tonight i had the car out to do a test pass, getting ready for a race on sunday. Launched the car, then hit 2nd gear ( car is a M6) then the throttle stuck at WOT when i pushed the clutch in to shift again. i kicked the gas pedal down again thinking it got cought on the floor mat but it didn't help so i turned the key off imeadiatly and coasted to a stop. got out and opened the hood and the TB was stuck all the way open. not sure what caused it. my rev limiter is set at 7,000 RPM. it was on the rev limiter for a good 3 seconds before i turned the key off. the motor has a ticking noise now at idle. i have chromemoly hardened pushrods in there that are only 6 months old from when i did a cam swap. the rocker arms and lifters are stock. i'm try'n to figure out what is messed up. do you think you can bend hardened push rods that easily, or could a lifter be collapsed, or even just the rocker arms loosened up? any imput would be apreciated.

 

bouncing off the rev limiter, it is less likely that you bent a pushrod. bent pushrods usually occur in an M6 when you accidently downshift instead of upshift at wot, thereby mechanically overrevving the motor. all Ls1's have valvetrain noise, and you might just be paranoid. but it never hurts to just go ahead, pull the valvecovers and take look. make sure everything is straight and tight.

either way, take a good hard look at your TB, you can't have that become a recurring problem. it's not safe for you.

 

Very difficult to bend hardened rods by just revving, is this a heavy tap or a light ticking...if it's light, you probably just partially collapsed one or two and they will pump back up after it cools down and the oil thickens etc.

I set my limiter a few hundred lower BTW, just a little extra precaution.

 

yeah thats a pretty high rev limiter, pull off the valve covers and check the rockers

 

I would check also if I were you.

 

Definatly check it out. Wont hurt to pull the pushrods and roll them on some glass, plus it will give you a chance to check out your rockers. If its a light tap, then it could be lifters... post what you find.

Ski

 

It could be a number of things....including your imagination like what was stated before. Only real way to find out is through a thorough investigation of the valvetrain.

 

Check the pushrods, I tried to teach a girl how to drive my car one night and she ended up bouncing off of the stock rev limiter for a few seconds. And she bent two. But this was with stockers, not hardened.

 

alright, i looked at it this afternoon. me and some friends started it up and listened to the motor. they all think it sounds the same as allways. becuase of the big cam that is in the car it has allways had noiser valvetrain sound than a stock LS1. i think i was just freaking out and hearing things. it just has light noise not a heavy tick. the reason my rev limiter is at 7k rpm is becuase the car made power all the way to 6,700 or 6,800 rpm on the dyno. as for the TB, i have looked this thing over carefully and i cant see what it got hung up on. everything opens smoothly now, i'm really confused on how it happened. but it took quite a bit of force to close the TB when i opened the hood to check it out. i had to pull it shut and it felt like something just broke loose and it slammed closed. i'm considering putting my buddys TB on the car that he isnt using just to make sure it wont happen again.

 

grab that throttle arm and SLAM it down, as if you had really punched the throttle. See if it sticks again. You definitely want to find out what that was about before you drive that thing. Imagine it sticking in heavy traffic!

 

How can you tell that you bent a pushrod? I did a misshift but it only took a split second and i pushed the clutch. The motor sounds as it always does. Is it still possible that i bent a pushrod? Can i still drive with the car if its only slightly bent? will i lose power? I would rather not open it up to check....

 

What kind of TB is it? FAST 90 by chance?

 

it is actually a stock TB.

 

I'm assuming you have an aftermarlet valvetrain setup, but 7,000RPM is still a lot of revs to turn on a pushrod V8. The LS7 redlines that high, but its got all lightweight internal components, less reciprocating mass, stronger metals (titanium rods and valves), and a lightweight valvetrain design.

Chances are you got some valvefloat with it bouncing off the limiter like that, no big deal, just not something you want to do regularly. If you hear any ticking noises coming from anything other than the valvetrain, check out the sam and crank bearing and make sure everything is okay

 

I pretty much agree with everything you've said. I experienced exactly what you mention by missing a shift and throwing it into a lower gear once... and it did bend some pushrods.

The only thing here is that he's got the rev limiter raised well past the stock settings. This doesn't sound too good.

 

Ahh... nevermind. I retract the previous statement.

 

Yes, it's possible. When I did it to my car, it wasn't audible from the sound of the motor. Yes you can drive the car, and yes you can lose power.

I went from trapping 109-110 consistently, to trapping 103-105 consistently. If your pushrods are bent, your valves are therefore not opening as far as designed, thus you're losing some flow and power - especially in the higher revs. It's pretty easy/cheap to get fixed and/or fix yourself.

 

I just finished installing my LS1 engine in my 67 Camaro, I was planning to go on a few trackdays with the car and i decided to see if i could find some weaknessess on the stock engine, and its a bit dissapointing to hear that the pushrods seems to bend so easily, i was planning to run my engine stock for a while, but by the sound of this I seem to be needing pushrods and a timing belt, a few threads here with timing belts snapping off a bit to soon maybe? What else do i need to be able to give the engine some beating? im not looking for high output yet.

btw, i've installed an autometer tachometer, where is the stock redline? 6500?

 

I have stock PRs in my motor that has a 228/232 cam .588 lift. been in there for about 5 months and no probs yet. i need some 7.425 PRs. just havent got them yet. my rev limiter was at 6700 for a while and i hit it on several occasions now its at 6500. 7000 is way too high for a stock motor. whoa you are lucky

 

kan you adjust the engines redline? program the PCm to do that maybe?