Yellow Bullet Forums banner

1 - 20 of 44 Posts

·
...failure to communicate
Joined
·
4,872 Posts
Discussion Starter · #1 ·
Cliff's Notes:

120 mph, 6K rpm, shifted from 3rd into 1st (maybe 2nd)
Back end washed out and wagged all over, but I saved it.
No idea what rpm it actually went to - I'm thinking 8-9K.
Would it have actually gone into 1st gear at those speeds (with a rev. manual VB C4 tranny)?

Full version:

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.
 

·
Registered
Joined
·
1,003 Posts
Cliff's Notes:

120 mph, 6K rpm, shifted from 3rd into 1st (maybe 2nd)
Back end washed out and wagged all over, but I saved it.
No idea what rpm it actually went to - I'm thinking 8-9K.
Would it have actually gone into 1st gear at those speeds (with a rev. manual VB C4 tranny)?

Full version:
You probably just gave your bearings a good polishing.
 

·
Registered
Joined
·
7,854 Posts
Jeeezus dude why didn't you pull it back into high gear??? Probably have to go thru the trans. I had a brain fart couple years ago going thru the traps and pulled it from 2nd to 1st on a glide. Only had it there for maybe 2 seconds though. On a glide all it did was TRY to apply the low gear band and scorched it a little. Never actually grabbed and went into gear. New band and I was good to go again. Good luck!

Oh yeah, for gods sake move your friggin' chute handle!!!
 

·
Registered
Joined
·
1,749 Posts
I have never seen a rev manual C4 with a first gear that did not free wheel or have no hold back. Does you car if you are putting in first gear at say 2100 rpm then you let off the gas go to idle? Sounds like you may have went to 2nd gear.
 

·
...failure to communicate
Joined
·
4,872 Posts
Discussion Starter · #6 ·
Jeeezus dude why didn't you pull it back into high gear???
Didn't realize I hit the shifter until it was too late and almost stopped. I thought it broke something actually since it started skating immediately. Rookie error - been 3.5 years since I've been in the car and my "instincts" were a bit rusty. I've "dry" practiced panics lke getting out, shutting it down, etc, but not that one obviously.

Wouldn't have been able to anyway - I needed both hands to keep it off the wall or the other lane. Might not have been as bad as it seemed, but in the car, that's the most out of shape I've ever been and never at the top end.
 

·
...failure to communicate
Joined
·
4,872 Posts
Discussion Starter · #7 ·
I have never seen a rev manual C4 with a first gear that did not free wheel or have no hold back. Does you car if you are putting in first gear at say 2100 rpm then you let off the gas go to idle? Sounds like you may have went to 2nd gear.
I believe it does - that's why I was thinking I may have just knocked it into 2nd. That's the first thing I was really trying to answer is what would it have done had I gone to 2nd.

I thought I lifted too late, but I never heard the rev limit hit, so even though the rpms were up, I think I must have been off the gas quicker than I recall.

Not sure which VB it has, but I think it's a PA. I think most of the other require you active the TB to go in reverse, right? Mine does not.
 

·
...failure to communicate
Joined
·
4,872 Posts
Discussion Starter · #8 ·
Along with soiling his BVD's

Vanilla
actually it wasn't anywhere near as puckering as I would have imagined. I was honestly more worried about collecting my friend than anything else. I could see or hear him so I had no idea where he was and I was expecting the chute to be out (though I never felt the hit)

Luckily I never crossed the center line. I got damn close, but saved it by that point and got over to the wall to get stopped.
 

·
Slow street car
Joined
·
1,666 Posts
I did the same thing with from 2nd to 1st @ 125 mine through the drive shaft out hit the right rear tire and cut it but not enough for the tire to go down got lucky new driveshaft tailhousing and new rear tires was all i had to replace.
 

·
Registered
Joined
·
1,231 Posts
Sounds pretty flippin scary man, at least you saved it!!!

I'm really glad I listened to some members here and decided to mount my chute release up on my rollcage instead of down by the emergency brake handle, I could see myself hitting the shifter with the release down on the tunnel...
 

·
Registered
Joined
·
5,494 Posts
It has no choice but to engage 1st gear if it is a manual valve body and 1st gear is selected. There is no governor, no throttle valve etc... to control the pressure or shift timing... the manual valve directs fluid to the circuits and that's it. Line pressure is locked down too. Think of it like switching the lights on or off... if it is placed into 1st gear it will achieve 1st gear.

Based on the fact that it got loose, I would have to say it hit 1st gear. I doubt it would stop the tires in 2nd. It would lock the tires going into1st at that speeds.

That is one of the reasons I try to get my customers to install a ratchet style shifter. You can't go more than one gear either way unless you mean it... ever.

You are a very lucky driver.

g
 

·
Registered
Joined
·
12,386 Posts
I went from 3rd to 2nd in a street race years ago and sheared 6 of the 7 flywheel bolts off and broke the crank sprocket.

That was fun :(
 

·
Registered
Joined
·
8,147 Posts
Wow, sounds scary.

A few years ago, I had the trans out of my Nova to install a shift kit (or something). I thought it'd be fun to start it up and rev it without the trans and converter on it, so I did... and I momentarily pegged my 8k tach. There was no resulting valvetrain noise though, so I got lucky. I'm glad I'm not the only one who makes mistakes.
 

·
...failure to communicate
Joined
·
4,872 Posts
Discussion Starter · #17 ·
ratchthed, thanks. Lots of different things would have made it better.

The more I think about it, since I have a T handle on the shifter, there is no way I would have mistaken it for the chute, so either I hit it forward with my forearm, or NOW I'm wondering if instead of grabbing the chute release, I actually grabbed the "lever" on the shifter that gets you change gears. They are a similar shape - especially with gloves on.

The interior, seating position, everything is new in the car now and I guess I need more practice in full gear to get a better feel where everything is. With the neck collar on, I can't see the chute lever. I think I may have to move it now.

Might rethink where I just mounted my 1/4 turn nitrous valve too. Hmmmm.

the only video I have of it looses the car right before the finish line. I can hear it rev up, but can't see anything.


Jay,try not to do that again:p
Good tip, Mitch - kinda like one of those "what does this button do" thing. "WAIT, DON'T PUSH THAT!" *poof* :D 8)

I'm glad it was a motor pass as it gave me another 2000 rpm to play with. Had I been spraying, I would have been around 7500 in the traps and it would have really been ugly.
 

·
الكتاب ا
Joined
·
6,697 Posts
ratchthed said:
It has no choice but to engage 1st gear if it is a manual valve body and 1st gear is selected.
Hmm. My old C4 with reverse manual Tbrake VB would not do any engine braking whatsoever in 1st gear... Almost like some sort of a sprag or 1-way?
 

·
...failure to communicate
Joined
·
4,872 Posts
Discussion Starter · #19 ·
Any other ideas? getting conflicting info on what it should have done in 1st if it actually went to 1st. Starting to think I "only" went to 2nd.
 

·
...failure to communicate
Joined
·
4,872 Posts
Discussion Starter · #20 ·
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!!!!!
 
1 - 20 of 44 Posts
Top