Intake valve guide wear problem

[SilverXJ]

intake (left) wear pattern looks like the roller is riding on the one side..
which tells me that the rocker stud is not square to stem/tip...

Looks like it.

exhaust (right) looking at the tip of valve sure looks to me like you have a
valve control issue. Looks like the valve is rotating looks like 3-4 wear patterns
from the roller?

I don't recall if the exhaust tips were cleaned up when reinstalled or not, so you could just be seeing different patterns.

[robert1]

As long as you have stud mounted rockers you will have contact patterns like you show. There is nothing that you can do to stop it short of having the lifter, valve guide, and rocker stud all having the same centerline which is not going to happen.

[BrazilianZ28Camaro]

Hello Silver, sorry to hear you are having problems again..

This topic I started some weeks ago may be helpfull:

viewtopic.php?f=1&t=30452

[BrazilianZ28Camaro]

I'm wondering right now, wouldn't the exaust pressure (on muffled cars) blow the oil off the exaust guides ?

[donc]

Ive seen the intake liners wear quickly from an over rich fuel condition, particulary the plain non spiral ones.

[SilverXJ]

As long as you have stud mounted rockers you will have contact patterns like you show.

They are pedestal mounted rockers.

I'm wondering right now, wouldn't the exaust pressure (on muffled cars) blow the oil off the exaust guides ?

Exhaust pressure would keep the oil out of the exhaust guide possibly while the intake vacuum would suck oil into the intake guide. I also remember reading your thread when I first found this. MotioMachine found no evidence of oil starvation and he installed spring locators when he did this head 4000 miles ago.

Ive seen the intake liners wear quickly from an over rich fuel condition, particulary the plain non spiral ones.

The AFR was around 14.7:1 in closed loop and went down to 12:1 at WOT in open loop. I hadn't finished fine tuning the WOT curve though, but it lived mostly in closed loop.

[DaveMcLain]

Somebody didn't cut the guides way down super short did they? I had some big Chevy heads come in one time where someone had cut the top of the guide down so that a PC seal sat down against the spring seat and on the other end they had ported/cut the guide much shorter too. Needless to say they had very little run time yet they were killed.

[SilverXJ]

Nope, the stock guides are intact, well at least the outside.

[Bos's5.0]

I only did a quick scan, but what are the chances the particular rocker tips haven't been hardened or not hardened enough, which in turn created excess galling and grabbing ? Like sand paper on the tip of your rocker.

Many people don't like Harland Sharp rockers. Just a guess, don't hold me to it.

[ICEMAN]

Galling comes pressures that exceed oil film protection, or from just plain inadequate oil supply. Have you observed oil flow to top end with engine running? Any restriction in place?

[Kevin Johnson]

Is this a 4.6 stroker? Even with a 4.0 I suspect Mopar's strengthening of the block led to energy being transmitted to the camshaft.

[SilverXJ]

I only did a quick scan, but what are the chances the particular rocker tips haven't been hardened or not hardened enough, which in turn created excess galling and grabbing ? Like sand paper on the tip of your rocker.

Maybe, but I don't think the stock rockers are hardened, are they?

Galling comes pressures that exceed oil film protection, or from just plain inadequate oil supply. Have you observed oil flow to top end with engine running? Any restriction in place?

I have and there is adequate oil flow. I have no real way to measure it though.

Is this a 4.6 stroker? Even with a 4.0 I suspect Mopar's strengthening of the block led to energy being transmitted to the camshaft.

It is a 4.6L stroker, but not a Mopar unit. But, what do you mean?

[SilverXJ]

Randy @ Harland Sharp just finished repairing the rockers. He didn't think it was an oil starvation issue as every he didn't see anything else that would indicate that and the rockers were well oiled. He said the rest of the rockers were like new. He was surprised at the wear and though it could possibly have been a material incompatibility or maybe the intake valves were binding in the guide. He also suggested using lash caps, but I am unsure if we are going to use the same intake valves again.

[SilverXJ]

Had an oil analysis done. Only thing unusual were the silicon and copper levels. Copper from the valve guides and silicone from the valve guides and possibly when I pulled the timing cover and oil pan off 200 miles ago and resealed with RTV. No gas contamination.

[BrazilianZ28Camaro]

And how about the valves Silver?

They showed some signs of overheating?