blown 346

iTrader: (25)

Here's the story.

My buddy has a 95 Z LT1 car. It has GM performance parts hot cam Hydraulic roller, 1.6 rockers with poly locks, lifter set, springs.

He decided one day to go out and do some donuts with it.The car sounded fine. He parked the car for a few days and went to move it outside of the garage when he heard a ticking noise from the passenger side valvetrain. He checked his oil pressure and it was at 40PSi cold and once warm 24 PSi warm which is what its always at.

Last night we pulled the valve covers off of it thinking maybe a collapsed lifter. I did the push on the pushrod test to see if the lifters would get spongy and they were all pumped up and hard as a rock. The valves are adjusted properly(not to tight and not to loose) I checked all the rocker arms, pushrods, cam, and everything still looks new no premature wear, nicks chips, hot spots.
The cam,lifters and rocker arms springs only have 2,000 miles on them.

Anyone have any ideas?

wrd1972

iTrader: (12)

Sounds like typical loose rockers. As they get closer to zero lash, they will tick more. Mine are definitely more quiet with them adjusted to 1/2" turn past zero lash compared to 1/4" PZL. Lifters are hard to kill.

Might try that.

blown 346

iTrader: (25)

Valves were gone over to make sure and the noise is still persistant.

hitmanws6

iTrader: (20)

exhaust leak?

94LTZ

iTrader: (5)

I agree with hitman, it sounds like he has a slight exhaust leak.. Usually properly adjusted valves kinda sound like a sewing machine..

BLK,97,T/A,M-6

It may not be valvetrain related at all. My old stock injectors ticked like all hell.

blown 346

iTrader: (25)

Why all of a sudden would injector pulse be amplified like 100 times louder. You could stand behind the car while its idling and hear the noise very clear.My buddies car isnt quiet.

hitmanws6

iTrader: (20)

from what you have said, the only 2 things that come to mind are either he has an exhaust leak or a bent pushrod

blown 346

iTrader: (25)

It might be an exhaust leak but I doubt it as the sound is coming from on top of the head.

The pushrods were all checked and are straight as an arrow. We checked them on glass.

RamAir95TA

iTrader: (2)

Make sure that the tabs of the SA rockers are still intact and haven't worn.

Badazz 97 TA

iTrader: (18)

or that the SA tabs are not hitting the top of the retainer. like premature wear on the top of the valve stem tip

Johnny-LT1-runner

iTrader: (15)

That's what my car sounds like, I love it.

blown 346

iTrader: (25)

Those were also cheked out and still looked like new. All the valvetrain was replaced and is still in new condition. But yet the noise persists

sdotlog

Try using a tube and hold it to your ear while you move it around the headers, sounds like an exhaust leak to me. I had the same problem, used an old lacrosse stick and bam the very back of the header gasket is the problem.

blown 346

iTrader: (25)

Went over everything again, and noticed a slight bend at the very top of one of the pushrods. I have never seen a pushrod bend at the very tip before. It looks like it was just enough to basically unseat from lifter and then re seat again which was the noise.

FrawG

This was your problem? I am having the same noise you are talking about and I ran across this thread while researching.

blown 346

iTrader: (25)

We replaced the the pushrods and the the lifters and no noise.