How easy should the crankshaft turn?

hobieboy · 11-20-2005, 10:05 AM

The other post got me thinking...

With the case split, how easy should I be able to turn the crankshaft, with nothing attached (con rods, ...)? Two fingers? Do I need to torque down both sides before trying this?

I am trying to make better judgement on whether I should shuffle-pin the case, and while at it, have it line bored. Did anyone do this on aluminum case?

thanks...

bbh03 · 11-20-2005, 11:42 AM

If the bearing webs are in spec and not out of round, there is no reason for line boring. I believe the crank should be relatively easy to turn sitting in one half of the case. How easy depends on where you grab it to turn it.

DonE · 11-20-2005, 12:12 PM

When I rebuilt my engine, it had 140,000 miles on it. I had it checked by the machine shop and it was perfect. I also asked about shuffle pinning but was told that unless I spent a fair amount of time above 7000 rpm, it wasn't needed. Since my redline is 6800, I think I am in good shape.

When I reassembled the engine, with the rods attached, the crank would move fairly easily after a certain amount of pressure to overcome the new oiled bearings against the crank (torqued in the case).

hobieboy · 11-21-2005, 08:09 AM

Thanks guys... my crank is in perfect shape and the bearing were all standard size + normal wear so I'm quite sure my case is ok.

I remember Wayne's book suggested that the crank may not turn well after the case are split (unless one re-torques it) hence wants to find out if anyone has experience.

Wayne's book also recommend agsinst shuffle-pinning but I just wonder if it would be needed after certain HP...

mppickett · 11-21-2005, 09:02 AM

The engine that came with my car is a 78 930. When I got it apart it turned out that the crankshaft was junk and the case needed a lot of work. Ollie's suggested line boring and shuffle pinning the case to bring it back to spec and to keep it straight. Evidently they do this for the more aggressive race engines. It isn't cheap, but at least I know it will be stronger than normal and not likely to shift around. I've got another 930 case that is straight, but I'll be using the shuffle pinned one for the EFI conversion engine.