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#61
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Good point! I forgot about that. Pass the crow, please. And the salt. (mmmmm.)
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#62
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My '80 300SD definitely has a ratcheting chain tensioner. I know because I had to replace it because it got stuck and did not keep the chain tight. Lucky I found the tensioner was bad when I was adjusting the valves before the chain jumped.
The only thing I can't figure is why the spring doesn't keep the chain tight. If the oil pressure and the ratcheting action keep the chain tight, what does the spring do? P E H |
#63
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P.E.,
The SD's had a turbo diesel before '82. I expect that's why it has the ratcheting tensioner. The 300D, '81 and earlier were non turbo and had the same tensioner as the four cylinders. Actually, even the later 240D's had the same tensioner. It appears that the turbo's got the ratchets. Have a great day, |
#64
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Just so that we can completely beat this into the ground. The first entry on this thread mentioned a 1984 300TD. That vehicle has the 617.952 engine.
I can't help but wonder if the poor guy that started the thead is still with us, of if he just went away shaking his head in wonder? |
#65
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I sure hope he didn't go away. These threads seem intense at times, but much information is pushed out of its deep, book shelf hiding place and forced into the foreground. We all learn from it.
Many of these debates have more to do with personal methods than they do with right or wrong. I hope there is no one that would be insulted or otherwise forced away from our brotherhood by such threads. If it is happening, it is not widespread, otherwise there would be no one left logging on. Have a great day, |
#66
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I'mmmmm still here, shaking a bit, but still here. Finally got the parts in the mail yesterday and just to stir the pot I am happy I got the chain tool, the only other chain tool I have used is for bike chains and this one is much different. Surprised that it actually mushrooms the ends of both chain pins at the same time. Also, the tensioner that they sent me ratchets...whatever that means, I guess it all depends on what ratchets means, I remember Bill Clinton talking about what is and does mean so guess anything is open to interpretation. The tensioner will only go in one direction and has a spring clip around the shaft and groves in the body of the tensioner where the spring ?ratchets? into to prevent it from going the other way. The slide actually has a softer material than I expected. Hope I don't have to replace this. plan to start friday!!
thanks for all the help.... |
#67
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If I'm not mistaken and not knowing exactly which tool you have - I think that one of the "blocks" on the tool is used to push the chain plate on and the other block only crimps one link pin at a time. Prior to installing the tensioner push the "piston" out of the tensioner housing like it is going toward the center of the engine until it pops out then reinsert it into the tensioner housing. Once you start inserting/tightening the spring fastener it should push the tensioner "piston" against the slide rail. After you start up the oil pressure will keep it pushed tight.
__________________
Jim |
#68
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Just an update on my 81 300SD timing chain job. I put it all together and checked the timing marks, as directed in the Haynes manual and on the CD. Looked ok. Still the engine did not seem to idle smoothly. But then, it never had idled smoothly before. A little smoky, but this is a diesel right?
Well I had been planning to check the IP timing. So I went to see my good friend and MB tech, he had told me to see him as he had the drip tool. He listened to the engine and said this was not right. Too much vibration at idle. Told me he thought the timing was screwed up. Maybe the IP timing would do it, but better check that chain again. So I did that today. Could not believe it. The cam was out 18 deg. Exactly one link off. So I get to reset the timing tommorow. Ain't it fun? I looked again at the pin for the banana slide. Now I remember the problem I had. Either you need to pull the upper plate for the front seal off, or come up with some way to get washers or a big not up next to it, That plate sits right next to the lower pin for the slide. Using the stacked washers won't work. I fiddled around and cut up a chunk of pipe to get around there. Not a great solution. Maybe you will work it out better. Good luck, and watch the timing marks. |
#69
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You are one, lucky Dude! It obviously was one link retarded. Had it been one link advanced it would've caused valve/piston contact. Been there, done that!
Congrats on the work. Many jobs work out like this, once you're finished, you still have some kinks to work out. Good job, |
#70
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we have only one MB dealer in town and they give out very little info. I called about the retainer that mounts about the sprocket on the cam to hold the chain in while rolling the new one in (I'll be doing the job alone). They couldn't reference the tool, and then told me based on the tool # I gave them that there are only 2 in the nation, both in Chicago and priced at $200. The pdf that I have (posted in an earlier message) based on the repair manual, service info. REf No. MBNA 58/92, says $20......is this a typo?? doesn't seem like a $200. tool to me? They have no tool catalogs at the dealer so they couldn't tell me if I had the right #...
ha |
#71
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One radical view
I didnt trust rolling the chain on and didnt think it was a safe way to do that job.
I did use the old chain to roll the new chain in, but i didnt stop there. I used the Crank timing plus the front camshaft gear to make sure everything zeroed in perfectly. To do this I had to pull the front camshaft gear off. I also remeber once removing the fuel pump to make sure it was lining up with the chain. From my memory, which isnt good now that I am 42, I remember I was so hell bent on getting my timing down perfectly and making the engine sound like a watch in (it was very loud prior to that) I pulled the Fuel Pump, and even the bottom Half Oil Pan to make sure my #1 Piston was at TDC. I remember pulling off the front cam gear several times to tweak this and tweak that. There is slack in the chain or whatever, so you cant trust it and close the link until you turn the engine over at least once. Using all the timing marks, inculding the camshaft and crankshaft and fuel pump, you tweak this and tweak that until everything 0's out like a watch. You also reset the Valves while everything is open. Everyone in my carpool really noticed the Difference!! They thought I was a Professional Mercedes Mechanic when I showed up with the car again. It sounded like a watch. I am probably confusing you GeoJer; only a few people will understand me, so dont worry if you dont understand what i am saying. It was a good feeling to do that right. Everyday I have a bad Day at work, i climb in the car and hear that engine tick and I reaffirm my faith in myself.. |
#72
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Geojer,
The part number I think you checked on was 602-589-01-40-00, which ONLY works for the OM601/602/603 engines used from 1986-1995 (in the USA). The current dealer net price is $18 as of Nov-2002. Most dealers will charge somewhere around double that, maybe $40. I don't know what they quoted you $200 on but it couldn't have been this tool. It wouldn't be the crimper either, which is well over $200 from MB (aftermarket ones are $190 or so.) I just ordered this retainer tool from *************** (for my 1987 300D with an OM603) and the price was $28, I think, should be at my door in 1-2 weeks. Note that this tool WILL NOT WORK for your 1984 300D, which has the OM617.95x engine!! I haven't been able to find one for the OM617 engines, I don't know if they exist... Regards, |
#73
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geojer
I was told to use a series of small vise grips on the cam gear to hold the old and new chain in place while rolling the new one in. Also tie up the ends as you go with some wire. Don't let it even think about dropping down there. Just roll it a bit at a time, reset the grips as you go. I don't know what went wrong with my effort here. I did do two timing chain jobs on both of my MB diesel in one day. The 81 was second. Fatigue may have set in by then. In any event I wanted to get the cam retimed with a minimum of trauma. I studied it late last night and again this morning . Called my dad in and we decided to try to just lift the chain up and shift it the one link at a time. Sort of a wave action there. It worked. Backed the tensioner out and there was plenty of chain there to do this. Then checked the IP timing. Comes in at 24-25 deg. Will leave it alone. The worst of it was that my dad drove over in his old Ford van. He went out to start and wouldn't you know it.. no start. Just a little fire. Sounds like his timing chain skipped a groove. So will spend the weekend in the garage again. Could be worse. I just love timing chains. |
#74
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Just for review, because there was another thread here recently where another famous MB mechanic got the timing a tooth off.
I reset the chain and everything is just right now. Reviewed what had gone down step by step with the first install this afternoon with my good friend and MB tech. He now runs a small parts shop. He spotted the problem and told me he is sure that is why he has heard from several other pros that have found the timing chain on this model MB off after install. Said when new chain is rolled in, there will be lots of slack in that chain too. Next step is to reinstall the tensioner. (The imfamous ratcheting tensioner) Then roll the chain over and check the timing. ( I had done that ). At that point if the cam sprocket is off a tooth you probably would not see it. That is because the tensioner needs to be fully tight to accurately check the marks. It would not be fully tight because that requires oil pressure, besides the small spring. So there, the mistake is made and you would not catch it unless you noticed the very slight variance within the marks on the cam sprocket and fixed mark there. I still do not know the answer to getting the install right everytime. But this time I held the banana slide over against the timing chain with a large screwdriver. I had noticed there was slack in the chain after bolting in the tensioner. That may be the way to do it. |
#75
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I had removed/installed the head when I got the chain one tooth off and had marked the cam sprocket/chain with tie wraps prior to removing it from the sprocket. I figured I got the timing off when I removed the tie wraps and laid the chain back into the sprocket. The bad thing about it is I had adjusted the valves two or three times after putting it together thinking it was a valve adj issue and never checked the cam mark. If I had done that it would have been resolved alot earlier.
That is a good explanation of how it is possible to get one tooth off - thanks
__________________
Jim |
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