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#1
10-22-2007, 03:59 PM
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Timing chain sprocket Vs. Cam alignment?
Hello again,
After months of denying that my timing/idle problems could be related to the sprocket/cam alignment, I was forced to admit it. The alignment marks are off 5 degrees or so after head gasket replacement. I've got the sprocket off, the mark on the thrust washer lines up with the woodruff key that the sprocket slides onto, but that doesnt line up with the mark on the cam tower. How do I rotate the cam to align these. Im assuming then that I take the sprocket out of the chain and rotate it to the appropriate place before re-assembly? Photo hopefully attached for reference. 1969 230 straight 6 (m180 i think?) Thanks! hopefully this will get me back on the road soon! Marc http://picasaweb.google.com/philthytrucker/Mercedes 
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#2
10-22-2007, 04:22 PM
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Almost looks like you are one tooth off on your chain. I think you know how to correct it. Be careful and don't drop anything; double check the crank marks and make the adjustment of the cam sprocket. Slip it on and recheck.
230/8
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#3
10-22-2007, 04:39 PM
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and by checking, that means hand turn the motor through at least two revolutions, if not four. -CTH
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#4
10-22-2007, 04:47 PM
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When you hand turn the engine, be sure to turn it only clockwise!!! If you go past the mark then crank it around again, 'cause if you go counter-clockwise and your chain or tensioner is worn it can "jump". Hmmmm?
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#5
10-22-2007, 07:14 PM
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Well, everything went back together ok, but basic problems still present. idle too erratic to try and time. RPM kinda hovers around 1000 but will go from 800 to 1300ish and stall at random. i tried to set the timing to the 'average', ran it around to block to almost no power, stalling in gear, and loud clattering sounds. Points were new, and yes Im aware of all the arguements for electronic ignition. carbs are pulling evenly
I feel better knowing the valve timing is correct, but so frustrated not being able to get it to run or diagnose the issue...
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#6
10-23-2007, 01:33 AM
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So where are the marks now that you have redone it? Is the pointer on the block pointing to the "TlO" mark on the crank pulley while the marks on the cam are lined up with the arrow on the cam tower? If not, I'd start by rolling in a new timing chain because yours has probably stretched.
Is your cam chain tensioner "pumped up?" If not, fill that reservoir area in the head with fresh oil and then lever the tensioner with a screwdriver (like it shows in the manuals) until the tensioner is rock solid. There is also an adjustment for how the tensioner is positioned. Once you get the chain dialed in, make sure the distributor is pointing in the correct location. Right now, you may have the timing too retarded, hence the lack of power and dying. You can always resort to just rotating the distributor counter clockwise by hand which will advance the timing, until it's running better, and then dial it in with a timing light. Of course carb sync come into play hugely, but dial in the cam and the timing first, and then move on (to the carbs) from there.
__________________
 1966 W111 250SEC:
DB268 Blaugrün/electric sunroof/4 on-the-floor/4.5 V-8 rear axle
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#7
10-30-2007, 03:00 AM
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Todd, Thanks for the fresh info. When I buttoned it all back up, the timing marks on the cam corresponded with the tdc mark on the block. When I pull the valve cover off to check all that you mentioned I ll double check again, but it seemed to be right on.
When you say make sure the distributor is pointing in the right direction, what do you mean? Im assuming that at tdc it should be pointing towards the #1 spark plug wire? Ive attempted turning it till I get a better response regardless of the timing light, but nowhere does it really run right, the best I can manage is the afformentioned, rough, sputtering, uneven idle. One thought has been sparkplug wires? I havent changed them in the 2 years Ive owned her, and never could point a finger at them previously, but have been suspecting everything lately....just a thought. It'll be a week or so before I can wrench on her again, but nice to have something new to look for! thanks. Marc
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#9
01-02-2008, 09:05 PM
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Inside the exhaust manifold...
are those warm-up valves, and 1 or both could be stuck. When stuck in the warm-up position, they don't allow full exhaust flow.
I had that happen on a 1971 250S. Try a Search on Exhaust+Valves
__________________
1970 280S M130 engine- good runner 1971 250 M130 engine- #2 rod bearing, gone 1971 280SE (blown engine,parts car) 1977 German 280S W116-only 33 years old
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#10
01-04-2008, 12:29 AM
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Update:
I did change out the spark plug wires. This made enough of a difference that I could time the car properly. Although I initially timed it at 1500 which worked...for a day. next day it was backfiring and stalling. I timed it to 4500 rpm and after finding a few loose carb nuts as well, she ran much better. enough to take it out and run it around town. It still has a leak on the forward carb, Ill get at that one soon. The warm up vents are indeed stuck, although I dont recall in which position. I need to get around to that one as well. So the short version is, its getting there. so nice to be driving it rather than cursing it. a few free weekends and I might get it dialed in just right! thanks everyone for your help so far!! Marc
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