Crankshaft locking tool

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Stu.B
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Crankshaft locking tool

Post by Stu.B »

I am now starting to rebuild my arrow engine following a strip down to replace the bearings and oil seals. This followed my unsuccessful attempt to start is and the low compression i found on both cylinders. The crank centre bolt was very tight and I did not have a crankshaft locking tool so used a steel bar through the con rod small end bushes. Any thought on this or should a buy the correct locking tool from dragonfly. The old oil seals were black rubber but didn’t look too bad. I replaced the offside crank collar T58 which did show wear.
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Roger Gwynn
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Re: Crankshaft locking tool

Post by Roger Gwynn »

I hope you did replace the seals anyway as they will not be made of a suitable material to cope with modern fuels. You don't need the locking tool, a bar as you describe works OK, the proper tool makes the job easier and you do need to get the centre bolt tight, say 60 ft/lb.
Roger Gwynn, Membership Secretary, curator of the Machine Register and the works drawings. Director of Draganfly Motorcycles, Craven Equipment and Supreme Motorcycles mostly retired.
Ivor Collins
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Re: Crankshaft locking tool

Post by Ivor Collins »

Using the small end location to strip the crank can carry the risk of elongating the small end journal. It all depends how much torque is required to release the screw and then how much is needed to then break the taper lock (this is usually the highest load) I’ve experienced ibis to be in the range of 150ft.lb.
If you’ve already done the crank separation, refitting it to the correct torque without a tool shouldn’t be a problem.
Expensive to buy a locking tool for one use, maybe you could borrow one depending on where you are.
Trev Sellars
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Re: Crankshaft locking tool

Post by Trev Sellars »

Don't be tempted with offers to buy "New old stock seals", they are possibly old rubber ones which wont last long. Use Viton seals, usually Grey in colour. Much better and last well too, particularly as Roger stated above, the old rubber ones don't like the new Ethanol fuels. Who does?.

Would it not be a good idea, if the club held these special tools for hire to members, to complete these jobs?
I am in the BMW motorcycle club and they do a hire scheme, £10 for the tools and a PDF copy of the manual, you just pay this and cover cost of postage both ways. About £30 all in.
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