oxrabidus

My engine was making a loud knocking noise at around 3000rpm or so.
I took the intake off, no pushrods were bent, the vslves looke fine from what i could see through the springs.
I ran the motor with the vslve covers off and one lifter was oiling ever third or so time, i checked to see if i was still at zero lash, and i was. So i took the rockers off and put a straight edge accross the studs to see if maybe it sleppied a little.
It all looked fine, so my question is how can you tell if a hyd. Flat tappet lufter is bad by looking at it? Because it looks fine, just like all the other ones, but id like to make sure.
And also with my cam, 214/224@.05 .447/.457 lift, you think id need to install screw in studs? Or should i be fine with the press in ones?
Thanks

Saculia

iTrader: (1)

How frequent is the knock that you are hearing? Usually lifter noise happens at 1/2 the rate the engine spins at.
I don't think that you have enough lift to worry about screw in studs.
If you have a collapsed lifter sometimes adding a little bit of trans fluid can help expend it or adding some sea foam can help expend it too. Also, I don't think that lifter noise will show up only around 3000 rpm.

oxrabidus

I dont know exactly. But it didnt knock at all at idle, it started at around 2800-3000 rpm and got louder under heavy throttle and progressively as the engine spun higher.

Saculia

iTrader: (1)

Have you pinpointed where the knock is coming from? It could be a bottom end noise.
You can use a piece of hose or a long screw driver to take a careful listen for where the knock is coming from.
Just out of curiosity, isn't the L30 vortec motor a roller cam motor? There probably is a way of retrofitting a roller block to take a hydraulic flat tappet cam, but why would you do it?

oxrabidus

Its not a bottom end knock, it would mske the knock at idle as well if it was.
The l30 is a roller block, but i didnt have the money for an aftermarket roller cam so i bought a czm i could put in there, it runs pretty damn hard that car, till it startrd making that noise.

InfernalVortex

iTrader: (4)

Ive seen a vehicle knock at high RPMs and not at low RPMs. Are you sure?

oxrabidus

im pretty sure its nota spun bearing, or something of that sort... but ill truly find out when i replace the lifter that wasnt oiling right andstart the engine up again...
i was just kinda hoping there was a way to visually tell if a lifter is bad.

Saculia

iTrader: (1)

I agree. I have seen the same thing before.