Rebuilding the Crankshafts - lets talk about the details

[malmac]

Well I got all inspired today and made the next step on the crankshaft project.

I knocked up the tooling to hold the crank while I push it's pins out.

One more bit in the puzzle.

Mal

[scottiesharpe]

https://photos.app.goo.gl/sCbT72hwYwXQ4Q7F8

[Rodolfo850]

Malmac, now you need a flat plate with a center hole (few mm more than crank pin diameter) that will help you to remove the Pin on both halves.

Then later need to turn on lathe a centering pin, that fits the crank halve hole and center halve hole (two diameters) y will help on centering, but first, for crude centering need to hole the cylindrical pipe support (used for disassembly)since it has to have as internal diameter the diameter of the complete crankshaft, then later center with this pin (as precise as possible) then press together.

[cwf]

Hello, I asked a friend of mine, who used to rebuild cranks and this is his reply :

Truing to my mind is the process of moving into
> alignment a newly built crank that is not quite true. It
> generally involved biffing with a copper mallet or in
> extreme cases where there was a really tight interference
> fit, such as with Ducati bevel twins, swinging the lump
> above ones head to land on securely mounted, but soft
> (Al) anvil.
> When I was being paid to do it commercially it was a
> leisurely process. However on a visit to a Honda factory in
> Japan I timed their truer and checker doing one every
> seven seconds!

My friend used to build Ducati singles for racing, so the methods might raise an eyebrow but I think his results were good.

Charlie.

[malmac]

Malmac, now you need a flat plate with a center hole (few mm more than crank pin diameter) that will help you to remove the Pin on both halves.

Then later need to turn on lathe a centering pin, that fits the crank halve hole and center halve hole (two diameters) y will help on centering, but first, for crude centering need to hole the cylindrical pipe support (used for disassembly)since it has to have as internal diameter the diameter of the complete crankshaft, then later center with this pin (as precise as possible) then press together.

Rodolfo

Thank you so much for your input to this thread. I feel sure that other people who are either on this adventure or thinking seriously about it, will appreciate the opportunity to ask questions or contribute material.

I do have a plate with the centrehole for pressing the pins out of the centre web. I have not yet turned up the alignment pin.
I have my big copper hammer, which I used to tweak the alignment of the crank in my No1 engine. So things are coming together bit by bit.

Regards

Mal

[malmac]

I just want to draw attention to the excellent description of rebuilding a crank which Jan has posted on the Salis site.
See link below.

https://www.bmwclassicmotorcycles.com/p ... rankshaft/

Mal

[karenlarson]

wow what a nice thread!