221 cubic inch 59a Block?

[modela4shane]

Can anyone shed a little light on the history on a 3 1/6 inch bore 59a? I just tore down a engine i had to see if it was a usable core and to my surprise found the bore size to be 3.147, in between 3 1/16 and 3 3/16. I was under the impression all 59a blocks were 239 inch, 3 3/16. This engine looks to be a 221 with a over bore from being rebuilt. The bell housing has the distinct 59 cast into the housing. Any insight would be greatly appreciated. Thank you.

[1931flathead]

yes it could be a 1941

[JSeery]

Replacement blocks. There were blocks cast in the 40s for replacements for earlier engines.

[GB SISSON]

I'm working on one now. Like J said, they were sold by the dealer to replace a cracked block and enabled the rebuilder to just swap over the internals from the old 221. Hence the smaller bore. Does this mean these blocks have extra thick cylinder walls?

[RalphM]

Originally Posted by GB SISSON

I'm working on one now. Like J said, they were sold by the dealer to replace a cracked block and enabled the rebuilder to just swap over the internals from the old 221. Hence the smaller bore. Does this mean these blocks have extra thick cylinder walls?

Don't know about extra thick, but you can bore them to 3-3/16" standard bore easy. Lots of NOS standard Pistons avail at good prices.

[Mac VP]

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59 series blocks......all those with the big "59" cast into the top of the bell housing, were made from 1945 through 48 for regular production use. Ford continued to run the blocks for service use for a few years after that (not sure how long).

The regular production blocks were all 3-3/16" bore for use in their new car and truck production. At the same time, they were also casting the 59 blocks as 3-1/16" bore for sales to the service department. These smaller bore 59 blocks were intended to be installed in pre-war Ford vehicles that came as the usual 221 cu inch motors. These were not mfr'd with the thin wall sleeves that some of the 39-40 blocks had.

Years ago I found one of those service blocks in new condition. After verifying that the block was good, I had it bored out to 3-3/16" and used the Standard 8BA pistons and rings. No problem and now had a 239 inch motor instead of 221.

[rotorwrench]

The 41A cylinder block likely used the internal core molds from the earlier pre-war and the outer shell cores from the new 59 series block in order to save bucks. Near the end of the war, FoMoCo started to gear up for civilian production again and folks were hungry for replacement parts.

From all the information I've ever seen about war time production, FoMoCo USA didn't make an abundance of V8 engines. The 1942 truck production mostly went to the military during the conversion to war time production. Ford made a lot of G8T trucks for military service but they all had the G series 6-cylinder engine.

[JM 35 Sedan]

All good information on these special 59 series blocks that were cast as service replacements for pre-war 221 ci engines, but the questions still remain....what was the cylinder wall thickness on these blocks with 3-1/16" in bore, and what is the cylinder wall thickness that remains after they have been bored to 3-3/16"??

[Mr. Will]

Originally Posted by JM 35 Sedan

All good information on these special 59 series blocks that were cast as service replacements for pre-war 221 ci engines, but the questions still remain....what was the cylinder wall thickness on these blocks with 3-1/16" in bore, and what is the cylinder wall thickness that remains after they have been bored to 3-3/16"??

A sonic test would reveal that information.

[RalphM]

The one thing I don't understand is why they would go through the trouble of casting a different block, when the new and improved 59 239 cid came out. Externally they were the same, so why build a smaller displacement engine, just for a replacement, when the customer could have a bigger, and better motor gor the same cost.

[JSeery]

Originally Posted by RalphM

The one thing I don't understand is why they would go through the trouble of casting a different block, when the new and improved 59 239 cid came out. Externally they were the same, so why build a smaller displacement engine, just for a replacement, when the customer could have a bigger, and better motor gor the same cost.

That's not how replacement parts work! If you are just replacing the block it would have to fit the existing parts. If you were going to install a new engine that would be a different matter. There was a cost difference between a rebuilt short or long block and a new short or long block.

[Mr. Will]

Originally Posted by RalphM

The one thing I don't understand is why they would go through the trouble of casting a different block, when the new and improved 59 239 cid came out. Externally they were the same, so why build a smaller displacement engine, just for a replacement, when the customer could have a bigger, and better motor gor the same cost.

The idea was to just replace the block and use the existing rotating assembly.

[rotorwrench]

For all the information I have ever come across, The 41A block had the same internal construction as the pre-war 221 blocks. It was essentially the same as the 21A engine block with the exception of the outer surfaces that were the same as the 59A. These blocks were not like the 239 CID blocks that had thicker cylinder walls. The 99A series blocks from 1939 up to the war had the thickest cylinder walls but the 59A had thinner walls. Still much thicker than 221 engines but not as thick as pre-war 239 engines. All auto manufacturers had to use their resources carefully during the post war era. There were shortages of all materials so they had to conserve on everything.

To this day, manufacturer's still supply spare parts for at least 10-years after the parts were considered obsolete or out of production. FoMoCo subcontracted some of this stuff out to other foundries that were considered as preferred sources.

[modela4shane]

Thank's to all who responded to my request, now i know what i have!

[tubman]

If you are going to build this engine, you should consider having the cylinder walls sonic tested to see how thick they are. I don't think anyone knows for sure, and it sure would be nice to have a definitive answer.

[JM 35 Sedan]

Originally Posted by Mr. Will

A sonic test would reveal that information.

Originally Posted by tubman

If you are going to build this engine, you should consider having the cylinder walls sonic tested to see how thick they are. I don't think anyone knows for sure, and it sure would be nice to have a definitive answer.

You guys are correct. The best way to determine wall thickness would be to do a sonic test on a service 59 block that has a 3-1/16" bore, obviously BEFORE attempting to bore it to 3-3/16", just to make sure you will have the minimum acceptable wall thickness after boring. I would not assume anything on actual wall thickness until the proper checks are made.

[GB SISSON]

I plan to keep mine 3 1/16. I bought two new .030 over pistons in cosmoline last spring to replace the ones I had to beat out of the bores due to being seized. Since I don't need bragging rights at car shows and don't drag race, buying two pistons seemed the right choice. The next generation, if indeed there is one can bore it out to 3 3/8 if they want, but I'm just gonna putt around Orcas Island and have a blast doing it... I can't wait til the fall when my business slows down so I can assemble this thing.

[JWL]

The Sonic Micrometer indicates a maximum safe bore of 3 3/16 on those 59 blocks which began life at 3 1/16. Those which have been measured DO NOT have extra wall thickness.

[Stenny]

Nobody has mentioned this but my 59 block with 3 1/16 bore has the lip on the front of the block above the distributor (pencil test). I seem to remember that all of the small bore 59 blocks had this. My block is factory relieved as well.

[modela4shane]

Did FoMoCo produce 2 different 59 blocks? One at 221 inch and the second at 239 inch, or was it the same casting and Ford bored replacement blocks to 221 and the production blocks to 239 inch? It seems hard to believe that as frugal as Ford was that they would make 2 different blocks. Why not just recast the original 221 block for service replacement if they were going to cast 2 blocks. It would stand to logic that the 221 replacement can be bored to 3 3/16 or 3 5/16 with no problem just like a production 59a, 239 3 3/16 block. This block does NOT have the ledge for the pencil.