Haha... This place, and all the chain paranoia; plus too much firsthand knowledge of what happens to any interference engine when the chain/belt goes kaboom, along with the previous (original) owner telling me that before it broke down (bad fuel pump) he was told it needed a chain.

I do understand the mechanics of an engine well enough, but to be honest when I first saw the benz engine there was a lot of "what the hell is that?" going on in my head. Most of my experience is with domestic & asian stuff from about '90 upwards. A fuel distribution unit was something I'd only ever heard of.

I do have to say, though, I'm falling in love with overall layout and engineering of the motor. Something about only having to pull spark plug wires and 4 bolts to remove a valve cover is a refreshing change from today's modern engines. Heck, the spark plugs are even angled the right way to make them easy to get out; I haven't seen that in a long time. Once my factory manual arrives, I'll be all set.

I got the car for free and timing parts were less than $200, so I'm pretty far ahead of the "is it worth fixing" curve; that, and I really need a hobby. Plus, the mile I did drive it had me sold...

Oh, And according to my wife, I'm definately keeping it.

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A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

Since one cam lined up at TDC but the other didn't, have you considered the possibility the chain has been changed but the timing wasn't done correctly?

10 degrees sounds pretty close to being one tooth off. The right hand cam, I believe, has the long chain run and is where the tensioner is. THAT would be the first place stretch should show. Check the chain for a replacement link.

Somewhere in the dusty recesses of my mind there's an abstract nagging memory regarding the M116 engines and timing marks but I just cant dredge it up.

Case closed!

The chain has not been changed. I was assured of that.

Maybe our lefts are opposite - my right & left are standing in front of the engine, not behind the wheel. The cam mark was off at the sprocket that was closest to the tensioner (U.S. passenger side).

Also, I thought a full tooth was around 23 degrees? The actual distance the cam was off was just over 1/8" of an inch, not enough for a full tooth. Plus, if it was a tooth off, I don't think it would have run as smooth as it did in the brief time I ran it.

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A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

Engine "sides" are defined by sitting in the driver's seat facing the front of the car.

Yup, the 10 degrees on the right cam would definitely indicate stretch.

Yeah, you're right on the 23 (22.5 degrees on a 16 toothed wheel) degrees tooth variance. My thinking cap wasn't on straight. I was distracted by thinking it was the left cam which was off 10 degrees.

Do we know the indicator on the crank wheel is actually TDC..... being as were having a finite discussion about engine timing. There should be a definate difference between compression from side to side if the performance has been effected. Why would the left cam be on and the right side so late, and I used to set cam timing with offset keys supplied through MB parts. Just more what if's
Bill

You know, I think that's even an ASE question, but even after facing engines all day, I never could get into the habit. We just used "passenger & driver".


Yes. I got TDC from the #1 piston, not off the crank - but they did coincide exactly. The timing mark position seems to make sense to me. The crank spins CW (facing vehicle), so max tension is between the crank and the left (driver) cam. The tension then goes from left cam to pulley to right (passenger) cam, so if the chain is stretched, then the left cam pulley mark should be on the left side of the indicator mark, which it is. Turn the crank a wee bit more and right cam marks align.

Note - the picture that's posted earlier of the timing is NOT the 10 degrees I got when I checked things "the right way" - that's the 7 degree shot I got after just lining up the left cam marks and looking at the crank.

I also got to thinking about the cam pulleys and took some pictures at lunch of the left (driver) sprocket. The chain on the right cam near the tensioner does pull up a good 3/16", but the left cam (drivers side) pulls up a little less than 1/8". As you can see, they appear to be very symetrical, and even though there is some obvious spreading on the sprocket valley face, I think they look OK. These are of the passenger side only.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

I tend to not use "driver's or passenger's" side term simply because this is an International board and the members who drive on the, ahem, "proper" side of the macadam tend to get a little confused.

That thought had crossed my mind, which is why I started saying things like "the side the tensioner is on"...

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.