ADM

Was taking my car out for its usual afternoon drive, found a long strip of road and went for a WOT launch and top speed run.

Transmission was in non-overdrive D during the run. My shift points are at 6200 and rev limiter at 6500. At the 2-3 shift, it bounced off the rev limiter for a second and then shifted to 3rd (never happened before).

All of a sudden, the car just stalls? I throw it in N and try to start it, noticed the tacho needle bouncing around, but it did start just in time to brake and not go through an intersection at 100mph.

Soon as it started back up, I heard a knocking sound, and it stalled again. I started it back up and pulled to the side of the road, got it home on a flatbed.

The battery was drained for some odd reason, the flatbed guy had some jumper cables, we could even jump it to crank one turn.

I charged the battery, tested out fine. Started the car up, alternator is charging. Pulled the valve covers, no valve train damage, no broken springs.

The sound is not there at idle, but as soon as I raise the revs off idle, it ticks and is consistent through the RPM range. Its coming from under the intake.

Still have my normal 60psi cold idle oil pressure, 20psi hot idle. When driving, oil pressure is at 40psi as it were.

My valve lash is set at 1/2 turn past zero.



http://www.youtube.com/watch?v=3nGj7X27jxI

Happy New Year

jester1614

iTrader: (13)

i would find the woodpecker that is in your engine compartment and untill you do quit pissing it off by revving the motor


seriously tho I would pull the valve covers and check for broken springs and pushrods that sounds alot like my car did with a bent pushrod.

RamAir95TA

iTrader: (2)

I would pull off the intake manifold and take a look at the lifters/dogbones/pushrods. What's 12 bolts, some gaskets, and some RTV?

Spiers

iTrader: (7)

Sounds like a spun bearing to me but hope Im wrong...like said I would pull the intake and check out the lifters etc...

MattSapp95_T/A

iTrader: (35)

Sounds fairly deep like a bearing issue... But just like Joe said your only 12 bolts away...and it takes less than 30mins to have the intake off...
That would be the first thing I done...

Some simple green wouldn't hurt either....LOL

tricked94camaro

iTrader: (1)

itss too dirty thats your problem

ADM

UPDATE :

I removed the intake lastnight, and disassembled the valve train.

Inspected all the rocker arms, none are damaged

Pushrods are all straight.

All the valve springs are intact, none broken and no valves "look" damaged.

The spider that holds the dog bones was not bent. Dog bones are also in good shape.

Now, the lifters. They all passed the visual inspection. None have any damage to their bodies, the rollers spin freely with no grinding feel.

However, how do I test them to know if one of them is actually collapsed and the source of the noise?

And if it did collapse, wouldn't the rocker arm driven by that particular lifter be loose? I did check if any of the lifters moved up freely before removing the polylocks.

I am trying to correctly diagnose this problem so that I don't go remove the engine, tear it apart only to find all the bearing are OK and it was just a lifter.

Can you actually get 50-60psi cold and a solid 20psi hot idle with a spun bearing?

Gurus, help steer me away from a 383 heads and cam/carb/TH350 rebuild

ADM

No one here knows the procedure for testing lifters?

LS1MUNN

I had pretty much the same thing happen to my car as well. I posted a few times and got zero response on diagnosing lifter problems. I used a stethoscope to pinpoint that the sound I was hearing was coming from under the passenger side valve cover. I took off that valve cover and inspected all the valves and springs. I noticed that there looked to be some clearance issues with my rockers not wanting to clear the head castings so I took off my shaft mounted rockers and reground some more clearance for them in the head. because I used an allen wrench to take them all off I squished out the oil from in the socket head bolts. I re assembled everything and started the engine. The sound was still there. I took the valve cover off again and this time I noticed that all but one of my rocker bolt heads had oil in them except one. I am taking this to mean that I have one lifter that isnt pumping any oil through it and therefore has failed. So Im going to pull my engine and replace that 1 lifter. I am only replacing one lifter this go around, because I only had about 200 miles on a brand new set of LS7 lifters, cam, and heads. I have a LS1 not a LT like yours, but it sure sounds like we have the same issue. Hope this helps you. If I were you I would buy yourself a new set and replace them.

ADM

Thanks for the input buddy.

I would really appreciate it if some of the gurus would chip in on how I can check my lifters and know they are not the cause of the noise.

I am allocating this whole coming weekend to removing my engine and trans if it turns out to be a spun bearing and will rebuild with forged pistons and ARP bottom end.

strokin93z

iTrader: (1)

I guess you could try and "pumping" up all the lifters and see if any don't become solid, or bleed off pretty quick. Then that would be a bad lifter. I'm sure someone will chime in with something more helpful.