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Chain strech, unknown engine history
I bought an 1983 300TD from a member of another board that he wasn't able to restore due to unemployment. He hadn't ever hooked the engine up (it was unhooked from almost everything) but he did turn it over every few months while owning it. He owned it for 1.5 years.
So now I'm done repainting the engine bay and ready to put the engine back in. I've adjusted the valves, the engine turns quite easily with the gps out, the turbo is tight (not that it matters to the question at hand) and the oil is a nice consistency almost like it had just been changed. So I'm trying to troubleshoot everything I can while the engine is out of the car and I checked the chain stretch. I've lined up the mark on the camshaft 5 times and keep getting 5 degrees. How many degrees does it take to worry? I'm new at engine timing and I've already read through the forums, but I can't find anything that says "danger zone" or "you should be worried". So what can I do now?
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Onus probandi incumbit ei qui dicit, non ei qui negat I recondition w123/w126/w124/w140/r107/r129/ steering boxes! 1984 300D "Elsa" odo reset 6/2011 147k 1983 300TD "Mitzi" ~268k OM603 powered 1995 E300 "Adelheid" 262k [Sold] |
#2
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How many miles? If it were me I would change the chain, just to be safe, also replace the motor mounts while the motor is out. It is alot easyer to change them with the motor out.
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#3
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Quote:
The only risk of late timing is a slight deterioration in performance. If the timing gets very late, say 8-10 degrees late, there will be accelerated sprocket wear due to the increased distance between the pins. M/B does not have any recommended interval for chain replacement. Personally, I believe that the chain is so overdesigned that it has a safety factor of about 20X when compared to the load that it sees. If you have an extra $125. laying around and want to keep this vehicle forever, you might consider it. Or, if you have an extra $10. laying around, you could just get a 4 degree offset Woodruff key from the dealer and return the camshaft to nearly perfect timing. Either approach would be satisfactory, IMHO. |
#4
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You might want to do the 2mm lift method before you order an offset key. The cam marks are known to be "ballpark".
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1981 300TD 310k miles 1970 280sel 172k miles 1966 230 Fintail 162k miles "Where are we going? And why am I in this hand basket?" |
#5
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Agreed!!
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#6
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Answer
Quote:
http://www.peachparts.com/shopforum/general-information/163604-timing-chains-dont-last-forever.html Here is more information you may find interesting. Warning, Danger: Please read this thread FIRST... Need Automotive Grade Prozac Need Automotive Grade Prozac = timing chain - PeachParts Mercedes ShopForum Diesel Timing Chain Links Thread Diesel Timing Chain Thread - PeachParts Mercedes ShopForum .
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ASE Master Mechanic asemastermechanic@juno.com Prototype R&D/testing: Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician. Noise Vibration and Harshness (NVH). Dynamometer. Heat exchanger durability. HV-A/C Climate Control. Vehicle build. Fleet Durability Technical Quality Auditor. Automotive Technical Writer 1985 300SD 1983 300D 1984 190D 2003 Volvo V70 2002 Honda Civic https://www.boldegoist.com/ |
#7
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Mate, please look at my post http://www.peachparts.com/shopforum/diesel-discussion/310533-om617-shakes-after-overhaull.html 'cos it might have lots in common with your either current either very soon to be situation please get a new chain regards ChO
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w126 500SEC gen II euro, powered by OM617 turbo stolen from 84 300SD 2.88 diff,EGR blinded next wish/project: w114 coupe OM603 powered |
#8
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No idea on the mileage. The odo was slipping a bit (now has been rebuilt and reset to zero) but it displays around 220K.
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Onus probandi incumbit ei qui dicit, non ei qui negat I recondition w123/w126/w124/w140/r107/r129/ steering boxes! 1984 300D "Elsa" odo reset 6/2011 147k 1983 300TD "Mitzi" ~268k OM603 powered 1995 E300 "Adelheid" 262k [Sold] |
#9
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Quote:
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Onus probandi incumbit ei qui dicit, non ei qui negat I recondition w123/w126/w124/w140/r107/r129/ steering boxes! 1984 300D "Elsa" odo reset 6/2011 147k 1983 300TD "Mitzi" ~268k OM603 powered 1995 E300 "Adelheid" 262k [Sold] |
#10
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There were several links to the catastrophe that can occur if the chain guides fail or the tensioning rail wears to an unacceptable condition. These are all valid points and it would be a benefit to take a careful look at them and not simply assume they are OK. If money is no object, as Roy suggests, replace the chain on principle. But, my SD has 230K on the clock with 4 degrees of elongation............and I'll probably defer it's replacement until the elongation gets above five degrees. |
#11
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Quote:
If the 1-2 degrees bothers you be sure to do the 2mm method because that is the most accurate. The original poster with 5 degrees should surly do the 2mm method. Some other thoughts: Who has or knows someone that has experienced a timing chain breakage/failure? http://www.peachparts.com/shopforum/showthread.php?t=203364 MY Question on Timing Chain Failure http://www.peachparts.com/shopforum/showthread.php?t=203364&highlight=timing+chain What in particular causes vacuum pump failure? http://www.peachparts.com/shopforum/showthread.php?t=204187 New Vacuum Pump Ruined due to too much Timer Shaft End Play (the title from my notes). http://www.peachparts.com/shopforum/showthread.php?t=258062&highlight=vacuum
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84 300D, 82 Volvo 244Gl Diesel |
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