Good afternoon Gents,

I just picked up a 56 Mercury Custom from an old man who wanted it to go to a good home. From the casting marks on the block and exhaust manifold I've come to the conclusion that it is equipped with a 312. The motor is very dirty on the outside. There was oil in the pan, and supposedly it ran when he parked it 7 years ago. My plan is to flush everything with some cheap walmart oil, and do the necessary prep work in order to try and turn the crank over. I'm new to Y blocks and was looking for some more insight on the certain details that someone with more knowledge could offer to make this job run smoothly. This is my first project car, although I've been wrenching professionally for 5 years now. Most of my knowledge is built around suspension and fabrication so any help with trying to get this motor running will help greatly. If this post is on the wrong section of the forum, I will move it to the appropriate section. Thanks again.

-Zach-

"What a waste of thumbs opposable, to build machines disposable." - A.D.

Welcome, Flamin'. You've come to the right place, this is the College of Y-block Knowledge. Your assumption about the Merc having a 312 is good unless it's been swapped for a 292. All '56 Mercs came with the 312. The sure way to tell is stroke measurement, 3.44" for a 312 vs 3.30" for a 292. Also, there is usually an aspirin sized dimple on a 312 crank flange, although there are some without it; a 292 crank will not have the dimple. Main caps will be marked "ECZ" for a 312; caps for a 292 are marked "EBU", or a 4 element ID beginning with a "C" for truck applications.

While your cleaning the engine up make sure you take apart and clean the road draft breather.

Thanks Lou. I don't want to miss certain details like that. As of now I have the intake manifold and carb off. Do yall think it's necessary to pull the heads off for a more detailed cleaning or should I just flush it and hope for the best?

"What a waste of thumbs opposable, to build machines disposable." - A.D.

All the Casting marks I have found are labeled ECZ-B.

"What a waste of thumbs opposable, to build machines disposable." - A.D.

Heads and manifolds are interchangeable between 292 and 312 and will all have the same casting number depending on the year. The B intakes are about the best Ford made.

Sometimes when they set that long the valves stick . Easy enough since you already have the top end opened up to pull the valve covers and make sure that the valves will move.

Avoid bending some pushrods if the valves are sticking.

Welcome to Y Block world.
Oldmics

The Main Caps read ECZ-6329-4

"What a waste of thumbs opposable, to build machines disposable." - A.D.

That's a 312.

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

One of the things to keep in mind about 312s is the torque spec's for the Main Caps. If you take them apart for any reason. do not over tighten the main cap bolts!!. Unfortunately, some early 1956 manuals printed spec's that were far too high, this could resultl in stripped bolts or worse, a cracked block!  The 1957 manual states max 105lbs.  To be safe, the Street Rodder series years ago,recommended max 90 lbs.         


Paul