Siezed crankshaft sleeved nut

sfcpiet said:
Poff said:
johan said:
My thinking is, NEVER use a rattle gun on a crank construction like laverda,Can put the crank out off tolerans esey.
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Don't think so - those cranks need 20 or 30 tons pull to get them apart. A 250 - 300 nm rattle gun isn't going to make the slightest difference (and is a lot safer than locking the crank by any other means).
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Uh, uh, Pete.

A typical early 180 crank will "give" at around 10-12 tons, a later type MkII and 120s give at around 7 tons.  Most twins give at 5 tons... rarely need more than 6 tons upon assembly. :D

A rattle gun can cause a bit of an issue, if used at full pressure for 5 minutes or so, but thankfully, any nut with decency will have given up by then.  INTELLIGENT use of one will cause no harm at all.  The torque action of the gun is in the crank rotation plane, so what's the difference of the rattle gun twisting the crank vs. bump starting the engine time after time?  Or changing down 3 gears at high revs to brake hard for a corner?  That procedure even loads the gearbox a lot more than it likes to handle, let alone the crank.

piet
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Only repeating what I was told by the gentleman who rebuilt my crank some years back. Think Keith has his rig now, so he would know  :D

Anyway, 20 or 30 tons or 10 or 12 tons are both considerably more than "A 250 - 300 nm rattle gun". 

Pete
 
I do know, I also watch the gauge when doing the job. Just chose not to comment.  :D

The copper mallet I use to true cranks weighs 4lbs, that is a lot less than 10 tons but it certainly moves the cranks, it is all about where and how you hit it, a crank fitted into its cases and supported across its bearings is a pretty solid unit, out of the cases they can be knocked out of kilter surprisingly easily. I only ever use my rattle gun to dismantle parts except for the 750 crank centre bolts, they get rattled up as the centres are splined and won't move and they are also an awkward bugger to hold on to if using a conventional bar.



  Keith
 
For those of you concerned about rattle guns overtorquing fasteners, some of them are actually available with adjustable torque settings, although they're obviously impossible to calibrate. But there is a tool you can borrow from the tyre fitting industry. Torque sticks are socket extensions designed to be used with rattle guns, but made from a spring steel so they start to twist at a predetermined torque. They're not adjustable and you need a set for a range of torques, and I haven't found one that will go to 200 ft lbs (for Jesus nut etc). But the better ones are claimed to be calibrated to +/- 3%, which is a lot better than most torque wrenches, even quite good ones.

Ken
 
It is not over torquing that bothers me it is the shock loading. Also tend to give tyre fitters a wide bearth, lot of them are wannabe powder coaters.  ;) ;)


  Keith
 
hi tom lock your primary with a billet of mild steel in between the crank and clutch sprockets 25mm w, 10mm T and 110 long,using mild steel will not damage your sprockets  ;). use  a heat sauce like boiling water or a heat gun and give it some wellie. : ;) ;)
all the best and safe riding Andy
 
A steel block WILL potentially damage the sprockets. Been there, done that in the past.
You could try a nylon block or buy the correct tool from Wolfgang or other dealers.
 
In my experience in heavy engineering for undoing nuts a shock load is ace, however in this case the inertia will of course shock the crank as the load is transferred by the nut before it finally gives in.
Sometimes I split nuts that are recalcitrant out of spite to avoid damage to something valuable.
Nuts are usually cheap.

As far as doing up it is more difficult to measure torque applied by a rattle gun because as Keith says it is an impact(inertia) load and not a linear torque rise to achieve an accurate result.
Have you noticed that your friendly local tyre fitter wangs up the nuts on your wheels with a rattle gun and then finishes off with a manual torque wrench?
Perhaps torque sticks have some value, I have not used them.
 
laverdas said:
hi tom lock your primary with a billet of mild steel in between the crank and clutch sprockets 25mm w, 10mm T and 110 long,using mild steel will not damage your sprockets
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I can assure you that the steel bar method does damage your sprockets, especially the clutch sprocket which is made from cast iron
have seen a number of engines with broken teeth on the clutch sprocket, all in a row across the sprocket, caused by the steel bar method I believe

 
redax5 said:
laverdas said:
hi tom lock your primary with a billet of mild steel in between the crank and clutch sprockets 25mm w, 10mm T and 110 long,using mild steel will not damage your sprockets
Click to expand...

I can assure you that the steel bar method does damage your sprockets, especially the clutch sprocket which is made from cast iron
have seen a number of engines with broken teeth on the clutch sprocket, all in a row across the sprocket, caused by the steel bar method I believe
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Not only that, but it puts scary loads on the primary chain and shaft bearings. It also puts bending loads on the shafts, which are obviously unsupported at their outer ends when the primary cover is off. This is possibly how some cranks end up with run-out at the outrigger bearing.

Cheers,
Cam
 
I made a socket for mine and used an impact gun to get it off. When I reassembled it the cyls.were off and I blocked the crank web closest to it with a length of Alu bar to avoid possibly twisting the crank.Kind of crude but it worked.
 
Andy,

I do have a very robust locking tool for the primary side crank nut.
It locks against the footrest and works like a charm.
I was more concerned about possible crank misalignment if the primary side was locked and I needed to apply big torque on the alternator side.

I would also hesitate to use the steel bar approach.
Seen too much damage happen that way, including bent mainshafts.
And, when tightening, I don?t think it allows the full torque to be applied to the nut. 

The plan, now, is to use a long socket and a rattle gun.
If that does not work, then I?ll take off the cover and surgically remove the nut.

Happy New Year gents, and ride safe!
 
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