I looked at a ’57 Merc 312 I have on hand and it does have a very pronounced 5/16” dot on the crankshaft flange so it’s not a ’57 Merc thing specifically but maybe a Canadian thing?.  Good thought though. 

Lorena, Texas (South of Waco)

I got out to check on my Y-Block stash and found my other '57 Merc 312 crank I've been saving for a good many years.  There at the cutout on the crank flange was the 5/16 dot.  That was also a Canadian car, so it looks like it's neither a '57 Merc or a Canadian thing.  Moral of the story is, just don't write off any engine as not a 312 until you pull the pan and look at the main caps.

Larry D

Winnipeg, MB Canada Eh!


'57 Fairlane 500 Club Victoria

'58 Custom 300 Tudor

'56 Crown Victoria

'61 Starliner Z Code

'51 Ford Victoria

We took the oil pan off the 57 merc engine and it is a 312. so like some of you said all 312s dont have the DOT on the crankshaft  Carl 

Just a reminder to anyone buying a 312 engine. Once it's determined that it is in fact a 312, your next step before you spend any money on it, is to determine that the block is not cracked where the main caps bolt on. Or in some cases the threads may be stripped due to overtightening or as a result of the wrong length bolts ( to long or to short) having been used. Some early 1956 engines were victims of a main bolt torque spec that was to high. ( I  won't repeat it here, or sure as hell someone will use it!) Also, when rebuilt by over zealous mechanics, the same happened. As I undertand it,(I'm not an engine guru) the "absolute" max torgue on 312 mains is 105 lbs!  The Street Rodder/ Classic Truck series recommended 90lbs..       

Paul

Well we finally got our Y-Block torn down and even though the crank flange didn't bear the usual 5/16 dot, it's a 312.  This looks like a good engine for a rebuild.

Check out the photos at http://www.fabulous50sford.com/mr/mr-5.html

Larry D

Winnipeg, MB Canada Eh!


'57 Fairlane 500 Club Victoria

'58 Custom 300 Tudor

'56 Crown Victoria

'61 Starliner Z Code

'51 Ford Victoria