Ferocity02

iTrader: (60)

If I pull the valve cover (and rockers?), how can I test to see if a lifter has gone bad?

wildcamaro

iTrader: (15)

You gotta pull them and check the roller tip for pitting. Another way to check them is rolling the roller tip on your forearm and since there are a lot of nerves you can feel for uneven surface. If you can check them while in the engine I don't know if or how you would test them.

Ferocity02

iTrader: (60)

I'm talking about testing the plunger part, to see if its collapsed or stuck. I know the roller can't be checked without pulling them, or by pulling the cam to check for abnormal lobe wear.

therabidweasel

iTrader: (5)

If the check valve is broken, you will be able to pick the nose of the rocker up to bleed it down. IIRC tThe idustry standard is to apply a 50lb weight to the plunger when filled with a particular fluid, it will take 35 or more seconds to bleed 0.062 of plunger travel. If it is way fast/soft, it is wasted. If the plunger is collapsed or a roller wasted you will most likely be able to rotate the motor and see a ton of daylight on that valve..unless the lifter is hung in the up position.

Ferocity02

iTrader: (60)

I used the dial indicator tonight to remeasure my lifter preload, and they definitely bled down slowly while torquing down the rocker bolt. Not sure on the exact rate, but it's in that ball park. I would turn the bolt 60 degrees and it would take about 5-10 seconds for the lifter to bleed down.

MikeLSS1

I might be stating the obvious, but i'll do it anyway just in case...
I had one go out and I just jiggled the pushrods. You might have a little play in all of them, but if you have the suspected one on the zero lift point on the camshaft, it the pushrod will move much more than the other ones on zero lift. I realize that doesn't fully confirm there isn't a lifter problem, but it can easily confirm there is! Good luck and I hope one didn't turn on you

Ferocity02

iTrader: (60)

Did some valve adjustments today and noticed a handful of spongy lifters, but only on bank 2. ALL of the lifters on bank 1 needed pressure from the spring/rocker in order to compress and bleed down, I couldn't compress them by hand. While tightening the rockers the lifters required several seconds to bleed down.

Then I did bank 2 and most of the lifters were spongy and I could compress them by hand easily, maybe with just a few pounds of pressure. Some would compress about halfway by hand, and then needed spring pressure via the rocker to continue.

I'm thinking that turning the motor over by hand while doing the driver side caused most of lifters on the passenger side to bleed oil their out. I did both sides with the engine warm. But what's strange is that the lifters on the driver side did not become spongy after they bled down. Perhaps there was oil left in the bank 1 galley and not the bank 2 galley?

Any thoughts?

therabidweasel

iTrader: (5)

If you did the same thing on both sides and only the passenger bank became spongy I think you've found your problem. I an no expert, but if you end up with a mismatch in leakdown rates that is big enough you effectively unbalance the valvetrain. The valve, cylinder ..,!bank!? With the higher leakdown ends up with not as much lift, and if you spin the faster than the lifter can recover it will bottom, which would make some noise. If one whole bank was failing I'd think the motor would have significant vibration.

That said, I can't think of why one whole bank would fail other than bad setup. Your measurements show a little deep IMO, but not bad. I don't know man, I've really come to hate lifters in general. But ls7s are too cheap to be precision and I've heard too many bad experiences to run them myself. With all your threads it sure sounds like you have bad lifters.

Hey, have you changed your oil and checked the plug magnet for metal...that would indicate a failed roller. You could cut open the filter and look for bearing material. You could also run a compression and/or leakdown to yield more info before you tear it apart.

Your thread really confuses me now. You say the tap is on 5/7 right...drivers side?

parks450

iTrader: (17)

The way I found my bad lifters is I removed the valve covers and rockers, leave the push Rods, I. Then took compressed air and blew into the pushrod. All of my rockers held the air pressure except for two. Two let air through almost immediately. I only held the air on them for a max of 1-2 seconds. It pin pointed my problem and worked.

Troy

iTrader: (10)

Back from the dead post....

When you say they held the air pressure, you mean the pushrods because the air was hitting the lifter, right? You don't mean to say the rockers, because you pulled the rockers.

WE TODD DID

iTrader: (2)

Running compression test.