Ted, do the same concerns apply when grinding 312 mains to 292?

It’s always a concern anytime the amount of offset between the connecting rod and main journals is reduced whether it’s the mains and/or the rod journals being made smaller.  The more the reduction, the more the concern.  Keep in mind that FoMoCo increased the main journal size for the 312 crankshafts to maintain what is considered the minimum amount of offset required to keep warranty issues with broken crankshafts at a minimum.  And here we are over half a century later reducing those main journal sizes on the 312 crankshafts so they will fit in the 272/292 blocks.  We are definitely not smarter than the engineers who originally figured all that out but we are also not making thousands upon thousands of these pieces either.

It’s hard to say if Joe Craine’s 303” engine is pushing the edge of the envelope at this point as the rod journals are cut to a 0.010” under Honda size while the mains are a 0.060” under standard 292 main size.  All the journal sizes were made as small as possible to reduce the bearing speeds which in turn makes for more horsepower.  As of yet, no broken crankshafts here yet so that horsepower limit if there is one has not been reached yet.  There are a number of Ford 312 crankshafts that have been offset ground for more stroke while also having the mains cut to the 292 main size with no issues on my end to date.

Having dealt with Buick 455 engines that had the stroke increased by offset grinding to a smaller journal, there have been zero issues with those, but those engines were internally balanced after offset grinding to eliminate any potential flex in the crankshafts at the higher rpm.  Those Buick engines were originally externally balanced and were known to have crankshaft breakage issues when offset grinding and keeping the external balance attributes.  The Ford Y is already internally balanced so that part of the equation is already taken care of.  The better the balance, the less stress on the crankshaft whether it’s marginal in strength attributes or not.  The Ford Y cast crankshafts are also fully counterweighted and that in itself adds an additional level of strength to the crankshaft versus many of the later model crankshaft from all manufacturers that are not fully counterweighted.

Lorena, Texas (South of Waco)

Here are a couple of pictures of the Y crankshaft with Honda journals.
  

  

Lorena, Texas (South of Waco)

Ted, are you using main studs or bolts on the engine? Stud girdle/windage tray?

Those two pictures were of my 303 Y in the early stages of fitment.  You will notice the crankshaft is completely polished, rounded edges for windage control. It uses grade 8 main bolts, 289 Windage Tray.  Four of the bolts were swapped for 351W windage tray studs.  The windage tray had to have the holes moved outboard and enlarged for the Y block spacing.  Joe-JDC

JDC

Here are a couple more pics of Joe’s engine with the windage tray.  The original equipment 351W bolts with their built-in studs do use spacers at the main caps to both compensate for the extra length of the bolt and to get the windage tray at a more appropriate height.  Those four 351W bolts that were used were originally designed for engines with rear sump pans of which there would be one bolt in each engine to hold the rear sump oil pickup in place.
  

Lorena, Texas (South of Waco)

That crankshaft started out as a stock cast crank? It's beautiful. A lot of work had to go into it to reach that point. How many hours?

Let's just say that I would not polish another one for a customer like I did that one for EMC.  Many hours in the porting booth with cartridge rolls, carbides and stones to take off the sharp edges, round over the counterweights leading edges, and polish everything but the bearing surfaces.  Ted had to remove a lot of weight for the balance since we were using custom lightweight rods, and forged JE Pistons.  Joe-JDC  

JDC

Joe, would you mind sharing the specs on the forged pistons you ordered from JE? I'm in the process of trying to get my pistons ordered and would like a reference. If for competitive reasons you're unable to I understand. thanks!

DiLL

Ted has all the information to order JE Pistons in any compression ratio or head.  He made epoxy copies of the -G heads combustion chambers, (both left and right) and sent them to JE for them to duplicate.  He also has epoxy combustion chambers of the Mummert heads.  If you need assistance in ordering, I would suggest calling Ted.  Lead time on parts is an unknown right now.  Joe-JDC

JDC