replacing lifters ?

[Bigmon]

I have a 85 500SEC that has a rocker arm that rattles. I was told it's a good idea to replace the lifter at the same time.

I've read the post and it seems pretty easy, but no one has mentioned how to remove the lifter. It has a nut shape to it so I'm guessing it just unscrews, but want to be sure. Are there any spacers or other parts to look for during removal? I have a valve spring compressor too.

Any help is appreciated.

[ctaylor738]

You remove the rocker arm and then remove the ball stud with a large (27mm?) deep-well socket. The "hockey puck" sits on top of the valve stem/spring and comes in various thicknesses to pre-tension the ball stud.

The noise could be coming from the rocker or the ball stud.

You should check the pretensioning of the new rocker/ball stud with the special tool, but if it still rattles, go with a thicker puck. The come in seven thicknesses.

It would be a good idea to replace the oil tube's plastic pieces while you are in there.

[Bigmon]

The rocker wiggles back and forth if you put your hand on it. None of the others move so I think I located the bad one.

Thanks for the tips.

[Bigmon]

Today I replaced the rocker and the lifter. The noise is gone. What a difference. While I was there I put in new spark plugs.

Now the car has a rough idle. I'm wondering if the new rocker and lifter need time to seat themselves or perhaps I screwed up on the plugs or maybe a worn cam?

The car has 300k on it. Any thoughts?

[ctaylor738]

The rocker and ball stud should be good to go immediately.

I would first check to see that you got all the wires correctly on the correct cylinders and that none are damaged, and check all of the vacuum connections. There are many other causes of rough idle, but these are likely if you were working on the engine.

It is barely conceivable that the new ball stud/rocker is not allowing the valve to fully close, so if you can't find anything else, try a compression check on that cylinder.