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  #31  
Old 09-24-2011, 02:01 AM
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Go back to the picture in post #20. The tab for visually checking crank position is at about 11:15 of the crank pulley bolt. The hole and the pin beside it are a holder for a factory diagnostic tool. Check crank position at the tab, not the hole.

Set the cam timing marks to TDC then check crank position. Unless your chain is elongated beyond spec, the TDC mark, 0T, should be very close to the tab. The IP tang won't be centered in the port.

Sixto
87 300D
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  #32  
Old 09-24-2011, 02:05 AM
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Quote:
Originally Posted by bigblockchev View Post
If the timing device was screwed up it would not have the correct timing at idle only when you revved it. Is this a logical statement?
87 TDT black smoke all the time


at idle, it will not be advanced.
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  #33  
Old 09-24-2011, 09:42 AM
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For all the time it takes put the tang in the injection pump into view. Have a look at the first cylinders valve lobes after you do. Hopefully through the oil filler hole if possible on your model. If not pop the valve cover.

The cam lobes of the first cylinder should both be somewhat pointing upward at an approximate 45 degree angle. If they are generally pointing downward the injection pump is installed on the wrong cycle. Smoking and much poorer power are the end results of this. Forget your cam and crankshaft and injection pump timing indicators as they will appear absolutly normal either way in this situation.

Again just a long shot but something is wrong. You are describing a very dirty burn on an engine with very good compression. Actually not that much of a long shot come to think of it. It is not a leaky turbo seal as the symptoms are wrong.

It is also not too much fuel or the engine would rev. It is not a pre or post engine breathing restriction as you have eliminated that pretty much. So in general the causitive of a really dirty burn as you describe could easily be fuel injected way out of sequence to what it should be.The engine just cannot burn the fuel it does get efficiently that way.

I am posting this because a long time ago I wanted to suggest this to another poster where the problem went on and on. The reason I did not at the time was I felt they as a group should already know this and had checked it. Unfortunatly they had not. Or if they thought about it ignored it as a possibility.

It became about the worse protracted problem on site. Eventually it was established the injection pump was indeed installed on the wrong cycle. You are actually fortunate as your compression readings indicate you have a really good engine.

Another indicator of that injection pump being on the wrong cycle might be a sluggish startup where the engine has to turn over a few times before it lights off. With your compression and things being normal it should always catch on the first revolution in my opinion. Thats if the starter and battery and glow plug circuit are reasonably good of course.

Again it may not be this but you have to know it is not. This is why I asked earlier what the acceleration was like. In hindsite I then realised you never have had the car in the normal state to compare what is now existing with what once was. Normally this 603 type engine is fairly quick.

Last edited by barry123400; 09-24-2011 at 10:23 AM.
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  #34  
Old 09-24-2011, 12:33 PM
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Maybe the light is starting to dawn

Sixto If I understand your pic correctly the timing mark is circled in red I have been looking through the hole circled in yellow. I will have to go back and see how this changes the diagnosis. I thought I was looking in the right place.
Barry I will check your suggestion also, I firmly believe that " īt is always something simple"" Getting a direct unequivocal confirmation of each element is crucial to any diagnosis. Otherwise you can go a long way down the wrong road, I suspect that my lack of knowledge has put me in that position. Thanks All I will be sure to post the results. Cheers Dan
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87 TDT black smoke all the time-front_view31.jpg  
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It's always something simple
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87 300D
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  #35  
Old 09-24-2011, 05:53 PM
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Pix of marks

I include pix of the three relevant marks. The cam pointer is lined up with the mark on the 1st cam bearing. The IP mark is pretty much in the center of the window and the Flywheel is at 11 deg before TDC. I would expect the flywheel mark to be after the cam mark if there was chain stretch since the length of chain would be longer than when new. I would not expect the IP to be timed dead on with the cam mark. I would expect the IP mark to show to at 15 ish degrees after TDC not before. this makes me wonder if someone put it together wrong since every scenario I can think of would make the chain more retarded not advanced. I also checked as Barry suggested and the cam lobes were indeed pointing up not down. Where to from here?? Cheers Dan
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87 TDT black smoke all the time-cam.jpg   87 TDT black smoke all the time-flywheel.jpg   87 TDT black smoke all the time-ip-mark.jpg  
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It's always something simple
91 300D 603.960 (from japan) 194K
92 Toyota Diesel Landcruiser HDJ81-t 116K
02 Golf TDI new head courtesy of PO
87 300D
97 BMW 525 TDS Wagon 5spd
bunch of Onan and other diesel generators
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  #36  
Old 09-24-2011, 07:23 PM
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This is the cam at #1 TDC -



Takes a bit of imagination to align the marks across the gap. Not MB's finest moment. Neither was 603.97 rods The cam marks don't align at 15* ATDC which is the reference timing point for the IP.

Looks like you need a new IP side cover gasket. Can be replaced without removing the lift pump. Use dabs of RTV to keep the gasket in place while installing the side cover. There are different gaskets for aluminum and brass side covers.

Sixto
87 300D
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  #37  
Old 09-24-2011, 07:54 PM
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Clearer pic

I hope you can see this one better. I put the scriber on top to show where the mark is on the front cam bearing. I get the feeling that someone put this together wrong as there are too many odd coincidences. I can't judge yet whether the timing chain is stretched. Cheers Dan
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It's always something simple
91 300D 603.960 (from japan) 194K
92 Toyota Diesel Landcruiser HDJ81-t 116K
02 Golf TDI new head courtesy of PO
87 300D
97 BMW 525 TDS Wagon 5spd
bunch of Onan and other diesel generators
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  #38  
Old 09-24-2011, 08:17 PM
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Looks like the chain was installed wrong, I don't think the chain can stretch that much.

R&R the IP & the cam chain. For the IP, turn the engine to 15 after first, then remove and turn the ip off engine til the mark appears in the window, and reinstall. The chain I'm not sure what the procedure would be, hopefully removing the tensioner would give it enough slack to get it off the cam sprocket.
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  #39  
Old 09-24-2011, 08:49 PM
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Agree with aaa that the chain could have been reinstalled on the cam sprocket wrong. It's really easy to blow. I've taken my chain off twice - and both times thanked my stars that a PO had put a stripe of white paint on the sprocket to remind / help me mark (twist-tie) and realign the chain. Also agree that these beefy MBchains don't appear to stretch much (if at all - especially compared to mt bike chains).
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  #40  
Old 09-24-2011, 09:09 PM
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If someone touched the chain you might have lost the reference to check for elongation. You can reinstall the chain correctly relative to the 3 sprockets but you won't know if you shifted a tooth to get it set correctly.

An alternative to resetting the existing chain is to roll in a new chain then reset the sprockets.

I've lost track of the start of this thread but it could be that someone installed the IP at crank TDC rather than 15* ATDC.

Sixto
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  #41  
Old 09-24-2011, 09:52 PM
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You've got a lot of options since your engine runs as-is... (maybe off just a little... smokes at start.)
You could shift a chain 1/ link - reassemble, test, pull back down and then do what? Ask Sixto how to thread in a new chain and reset the sprockets - so you start to get a clue about what you could be in for... (And we who've opened these heads think you might have good engine - because it runs!)
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  #42  
Old 09-24-2011, 10:39 PM
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I will be doing something for sure

Now that I have some direction I will try to figure out if the chain can be jumped a link without taking everything apart,(not quite the same degree of precision but when I worked as a mechanic in a bakery if a machine got a tooth our of whack we would use a piece of rope on the sprocket to get it back in time, while ir was running often, quite an art!!), If it cant then I will for sure be learning how to do a R&R. I am wondering if the problem came about as a result of a botched chain replacement job since it is not something one would do without a real good reason!! I have no history on the vehicle, the PO was very unclear & I dont think it ever ran properly for him. I have a feeling I am going to timing chain school. Even though this is much more complicated than I was planning on it is much better to know what is wrong than to be in the dark, I will pull the motor if I have to. Cheers Dan
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It's always something simple
91 300D 603.960 (from japan) 194K
92 Toyota Diesel Landcruiser HDJ81-t 116K
02 Golf TDI new head courtesy of PO
87 300D
97 BMW 525 TDS Wagon 5spd
bunch of Onan and other diesel generators
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  #43  
Old 09-24-2011, 10:48 PM
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The chain can be reset on the cam and IP sprockets. You might have to remove the upper chain guide for enough slack to get the cam sprocket off the cam. Not enough slack to move the chain over the cam sprocket in place. At least I don't think so. For the IP, cut up a soda can for a strip of aluminum to slide between the sprocket and chain. Turn the IP to the desired position and reset the chain. Obviously done in separate steps since the cam is set at TDC and the IP is set at 15*ATDC.

Sixto
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  #44  
Old 09-24-2011, 11:31 PM
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Thinking of this

It occurred to me that if I removed the chain tensioner & tied off the chain below the sprocket with a piece of bailing wire secured solidly to something out of the way on the head on both sides of the sprocket that I might be able to remove the cam bolt drop the sprocket a fraction enough to rotate the sprocket one tooth. Then rotate the cam slightly bolt it back in place and remove the wires and recheck the position of the mark. If it was only a couple of degrees off I would leave well enough alone but 11 degrees is too much to let go in my opinion. As far as the IP goes it seems to be 26 degrees off by my reckoning but I will check it again after resetting the cam timing. So to move the IP timing the idea is to set the crank to 15 degrees ATDC, remove the chain tensioner to get some slack. Remove the Vacuum pump to get access to the IP sprocket, slide the alumiinium shim between the sprocket and the chain rotate the sprocket under the shim until the IP mark shows up in the IP window remove the shim to allow the chain to rengage the sprocket & reassemble everything then check the timing of everything. Hopefully I have visualized this correctly. Cheers Dan
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It's always something simple
91 300D 603.960 (from japan) 194K
92 Toyota Diesel Landcruiser HDJ81-t 116K
02 Golf TDI new head courtesy of PO
87 300D
97 BMW 525 TDS Wagon 5spd
bunch of Onan and other diesel generators
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  #45  
Old 09-24-2011, 11:55 PM
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IIRC you can't pull the sprocket away from the cam with the upper guide in place. The chain just doesn't have enough lateral play. Remove the tensioner and see if there's enough chain slack to move the chain one tooth over the cam as it sits. Then turn the crank CW to shift the slack to the tensioner side and refit the tensioner. Don't forget to prime the tensioner.

Sixto
87 300D
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