Model B Crankshaft
 

Will a Model B crankshaft work in a Model A block. Any real changes necessary?

Re: Model B Crankshaft
 

Other than the obvious (journal/rod diameters) the only other issue I've heard of is a tendency of the rods to hit against the sides of the crankcase. I believe the B block is relieved a bit for clearance at this place.

It is possible to compensate for this.

I explored the option but have yet to act on it.

Joe K

Re: Model B Crankshaft
 

The main beartings will need to be cut down to model A size. You will need model B or aftermarket special connecting rods. If model B rods are used, special rod nuts will be needed or the oil pan will need some minor mods to clear.

Re: Model B Crankshaft
 

A quick look to refresh my memory confirms Purdy on this.

See http://www.jalopyjournal.com/forum/t...engine.506451/

Joe K

Re: Model B Crankshaft
 

The minor mods of the oil pan are extremely minor. Bolt the pan in place and turn over the engine. A rod will hit the pan. Remove the pan and with a ball peen hammer install some clearance for the rod. You will have to R&R the pan at least 8 times to get all you locations marked. Not rocket science. :D

Re: Model B Crankshaft
 

Thanks, it all sounds rather simple, just time consuming and a few bucks for the machining.

Re: Model B Crankshaft
 

Hey davey,
The rods will clear block, but will touch pan..ergo pan dimples, as said. You will have the benefit of larger/stronger rod journals and use any B crank that you wish to do this, i.e.- Ford first edition..without counterweights, right up thru C crank.

If I were you, I'd get a copy of member Jim Brierley's book and you will not only have answers to the instant inquiry....but much/much more, IMO :) ! And, if you do not comprehend what you are reading (my problem,eh :p !), you can contact Jim B to clarify such. He (Mr. F.A.S.T.) is easy to talk to and most knowledgeable !

Re: Model B Crankshaft
 

The beaver tail crankshaft isn't a mobel B crankshaft. The beaver tail crankshaft was used in 1928 and has the same journal sizes as the later model A crankshaft

Re: Model B Crankshaft
 

daveymc29,

I recently did this. Had the mains ground to standard A size and used Snyders B rods which had nuts that did not contact the sump. Also fitted a modern rear seal which I hope will not leak too much. I expect to run this engine in the next month or so.

Cheers,
Gavin

Re: Model B Crankshaft
 

The oil slinger is a different size and needs to be machined to fit the A block if it is off by just a few thou diameter, thickness and taper it will leak
find a machine shop that has done this
or you have you have it machined for a modern seal easier

Re: Model B Crankshaft
 

use ARP nuts, the 12-point kind and they clear the A pan with no mods needed.