[email protected] (Dave Williams) 
ford  30 Nov 94
- -> When I had my 5.0 rebuilt, the machine shop cleaned up and
  -> "teardropped" the oil holes on the crank journals.  In theory this is
  -> supposed to help get oil to the rod bearings.  Any opinions on this
  -> practice?
- I don't like it.  Teardropping couldn't do much even if it worked,
  which I have my doubts about.  '72-up VW flat fours used an "oil scoop"
  ground into the leading edge of the mains.  GM 2.0 pushrod motors have
  it too, and GM's factory performance book recommends it for everything
  except big blocks.  [yeah, well, Ford's a little behind GM and Mopar in
  the information department, unless you count 25-year-old Muscle Parts stuff]
- On my stroker crank, I carefully explained I didn't want any of the
  holes teardropped, and sure enough, I was standing right there when the
  guy finished up the final cut, reached over for the die grinder, and
  managed to do the #1 main before I could stop him.  I now have a crank
  with one teardrop.  
- On the other hand, lots of reputable crank shops, like Chrome-A-Shaft,
  not only like teardrops, but will do extra-big ones for an extra charge.
  Like a lot of things in engine building, you pays your money and you
  takes your chances.
- -> Re the subject line: It seems to me cross-drilling could create a
  -> stress raiser (actually two!) at a place you need one least, the rod
  -> journal.
- The cross-drill is at the *main*, not the rod.  At least some of the
  rod journals are hollow, depending on how much was drilled out for
  balancing purposes or lightening.
- On the main journal you have one oil hole drilled off at an angle
  through the crank cheek and up to one rod journal.  90 degrees around
  the journal is another hole, drilled to the other rod journal.  What you
  do is enter each hole and drill straight through to the other side.  The
  two oil holes will intersect in the center of the crank.  Now, instead
  of feeding one rod for 180 degress, then the other for 180 degrees, you
  feed them both all the time.
- -> I'd guess this could shorten the fatigue life of the crank.
- Not enough to notice.  BOSS and the high end FE cranks were cross
  drilled, and it's common on race motors.  You're drilling a nice,
  smooth, round hole and taking only a small amount of the journal's cross
  sectional area.  If the crank is loaded enough to make that important,
  it probably doesn't matter whether it's drilled or not.  
- Even a cross drilled 302 crank is pretty simple compared to some of the
  wild schemes some OEMs have come up with, like connecting all the rods
  and mains together with a complex scheme of drillings, cored passages,
  and threaded or snap ringed plugs.  Yow.

[email protected] (Dave Williams)
gnttype  12 Feb 1996
- -> I'm removing my crank tonight for polishing.
  -> Should I chamfer the oil holes while it's out?
- A chamfer won't hurt anything, but I doubt it would help anything,
  either.  I usually either leave them alone (other than deburr) or go
  full-bore with the lead-in grooves Chevy recommends in the Power Manual.
- Doing the lead-in grooves can be stressful.  It takes big brass cojones
  to take a die grinder to a pristine bearing journal, at least the first
  time.  After that, it's no worse than inserting a soft contact when you
  have a hangover.