SlowFRC

iTrader: (2)

Maybe I posted this in the wrong forum, if so feel free to move mods. Anyways, so I went for a little drive today I'm sure you have all done this when you were bored. I was going on a highway on ramp so I went WOT 2nd and 3rd gear, and here's where the problem comes in. I went to shift from 3rd to 4th, the car felt like it went into 4th fine but what I felt next tells me it didn't go into 4th AT ALL.

When I put it into gear the tach shot through the roof, a bunch of warning lights came on (the only one I saw before panic set it was ABS light). As soon as I noticed this I put the car in neutral but it was too late. It was hard to hear over road noise but I knew the car felt werid. I drove another 1/4 mile and pulled off at the next exit I could find. I shut the car off and let it sit for a few minutes. When I turned the car back on it had trouble starting, idle was all messed up (sounded like it had a huge cam in it) and the car shook severly. Needless to say I shut the car off and called for a tow.

No fluids were leaking from the car but something is definately messed up. The car is an M6 and I'm guessing instead of going into 4th I went into 2nd.... at 100mph!! Any guesses what kind of damage I did? I'm hoping I just floated a valve since the car was able to start up, but one of my friends thinks I may have thrown a rod and spun a bearing, I hope its not that bad...

Camaro396

iTrader: (14)

You probably wiped out a couple valves. A friend of mine did that exact thing, and the motor spun to like 8k, needless to say, as far as I can remember, it needed a new set of pushrods and valves.

KMS.1320

iTrader: (1)

Dude, you are not even close to the first person to do this. You may or may not have tapped the pistons with a few valves, but you DEFINATELY bent OR broke the **** out of some pushrods. The stock pushrods are kind of a fail safe and may have saved your *** on this one, they're weak! Take the valve covers off, unbolt the rockers, pull the pushrods out, roll them on a flat surface. I'll bet you almost every single one of them is bent. If you are concerned about valves, while you have the rockers unbolted, take the sparkplugs out and do a compression test. But I think chances are 50/50 it's just the pushrods. One quick spin to 8k I don't think will spin a bearing.

y2kc5

did the same 3 years ago didnt bend the pushrods but bent 12 valves lol needless to say i dont have to flycut my pistons I put a new set of heads on and all was fine... I wonder what rpm my motor actualy saw 6400 rpm top of third and powershift into 2nd ouch

SlowFRC

iTrader: (2)

Wow I thought I had it bad not pwoershifting at 5800rpm but damn y2k thats painful. Keep your opinions coming guys. Also what other damage should I worry about, I would think the tranny and possibly the rear would have taken a good beating with the sudden force of 7k+ rpms being put on the driveline, do you all agree or am I being over cautious?

NateZQ8

iTrader: (3)

And I thought It was bad when I got it half into 4th and spun it to 7K in Neutral........Hopefully its only a head/valvetrain issue........

y2kc5

Well i feel i was lucky.. didn't hurt the trans or rear diff or the torque tube its in my 2000 vette.. I was worried about my new valve relieves in the pistons but everyone assured me that it would be good and it was this happened 20k+ miles ago..
If you need a set of heads I have 2 sets of 241s.75+shipping for a pair The set i just took off the car are perfect..

JohnHF

iTrader: (5)

man i keep hearing all these people going from 3rd to 2nd, its got me pretty scared that im gunna do it

Pharcyde50

iTrader: (11)

If you flip your hand over for the 3-4 shift this won't happen. I did the old 3-2 in my Z28 and took out like 6 pushrods.

01z

iTrader: (3)

my friend went from second to first, meant to go to 3rd, everything was ok.. . until he did it again a week later lmao POWERSHIFTING

vsocks1

iTrader: (6)

Get out there and pull your valve covers off and look!! Then you will know for sure and report the results. Rear and tranny are most likely ok.

SlowFRC

iTrader: (2)

I would have begun to try to figure out the damage but I am at schools and left all of my tools at home so now I have to wait until I can get it in the garage of the local club here and then I'll see if I can figure out the extent of the damage. Pharcyde what do y ou mean flip my hand over I'm having trouble visualizing what your talking about?

Also what do you guys think the possibility is that my shift linkage is to blame for this? I say this only because the car went into gear fine (leading me to believe the shifter **** was in the correct place for4th gear) and I would think going into 2nd at 100 I would get some resistance from the tranny but if this linkage is out of whack this wouldn't happen.

SladeX

Pushrods were never meant to be a failsafe, it's simply a failure of the valve train at higher rpm. Your failsafe was supposed to be the rev limiter and common sense, but common sense doesn't cover bad shifts.

I did this a month ago as an effort to wake myself after a long portion of a drive. Sloppy shift and imagine that my car has a 6600rpm redline and I dumped the clutch thinking I was going into 4th...

Pegged 7k rpm on the tach and yeah it woke me up.

If I had the stock valve train it would have floated all the valves and kissed each piston. Luckily I have hardened pushrods and springs meant to deal with high rpm aka dual springs.

Now what can cause the bad shifts? If you are a competent shifter, then I would suggest upgrading the shifter itself and making sure you run a poly trans mount. If that was giving way, picture you almost redline then you "release" the load on the engine which torque snaps the whole drivetrain and in essence moves the physical location of the shifter. If the trans mount or engine mounts allow that play, it could very well be the difference in between 2nd and 4th.

If you also take into account that if you have a stock or sloppy feel shifter, you add in yet another bit of play to the shift. Include the idea that your arm isn't 100% pulling straight back due to shift technique (or lack of it) and you have the engine torquing it the way it is and it's almost guaranteed to do a 3-2 shift.

Clevite Kid

Sell that car and get a C6. It will do 85 in second, so you rarely have to worry about an all-out 3-4 shift .

SladeX

So will a bolt on f-body... lol strange mentality there.

also the 3-2 shift in a c6 is still very possible AND there's still no protection in the engine from bending pushrods, so this doesn't solve the problem at all for the case of bad shifts. At least with the transaxle design, it won't torque the shifter as much, so if you do manage to pull off a 3-2 shift in a LSx vette, then you deserve the repair bill that's coming to you as it'll be more your fault than anything.

5.3LJimmy

iTrader: (10)

That's no guarantee either. I let my wife make a pass in my car at the track and she did the 3-2 shift, it bent 6 exhaust valves. This was with dual springs, hardened pushrods, stainless valves, and 4cc valve reliefs.

You need to do a compression test to check for bent valves(as stated above). The chance of not bending pushrods is pretty slim, so you should have a set with you when you start tearing into it. And I would say your driveline and bottom end will be okay.

DaddySS

Thumb points up on 1 - 2 shift, thumb points down on 2-3, 3-4 shift, Try ity, you'll not miss a shift that way.

bczee

iTrader: (12)

Replace the shifter with a good aftermarket one to keep from doing the 3-2 shift.. Pro 5.0, B&M or a Husrt. If anything it will help all around shifting.

SlowFRC

iTrader: (2)

What makes this worse is that I bought a Kirban shifter about 2 weeks ago and just haven't gotten around to putting it in. Lets just say that will be going in ASAP. Makes me feel a little better knowing i'm not the only one whos ever done this.

99345hp

I did the shift to 2nd instead of 4th a while back, but I got lucky when i did it. I was just cruising around at 60 in 5th and meant to downshift to 4th and accidently hit second. It scared me and I quickly pushed in the clutch. Im just glad I wasn't going faster when i did this. Hasn't happend since then.