Featured Technical Another valvetrain noise

Chasing a valve train tick on a customer's small block powered 32. While running the engine with the valve covers off it's definitely number five and seven intake. Check adjustment and they were good But re adjusted to make sure and the noise is still there. Pulled both of the rockers and found this. The valve stem tips are worn pretty bad and so are the rockers. What the heck could Have caused this?

 

No experience with roller rockers so I have to ask, do the rollers on the stem actually roll?

 

Yes, the rollers roll just fine by hand but looked like they never did when installed Causing the gouge in the valve stem.

 

It is interesting that both the roller and the valve top have gaulling. I would hazzard a guess that it would be from lack of lube. Does the roller still roll?

 

A problem with the geometry?

 

Yes, the roller still rolls. When the
Engine is running. It takes a while for the oil to overflow onto the tip at a idle. But I guess at higher rpm it would shoot more out

 

As far as the geometry it is worn directly in the center so I'd say that the ratio is correct?

 

Looks like it ain’t gettin enough erl

 

Looks to me there’s a problem with valve material being to brittle, which brand of heads are they?

 

Unknown head manufacturer they are aluminum. Customer has a build sheet at home. He's going to look at tonight.

 

Is there any way this could be fixed without pulling the head? I imagine the valves are hardened.

 

Based on the location of the swept area on the valve tip the push rod length is probably OK, but I would double check. The damage looks like more than just lack of oil. Just to rule it out, I would check for valve spring coil bind and valve spring retainer to guide top clearance. Cam may be putting valve spring close to coil bind. Head spec sheet should list max cam lift allowed. Or, it's just cheap roller rockers coming apart? Think I would be checking the rest of the rollers. Please report back what you found after you get it fixed.

 

Are they supposed to have lash caps ?

 

Who made the rockers?

 

I've never seen lash caps on a small block Chevy. The rockers are made by comp.

 

It’s either oil or material, Comp are reasonably trustworthy I think. I wonder how hard the tip is. Can you scratch the top of the valve?

 

I
Can scratch the top of the valve tip with a file So i'm guessing these aren't that great

 

It would depend on the valve material.

 

Are these valves supposed to rotate?

 

If they are supposed to Rotate it looks like they are not.

 

@wheeltramp brian

Cheap rocker even if C-C's
Just what is seen in pictures.
Cheap 90s rocker better then those ,
They look new made.

Talk with customer , explain to him
95% Fix , ( Im not scared to use)
What is shown in pic's,
install a lash caps
Clean up with file ,
Check guide,
Install lash cap ,
New rocker or change roller.
Then check geometry you might beable to use same push rods .
This is problems with cheap heads
& unknown parts used,
Lash caps are common even on sbc,

Head Do not need to be removed

 

I've got to go pick up a flywheel That's getting resurfaced at the machine shop and I'll ask them about my problem and lash caps.

 

@wheeltramp brian
If you are doing For customer and you don't want to possibly have issues down the road it might be best just to pull the both heads, disassemble both check seats and guides all the vavle stems
& rocker ,
Now customer labor &
Gaskets $900- $1,500 no other parts.
Lash cap set $50 -120 ish
2 Rocker $40 or so each cheap ones

Labor hear is $180-240 hr,

But me for myself I would just
2 or set of Lash cap & the 2 rockers

 

It is a customer and also my best friend. So he understands doing it cheap right now, Or doing the full job. We will see what he wants to do.

 

Remember also that if new valve guides are installed the seats will need to be reground or cut.

 

I was gonna toss a set of stock stamped rocker arms on just to see if the noise would go away, but the studs are 716 so they won't fit.

 

Could valve rotators be added to these aftermarket heads and roller rockers?

 

I would say the same. Galling is a type of wear that that falls into the category of Adhesive Wear (as opposed to abrasive or erosive wear), resulting from contact between moving surfaces where micro welding occurs and metal is transferred from one surface to the other. A well lubricated surface prevents contact between the parts. With a roller tip the load zone between the roller and the stem tip enters into eloastohydrodynamic regime of lubrication, i.e. extremely thin film of oil that develops under extremely high pressures. If there is insufficient oil supply to the top end, even momentarily such as on start up or with a low oil level that uncovers the pickup tube on cornering or hard braking, that would allow contact to occur, metal transfer to occur, which then exceeds the thickness of the oil film and subsequent cycles will result in increasing levels of metal transfer even after the oil film is restored. The same thing can occur with too low of oil viscosity, or too high can also cause this as the oil, if too thick, will not flow into the load zone properly to form the film in place before the load applies. Viscosity is often called the most important physical characteristic of a lubricant.

 

Let me rephrase my question, when roller rockers are in operation to those rollers actually roll?

 

I went by the machine shop to pick up my fly wheel and asked the guy about the heads. He believes they are comp heads and they have titanium valves and they should have valve caps. He thinks the dissimilar metals is what's causing the problem and says that the rest Are probably starting to go also. It has the proper valve locks that are made for the caps To clear.