GTPprix

Ok I'm sure there are quite a few of you who have done it with your F-cars and the GTO's less than precise shifter doesnt help too much. I'm talking about missing third and hitting first instead, yes I know "Good move genius!". I'm curious on the what the odds are that I actually DID bend my pushrods since as soon as the back end got loose for about a second I pushed in the clutch and upshifted to third correctly.

The reason I ask is my car dynoed pretty low for being blown, BUT I don't have any abnormal valvetrain noise.

Any insight is not only appreciated, but encouraged

JZ'sTA

iTrader: (23)

Mods and dyno results?
Normally I would say the odds are about 1 out of 10 or so.
It is a somewhat common thing that happens, and sometimes you get unlucky and break ****.

Z28Venom

iTrader: (13)

If you went into first instead of third, I'm pretty sure that you bent a pushrod.. Take off the valvecovers and check them out. Its actually only about a 1hr job.

777

iTrader: (21)

what else could happen from a miss shift like this...i'm wondering what else could break...since a pushrod doesn't seem to hard to change and is fairly cheap.

Boostaholic

iTrader: (4)

You can over rev your motor and the piston can contact a valve, causing a bent valve, pushrod or worse combinations of the above, im sure other things can happen too but these are the most common

GTPprix

Mod wise I've got the Magnacharger (with the maggie tune)and thats it, it only put down 370 it's first pull and after letting it cool down a bit more and adjusting the throttle stop to allow 100% throttle opening I got 382. A far cry from the 415/420 I was expecting. All testing was done on a Dynojet.

Also do these pushrods typically bend enough that if I simply pull the valve cover I can see the bend? Or do I need to go the full nine and pull them and check them out?

~JOSHUA

iTrader: (92)

If You Pull The Valve Cover And Are Easily Able To See A Bent Pr I Would Say That Would've Been A Serious Misshift. Pull All The Rods And Roll Them Across A Flat. I Found One With A Very Slight Wobble When I Did My Spring/rocker Arm Change. At The Very Least It Would Be A Good Excuse To Uprade To A Full Rr. Harland Sharp Make The Lowest Priced I've Seen.

GTPprix

Ok I just pulled off 1,3,5,7 and checked them out, they all look true, no rub marks or anything. I'll pull 2,4,6,8 next friday when I've got some more time, otherwise I guess it's time to start figuring out whats wrong with my car

I8RICE

iTrader: (13)

My guess is a bent push rod. Assuming it is all stock. I bent 3 pushrods and expolded a lifter on a stock motor with all the bolt ons in a 99 ta w/ an A4 50k mi.. One of em was the REALLY BAD. My limiter was set at 6300 or 6400. You can see them here. http://community.webshots.com/user/liteemup
~Rob

Scalpel

iTrader: (4)

What's the point in "guessing" it happened.

Just pull the rockers and check the pushrods. It'll save you a lot of time.

If no luck with that, do a leakdown test, that'll pinpoint the problem.

OneBad98Z

iTrader: (1)

Man Chris you need me to show you how to drive that thing.. j/k

in all honesty it takes a little more than youd think to bend them, the big question is did you get back on the clutch soon enough.

i've too done it, and feared the worst, you best bet is to roll them on a known flat surface, Glass works well and watch for wobble or runout..

good luck if you need any help give me a call..

Later,
Greg

LS69TA

iTrader: (30)

I got lucky in my '98 T/A a few years back. Did the same thing..was in 6th and went for 3rd about 65mph and hit 1st..I think the backend of the car came off the ground..no damage though. But that was after waaaayyyy too many beers. Hopefully yours is fine. I hit the clutch just as soon as I did it as well..

777

iTrader: (21)

those pushrods aren't bent that bad

GTPprix

Ok last stupid question for awhile, as I said I took out 1,3,5,7 and they were fine, the LS1 rocker arms bolts are NOT torque to yield correct? The service manual doesnt mention it but I'm just making 100% sure PS how many of you guys follow the sequence for torquing them down then rotating the crank 360 and torquing the rest like the manual? Just curious if this step is even necessary?

DONAIMIAN

iTrader: (18)

Another reason why you may be down on the power is because you need vlave springs. I dont remember exactly, but it was a stock internal vette that someone had put a turbo on, and when they dynoed, got a really low *** number. The motor was **** at high rpm. They did a valve spring change and fig out that once the turbo got going that it was putting so much preasure on the back of the valves, it was causing them to float and loose power, that could be your case.

OneBad98Z

iTrader: (1)

Chris,

im pretty sure the rocker bolts are torqued to 19ftlbs im sure someone else can chime in on this..


later,
Greg

Patman

During the time I owned my 98 Formula, I did a 2-1 misshift three times and after the last one I pulled all 16 pushrods out and to my surprise they were all perfectly straight. I must've clutched it in fast enough on each mistake in order to save the motor.

GTPprix

Thanks guys, gonna pull 2,4,6,8 on friday and see how that goes but I think I'm ok

Tweakd

Ask Kumar75150 what a miss-shift can do, I'm sure he will even show you pictures.

Velocity

I bent pushrods on a 3-4 shift... put it into 2nd. Bent all of them just slightly enough to knock me down about 30 HP or so... no valvetrain noise either.