maksik7

Today I was racing a friend on the highway. I have a 700R4 in my car and I had it in D (not OD) to accelerate faster. When I beat him, I was about to shift back into OD, pressed the button and right at that moment I went over a big bump and accidnetally put it into 2nd instead of OD (I know I didn't need to press the button to go to OD, I'm an imbicil, what can I tell you). It was in 2nd for a split second and I slammed it back into OD as soon as I realized it. The car ran for another 15 or so secs fine and then it just died on the off ramp.

I tried to start it and it did start but sounded VERY rough and slowly died as soon as I let off the gas. Car shook pretty bad too. Now here is the question:

By the description, what do you think got damaged here?
I am guessing its not the pistons or rods (they are both forged) and the engine still runs. So my guess is its either a) bent valve or b) I shot a spark plug out of the block.

This is my ONLY car so I reallly need it fixed fast, so for the love of G-O-D help me guys!!!

Thanks a lot

PonchoTA

I don't know if this will help, but the first thing I would do is disconnect the battery for a few minutes, then reconnect and start it again. You might have over-revved it and the computer may have set a code to force it into "limp-home" mode.

If it runs ok after that, then consider yourself lucky!

I don't think any major damage would have occured if you were in 2nd for only a split second, especially if you didn't rev it past red-line.

If it still runs rough, I would suspect something is amiss in the valvetrain (bent valve or pushrod, broken valve spring, etc.)

If you shot a plug out, you would DEFINITELY know!! It's loud as hell! especially in a tunnel!! (don't ask me or my dad how we know!!)

Let us know what you find out!

maksik7

Well thanks for the help,

My car doesn't have a computer so thats out, I didn't hear anything out of the ordinary so I doubt I shot a plug, soooo

Please put my fears to rest here. If I had a broken rod/piston the car wouldn't run period, so this should isolate the problem to the valvetrain, correct?

Now say I have a broken push rod, how would I go about removing the broken piece from the inside the block? Do you think I will ahve to pull the heads for this?

One last question, what I did shouldn't affect the tranny or rear end, right?

Thanks for the help, and PLEASE keep the replies coming!!!

ZZ28ZZ

How many miles on eng?
Check ign timing. Timing chain may have jumped a tooth if eng is old.
Compression check wouldn't be a bad idea.

Eng could still run with a broken piston/s.
Just depends on what part broke.
Let's hope that didn't happen.

Drain oil thru a small mesh screen and check for chunks.
Take old oil filter apart and check for debris if you can.

You can probably retrieve a broken push rod by pulling the intake manifold. Shouldn't need to remove a head for that.

Pull valve covers and give it a visual. If all looks good, start eng and watch valves operate. (Be ready for oil to go everywhere)
Look for any valves not operating normally.

Rear-end should be OK.
Hopefully, tranny is OK too.

How do you shoot a spark plug out of the block?
I've never heard that term before.

Bralgar

I did that once, car ran bad, and I was scratching my head until I took the valve covers off. I had busted a few rocker arms and partially pulled the studs out of the head before the rockers broke (pressed-in studs and stamped rockers) Just pull your valve covers and make sure you didn't pull any studs or have some rockers just laying in there. bad thing about this scenario is you might also have to pull the intake, because is your push rods didn't get launched out the vavle cover they are more than like ly wedged up under the intake and head

Mark A Shields

I know how you feel, I accidently shifted into N @ WOT once, that's why I got the B&M Megashifter, once you find your problem, I'd invest in some kind of aftermarket shifter.
Good luck.

pyro

dont be scared to just pull the valve covers off and have a look
if its your valve train you should see something out of the ordinary even if you dont do much engine building upon inspection it should be apparent if you have a broke push rod
lokk accross them from the front if they are out of alignment with each other maby the one farthest out is bent pull it off have a look roll it accross something flat that will make it really easy to see. Also check your timeing anyway why not its not hard to do youwould probably need to anyway if you run it hard you may have streched the timeing chain (it does happen) as for the shakeing maby you should pull all the plugs give them a look at
you may gain some insight there depending on what you see

maksik7

Well its at my mechanic's right now. They are pretty nice, and will hopefully let me know whats wrong free of charge (at least they did before). I am PRAYING for a broken rocker arm or valve spring but I am afraid that at least one fo the pushrods broke/bent and the timing chain might have slipped. Thatbks for the help, they are suppossed to call me before the end of the day with the bad news.

goneracin

odds are pretty good you didnt bend any valves, as unless you have a HUGE cam, you should have plenty of piston/valve clearence. If you beoke a piston bad enough to run bad, it should have clattered like hell. How high did it rev???You probably had the valves float(hydralic cam?) and it broke and/or bent a few pushrods. Maybe jumped the chain or broke a rocker. If the exhaust side is damaged, it would have fired out the intake and popped loudly. Just have a mech check over the valvetrain, and I'd also have someone check timing, as a jumped chain would also retard your timing. Good luck

RJR99SS

this may be a little late asking this, but did you make sure all the accesory belts were still on?

maksik7

Well frist of all, the belts are all on there.

Today I got a call from my mechanic, they did a comp. test on the cylinders and No. 4 has no compression. They are goign to pull the valve covers and check the springs/rocker arms/pushrods becasue 95% chance is that teh problem lies there. I realy doubt I bent a valve since my cam is pretty mild and I maybe overrevved by 1500RPM at most so I doubt any valves are bent. I should get the results (and my car) back tomorrow and I'll let everybody know how it turned out.

robertg

iTrader: (2)

Just because you broke a rod or piston doesn't truly mean that the engine will not run.

A few weeks ago, a customer brought his commercial mower in, it was vibrating very badly.

When the mechanic tore the engine apart, one of the rod bolts had backed out, and destroyed the rod, crank, and the block as well.

The engine was still running, but shook very badly.

88IROC350TPI

A car can run with serious bottom end engine damage. My friend recently built a 350 for his 79 camaro. He got it all together running perfectly. He took it down the road and BANG something blew up. He pushed it back to his garage and there was a huge hole in the oil pan. Tore it down and a rod bolt snapped and ruined the entire bottom end.

The car still ran but it would shake really bad and die after about 30 seconds.

maksik7

Thanks for the "good" news. But I don't see why the rods/pistons would break. I ddn't overrev that much and both pieces are forged, and realistically speaking I would put my money on a broken valve spring out of all of these

Vader

WOW! Does this sound familiar? Seems I recall something like this just recently....

You don't have to over-rev by much to float a valve and bend it, especially with mild valve springs. You only have to float one a little bit for the valve to stick in the guide on the varnish buildup on the stem, then get slammed shut by the piston top. (Pray that you didn't hole out a piston.) One of these can bend a warm valve pretty easily.



Ask for a cylinder leakage test instead of a straight compression test. That should reveal the loss of compression by sound. A broken valve spring{s} would make you really lucky.

A bent/broken push rod, pulled rocker stud, or mangled rocker arm wouldn't necessarily completely kill compression. The exhaust valve will still admit air if the intake valve is stuck shut, and the intake will obviously admit air if the exhaust is shut. Either of these would still allow some compression pressure to build, albiet quite a bit lower than normal.

As for the transmission, the 1-2 clutch pack and planetary shell band probably wasn't done much good by a high-speed downshift. You probably hit some pretty high trans oil pressures briefly, too. Change the trans oil at a minimum.

When you're all finished, readjust the TV cable to the trans so that you don't have to manually shift for peak performance. Your transmission and valves will thank you.

maksik7

Well they are not good. The top end is fine so that leaves the problem in the bottom end. I have one concern though. they told me that the valves were all ok, without actually pulling the heads. Can anybody explaint to me how in hell they can see if the valves are bend without pulling the heads?

Thanks for the help,

Very pissed off,
-Max

goneracin

as vader said, they could do a leakdown test on the engine. If it has a bent valve, the air escaping thru the bent valve/seat area will make a noise, and you can trace it to intake or exhaust by the sound. If a piston is broken, the noise will be in the pan mostly. Just because the pieces are forged doesn't mean they cant break. We use the most expensive rods/pistons/lifters/crank, etc in the prostock stuff, and I have seen prettymuch every piece in an engine break. Admittedly this stuff is subjected to an extreme environment, as I said, it is the best pieces money can buy, eg $4800 for just the crank!!!!!!Hopefully, your problem is a bent valve, and all this will be just for conversation. Tell your mechanic to do a leakdown test before he pulls it out or disassembles it. Let us know what haappened.
sorry your having such bad luck dude.
Bob

Fast3rdGen

you can do it if you have one of those nifty bore-o-scopes (sp??) has a little fish-eye lense on the und of a really long wand you can look through the spark plug holes.

TomP

I love those disclaimers for the boroscopes... "not for personal use"

maksik7

Thanks guys, Ill have them do a leakdown test before I pick my car up and swap the engines. If anybody could go to my post on the motor swap board and help me out, that would be great.

Thanks,
-Max