McFizzer wrote:JE 1040 kit n the basket... Hmmm damn near 2 grand with all the gaskets. ...How much HP/Tq is to be gained from just the crank? ...
And by shaving and polishing the lobes, does it make the crank weaker at all?...I got quoted for 240 to have my headed bored and honed for the 1040 kit.
2 grand is pretty well minimum price for a rebuild, you're doing well. It
WILL be worth it.
YES DO get a billet basket from Falicon. The stock basket is fatally flawed
in my opinion, and has to be babied when taking off from the lights
instead of thrashed like it ought ta!
JE or Wiseco 1040 is a good idea while you're in there. No point building a
motor with tired pistons and rings, that's where the power comes from.
HP/Torque from a lighter crank? In effect, yes. See,
what happens is, some of the energy released by burning the petrol is
used up in spinning up the crank to a higher RPM. If you have a lighter
crank, more of that energy gets to the back wheel and the crank spins
up quicker. So, faster acceleration! If you put it on a dyno, the effect
will be to show more HP at any revs, however the amount of extra HP will
differ according to what gear you are in (!).
Shaving and polishing the lobes does not weaken anything. It makes
the crank stronger. The lobes are just there for the weight, if you lighten
that weight there is less stress on the crankshaft. Polishing seals the
surface and makes it difficult for cracks to start. I'm not sure there's any
measurable benefit in terms of hydrostatic drag, but it's certainly not
going to be worse.
240 for boring and honing sounds normal. Same as mine was.
BUT when you have the block off, get the head gasket mating surfaces
re-finished. That'll give a better seal on the head gasket. You might also
like to take 0.2mm-0.5mm off the block to increase compression
(makes 12.7-13.0 with a 1040 kit). That gives power everywhere.