Denali08

Worn Out Valves Stems:

I took out my engine for cam change and to fix some gaskets leaks. Took valve covers to discover some worn out at Valves stems.

What could be the cause? Anybody had similar issue?

I suspect rockers or push to rods issue. Could this be caused by bad lifters.

I'm taking the heads off to change the Valves and will check the lifters.

It has stock Valves, stock lifters and 7.4 chromoly push rods.

The worn out is from the middle of the stem towards one side of the stem. Not Valves stems are worn out, only few. I forgot to take picture at the shop.

Gadgetized

iTrader: (9)

Did you check the wipe pattern from the rocker on the tip of the valve? Were the seats ground or the valves cut? Any time you change the height of the valve it can effect the wipe pattern. When the wipe pattern is not dead center it would be like trying to drive a post in the ground with a sledge hammer and not hitting it dead center on the top. If you hit a little to the side it would force the post sideways and elongate the hole in the ground.

1994Vmax

iTrader: (4)

Wipe pattern is one but whats your oiling like to the top end. Have seen a few LS heads roll through now where the valve tips are wrecked from total lack of lubrication. They usually run quiet enough until the damage is done. But as mentioned you really need to look at your wipe pattern. I have had to shim up a few rocker pedestals now because the rocker tip is too far towards the intake side of the valve tip.

Denali08

I should have clearly stated that the worn out is at the top of the valve stem where the rocker hits the valve stem.

I will have to check the rockers and pedestals for wear. I doubt the lubrication cause it has melling oil pump with hi pressure spring. WOT oil pressure is 80psi and idle oil pressure is 40 psi.

As I mentioned, the worn out is on half of the top of the valve stem with top of the valve stem elongated to outer side. So, it could be that 7.4 pushrods are long and needs shorter rods. Engine has been running good for 3-years now.

I will take pics of the worn out of the top of the valve stems and post it tomorrow.

1994Vmax

iTrader: (4)

Oil pressure doesn't mean a thing beyond you have good bearing clearance for now..... It's what kind of oil flow you have to the rockers that does. Pushrod length will not affect your wear pattern on an LS..... it's not a small block with rocker arms floating on a stud unless you have some aftermarket adjustable valvetrain setup. Your pedestal height that your rocker bolts down too is not correct... or you have some monster cam that is too much for stock rockers..... etc. Pictures will help.

Denali08

Some pics.

MikeGyver

iTrader: (5)

I vote for the "no oil to the valve train" answer. Sorry I don't have a helpful reason that the oil isn't there.

Denali08

Can this be caused by low oil level in the engine?

kbracing96

iTrader: (26)

That looks like valve float to me. Been hammering the crap out of those stems! What cam and valve springs are you running and how hard do you turn it?

Denali08

Comp cam 224/230/114 with patriot gold springs.

Rev limiter is 6200 but it rarely hit the limiter with A4 transmission.

I'm switching cam to Isky triple. Hence, I discovered this by chance while doing the cam swap. I'm also replacing piston rings and engine bearings.