380SL engine konck
 

1981 380 SLC with 50K, Has been sitting in cc storage since I drove it on a 1000 mi car tour in Oct. When I started it today there is a loud knock which seems to be coming from the front drivers side rocker cover area. Where do I start? Thanks, Bob Smits

Let engine warm up. If oil press is good rev at 2k for 30 seconds then let idle If noise is still there you might have a lifter that has failed.

Engine Knock
 

Thanks for the suggestion. Noise is still there. Time to pull it apart. Bob Smits

Engine Knock
 

Update; Engine knock did not go away after allowing engine to warm up. Pulled both valve covers and lifters are ok. loosened all belts and no change in knock. Timing chain and tensioners are good. Interestingly when I disconnect the flywheel RPM sensor and crank the engine without allowing it to start the knock is not there. Any help would be appreciated. I can text a 10 sec video to anyone who would like to listen to the engine knock. Thanks I really need help with diagnosing this problem. You can text me at 979 575 9371

380 SL engine Knock
 

HELP

How did you determine the lifters are okay?

I experienced a collapsed lifter during warranty on my erstwhile '84 190E 2.3. I knew immediately what it was, but the dealer did the work.

With the valve covers off and the EZL disconnected, crank the engine, and it will crank faster if you remove the spark plugs. You should be able to spot a collasped lifter by eyeballing valve lifts as the engine cranks.

I would describe a collapsed lifter as more of a loud ticking sound rather than a knock.

Duke

turn engine over by hand and feel for any loose rocker arms

Thank you to all who replied. Sorry for my absence but other health related matters tied me up for the past year. I just re-posted an update titled "motor Seized 1981 380SLC" Bob Smits