Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: jan lauwers on June 27, 2015, 21:54:40
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Gentlemen,
I am busy replacing the back and front crank ace seals. I have cut the lower half circle of the back seal as described on this forum, leaving some 0,6 mm on each side etc. Obviously I have my engine out, but not the crank since I am only replacing the bottom half of the rear seal. While I had the oil pan off, I noticed at the front of the engine, that the chain was hanging somewhat loose… it troubled me, because I was not sure if this is normal or not (see attached pic). After I had put in the 2 new seals, I decided to rebolt the oil-pan without any sealant, only to give myself a rehearsal for the real work later (WITH the sealant). A second reason for doing this was to check if the crank can rotate freely… to check if I had not cut the rear seal too tight. So, I bolted the pan at the right torque settings, tried to rotate the crank… and found that it is stuck!. I then removed the oilpan again. Then I guess I probably did something stupid… I tried again to rotate the crank without the oilpan on… I am not sure now, but I think the chain may have jumped one tooth. Questions:
Is it a problem that the chain was half loose over the wheel of the crank?
Why is it stuck now?
What should I do?
Help please!
Many thanks!
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is there nobody here who can help me? I 'd really like to understand why the crank ace suddenly is stuck... and how I can resolve it. I am a bit desperate folks...help needed please!
Many thanks.
Jan
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.../... I 'd really like to understand why the crank ace suddenly is stuck... and how I can resolve it
Probably the chain is stuck at the screw you see in my diagram here... unscrew it, should release your chain
/Hans in Sweden
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Thanks a lot Hans. I will try that tonight... even though I have not touched that screw... so I'd be very surprised... BUT I am very grateful for your reply!
Jan
Greetings from a sunny Belgium!
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Hello Jan,
Your thread is lost in "General Discussion" you will have more response if you post it in the other category "drive train etc." I just accidentally came across it myself.
Yes, your chain is stuck. You may have to gently back up the crankshaft. Try using the Flywheel to move the crankshaft. After it is free again, turn the engine only in the normal rotation.
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Moderators just moved it.... but Joe, you are right!
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Thank you Joe. I will try yr suggestion. I will report back. I will also keep the advice in mind about the forum categories. Continuous learning!
Jan
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If your timimg chain is loose and it did slip a tooth or more then you could have a valve hitting a piston. If this is the case, your engine is definately out of time.
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Something is wrong here. How did the chain get the slack in the first place? Did you take the tensioner out?
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Just a recap to make sure I am giving you guys the correct information.
My engine is out for replacing the crank seals. Since it has been out, I have always been able to turn the crank ace, using a 27mm wrench. A while ago I noticed that the chain was not taut at the righthand side of the front sprocket (while standing in front of the engine, see pic at the beginning of this thread). Not sure if that is normal or not. Then later I suddely could not turn it anymore. It is stuck, I can move it about 1 cm back and forth, and yes it feels as if it is touching someting, so I also think that a piston is hitting an open vale.
I do not understand how this could have happened. I think I have not done anything that could put it out of time… at least not conciously!.
To answer Chuck’s question: No I did not take the tensioner out.
What is the best procedure now?
Thanks guys!
Jan
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Hello Jan,
You might also try taking up the slack on the IP side of the chain by backing up the camshaft. If the chain becomes taunt then you can continue turning the engine via the crankshaft in the normal direction of rotation.
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Hmm that didn't work Joe.
Jan
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Before I went that far, I would try loosening the bolt discussed earlier, and turning the cam backwards to pull the chain back, then see if you can go forward on the crank. Then bring the engine to TDC on #1 and see where the marks on the cam are.
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I think I would had the head off a long time ago.
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Chuck,
I suppose you mean the bolt that Hans was referring to, right? what is the function of that bolt except for holding the Power Steering reservoir?
Thanks,
Jan
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Yes. It makes sure that the chain stays on the auxiliary sprocket. It's also the most likely place for the chain to bunch up and jam.
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Thanks Chuck. How far can I loosen it? is there no risk that I loosen something inside that I have no access to?
Jan
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Try two turns. It just sticks out on the inside, it doesn't hold anything.
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Today I found that my engine is definitely out of time. I removed the circular cover that holds the front of the axle of the injection pump. There I could see another big part of the chain. The chain was not jammed there. The bolt that Hans talked about did not hinder the chain. Then I removed the rocker arm of the valve that was standing lower than any other valve. Now I could turn the CA a lot further, which proves that a piston was hitting that lowest valve.
Here is my plan, I will:
Remove all the rocker arms so that no more valves are open
Turn the CA untill 0 on the damper is up against the triangular mark.
Hopefully I can then see the master link of the chain on the camshaft sprocket.
Undo the master link and make sure that the chain stays streched at both ends
Turn the camshaft on its marks.
I must make sure that the chain stays taut between CA sprocket and injection pump sprocket so that injection pump stays in time.
Close the masterlink.
Is the the right procedure gentlemen?
Key to my problems is to understqnd why the chain went loose in the first place. As long as I dont understand that, I run the risk of it getting loose again. I think it has to do with the chain tensioner not doding it’s job, but I dont understand why. Is it because I have drained the oil of my engine? Can anybody explain that part for me as well please?
Thanks a lot!
Jan
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Jan, the chain most likely went loose by turning the cam or crankshaft the wrong direction. Turn the engine by the crankshaft bolt only in the correct direction. Check the timing marks after turning the engine in the correct rotation. You may not be out of time.
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OK I was not aware that it should only be turned clockwise. So, this must have caused my problem. Not that I have ever had the need to turn it anti clockwise, but perhaps this has happened accidentally while I was trying to move it... going up and down a bit with the wrench.
But then still Joe, the fact that I hit an open valve can only mean that it is out of time, or am I misreading something here? In any case, in order to set it at the marks again, I must be able to turn it. So, the only option that I see is to remove all the rockers and work out the plan that I described.
Thanks for all your help guys.
Jan.
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Joe,
I was doing some more searching here and then I found this topic:
http://www.sl113.org/forums/index.php?topic=1811.0
From reading that topic, I am thinking:
My engine is out of the car, the oil is drained, so, no oil in the tensioner, thus the tensioner does not work, which caused my chain to jump. Is that correct?
By the way, by turning the CA clockwise I see the tensioned arm move up.
Sorry for all my questions, but I am trying to learn here.
Thanks again,
Jan
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The tensioner shouldn't move when you turn the engine. I would say you need a new tensioner. It has it's own little pool of oil in the cylinder head, so it would have oil unless you turned the engine upside-down or on its side to work on the seal. But even then, it should have stayed pressurized, IMO.
Your plan sounds good, but I suggest removing the sprocket from the camshaft instead of un-doing the chain. Bring the engine to TDC on #1, remove the sprocket, turn the cam to align its marks, and reposition and reinstall the sprocket. You may want to take the tensioner out to get more slack in the chain.
Good luck,
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Chuck,
Many thanks for your reply, I find this very helpful.
I have now removed the rocker arms and I can turn the CA round now. My engine is definitely out of time, I measure it to be about 100 degrees on the CA damper. The good news is that I don’t see the tensioner arm move anymore, so I presume it is still working OK.
Chuck, why are you suggesting to remove the camshaft sprocket rather than undo the chain? For me I think it is easier to open the chain, I am not so confident to remove the tensioner. I will make sure that I keep the chain taut while it is undone.
Then my last concern now is the timing of the injection pump. I don’t think that one is off, but I would sleep better if I knew 100% sure. Is there a simple way to check and set this?
Thanks!
Jan
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First of all, to break the chain, the master link will need to be in a place where you can work with it. Second, the tensioner will push against the chain, and may make it difficult to position it on the cam sprocket. Third, it is very easy for one of the clips or part of the master link to fall into the chain galley.
Again, I think you should replace the tensioner in any case.
Cheers,
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Yes, I agree with chuck, it is much easier to remove the cam sprocket. You should not have any issues as long as you are careful to keep the chain taunt.
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Thanks for your help Chuck and Joe.
I just finished putting it back in tune..., but I want to show you the result. Please tell me if this is good enough or do I need to make it more precise? The pictures show you... CA on its mark and the camshaft too.. well... within 2-3 mms. Is that good enough?
I admit that I worked my head out and did not take the camshaft sprocket off like you kindly suggested. Reason: I was worried of doing something wrong with taking the tensioner out. I am not sure how to do that. Is it with bolt that I am pointing at in the picture? If you think that my 2-3 mm is too much, I will re do it...and perhaps take the tensioner out if I know that it is no risk.
Opening the chain was a bit tricky but OK. I held both ends taut with a pulley.
Thanks guys!
Jan
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Jan, the bolt that you are pointing to is not the tensioner, the tensioner is located at the front of the manifolds and is very easily removed (there is a picture in the tech: manual).
With what you have done there is the strong possibility that the fuel pump could be out of time, with the engine in the same position that you have it in the above pictures can you take a picture of the distributer (with the rotor arm in situ), it would help to see if the rotor arm is facing the slot in the distributer body.
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Thanks Eric,
I have mounted the distributor and rotor. see pic. pl. With CA at mark, the rotor is at the mark while the mark is at about 8 o' clock if middle of the car front is 12 o' clock as described elsewhere in this forum. My IP has not been out, so can I now safely assume that my IP is still in time?
second, I have tried to improve on the 2 mms difference on the camshaft marks. This time I did follow Chuck and Joe's suggestion and loosened the camshaft bolt. Thank guys you were right; loosening the tensioner is no big deal.
BUT, doing this, I still have the 2mms difference on the cam shaft marks and I can not improve on it. Is this acceptable? The 2 mms represent 10 degrees on the CA damper which seems a lot... no????
Merci!
Jan
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If the distributor was not removed during this exercise, then the IP timing is most likely OK. But if you had to take the distributor out and move it to get to this position, then the IP timing should be checked.
If the cam is ten degrees behind the crank, then you have some chain stretch and/or sprocket wear. This would be a good time to roll in a new chain (and replace the tensioner).
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Thanks Chuck,
My distributor HAS been out, so I guess I then have to check the timing of the IP. I have found a procedure on the forum, written by Joe Alexander.
I will try that tomorrow:
QUOTE:
I do have a method by which you can check without taking the injection pump off. You would need to unscrew some injection lines and remove one fitting and check valve in the pump to do the check.
Unhook the three rear injection lines. Remove the injection pump #4 19mm fitting (third from rear). Remove the check valve in the injection pump. You can now feel the position of the #4 plunger (piston) in the pump using a nail or such. When the engine is at 12 degrees ATDC (after top dead center of #1 cylinder)on the compression stroke (#1 cam lobes upward ), the plunger in the pump should be near the top of it's stroke. You can feel it travel upwared and downward as you turn the engine by hand. When it reaches the top of its stroke check the crankshaft timing. During re-assembly be sure not to overtighten the 19mm fitting. 18 ft. lbs is the specified torque.
UNQUOTE
I am just not sure what the 'check valve' is that I have to remove, but I hope it will be obvious tomorrow when I try this.
thanks guys!
Jan
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Hello Jan,
As you are aware the consensus of opinion is that your pump is out of time, why not just accept it, remove the pump and set the timing correctly.
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Boy.. I am learning so much through this experience...
I found a note by Joe Alexander where he explains how acceptable (or not) the 10 degrees after TDC on the damper are and why a deviation before TDC is a no go. Thank info was EXACTLY what I was looking for. You`re my hero Joe.
Now I am thinking of changing chain and tensioner.
I have tonight taken the injection pump off, that was easy... found the timing procedure for the IP elsewhere on the forum...so all that is OK, but I have a few questions again:
Should I replace the seal? I read somewhere here that there are several seals, I only have this thick one. Can I keep it and add sealant on the 2 sides or is that not a good idea? Am I missing seals?
What about this sleeve with teeth inside? There is a ring in the middle that is interrupted. Why is that? Is there something to know about how to place it back?
Finally, I read that a new IP needs to be filled up with some oil. Is this also the case when we are replacing an existing pump? If yes, how exactly?
Thanks !
Jan
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Jan,
The thick seal that you call it is an insulating block, you have no need to replace this item(if it is not damaged), but you should replace the two paper gaskets that are located either side of the insulation block.
The sleeve is the drive between the engine and the fuel injection pump, the circlip is a normal feature and is there to stop the sleeve from moving forward or backwards, if the sleeve was to move either way drive would be lost to the injection pump.
As your car is a 280sl there is no need to fill the pump with engine oil, this is done automatically through the oil pipe that runs from the timing chest to fuel pump body, you must have removed this pipe to get the pump away from the engine, there is a picture in the tech: manual that shows the oil supply.
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Jan, Just set the crank at 20 degrees after top dead center (ATDC) on the compression stroke of #1 cylinder. Make sure that you are on the compression stroke of #1 cyl. The camshaft lobes of #1 cylinder must be basically upward and the distributor rotor must be pointing to the slash-mark on it's rim. If the cam shaft lobes on #1 are pointing downward, then you are 180 degrees off! When you have that right, line up the marks on the IP and slide it in. (not supper critical ), just get it as close as you can by eye. The important thing is to have the cam shaft on time (20 dgrees ATDC of the compression stroke of #1 cylinder
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Eric,
Thank you, your explanation is very clear. I will then buy the 2 paper gaskets since they were not present in mine. Strange, I never had a leak there. Guess I have been lucky then.
Joe, Great, Thanks... you must have explained this so many times on this forum, I had already found that procedure from you a few times.
As I have said earlier, I have a difference on the camshaft mark of 2-3 mms, which represents 10 degrees on the damper (After TDC). I think my chain has stretched. (I don't know the history of my car). I read another great post of you where you explain that one chain link represents 18 degrees etc. There you say that a deviation of up to 10 degrees is Ok. I hesitate if I replace my chain now or later, since I plan a full overhaul of my engine by a specialist when the finance allow, probably in a year of 2. IF I decide not to change the chain YET, does the 20 degrees setting on the damper to line up IP, not have to become 30 (20+10 deviation)? Or should I just set it at 20? (note: I don't do much milage... say 2000kms year).
I hope I am making myself clear here.
Thanks again!
Jan
Jan
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Jan,
When I look at your picture above it looks like you do have a paper gasket stuck to the block, it is very unusual not to have a leak if these gaskets are missing.
If I were you with all the relevant parts exposed I would fit a new chain, they are not all that expensive (check out SLS or other after market suppliers), you did indicate that you would change the tensioner, why, I would strip it down give it a good clean, inspect it carefully and if there is no wear or scoring I would refit it, why waste money?
When refitting the tensioner fit a new sealing rubber O ring.
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Good thinking Jan, however the IP setting is not that critical. Also the amount of chain stretch is only a fraction of the total since the distance from the cam to the IP is only a small portion of the total chain length. Just use the 20 degrees ATDC setting. The term "chain stretch" is just another way of describing a chain which lengthens due to wear mostly. Each of the pins in the 134 link timing chain wear a very slight amount. Multiplying this wear by 134 times creates a longer timing chain. Once the chain becomes long enough it can exceed the capability of the chain tensioner to take up the slack, causing noise, more wear and possible catastrophic damage. Don't panic, the timing chain should last for at least 100K in these engines. The chain tensioners are very reliable, but can become stuck from dirty oil deposits.
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Thanks for all your help gentlemen, I think i have everything I need now.
Jan