59AB flathead with 3 1/16 bore question!

[31pickemup]

Hey guys I have a question about a 59AB flathead that I found. This 59AB is a 221ci not the 239ci. My question is can I just bore it out to 3 3/16 and just replace the pistons? Are the rods, crank etc still the same?

[OLD...BILL]

I'll bet its sleeved?? punch em out and you there, hone to new pistons, all else is good to go...the trick is to find a shop/builder that know flathead and can prove it, with past customers ?? it's a big if...and post where you are, someone here will help....OLD.....BILL

[supereal]

Some blocks were sleeved because one or more of the cylinders had a casting defect such as a sandhole. Sleeving saved the block, and it was used as a "service replacement". This was common practice at both the factory and "authorized"rebuilders. You won't know what you have until the sleeves are pulled, then you would to resleeve the engine if any cylinder walls have been breached. If the sleeves are in good shape, I'd have a good shop inspect them and see if they can be honed. Most can't tell the difference in displacement, anyway.

[31pickemup]

This block has no sleeves in it. Its a low milage 1946-48 59ab 221 replacement engine.

[Pete]

There is a very good chance that block will bore to 3 3/16 safely.
In the old days, we would just bore away to any size we wanted and 99% of the time all was well.
What with good blocks being scarce nowdays, I sonic test them first.
There is always a one in a thousand chance it was a core shifted block and they only bored it to 3 1/16 to save it.

[scooder]

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The one I have here looks like it has the meat to go 1/8" over (to 3 3/16") but I haven't sonic'd it yet. What Pete said about good blocks being scarce is good, I wouldn't bore it that far on a chance, get it sonic measured be on the safe side.
Most other parts in the engine are fine when going 3 3/6", some of these service blocks (the ones I seen just have 59 on the bell, no AB) have a slinger on the back of the crank rather than a rope seal, due I believe, to the crank being a pre war 2" rod crank. So if you want to flick an 59A or 8BA style bottom end up it, you'll need to swap out the seal housing/slinger castings.
Martin.

[31pickemup]

I thought all 46-48 motors were 239's til I found this one. I thought he seller made a mistake and measured wrong. Then I read Van Pelts page about some post war 59AB's being bored to 221 as replacements. Since it's a raised 59 number in the bell block I figured they used the same rods etc. but just bored it to 221. Block should be the same as a 239 so I should have tons of meat

[Lawrie]

easy way to tell if its 3-1/16 or 3-3/16 is the centre water passage ,round means 3/16, funny square triangle ship means 1/16 from new,
Lawrie

[31pickemup]

Lol mine are round and its 3 1/16

[Lawrie]

well, Like walt says ,you learn something every day.
are you sure it has,t been sleeved.
Lawrie

[JWL]

The 3 1/16 blocks with 59A bells were NOT of the same casting arrangement as the 3 3/16 blocks. Yes, they can usually go to 3 3/16 safely. But, certainly not much more.

[scooder]

Lawrie, these blocks arnt sleeved down to 3 1/16" they are cast as such. As John said above, they are different castings to the 3 3/16" blocks. In fact I believe they are different to all other blocks. They are an odd mix of cores, some parts of the casting are pre war, some post war. The one I have has 59 on the bell but a pencil ledge on the front, round water hole as the op's engine has, and post war valve angle. Real odd engines.
Martin.

[Fe26]

I too have one of these engines and mine is factory relieved, they are odd wee beasties.

[31pickemup]

Is it worth rebuilding?

[Ed Pitts]

This is the one that I have, a Z block, and it built a nice engine. Ed

[31pickemup]

is it also a 3 1/16?

[31pickemup]

Here are some pictures. Has no cracks. Just not sure if its worth building with a 3 1/16 bore. This does not have the pencil shelf as scooder's does. Looks to have inserts and been relieved

[Mike B]

Building for..????

I just took my 221 up the road yesterday in my '42 PU...sure...not a high HP engine, but plenty of get up and go...I'd think you have a good start, unless you have to have more cubes than the block would.could yield?

[31pickemup]

Mike my 59AB is wasted in my 31. I'm building a replacement. This one was built in 1959 then upgraded though the years

[tub1]

a good 221 is so much better than a cracked and repaired 239 anyday most don't pull loads with our flatmotors or race them we just want to get there and back home