tnmotown

iTrader: (107)

Ok, here is the scoop.....i had a small ticking noise at first and thought it was kinda an exhaust leak. Checked all the header bolts and noise still there.

Last night i was on the highway going about 70mph and downshifted into 4th (messing with some mustang) and was shifting around 6K RPM's

Now ever since then, the car is shaking and feels like its missing. My "service engine soon" light came on and was actually blinking on and off!! Now i know thats bad so i hurry up and got home.

When the car is on you can hear a loud ticking noise, cant really hear that much if you pop the hood and listen near the engine bay, BUT you can really hear it from the exhaust and expecially out the tailpipes?

So....im thinking maybe a bent pushrod? sticky valve? did i flaten the cam?
I know the car is hurt so im going to be spending some time on it, just wondering what you guys think it is. Any help i would appreciate and i will keep you guys posted.

ShevrolayZ28

iTrader: (4)

Looks like the motor is stock. I'd guess/hope it's just a valve train issue, probably bent push rod(s).

I'd read the codes, do an oil change and look for metal, and remove the valve covers and check things out. Look at the lifters,cam lobes, rockers, PRs, valve springs, valve tips, etc.

How's the oil pressure?

tnmotown

iTrader: (107)

check for codes and got DTC P0300 which was engine misfire (used the TECH2)

It also shows cylinder 2&7 that had most counts of misfire per cycle.

Oil pressure is good when i started it. When i take the valve covers off how do i check all the stuff? I mean i can check for a bent PR, but how about the cam lobes,lifters,etc..?

Yeah my motor stock btw, just with the exception of bolt-ons

ShevrolayZ28

iTrader: (4)

Undo the rocker arms, pull out the pushrods.(Keep track of where all valve train parts came from, if they are not damaged and you do not wish to upgrade the parts, you'll want to return them to where they came from, ie ex/int and their respective cylinder #'s.)

Roll the pushrods on a flat surface looking to see if they are bent, usually a flat peice of glass or stone countertop will do. Often times the bend is pretty dramatic and you will not need to roll them. If they are bent I would replace all of them with hardened chromemoly.

Inspect the lifters, look for damage to their rollers as well as the plungers. Make sure they are not colapsed. Take a look at the rocker's contact surfaces as well as the needle bearings they pivot on.

Once the rockers, lifters, and pushrods are out, take a look inside the motor with a light source, I think you will be able to see the cam lobes ( I know you they can be seen with AFR heads.). There should be no burrs on any of these parts at their contact surfaces.

You may also want to remove the spark plaugs so that it easier to turn the motor over for inspection of the cam. Check all spark plugs for damage, especially #2 and #7.

Bent pushrods is my best guess.

Since your oil pressure is good, I hoping you can get off easy and it's just a minor valve train hickup.

tnmotown

iTrader: (107)

well here it is....took it out of #7 cylinder and havent checked out #2 yet but sure is probably the same. Now i will get some hardened chromemoly but i just hope its that and i dont have to replace anything else. Im probably gonna put the PR's in just to get it going and then maybe SOON look into a head/cam package

ShevrolayZ28

iTrader: (4)

Nice. Busted it clean in half.

Check the rest of them and take a look at everything else while you're in there, chances are you'll be good to go if all you do is replace the PRs.

Too bad you're not closer, I have a couple extra sets sitting in the garage.

If you need the car back right away and chromemoly's are unavailable, you could replace them with stockers, just watch the mishifts and avoid ultra high rpm.

tnmotown

iTrader: (107)

yeah the car is my daily driver. But i can have it sit for a few days so i can get the chromemoly's just to help prevent it from happening again

lol, i'll watch my miss-shifts and try to avoid the high rpm's

thanks shevrolay!!

ShevrolayZ28

iTrader: (4)

BTW, weak,worn valve springs could have caused this. Just a heads up. Or maybe it was just an over-rev.

tnmotown

iTrader: (107)

i think it was the over-rev on the down-shift i did on the highway. Cause right after that, thats when everything started to happen. I'll control myself now though, lol

Brismo7

iTrader: (3)

very interesting. my car is making a LOUD noise in the exhaust to. but not mis-firing like yours. I'm praying its a bent PR like yours. i'll check it out tonite.

theblur98ss

iTrader: (71)

If you're running a stock motor just put in stock pushrods. An aftermarket won't give and you'll be looking at something more serious. Are you sure you didn't miss a gear on the shift...like 5 to 2 instead of 4? that's a pretty serious pushrod you pulled out.

tnmotown

iTrader: (107)

haha, didnt know this post got brought back up.
I already replaced my PR's and car drives great now. Thing was when i was on the highway going about 75-80 mph i downshifted from 5th to 4th and nailed the gas at the same time. Well with 4.10 gears also, it kicked the RPM's pretty high and im sure that put a lot of stress to the pushrods.