05-05-2020, 09:32 PM
(This post was last modified: 05-06-2020, 11:32 AM by 24c.
Edit Reason: Grammar
)
As this forum is so slow, and I was busy today, with an itch to scratch, I'd thought I'd post this - it might stimulate comment 
Years ago, I used "fox wedges" and hardened Fiat 124 camshaft shims to separate crankshafts, but aligning four wedges, four shims, and using left and right hand simultaneously isn't something most folks can do, so I came up with a better way, if only to avoid the ridicule from some negatory souls that don't get it.
The problem is whatever you do to a Panhard crankshaft it will always create an offset load, nothing I've seen addresses this easily, and these pesky crankshaft sure test the grey matter. The easiest & best solution is to make a small hole opposite the crank pin centre and use this as a push point, which by its nature is acting on the centre of the pin, and with clever supports, no rocking couple is introduced. It's nothing new the old Panhard crankshafts had a removable plug, so all you're doing is recreating this. Purists will say this is heresy, as you're ruining the balance, but the Panhard crankshaft is deliberately imbalanced to stop a destructive harmonic, and drilling a 10mm hole here is not a huge issue, but you can restore the status quo, if you feel the need by modding the flywheel further to compensate, or drilling another hole on the other crankweb. This way you can split from any side.
As an example of a "Heath Robinson" approach, all you need is two or three aluminium blocks and two long straps of 15mm steel, although this could be refined with a bespoke laser cut plate, and some special standoffs, welded or affixed to it that sit on your press bed, but this simple approach will work. The minimum requirement for the hole is 10mm, as an 8mm carbide will shatter at the first press release shockwave, and 8mm silvered steel will deform at around 6 Tonnes, and BTW (typically) the Panhard crankshaft will release at around 7.5 Tonnes, and decrease thereafter as it moves out. The science of an interference fit says the first few millimetres and last few millimetres of the interference do all the work (stress distribution curves to be more precise look like a suspension bridge across the hole's axial section).
All you need is a small fastener of 10,8 or 12,9 strength like a socket screw (threads cut off - they will deform at the threads, I use a dowel pin), and a small larger diameter packer to take you up to the ram, and once centred, pump till you hear the "crack". After this it'll ease, on subsequent pumps, and before you know it, the crank web will fall onto that softwood packer you placed underneath.
Then flip the crankshaft over, and just push the exposed crankpin out, using another pin or cylindrical scrap of metal, like you do with any motorcycle pressed crankshaft.
Hopefully you won't see this
All the best
Mike
Years ago, I used "fox wedges" and hardened Fiat 124 camshaft shims to separate crankshafts, but aligning four wedges, four shims, and using left and right hand simultaneously isn't something most folks can do, so I came up with a better way, if only to avoid the ridicule from some negatory souls that don't get it.
The problem is whatever you do to a Panhard crankshaft it will always create an offset load, nothing I've seen addresses this easily, and these pesky crankshaft sure test the grey matter. The easiest & best solution is to make a small hole opposite the crank pin centre and use this as a push point, which by its nature is acting on the centre of the pin, and with clever supports, no rocking couple is introduced. It's nothing new the old Panhard crankshafts had a removable plug, so all you're doing is recreating this. Purists will say this is heresy, as you're ruining the balance, but the Panhard crankshaft is deliberately imbalanced to stop a destructive harmonic, and drilling a 10mm hole here is not a huge issue, but you can restore the status quo, if you feel the need by modding the flywheel further to compensate, or drilling another hole on the other crankweb. This way you can split from any side.
As an example of a "Heath Robinson" approach, all you need is two or three aluminium blocks and two long straps of 15mm steel, although this could be refined with a bespoke laser cut plate, and some special standoffs, welded or affixed to it that sit on your press bed, but this simple approach will work. The minimum requirement for the hole is 10mm, as an 8mm carbide will shatter at the first press release shockwave, and 8mm silvered steel will deform at around 6 Tonnes, and BTW (typically) the Panhard crankshaft will release at around 7.5 Tonnes, and decrease thereafter as it moves out. The science of an interference fit says the first few millimetres and last few millimetres of the interference do all the work (stress distribution curves to be more precise look like a suspension bridge across the hole's axial section).
All you need is a small fastener of 10,8 or 12,9 strength like a socket screw (threads cut off - they will deform at the threads, I use a dowel pin), and a small larger diameter packer to take you up to the ram, and once centred, pump till you hear the "crack". After this it'll ease, on subsequent pumps, and before you know it, the crank web will fall onto that softwood packer you placed underneath.
Then flip the crankshaft over, and just push the exposed crankpin out, using another pin or cylindrical scrap of metal, like you do with any motorcycle pressed crankshaft.
Hopefully you won't see this
All the best
Mike
