Fast98Z28

Well, this all started as a ticking noise coming from the drivers side head. I checked everything... pushrods, springs, valves. Car was still running fine, just with a slight tick. So i checked pushrod length determined i needed longer pushrods, put them in and the car ran like crap. Re checked my measurement, and determined i needed shorter rods. Put the shorter ones in and it ran even worse. I never heard the ticking either times.
So this is when i decided to go ahead and put the 7.4's back in, and while i was at it do the trunion upgrade. I just finished installing them tonight. Started it up, no weird noises. I took it down the road and the car was basically falling on its face, It would run REALLY rough at lower rpms and felt horrible. My exhaust would pop as if it was rich. The car did not do this before, even with the slight ticking. I used the method of torquing them down one by one, turned the motor over a few times, and re checked torque. I know the service manual says to do each on when its TDC on that valve. But i have seen people use this same method and have no issues. I have checked all my wires, sensors, etc, that i had disconnected along the way. No check engine light.
So at this point i have no clue on what is making my car run like this, could i have them overtorqued? I put them at 22ft lbs. Could the engine have lost its correct timing? I have no clue.
Thanks in advance.

jrpimp00

iTrader: (17)

Were you at tdc when you checked your pushrods? Could it have been an exhaust leak

Fast98Z28

Yes, i was at TDC when checking PR's. Definetely not an exhaust leak. This engine has 2.2k miles on it. Basically the whole motor/drivetrain has been rebuilt.

Old Geezer

iTrader: (3)

TDC?? The pr length is checked w/ the lifter[s] on cyl you are checking, on the base circle of the cam lobe.

If the engine ran well for some time, the prs were likely good to go, and didn't "change length"..[Unless they are bent.]

Fast98Z28

I had meant TDC on Cyl number 1 when i checked, either way they are the same pushrods that were in before i had checked them. The car ran fine then. When it comes down to it after everything, all i ultimately did was just do a trunion upgrade from comp cams. Tonight i will double check all my vaccuum lines, wires, coils, sensors, etc... It just doesnt make sense to me unless my fuel pump decided to go out while i was changing these, but it seems odd. The only thing i touched were the rockers and pushrods basically.

Fast98Z28

I am going to also check my fuel pressure, my symptoms seem to be as if its studdering and misfiring. Running very rough

Fast98Z28

Anyone have ideas?

combs_425

iTrader: (3)

I would try a leak down test.

Fast98Z28

What exactly does the leak down test check for? valves? pistons?

crainholio

iTrader: (2)

We keep that info in a secret website, but here ya go:

http://bit.ly/15ecmKC

Fast98Z28

I come here for help and advice, not critisism. I did google search it but didnt find a difinitive answer as to if i have 50% leakage does that mean the valves or bad, or the piston/ring?

MyFirstLS1

iTrader: (8)

leak down is testing how well the combustion chambered is sealed. valves, valve seats, rings piston, cracked head. Generally I wouldn't want to see more then 10% max. Usually 100 psi air I wouldn't want to see less than. 90 psi being held.

you leak tested it on the tdc after compression ?

could be bent valve, or failed rings from improper break in or it was completely at TDC. The adapter to the spark plug may have a leaking o ring as well so it isn't sealing.

Did you have a cracked spring when you took it apart ?

pcsmits1

I had a similar ticking issue one time on a mustang I was dead set on it being a rocker issue I shimmed rockers 3 times changed to a diff set of rockers and it was a dam leaky header gasket the copper seal ones had a small blow out the size of a pencil eraser on the bottom just my experience as to the running like crap issue depending on what your motor is did the longer pushrods cause piston to valve touching?

Fast98Z28

I have not done a leak down test at this point. The car ran perfect before i changed to the trunnion upgrade. No cracked springs.

It ran fine with the 7.4's, ran like crap with both the 7.425's, and the 7.375s. Now that the 7.4's it runs like crap. I have a hard time believing something i did was wrong when putting the pushrods/rockers back in. This does bring up a good point that i have not thought of. Because with the longer ones it may have caused that to happen.

I am going here in a few to get a compression tester, fuel pressure tester, leak down tester, and some TB cleaner and starting fluid. Going to try to clean the IAC, MAF, TPS. Starting fluid for checking vacuum. Another thing i have noticed... is that if i unplug my IAC it changes nothing, if i plug it back in it changes nothing. Could this be the culprit? It sounds like its spitting and sputtering... but the only thing i messed with was the rockers, and pushrods.

Fast98Z28

Fuel pressure reading is at 60 psi

crainholio

iTrader: (2)

I come here for entertainment. If I help or advise it's strictly accidental.

If you'd read the more useful articles the google search returned, you'd have found that the hissing noise will point you in the direction of the leak. Could be either of the valves, or the ring package, or the piston ringland(s) in extreme cases.

pcsmits1

does it sound like valve issues or just a sputtering?

Fast98Z28

More of a sputtering when trying to drive. When in park and sitting, it slightly surges here and there and when i give it gas, it runs rough untill about 2000-2500 rpms. but after that it seems normal. Could it be a dead miss?
Another thing to note, is when the car was idling, i unplugged the IAC and it changed nothing. Same when i plugged it back in it changed nothing. However it did throw a code. Could that be a sign that i have a bad IAC?
The car is still not throwing a code after i clear them.

chevybayboy

iTrader: (6)

Did you happen to take your harness off you r coil packs?

td1168

iTrader: (2)

First off, when you post on ls1 tech you're gonna run into jacka$$'s that wanna make you feel stupid! They know it all. Do a compression test on the cylinders to rule that out. If this happened after messing with the valvetrain there is always a improbable chance that a valve got bent somehow. This would cause the dead miss and popping. Once you establish that you have good compression in all cylinders you can move on to fueling and ignition issues. We all run into problems with our cars. There are some guys on here that know there **** and hopefully will chime in. You'll know who they are right away because they'll try to help you instead of criticizing you bud.