Top end LSX knocking sound

[91CoupeMike]

Buddy of mine has a 98 TA with heads and cam, he recently got the car and it was running decently with no noises. He was out flogging it for the first time and it slowly developed a knocking sound. He pulled the heads and found a bad lifter, he said it came apart on the top side and the roller was still fine.

He has it all back together now and it's still making a knocking sound, it sounds like it's coming from the heads, had it idling with the valve cover off and the sound is louder but visually everything looks fine.

Any suggestions? It has good oil pressure.

Seems to make the noise when the valves close.

[DON SVO]

another bad lifter, broken spring, bent push rod....

[91CoupeMike]

another bad lifter, broken spring, bent push rod....

POS lsx....

From reading the ls1 forums sounds like you're right Don, thanks !

[Sleeper]

make sure he replaces the lifter trays.

[91CoupeMike]

Oil doesn't squirt from the pushrods either just a dribble.

[Lone Star Performance]

If it were me, I'd replace all of the lifters and lifter trays, and spray all of the pushrod middles with brake clean before reassembly. I assume the valve springs are dual springs? Make sure none of the springs are broken, inside or out.

[JC316]

There is an issue with the LS7 lifters being crap, I've heard a few stories about them being bad.

[91CoupeMike]

There is an issue with the LS7 lifters being crap, I've heard a few stories about them being bad.

I heard the ls7 were the ones to replace with.

It's a catastrophe...

He left the valve covers off and water got in the crank case and it's still there after 2 oil changes.. And before that they had taken the lifters out, half way disassembled them, clean and pumped brake clean through them and put them back in dry, and I'm afraid they may have bottomed out before getting a chance to get any oil, and it may have damaged the lifters, as oil doesn't shoot out of be pushrods but dribbles if any oil gets to the top.


It's going to be a fun time fixing this one.

[Lone Star Performance]

It's really not a bad job, shouldn't take more than 6-8 hours in the garage

[shumpertdavid]

It's a catastrophe...
And before that they had taken the lifters out, half way disassembled them, clean and pumped brake clean through them

It's going to be a fun time fixing this one.

Good chance that somewhere in here lies his noise issue. I'd do a fresh set of lifters as mentioned.

[91CoupeMike]

Good chance that somewhere in here lies his noise issue. I'd do a fresh set of lifters as mentioned.

Are you saying brake clean is the issue, or that they are full of air? Or possibly damaged?

I ask because I cleaned mine with Chen dip and brake clean, taken all the way apart and will be soaked over night before I install them, all the components were in good shape. (For the coupe)

[Lone Star Performance]

You should never install the items dry after being cleaned. I put some Lucas Oil Stabilizer on the lifter rollers, some on each side of the pushrod, and some on the rocker tips when reinstalled. It is crucial these parts have lubrication before the oil gets to them.

[91CoupeMike]

You should never install the items dry after being cleaned. I put some Lucas Oil Stabilizer on the lifter rollers, some on each side of the pushrod, and some on the rocker tips when reinstalled. It is crucial these parts have lubrication before the oil gets to them.

Oh yeah, I know this. But he was told by another.. "Naw it'll be fine, they'll pump up" smh, I don't even think they primed the system, if you can on those motors. I know on my truck I shut off the fuel and cranked it until I had oil pressure before I even thought about starting it.

[shumpertdavid]

I'm mostly going with the fact that he disassembled them and put them back together. Easily could have got something out of place or missed something if not careful. I generally throw lifters in a tub of oil and let them soak until they quit bubbling. I had to put a set in a vortec 4.3 last week. It had 2 collapsed lifter on a 114k mile motor that appeared pretty clean once opened up. I soaked them, installed and reassembled everything and fired it up. Had a little lifter noise for about 5 seconds until they pumped up then nice and quiet.

[91CoupeMike]

I'm mostly going with the fact that he disassembled them and put them back together. Easily could have got something out of place or missed something if not careful. I generally throw lifters in a tub of oil and let them soak until they quit bubbling. I had to put a set in a vortec 4.3 last week. It had 2 collapsed lifter on a 114k mile motor that appeared pretty clean once opened up. I soaked them, installed and reassembled everything and fired it up. Had a little lifter noise for about 5 seconds until they pumped up then nice and quiet.

Only the top part came out and they used a screw driver to pump the old oil out and sprayed brake clean until clean brake clean came out. Then installed.