endfloat on a crank in a aluminium or magnesium alloy case usually occurs after other bearing wear. for example an extreme case
on a flat 4 VW case (AS21 or AS41 Magnesium alloy case i.e standard and soft) thrust is take against the main bearing behind the flywheel.
bearing trust face 3-6 thou clearance set with 2 or 3 shims against the perfectly flat and parralell to the thrust face flywheel boss.
Bananarama! way past red line 4,500 and crank/case flex wears all bearings which allows a bit more flex which allows a bit more ware and some hammering of the bearings.
some of the time the crank doesn't run true to the thrust face
repeated running like this wares the thrust face bearing and hammers the saddle it is in
once you get some ware there, every off on action you do on the throttle thwacks the crank back and forward. on a 4 speed add in clucth action to the mix as well all of which just pancakes the thrust face and anything that yields beneath it
add in the propensity for any odd shaped shaft with a big bob weight on one end to try an do the drunken spinning top. i.e the balancer bolt instead of spinning round centered would rather try to scribe a circle in space approx the size of the damper at certain rpm due to mismatch of mass between it and the other end then.......... the crank is going to spend a lot if its time slightly flexed, and in this case a flexed crank meant the flywheel boss would not be running parrellel with the trust face
had a VW engine with approx 4mm end float. case was scrap..... timing varied widely (dizzy runs off crank gear) and the bearing sizes stamped into bearing backs had imprinted themselves into the bearing saddles in the case.
i.e i screwed it big time....i didn't learn....i snapped the crank in the next one:)
flywheel was still torqued correctly but the stepped saddle for the thrust bearing ( a 1 piece bearing) was noticeably thinner and the bearing just fell out of the case (and i used to glue them and their dowels in with super glue
.)
cast iron is different and v8 cranks are a bit more robust but i guess similar forces exist.
running without a balancer produces interesting results compare with power output with an engine runing a balancer
same for some parts of the rpm range but has a massive dip in power output and huge vibration at others. all that energy is going into knakering ya bearings which ultimately results in increasing the end float
VW engine fix was to run a forged crank from a 2.1 litre wasserboxer or an aftermarket forged one (same bearings same saddles)
both much stronger heavier with less flex and the cases lasted years longer
sling in a proper balancer not a pressed steel pulley
hey presto end float Bye bye even when running massive heavy clutch with ceramic or metalised un sprung clutch plate (the kind you can just side step and break your gearbox
) on a 12 lb flywheel (very light)
god knows if this is applicable to a 383 or a 440 mind.... you both could have just had bearings made of cheese n pickle...or forgot your super glue
Dave
