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cylinder nut torque


sallen
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The MT16 manual call for 1.2-1.6 kgf*m torque, if I've correctly done the math right it should be 31-40 inlb torque. Any comments, don't wan't to muck up my rebuild.:feelssogood:

 

SA

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The general concensus appears to be that Head bolt torque for all 650cc OHV Dnepr's is 12lbs/ft as a first stage and 18 lbs/ft as a final tightening (to be checked after 500 miles.)

 

Please read the whole thread as this post has now been edited in light of more research

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The numbers are on page 91 of the MT16 operation manuel KM3-8.922

 

 

Yup, found it, funny I've never noticed before.

 

Those figures equate to about 8 lbs/ft and 12lbs/ft. I have heard of them before but many people consider it to be a printing mistake with only the initial torque figures show and not the final figure. There was a posting on B-Cozz a long time ago that recommended 18 lbs/ft as a final figure . There is a full table of torque figures for Dnepr's on the net on the Cossackpower website bit I can't find the link now. Maybe someone else can?

I have a copy that I can send to an email if you give me one.

. It is important not to tighten up the head bolts too tight as it's quite easy to rip the studs out of the crankcases.

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U-2 Cycles......we do head nuts to 18 ft lbs max, you can do more, but you may well end up with pulled threads in the crankcase, and or stripped nuts or studs. Think about this. The cylinder heats up more than the studs, thereby expanding in lenght, which now draws down the head at a force far greater than the original 18#. ...like my old mentor use to say " don't twist your nuts too hard".....Ken :feelssogood:

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U-2 Cycles......we do head nuts to 18 ft lbs max, you can do more, but you may well end up with pulled threads in the crankcase, and or stripped nuts or studs. Think about this. The cylinder heats up more than the studs, thereby expanding in lenght, which now draws down the head at a force far greater than the original 18#. ...like my old mentor use to say " don't twist your nuts too hard".....Ken :feelssogood:

 

 

I've used 25 lbs/ft before now and I must admit it doesn't seem nice Ken. There is a bit of disparity between recomendations as I've just found by searching the net. this is what I have found:

 

Dnepr manual first stage 8 lbs/ft second stage 12 lbs/ft

B-cozz( Multiply) " " 12lbs/ft " " 18 lbs/ft

F2 Cycles " " 10lbs/ft " " 25 lbs/ft

 

I think I'm going to go off the B-cozz and your recommendations in future Ken, It certainly sounds the most sensible and less likely to pull the studs. My original post with the figures from F2 has now been edited to be on the safe side.

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Got one nut that gave up at 10ft/lb (120in/lb), the other seven felt mushy at 10. Thinking of making replacement nuts from hex stock and making them longer to help disperse the load along the stud.

 

Any comments?

 

SA

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The original head nuts were elongated, to disperse the load on the threads. Russian technology often seem to rely on a larger volume of lesser quality metal on certain things (like nuts), as opposed to higher quality steel nuts, but then you have steel nuts on a fairly soft head stud. The right thing to do is stay with the Russian approach, and use longer nut, either make them up of 1020 hex stock or obtain the originals. The originals if they have not previously abused by over torqueing in most all cases, are happy with the 18ft lb limit. A simple eye-ball check will useally weed out any "iffy" nuts /and or studs......Ken

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Needed new cylinder head nuts and the best 12mm stock I could find was my 12mm allen wrench. Anealed, cut, drill, tap and reheat treat, 8 new head nuts at 3/4" long.

 

Cost, allen wrench $0.00 (surplus tools), 12 pack Modelo Negra beer to machine shop owner $11.99, my time (out of the house $priceless (playing with the machines)

 

You can't beat it

 

Original nut in photo to show size difference, hope this will work.

 

Not the clearest pic but downloading from an 8mpix phone got to get it down to what will up load

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The MT16 manual call for 1.2-1.6 kgf*m torque, if I've correctly done the math right it should be 31-40 inlb torque. Any comments, don't wan't to muck up my rebuild.:feelssogood:

 

SA

The dealer told me they reviced it? not 42 in pd. but 38 in pd. he said they were stripping them.

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