George, I cant imagine how that got cracked; have you miked it and noted if it has been turned before? Im thinking it may have either come out of a F600 and had a real hard life or out of a racer that wound a bit too tight. Must have missed this thread when I got back the other day.

Nothing wrong with a used crank but be sure it is at least miked and polished; undersize bearings in the .001-003 range are available. Otherwise it will need turning; nothing wrong with that if it is done competently. No need for a new crank in a street engine. This aint no weak SBC.
I would reuse rods and pistons but ONLY if they check out 100%. Y Block rods are very rugged but if they came off that crank I would be cautious. What do the bearings look like AND ARE YOU CERTAIN the old 272 block isnt cracked in the mains webbing? Altho that is another common 312 fault I have seen others cracked. Have the new block magnafluxed but odds are that with a slush drive it is perfect.

And since I get confused easily; WHICH block are you going to use?

Dewayne, the 239 Im talking about is a Y Block. Racers put that crank in a 292 and used to kick Chebby butt in the under 276 cube class. Thing winds up real good.

 

"Dewayne, the 239 Im talking about is a y block. Racers put that crank in a 292 and used to kick Chebby butt in the under 276 cube class. Thing winds up real good."

Really? I know exactly one person with a 239 Y-block. His truck isn't really very fast at all. OK, so it's in a 1953 2 ton dump truck. I suppose that might explain the poor zero to 60 times.

 

Carl,

We're going to use the original 272 block and bore it out to 292. The original block has been thoroughly cleaned, Magna-Fluxed, and carefully checked, and it's in good shape. Fetters also did ultrasound thickness testing of the cylinder walls just to be absolutely sure they could do the overbore with no problems.

After cleaning, Magna-Fluxing, and measuring the original 272 rods, Larry said they are fine and we can reuse them. As you suggested, he was very cautious and checked them thoroughly after seeing the condition of the crank they came off of.

With respect to the 272 crank with the cracks, it didn't appear to have been ground before. The dimensions are very close to the stock numbers. Larry couldn't figure out those cracks either. They found a few cracks in various places with the Magna-Flux and then stopped messing with it. A friend said it sounded like somebody had dropped it (a few hundred times ) and then put it back in the engine. Some of the main bearings were worn through to the copper.

Both the main and rod journals on the crank from the 292 have been ground 0.030" undersize. It does need to be reground again. They are going to Magna-Flux it after cleaning it. If it doesn't have any cracks and is fairly straight, taking it down to 0.040 or 0.050 undersize would probably be enough to clean it up. Then we can use it with the original 272 block.

I'm sort of getting the picture that you check the block, heads, and crank. If they are good you reuse 'em. Everything else gets replaced. Am I way off on this?

 

<i>I'm sort of getting the picture that you check the block, heads, and crank. If they are good you reuse 'em. Everything else gets replaced. Am I way off on this? </i>

George, the FIRST thing you do is check parts availability. I am not aware of any currently produced bearings over .030 tho NOS may still show up.

Rule of thumb: If it moves replace it, if it doesnt then surface it.

As I said earlier Ive had no problems using old rods. Same with rocker assemblies altho I have had to swap out some rockers and push rods and polish a few shafts.
I always replace the cam as well as having the lifters resurfaced. NEVER directly use old lifters on a new cam.

Timing gears, etc get new, same for water pump.

Might as well go to Advanced Auto and get the best of the distributors. They now stock the C5TF which was a Ford replacement dizzy that has an O ring seal similar to the SBF. Only $51 which includes points and condenser. Their part # 30-2808. Makes adjustments as well as removal a snap, just like a ChebbyOo This requires a 57 or later intake.

Always take a cleanup cut on the heads and if you have any money left then zero deck the block for your pistons & bearings.
Oh, try and use a decent set of heads, the best ones were in the 56-9 era. After 59 they are poor breathing slugs. I personally prefer the 56 ECZ-C for all around truck performance as well as ability to run regular gas.
.

 

"George, the FIRST thing you do is check parts availability. I am not aware of any currently produced bearings over .030 tho NOS may still show up."

Ouch, that ain't good. Carl's right, I'd start calling before you waste money on a crank grind. Let us know if you need help looking for bearings. Over .030 is a huge total cut on a crank. I agree the parts could be a toughie. I would normally never dream of cutting one like that. But I also know your intent for this engine so it isn't going to blow because of it.

 

Thanks guys. Larry already checked his supplier and can get both main and rod bearings up to 0.060 under (full finish bearings, not semi-finish).

They are also going to deal with any deck and head warp plus fix any minor crank or cam issues with the block. They felt that the thicker composition head gaskets I've got would put the final combustion chamber size pretty close to original after the deck and head cleanup.

Generally got the same advice as you've given. Thanks again - you've improved my confidence that we're going about this correctly quite a few notches.

 

George
Check Joblot
One of their catalogs are showing
std +002, 010, 020, 030, 040 - Main Bearing Sets.

std + 001, 002, 010, 020, 030, 040, o/s - Connecting Rod Bearings

 

Yeah Dick, I FAXed a list of all the parts I found (including the stuff at Joblot) to Fetters. Larry checked on stuff and had better prices. He's been doing this a lot longer than I have!

 

George, do you mind sharing the source of those bearings? Dont need anything that extreme but will add it to the parts data base.

OK on Joblot, I try to not buy from them, too pricey whenever Ive checked on flathead stuff. Did get some sleeves a few years ago.

I stick to Reds and Mummert most of the time; friendly and fast.

 

This thread was moved from the 1948-60 forum, to the Y-block forum with Earl's permission. A re-direct has been left making the thread accessable from either forum.

Thanks to George (Earl's owner) for letting us spread this great info!

 

I don't think Fetter's would have a problem with that. I probably won't be getting back with them until late next week (after the holiday). I'll be sure to post the source they are using.

 

Could the harmonic balancer be damaged causing the cracks? I know from that the balancer can spin on the pully causing it to be off. The early Y blocks did not have a damper so I don't know how important it was anyway.

 

Got a call from the shop and the second (292) crankshaft is also cracked! At least this one had only one crack. It was at the corner of a rod journal at the back end of the engine. Too deep to fix.

I've tried contacting the fellow (dan none?) a couple of times who has the ad in the FTE classifieds for engine parts (uncle is closing a shop). I haven't gotten a response yet from him. I also looked at Y-BlocksForever and no ads there, although there apparently was one a couple of weeks ago. None on eBay either.

Sooooo, I've got to clean up the 292 parts and auto tranny mess in the garage, then find another 272/292 crankshaft that's not cracked. It's starting to feel like a full-time job.

 

Too bad. It's just like my engine search. First siezed bad and heavy scale in block. Second spun over but owner keep it. Third heavy valve rust. Now I'm looking again. Hope my crank isn't cracked.

 

Good Lord!

I am sorry to hear the problems you are having.
If you don't trip over one in the garage, start frequenting truck and industrial salvage yards.
And if you STILL can't find a decent crank yell again. There are many y-blocks laying around down here in the south. Since shipping is the killer I wonder if you could arrange to have it Magna-Fluxed first to verify it's a good one before shipping.
Good Luck!
Brett
PS. A long shot but have you tried some of the old time mail order machine shops like PAW (www.pawinc.com) or speedomotive (www.speedomotive.com)?