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#1
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rod bearing nuts
Just reinstalled the crankshaft after rear main seal replacement. Everything looked too good & all specs well within for a 290,000 engine. Just one thing that left me a little apprehensive. When torqueing the rod nuts, the secondary 90 degree torque after the initial 40-50 nm seemed too easy-no increasing resistance. The rod bolts measured above the minimum thickness, so I reused them, but figured this was the last time. Was I just feeling them stretch again? Will the head bolts feel this way when torqued? All I need is to throw a rod after all this time, money, & work spent. Thanks, Paul.
__________________ 1984 300CD 290,000 |
#2
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I've never had one of our diesels apart but I have gone through many other engine with "torque to yield" fasteners and they do feel weird sometimes during the final tightening. I wouldn't sweat it. You checked the thickness before and tightened them per spec which is all you needed to do, so you're good to go. Eric.
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1984 300D, 246k, veggie, sold 1982 300SD 301k |
#3
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Thanks, I feel a lot better now! Paul.
______________ '84 300CD 290,000 |
#4
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Are you sure the rods get 2 x 90 deg after 40-50 Nm? This is almost as much as the head bolts. I'm not saying it's wrong, but I don't seem to remember that much. What size are those fasteners, I don't remember? Torque to yield on an alloy steel M8 is about 65 Nm, M10 about twice that.
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'82 300SD - 361K mi - "Blue" "Good judgement comes from experience. Experience comes from bad judgement." listen, look, .........and duck. |
#5
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DON'T reuse rod bolts.
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You can get farther with a smile and a gun than you can with just a smile. 1984 300D 1985 300CD 1980 300SD 1993 SL500 |
#6
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The 617 Service Manual says you can reuse the rod bolts until they reach a minimum necked-down diameter of 8.0 mm.
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#7
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just once
After the initial torque of 40-50nm, they are to be rotated 90-100 degrees just once, which I did. The necked down part of the bolts were above 8mm before starting. It was by the book, so I guess that's all I can do. Thanks again for the responses. Paul.
_______________ '84 300CD 290,000 |
#8
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One rotation, that makes sense. And since the neck is 8, the thread must be M10. FWIW, I miked all of mine, they measured OK, and I reused them. 10K on it so far...
__________________
'82 300SD - 361K mi - "Blue" "Good judgement comes from experience. Experience comes from bad judgement." listen, look, .........and duck. |
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