i looked at a 57 merc.  engine today that was supposed to be a 312 but it didnt have the raised bump on the rear of the crankshaft like the other 312 engines i have.  the question is did all 312 have this raised bump or was some without it.  carl 

More than likely, the original 312 was replaced soem years back with a 292.

TC

You gotta have the right tools and know how to use 'em.

TC - Austin, Texas

Not all 312's have the rivet on the crankshaft flange. I have 57 Merc 312 engine without it. 312 Cranks without the rivet are very rare. The best way to be certain it is a 312 is to pull the pan and check the rods or crankshaft. The crank will have ECZ stamped on it, original rods will have ECZ also. If it is a Canadian engine it will have two letters followed by a number stamping on the front of the block drivers side just below the head/engine deck such as TV ####, 1956 blocks or VV####, 1957 blocks

marv

I have a 312 crank.  You need to look VERY closely at its flange to see the bump, but it is there, barely.  When I first saw the crank the bump wasnt visible, but the mains measured proper.  It is now newly turned to 292 mains.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

Carl, just to clarify the 312 bump as you called it, is found in the notched area of the crank flange & is fairly short, but is about 5/16" in diameter.  

Paul

Thanks for the info. i know how to check the engine on the inside but wasnt sure about all 312 haveing the bump on the crank.i suppose i will have to buy it just to pull it apart and see if it is really a 57 312  carl

With the engine installed in the vehicle, the aforementioned 5/16” dot or bump on the crankshaft is most easily seen from the bottom of the vehicle when the TDC on the damper is at the six o’clock position.  The 5/16” dot will then be at about the 5:30 position on the lower edge of the crankshaft flywheel flange when viewing from the front.  Any covers or shields that block the view of the crankshaft flange will of course need to be removed to see this crankshaft flange.

Ditto on some of the 312 cranks not having the 5/16" dot as I've had one of those also.

Lorena, Texas (South of Waco)

the engine is out of the car with the bellhousing and flywheel off so it is easy to check the end of the crank.we pulled a head off yesterday and it has the standard 312 bore.next we will put it on a engine stand and  drop the pan and check the main caps.  carl  

I recently bought a 312 crank with no dot or flat on the flange.   I measured the mains and compared to another 312 crank and it checks out.   First one I had seen too.  I thought I got took until I measured it. 

Pat Fleischman

I'm just pulling a 312 apart that has no dot on the crankshaft.  It's a Canadian 312 engine from a '57 Merc and has the VV suffix stamped on the left side of the block below the cyl. head.  It's a 3.80 bore with ECZ main caps.  This is the second '57 Merc engine I've seen that doesn't have the dot on the crank.  Maybe it's a '57 Merc thing?

I'll be posting photos of the teardown later this month on www.fabulous50sford.com

Larry D

Fabulous 50's Ford Club of MB

'57 Fairlane 2 dr. HT. - '58 Custom 300 Tudor - '61 Starliner Z code - '56 Crown Victoria Skyliner (clone)

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