I'm still in the planning stages of my build, and what Tim's done with his FED Project as got me thinking a little bit outside the parameters of a "normal" y block rebuild. Initially I was planning on building a wicked little motor by boring my 272 to a 292 and running performance parts on her.



Now I'm wondering what it would take to sleeve my motor, and run with a 4 inch bore, and the stock 312 crank stroke. It would take the displacement up to 344. I just have never "planned" a project like this before and really would appreciate a little sage wisdom.



My questions would be what pistons could I use? 302's are a 4 inch piston. Would that be an option?



What about rods? I'd prefer to find something that doesn't have to be custom built for boo-koo bucks. Any ideas on what might work?



I want to make sure the rod length works with DH, CH, and stroke to come out at about 0 deck clearance. Any suggestions or guidance would be greatly appreciated. Thanks, the Dawg

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie

The easiest, and most cost effective way for you to achieve your goal is to find a block which will bore to 4".



If you don't want to spend boo-koo bucks, then I think you'll need to consider other options.



To sleeve an entire V8 in my area was about $1200 3 years ago - that won't equate to $1200 worth of performance. The likelihood that you find parts that will fall together is slim. The only rods which will "bolt on" to a Y crank are Y rods. Any other option will require custom machining of the crank and/or rods - may as well offset grind the crank for the extra cubes in this case. To keep the crank/rod costs low, you'll need to find a piston which is taller than the deck but not so tall that it can't be cut to fit and fits, or can be modified to fit, the stock rod. And there still may be other issues with the piston, such as counterweight interference, that will have to be dealt with. The one thing good about the 4" bore is that the selection of pistons will be practically limitless.



I think the cost of sleeving can be better applied elsewhere, like stroking, porting, finding out how big you can bore it and custom order that size, etc.


Lawrenceville, GA

I was planning on turning the mains on the crank. I have thought about offset grinding th crank and running a stock 292 piston, but that puts displacement at about the 308-309 ball park. So, offset grinding the rod journals might add a few additional cubes over standard rod journals on a 312 crank. I was also thinking about the possibility of turning the rod journals down to chevy rods (I know that might be blasphemous, but it might be a solution).



Are you basically saying that the additional 1-1200 cost of sleeving and boring to gain 30-35 additional cubic inches won't pay off? I'm also planning on porting my g heads, using oversize intake and exhaust valves (2.02 intake and 1.80 exhaust- I think those are the sizes).



Maybe I'm just curious as to what Tim's set up was, or if anyone has done something similar. I know with engines anything is (theoretically) possible with a big enogh budget. I don't really have a "master" engine builder to help answer my crazy questions when they pop in my head. But it sounded fun (as if rebuilding a quarky y block isn't already enough fun.



Thanks for the response. Any other suggestions are appreciated. The Dawg.

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie

Charlie, I also wanted to say I have the 312 crank that I'm planning on using, I've sonic tested my block and it will "comfotably" go out to a standard 292, with an average wall thickness of about .167 of an inch. I don't know if that helps.

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie

I don't think Chevy rods are blasphemous. Besides, you probably won't actually use Chevy rods. It'll probably be an aftermarket rod designed to fit a Chevy - by the time a set of stock rods is refurbished, you probably could have bought a new set.



It's not so much that it won't pay off as it's just not the best bang for the buck. Within that price range, you can find several 292 blocks. Without a doubt, you will find one that will comfortably bore to std 312 (or bigger, maybe 4"). In reality, you can probably find a 292 block for the price of boring the 272 to 292. There are just more cost effective ways to achieve the same goal.

I'm all for using original stuff, if that's what you're trying to do with the 272 block, but if it doesn't make financial sense, I personally can't justify it. A 3.86" bore with your 312 crank offset ground to 3.60", using Chevy rods, will produce 337ci. A 3.90" bore with the same stroke is 344. The same stroke with a 4" bore, 361. If you plan to turn the journals to the Chevy spec, then it makes sense to offset grind as well, otherwise you won't gain much.

You need to determine how much you want to spend on it. If sleeving fits the budget, then by all means go for it.



There is also the potential for reliability issues. Last years intended Engine Masters entry was meant to be a 4" bore x 4" stroke combo. The block had to be sleeved to achieve the 4" bore. It didn't make it past the first dyno test session.



http://www.y-blocksforever.com/forums/Topic33114-5-1.aspx


Lawrenceville, GA

Thanks for your posts Charlie! It seems that in your experience the better design for a Y block is to find a good 292, bore it out to a bigger diameter (within a safe margin to maintain wall thickness) and then use an offset ground crank to achieve higher displacement.



Can I ask a few more questions? What is the limit you can offset grind rod journals on a 312. I know Mummerts web site says 3.6 is the upper limits of a stroke that a block can handle without having to relieve parts/pistons/block. Can you offset grind a crank out to 3.60 safely or without welding it?



Another question. What rods can I use at that point, if I did stroke it out to a 3.60? What have you been able to use in the past?

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie

DAWG, I dont think the 4" bore is a practicle way to go, by the time you bore the 292 block out to take sleeves, theres no original walls left and would or should have the sleeves brazed to the deck for support. I think ted or john have a 4'" project as i have and think keeping the block integrity is more important than the magical 4" bore. Keep on with project.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

There isn't really a formula. The 1st step is to determine just how much stroke can be gained with your crank. If it's standard, you will be able to get the most. If it's 10, 20, 30 under, you won't be able to get as much. Once that's determined, you will be able to choose the rod and piston. Since you're wanting to use off-the-shelf components, you'll have to browse catalogs until you find a combination that gets you where you need to be. If you're willing to go the custom piston route, then choose the longest rod which allows for a reasonable compression height so that nothing exotic has to be done about supporting the oil ring. I don't know where the limit is with the stroke as far as having it drop into the block without having to worry about clearancing - but really, if your considering going so far, it's no matter.


Lawrenceville, GA

The limit on a Y block stroke is the rod big end hitting the camshaft.  Cams with smaller base circles and lobes can be ordered, and aftermarket rods for smaller journals are smaller on the outside also.  Ted got a 4 inch stroke by using a special cam and Honda size rods.  Still had to grind some clearance on the rod big ends.

John - "The Hoosier Hurricane"

Aussie Bill: I'm for sure not set on a 4 inch bore. I just thought it was a cool idea. But because you guys have had less than stellar experience with sleeving, and it seems there are better uses for my money to reach larger displacement I've put the idea to rest. I've got two 292 blocks in my area, one for about $150 bucks, and the other for $250. I'll probably buy the lesser expensive C1TE block and give it a good wash and magnaflux before I start going crazy.



Charlie: Where should I start shopping for aftermarket rods and pistons? I'm really that much of a newb!!!



Let's say I take the 292 out to a standard 312 (practical, and feasible with almost any 292 block). So, I can still use 312 pistons, or search around for a forged pistons (maybe Ross? I'm dropping that name so you'll think I'm smart)



And then off-set grind the crank out to whatever my Crank-Miester says will work. At that point where should I look for aftermarket rods?

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie