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King of Smart Gadgetry
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Discussion Starter #1 (Edited)
I did a screen shot of the timing mark locations on both cams and crank dowel pin locations before I disassemled it for my future reference. There has been alot of confusion on the forum in the past as to which timing gear marks line up to be sure the engine is timed properly at reassembly. The pics are a little blurry because they are screen shots taken from a video I did during disassembly, so I apologize for that ahead of time. But they serve the purpose to show the proper marks to line up. The exhaust gear has several sets of markers that make it very confusing of you don't know which marks to use.



Here is the reference pic of the cam gears. The intake cam has the variable valve timing mechanism on the end of it that controls valve timing by sensing oil pressure. On the shiny mirror like edge there is a set of numbers or letters or a combination of both numbers and or letters that is ALMOST inline with one of the bolts on the front of the cam. That string of numbers is ALMOST inline with an indentation on the intake gear. That indentation lines up with a line cast into the exhaust cam. That line is the only mark you need to worry about. The exhaust gear also has a set of double dots, a blue dot and the letters "EXT" but these are irrelevent for our purposes, although it does appear that when the dash line is properly lined up the blue dot is about 12 o'clock.




Now this picture of the front of the crank is not clear at all, and is the wrong angle, but I think you can get the simple idea from it. There's a dowel pin that sticks out on the front of the crank snout that locates the position of the bottom pulley. This dowel pin is also inline with a dot on the crank gear if that is more comfortable for you to line it up with. Now the dowel pin lines up with a small triangle that is on the block right in the middle just off center from where 12 o'clock would be.

Now after you line up all your marks place the chain on the gears and keep all the slack in the chain on the adjuster side. Then rotate it a few rotations clockwise and recheck to be sure it is still right.
 

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Thank you for your efforts, but so far NOBODY ON PLANET EARTH has a clear image of the necessary timing marks. Not MB, not Alldata, and you're almost there and still haven't perfected it. :D :rofl:
 

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It's pretty hard to tell what to line up based on what's shown here. For example, the intake sprocket could easily be out of position by a tooth clockwise, and the exhaust sprocket out of position by a tooth anticlockwise, and the "marker dot" and "slash mark" could still visually "line up" according to that photo.

Also, by "12-o-clock" orientation, what's your frame of reference? Do you mean "as installed in the vehicle", or "relative to the angle of the cylinders"?

I'd strongly recommend to anyone taking the camshafts out of this engine, to make your own set of markings with the crank and both cam sprockets referenced to your own marks on the engine block and cylinder head. That way the orientation is referenced to something solid in all three cases.
 

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King of Smart Gadgetry
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Discussion Starter #4
I know the pics are a little fuzzy but I laid it out in an elementary manner based on center lines. I don't know how I could have made it any clearer. I did what worked for me and I opted to share it here with my friends on the forum for reference, if my method doesn't work for you then just use your own method and please don't blast me for what I did. I painstakingly checked the marks and there is more to my method than these 2 pictures. As I said this was a video I did. I will try to elaborate........

1. I made sure the engine was on true TDC. I didn't worry about lining up TDC to the timing chain cover as it was already removed at this point anyway. I put a 17mm socket on the exhaust cam bolt and rolled the engine while holding my finger over #1 cylinder until I felt air coming out of the cylinder. That told me both valves were closed and the cylinder was coming up on the compressiion stroke. I then placed a long shafted phillips screwdriver in the cylinder through the spark plug hole and rolled the engine until the cylinder was at TDC. You roll it up and just past TDC then go backwards again and then forwards again to find the spot that it is on true TDC.

2. Then I noticed if I drew a true centerline according to the cylinder or should I say if you drew an imaginary line fron the enter of the crankshaft snout up to a bolt hole that is centered between the 2 cam gears you find the the dowel pin on the crank is in that centerline at 12 o'clock position. That's an elementary fact for about all engines I've ever put timing chanis in.

3. Then look at both cam gears and their bolts that fasten them to the front of the cams, draw a center line acrossed these 2 bolts horizontally and you have your other reference point. Then you will see on the mirrored part of the intake cam there is a string of numbers and or letters that line up with that center line as well as a bolt on the front of the intake cam AND as well a mark on the intake gear tooth as well, and they all line up with that centerline facing towards the exhaust cam reference mark.

4. The real confusion comes with the exhaust cam gear because there is multiple marks on it that makes it confusing if you carelessly disassemble the chain and didn't note what was lined up and what wasn't. There is a long line or slash mark and that line is perfectly lined up with the above said centerline and it perfectly faces the marks mentioned above on the intake cam gear assembly. Now the other marks on the exhaust gear include a set of dots, a blue marked dot, and the designation "EXT" and there might be a designation for these other marks, but they are unknown to me and I don't speculate on them because they are irrelevant to my purpose of timing the engine.

5. Now after lining up the marks you install the chain. You may find that in order to get the chain seated in the teeth of the gears that you have to move the gears ever so slightly. So now your marks are ever so slightly off. Now just roll the gears back to alignment and you will find all of the slack should be on the side of the chain that the adjuster and adjuster rail is on. Now you need to compress the adjuster so that the plunger is totally retracted and put a small nail in the hole of the adjuster to hold it in the compressed position. Now install the adjuster and then pull out the nail and the adjuster plunger will pop out and the adjuster rail will take up the slack in the chain and all should be in alignment.

I know the pics are fuzzy and I apologize for that but if you pay attention you will not be a tooth off. When I dissassembled mine I used acrylic paint and marked the chain in relation to the gears in 2 spots for each gear and also 2 spots on each guide. I didn't have a picture of that. But I re-assembled everything by lining up all my marks and then confirming the chain was in the same position by all the paint marks (10 of them) and you should be good to go. DCO
 

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King of Smart Gadgetry
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Discussion Starter #6
No matter how hard you try to do a good helpful post on here, there are always those that think it is never good enough. Just par for the course. Everyone that complains that I'm wrong needs to post their own version on their OWN car and then post your own. How many combinations do you think will run? Mine's right because the car runs. That's good enough for me.

 

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I have been worried about timing this engine for a while now... I have a feeling I'll be doing valve guides at some point on mine. I work on BMW's for a living, and timing some of the old VANOS engines is a pain. Thanks for the post, looks fairly simple.

Sent from my SAMSUNG-SM-N920A using Tapatalk
 

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No matter how hard you try to do a good helpful post on here, there are always those that think it is never good enough. Just par for the course. Everyone that complains that I'm wrong needs to post their own version on their OWN car and then post your own. How many combinations do you think will run? Mine's right because the car runs. That's good enough for me.

Forgive me. I wasn't laughing *at you* or your pictures. You recently joined the forum. This timing marks issue goes back many years prior to you joining the forum, nobody seems to take a crystal clear picture of those timing marks at either the cams or crank. MB's own internal photos for their techs aren't clear, neither are Alldata's, and neither are pictures various people on the 'net display. It isn't your fault, you're just getting my end rant so sorry try not to take it personally. Your pictures are the best I've seen in 8 years! But it would be just our luck that you had a great video and took a snapshot of the video! We were oh so close to a perfect hi-res photo!
 
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