Y Block Help Needed

OK, the engine is out and everything but the rotating assembly has been taken apart. Here's my initial observations while tearing it down.

  • Relatively clean inside, piston tops have a bit of carbon, more than I would have expected.
  • Flat top .060" over pistons, no ridge at the top of the cylinders, just a layer of carbon.
  • The cylinder walls have a nice glaze, no crosshatching is visible.
  • The cam is out, and it's labeled CRANE F-294-2. A search of Crane's website and a Google search don't come up with anything. I did find some stuff about an F-294 cam for an FE, but no telling if it has the same profile.
  • Once I get the garage back in order, I will pull the bottom end apart, starting with #4 (the one with 75% leakdown). I'm guessing the ring lands are full of carbon, but we'll see.
 
#4 piston is out, but the rings weren't stuck like I was suspecting. However, the compression ring gap overlapped about 50%, so that should explain the leakdown for that cylinder.

I did a quick check on the bore and came up with 3.860", which can't be right. I don't have a bore gauge, so I have to do it with dividers and caliper, but that should be close enough for a rough measurement. I triple check, even changing calipers, but get the same reading. How could it be .110" over and be running .060 pistons? Could this be a 312? So I check and see the stock bore for a 312 is 3.800". Looking at McMaster's & Mummert's sites confirms that it's a 312. Casting number is ECZ-6015-C and it has ECZ main caps. The heads are the ECZ-G.
 
Now I'm curious to see how they lined up the other rings...
 

Attachments

  • 312 piston.jpg
    312 piston.jpg
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Be sure to check ring gap with the rings in the cylinders. Someone may have used 292 rings so the gaps are huge. Normally it does not matter where the ring gaps are because the gap area is so small and the rings constantly rotate in their grooves anyway. So the gaps will all line up and then move on, not lining up. Doesn't affect how the engine runs at all. You need to be concerned more with how well the rings are sealing against the cylinder walls as well as the ring lands (check for side wear on the rings).
 
with the ecz caps you do have a 312 but its common to bore a 292 to that size.the wristpin is in the same location so no problem.whoever did your engine was no pro.
 
Measured gap on one of the compression rings on the #4 cylinder and it's .025", which is in Ford's spec range of .010 - .027", so they are the right rings.
 
countrysquire said:
Now I'm curious to see how they lined up the other rings...
Click to expand...

It's not unusual for the rings on a piston to be aligned once the engine has run for awhile. The rings do rotate normally and once the two compression rings align, they'll have a tendency to stay that way as it's the path of least resistance.
 
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