Mebbie!!

Frank/Rebop

Bristol, In ( by Elkhart) 

Frank, are you trying to say that Detroit wasn't putting out precision race engines back in the 50's???

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Dan,

        The center of the crank may not necessarily be moved from factory, if it's done with care. The ALIGNMENT of the bearings should improve though. Of course we don't really know that the factory machining was all that accurate, do we?! Ask Mummert about deck heights and how parallel the deck planes are to the crank center if you want to scare yourself! 

       Also, any misalignment won't be caused by a casting "shift". the casting will be machined wrong because of worn out machine tooling, or a sloppy setup, loose fixturing, blah, blah. "Casting Shifts" will produce erratic casting features, but not (usually) machining errors. Although, typically, the machine shop will try to blame any problem on the casting.

Frank/Rebop

Bristol, In ( by Elkhart) 

I can see where (if perfect alignment was absolutely necessary) the best approach might be drilling for aftermarket oversized adjustable eccentric dowels. As long as the bolt holes allowed enough movement, you could dial in the bore runout after shimming.

6 VOLTS/POS. GRD. NW INDIANA

Washer was ID plate from an old toggle switch.



Re: shop manual shim/alignment procedure: If your block was out of whack (casting shift) I could see where shims might prevent bearing failures, but it's a bit disconcerting when a brittle cast iron housing designed for 360 degree contact ends up touching the block only at the 4 bolt bosses after leveling!

6 VOLTS/POS. GRD. NW INDIANA

Interesting. Halving the parallel face runout with shims doubled the bore runout. This could get complicated.

I noticed the manual describes the face shim procedure first, and then, when the next test shows the bore is out of spec., their only remedy is replacing the bellhousing! I'm starting to think the original measurements may not be so far out of spec. after all for my mildly spirited driving style. With my luck, once the bore is trued and the dowels are drilled oversize, the face runout will change, and more shim juggling will move the bore center again, and on and on.

6 VOLTS/POS. GRD. NW INDIANA

All but the softest aluminum should work. Even then it can take years for it to be compressed any measurable amount. Do you have any idea which alloy the washer is? Many bellhousings are aluminum. If it didn't work, it wouldn't be used.


Lawrenceville, GA

Thanks Ken, good advice.

Will have to locate some shim stock. Have a washer the perfect size, but made from aluminum. Can't predict compressibility over time, so will go with steel.

6 VOLTS/POS. GRD. NW INDIANA

I would shim it first and get the parallel right first and check the runout again. The shims will move the hole a little and a thou or two isn't much. Dowels will usually come out with a vice grip, but I would sure try the shims before I went to all that trouble.

Kenneth

Fredricksburg, Texas

John,



Finally torqued down & measured that NOS bellhousing on the align-honed block. Surprisingly, the bore center is .006" HIGHER than the new crank center (shop manual max. spec. is .005"). It also needs a shim. Parallel face runout is .012" at the 6.25" bore/diameter. Ford spec. is .007" max. measured at 8" diameter (with dealership service tool).



Though the crank center is not that far off, I might pull the dowels anyway & drill for oversize (1/2" FoMoCo) pins, but I wonder how hard it will be to remove the orig. 3/8" dowels? (don't want to chew them up, and have to drill them out).

6 VOLTS/POS. GRD. NW INDIANA