Just pulled the heads on my Y, good thing - it is a 312, bad thing - no.3 has leaked coolant at some stage, and the +.060 bore is ruined.Not sure if +.080 would clean up the bore, maybe .100, are pistons available?
Or would it be worth sleeving the one cylinder?
Have 2 spare truck engines, one a b9, the other a c2, have not opened to look at condition.
Which would be the better block for the 312 crank if i can't save my current engine?






Doesn't look deep, but is fairly. Hard to measure.

Engine is only supposed to have done 5000 miles last 13 years,
still got cross hatches. Sat for too long between drives i guess...

Tia, Al.

.


South Australia

Particularly, since it still has the cross hatch, sleeve it. You'll need custom pistons to go bigger and a sonic check of cylinder wall thickness would be wise if you do that.
Regarding the B9 or C2, I think either will serve your needs.


Lawrenceville, GA

I second Charlie's recommendation. Sleeve the bad cylinder and have it bored to the same dimension as the other cylinders. Re-use your existing piston.

IF there's a problem with the head bolt holes where the wrong length bolts were used, consider using 'Time-Sert's. I think that they're better than Heli-Coil inserts for thread repair in this application.

Starting over with rebuilding a 292 block is no inexpensive project. If you go that route, sonic testing is a good idea, but realize that it is like a biopsy. It will tell you if there is significant core shift in the block casting process, but will not tell you if there is a thin spot somewhere. While back-in-the-day 3.875 (.075 overbore) pistons were commonly advertised, I personally don't like going bigger than .060 oversize of the original 312 bore.

Both of the later blocks that you mentioned should have the longer main cap bolts. As you likely know, if you use the 312 crank in the 292 block you'll need to have the crank mains, rear slinger, and rear seal surface ground to proper dimension. The dimensions for this are on John Mummert's web site, www.ford-y-block.com, in the 'Technical Info.' section, sub-heading 'Crankshaft Identification'.

Hope this helps.

NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

Slick: In the cylinder photo, the damage doesn't look that extensive, however, what shape was the top ring in on that piston, damaged? And the piston itself? Worst case I'd go with the suggestion of having it sleeved. An overbore on one piston doesn't seem like a good idea. Also, note that Ford only made pistons up to 0.040" over size for 312s. Things to consider...

Paul

Have not pulled the engine down yet, however i checked the cost of sleeve, re-bore and decking today; around about AU$250, not bad i thought.

As a matter of interest, the engine machine shop (JH Southcotts) in Adelaide, is doing two 312's for a customer with a black 56 TBird,
one an ex Nascar engine he is de-tuning for the street. The other engine is gonna be full of Mummert gear, which is sitting there already.

Talk about ' green with envy '


Going in for shoulder reconstruction on Monday, so won't get back to engine 'til Christmas...


South Australia

I'm leaning more into Pauls direction, if the damage isn't that bad and perhaps will clean up and the top ring is OK I would NOT resleeve it. Heck you can bore it .075 over and use 283 standard size pistons and have a more powerful engine if you're going to tear it down for a rebuild anyway. I'm talking about the cylinders being bored .075. Just my two cents, we've built several yblocks this way and no problems.

-Gary Burnette-

Hey Gary, thanks for tip about the 283 pistons.Are they a bolt in replacement, eg, wrist pins the same size, or do the small ends need bushing?
How about pin to top of piston height?

I am inclined to sleeve the one bore, as the engine has very few miles since recon., and the
+.075 will give me further life out of the old 312 in the future.

.


South Australia

I think resizing the bushing will do it, everything else works out beautiful. Ted can chime in on this one and I believe a good example is the station Charlie dover drives and takes down the drag strip once in a while, his 57 custom ets. I have a built 312 with those pistons I had built a year ago in my garage waiting as a backup engine if I need one. We've been doing this for years.

-Gary Burnette-

I have 283 pistons in my 312 in my car hauler. The rods have to be honed to the chev pin size, the rod is too big to go between the pin bosses and have to be narrowed. The chev is set up for press fit pins, so the pistons have to be machined to accept wrist pin locks. The pins are now too long to fit between the locks and have to be shortened. The compression height is taller so the pistons have to have the tops machined to the correct height. There will still be four partial valve relief notches remaining in the tops of the pistons. Not exactly a "bolt in" operation.

John - "The Hoosier Hurricane"

Just sleeve it !

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia