Knocking lifter? - PeachParts Mercedes-Benz Forum

C. Landry · #1 12-11-2006, 10:24 AM

I can hear what sounds to be a knocking lifter in my engine. What should I do to remedy this? I have been keeping up on my oil changes. Is there an easy way to deal with this, do I need to adjust them?

Thanks,

C. Landry

aermotor · #2 12-11-2006, 06:23 PM

What side of the engine does the knock come from? I've owned two 1986 420SELs and both developed such a noise on the passenger side. Each time when I removed the valve cover, the cause was obvious - a bad cam lobe or two, along with the associated worn rocker. I replaced the cams and all rockers. My wife has a 1986 560SL and same thing there two weeks ago, and I installed a new cam and rockers. Not a huge job. Irritating, however. While in there, do the timing chain.

86560SEL · #3 12-12-2006, 12:27 AM

My 1985 380SE seems to have this noise as well. It has the lifter "tick" or "chatter" when the engine is warm, especially on the passenger side, but also when driving, under acceleration- between 1500-1800 RPMS, there is a different noise- more like a knock that I can hear if the radio is off. I am assuming that my camshaft is worn as well, especially since the car has 268K.

I am wondering- will it damage the engine, continously driving it like this? I have owned mine for over a year and it has been doing this since I have bought it and it has not seemed to have become any worse.

Strife · #4 12-12-2006, 12:51 AM

I had this problem on the RH side of a 380SL. The rocker actually had a significant concavity in it. You MIGHT be able to replace the rocker(s) alone but look at the cam. Mine had scores, gouges, and chunks missing. This will cause the new rocker to fail fairly quickly I'm told. Guess where all that metal went.

The root of my problem was insufficient oil to the RH cam, caused by the oil tube popping out partially due to an old shrunken plastic fitting. This little $3.00 part caused me to have to change the cam ($300), and 8 rockers (70). MB list prices are more than double that, never mind the labor.

I did the timing chain while I was in there.

Following the manual's procedures on cam bearing removal/ replacement/ torquing to the letter is critical on this job. Strip a head bolt thread and the total cost of the project just quadrupled.