When to Replace Ball Pin Adjusters

[Pawel66]

I know, I saw pictures here, how really worn ball pin adjuster looks like - it has a crown developed, on the picture the crown had something like 1mm. Clear.

I am replacing camshaft and rockers. I thought it would be good to look at the ball pins if I am placing the new rockers there. I am not sure if I the pins are ready to be replaced. I do feel some crown there with a tip of my finger. You cannot really see it as it is fairly smooth shaped. But I feel it. It is not this 1mm high crown someone here showed on th epicture, but it feels it is there.

This is a bit hard to describe, but does this seem to you like an item to replace?

I would probably just screw out the adjusters, not the bases from the head.

[wwheeler]

My understanding is that the ball pin is usually sold with the base. The reason is that the ball pin thread is a "locking" thread in the base. If you just replace the ball pin, the threads in the base are still the old worn threads. Therefore, you may not get the correct "locking" action with just the new pin alone. And you for sure do not want the ball stud to be loose in the base as it will rotate and change the valve gap. Replacing both the base and stud will assure the correct locking thread.

However, however replacing the bases can be problematic as many more experienced than I will tell you. Hopefully I did not make your decision more difficult.   

[stickandrudderman]

I replace ball pins only without issue.

[Tyler S]

I too have replaced just the ball pins without the bases. If one is of questionable tightness you can swap out 2 different pins to find a tighter one (requires a bit of whackamole). The pins interference fit threading seems to be inconsistent.
If you barely catch your fingernail on the crown that has developed, you can also ground off this crown flush and continue to use them. Removing the crown makes valve adjustment easier and more consistant. The clearances stay put.

[Pawel66]

Thank you very much for your attention and answers!

Yes, I am aware of the necessity to have the ball pins turn tight in the base, but if I were to replace the pins, leaving the bases in the head - I would sttill try it as the bases replaceement is more difficult (did my homework reading on this).

Ok, so you say grinding is also an option at this stage - thank you for that. This is what my mechanic suggests, he says, given the financials.

Thank you very much for helpful answers so promptly!

[wwheeler]

I have also replaced just the pins and as Tyler said, the fit was inconsistent. So I ended up swapping back and forth and took some time. The point being, don't just simply sub the pins w/o making sure there is some locking effort. I would have to look to be sure, I believe there is a spec for minimum torque on the pins.

[Pawel66]

Yes, there is a spec to the torque for adjusters (saw it on the forum). I will observe that, I realize importance f this.

[Pawel66]

Ok, I took a closer look at my ball pins again before leaving for the airport. What I think may be the case is that someone sometime already ground the crowns from the ball pins. I see the flat spot on the ball much wider that I see on the pictures of the new parts. The new rockers are a bit lose when you place them on the ball pin. This tells me I probably have very old ball pins, already  ground and I htink they need to be replced.

A set costs a horrifying money in Mercedes. I see them in SLS at EUR 38 and I may take a risk.

Unless you know a better source.

[Tyler S]

Pawel, the ball studs and rockers are a bit loose even on new parts. There will be a little bit of lateral movement. The important thing is to set the clearances and cycle the engine. Then go back and remeasure to make sure the clearances have stayed put.

[Pawel66]

Tyler, thank you. I have just ordered one ball pin from MB to check how it fits to the rocker vs. the ones I have now. I need to make up for lack of experience somehow and see how it looks like myself. I will also be able to measure the ball - old and new - very curious what I will see.

It is important what you are saying - set clearances, then, as I understand, turn the engine a couple of times and see if clearances are held. I thought you need to drive the car a bit to check that, but if you are saying they may lose the setting so quickly - this is very helpful.

[Benz Dr.]

I would also check them after driving to see if anything changes. You can't usually hear a tight valve - only the loose ones.

[Pawel66]

ok, thank you!

[Pawel66]

I received one ball pin adjuster from SLS and one from Mercedes (quite similar, to my surprise  ). I measured diameters, heights, etc. and I came to conclusion that what I have now in the cylinder head is not much different from new. Even the little "curb" I can feel with the tip of my finger where the spherical surface becomes flat on top - I can also feel a bit of it on new adjusters.

So I am not replacing them.

I also bought a new febi upper chain gear to see the teeth on new gear and the gear I have on camshaft - they look the same.

Funny: febi sprocket was $25. Mercedes sprocket $250.