I'm new to flatheads.....only worked and messed with Model A & Bs....I need help on finding out if my 8BA has a 4" crank and where is the most likely place to look for cracks??? thanx for any help...
In my experience we found most cracks when crack testing a crank using specialised equipment. If you can see a crack in a crank its as good as broken however the minute inspection visa a proper process can and will veal all the small minute ones - some you can live with and others are a no no. As an example we used to find minute cracks around the oil feed holes on 351c cranks and never really bothered about them. However a crack at the edge of the journal means shes a goner.
I may be mistaken...but 8BA came with a ford 3 3/4" crank and the 8CA would be the Mercury 4" crank unless someone installed the Merc one at some point. I would imagine you have the standard 3 3/4".
A quick way to tell a 4" crank is if you can stick your finger ini the clean out galley plug it is a Merc crnnk.
To check for cracks you need to remove the heads. While they're off, stick a ruler down in the cylinders where the piston appears to be at bottom. If the measurement from the piston to the deck of the block is over 3 3/4" up to 4", you have a Merc crank. If it never exceeds 3 3/4", you have a Ford. Look for cracks in the area between the cylinder bores and the valve seats. Those are serious but not necessarily fatal. Cracks between water holes and bolt holes usually don't mean anything. Tturn the engine upside down and remove the pan/ Look for cracks in the pan rail and just inside it-especially near the center main bearing web. Anything there is serious and often fatal.
this is what I was told (& shown) by an old timer. he wanted me to leave my 4" crank with him, didn't happen
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