and hook. obviously these tips dont fit every situation so you have to know when to use them. as for what a c4 does, it will go into gear at 2nd but 1st is usually just like neutral.
it went past 8K, it just didn't do it under throttle so the rev limiter didn't do anything. I'm just not sure how FAR past 8K it went.

As for throwing the chute - good idea, but the whole scenario happened because i *thought* I DID pull the chute :D lol.

I'm gonna pull it off the trailer tomorrow morning adn I'll check and see what it does in 1st when off the throttle. I'm leaning now towards thinking I only pushed it to 2nd.

I'm getting conflicting info though on whether a rev man VB will actually go to 1st at those speeds or if there it will act like nuetral. If it's like nuetral then without a doubt I pushed it to 2nd, but if it CAN go to 1st, I'm ntot sure.


But since it would hit 16000 rpm at that speed in first, I'm pretty sure it only got to 2nd otherwise I'd need a dustpan to piece up all the pieces.
 

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...failure to communicate
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Discussion Starter · #7 ·
Yeah, I'm going to look into other places for the chute release. I had it on the top of the cage before, but I didn't like it there. I could never quickly find it. Plus I sit a lot lower now and I'm short so that would put it even farther from reach. I have some other ideas that wouldn't be around the shifter.

I could also convert the handle assembly to a pull release instead of a push. That way I'b be pulling back towards high gear where the shifter would already be.


You should feel extremely lucky (you are) that you did not wreck your car irregardless if there is any transmission damage. I would also check the engine over real good as well. When you mechanicaly over rev an engine a rev limiter does no good. Do a leakdown, check the valve lash and springs to determine if anything bad happened there as well.
yeah, I do. I've been loose before mid track in a much slower car when I got into some oil dry and turned me a bit sideways, but I've never been THAT loose at THAT speed before. I'm glad to have experienced it though and I'm glad to know myself that I didn't panic at all and was able to reel it back in. Once of those things you practice and prepare for, but you never what you will actually do until it happens.

Going to leakdown and comp check tomorrow and check over all the valvetrain real well. It's running like it is perfectly fine, but I'd be shocked to find I didn't bend anything at all.
 

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The C-4 will downshift and have engine braking in 2nd but may or may not in low (some do , some don't) .
The trans may actually be ok as you downshifted at WOT but be sure to check the oil for clutch smell and if its good and clean you should be alright.

Hutch
 

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...failure to communicate
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Discussion Starter · #9 ·
Thanks Hutch. if this VB is the type that DOES have engine braking in 1st would it have gone there if commanded or is there still sort of governor. Or does it still depend on brand?

Thanks.
 

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Discussion Starter · #11 ·
Good news...

Fired right up today, ran great, steady idle, normal and steady oil pressure and no leaks.

Tranny fluid looks and smells like it's fresh from the bottle (though I am going to change the filter)

Engine oil looks great - no particles there either.

Checked vales and one is about 0.007 looser than the others, but that could have been me doing that one wrong last time - not on the base circle perhaps. I also found one that was VERY loose but the poly lock on there was loose. It was backed just about all the way out. (0.045")

Also I had set the valves WAY too tight last time for some reason. Cam card calls for 0.024" hot, so I was putting them around 0.020" cold to start. Most of the were actually between .015 and 0.017" cold. Hmmm - odd. That is probably too tight for this engine (iron block, aluminum heads) so maybe that'll pick up a bit next outing.

Gonna run through them again in the morning and do comp/leakdown test, but I think she's gonna be fine.

I was L-U-C-K-Y!!!!!
 

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thats good to hear. just some things, .007 is alot when it comes to lash and it can also be an indicator of a problem as well as a totally loose rocker. i know youre unsure if it was your mistake, so id say remember the rockers that were loose and keep an eye on them. also if you had a loose rocker before you would know, so again keep an eye on them. also you have room to play with lash, usually .006 either way so its not that critical what you set them at but it is important to be all the same. good luck with it.
 

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Discussion Starter · #13 ·
Yeah - I recorded all 16 values as they were before I just set them. That way I can see if the same ones end up looser or not. That was onlt the 2nd full pass and the first actually CLEAN pass on the car since I put it together again, so there wasn't any runs to notice if it was loose before, but good tips.
 
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