Well, I have a premium grade block, it was a service motor on the back of a septic truck. When it was pulled off the meter read 142 hours ran. The truck was used inside a plant and never saw cold weather outside, thus NO CRACKS anywhere. Pulled the sleeves and had it mag tested to check and confirm, it is good. I am in the middle of a build up on this motor and want to put in a stroker kit but I am limted on selection because I do not want to go beyond 3-3/16 bore. I would like to go 3-3/16 x 4-1/4 but Ross doesn't make the pistons. If I wanted to stay with the 4-1/4 stroke I would have to goto 3-5/16 bore. Can I take a 221 block out to 3-5/16 without concern? From what I have read, the blocks can be a little thin to start with. What have you done and what are the limits?
I can't say to much about the 37/38 block you have except it is a 21 stud with original bore of 3-/16th. I believe they can go out to 3-3/16, but I doubt that you could bore this early of a block out to 3-5/16 because there isn't enough material. I know this is a pristine block but if I were you I'd put the 3-3/4" crank and 8BA style rods with some aftermarket pistons (non forged) pistons, small cam and two carbs........finding 21 stud aftermarket heads will be a hard as I don't think anyone makes them. Also, I think if you put a stroker Merc crank I'm not sure that you won't have interference issues with the crank throws and rods hitting the block. If you want to build a stoker motor go find a good 24 stud motor where you can bore them out to 3-5/16 and put a 4.125/4.225 stroker crank in without any issues. You can also find speed equipment much easier than for a 21 stud. IMHO
OK, little confusion here. This is a 24 stud block that was sleeved to 221. It was a service duty motor, over the counter motor. I don't know why it was sleeved, no cracks. I probably should have it sonic tested to see what the walls are at. I was hoping to save the expense by sticking with the least amount of overbore possible. I would leave it as it is, the walls are perfect except where the sleeve lip was. I am concerned about loosing too much compression in the groove left from the sleeves.
OK, now I am totally confussed. So this must be a 1939 to 1942 Ford block, as they were 24 stud and 221 cubic inches. Something must have been wrong with the two cylinders that were sleeved??????????? What is the bore of the cylinders after you took the sleeves out? If this is in fact a 39/42 3-1/16 bore block I would have it mag'd and sonic tested to make sure how far you can bore it to. As I mentioned, there had to be a reason the two cylinders were sleeved. About the grooves in the block for the sleeves.............you will probably have to put new sleeves back in, depending on the size of the sleeve you are going to use. But once a block has been sleeved I don't think you can take them out and run the motor with a relief around the circumferance of the cylinder as you will blow the head gasket. I still think you will have clearance issues putting a stroker crank/rods in the motor, but I think a little relieving of the block will allow the crank/rods to fit. How about sending some pictures of the block. My best guess would be that you bore the block to 3-3/16 and resleeve the two cylinders (with sleeves) to 3-3/16 also. I would think that someone like Egge would make the pistons you want although I doubt they will be forged............but that doesn't make much difference excpet in the pocket book. Give me a PM if you want or post a couple of pictures.
This is 39-42, raised deck block, 221 CID. The whole motor, all 8 cylinders were sleved and like I said it was mag tested with no cracks found. The current bore on all 8 holes is a little (~0.040) under 3-3/16. The sleeves that were in took it down to 3-1/16. If I take the bore to 3-3/16, there would be no evidence of the sleves left. This was an industrial service motor so I am guessing that they sleeved the entire block for longevity.
If these are sheetmetal sleeves with a lip, not cast iron cylindrical ones, they are original to the block. Many (not all) 221 and 239 engines roughly 1939--41 were made with sheetmetal sleeves that were designed to allow overhaul by just pressing in new sleeves with a dealer tool kit. The bore of the iron is obviously more than 3 1/16, but smaller than 3 3/16, and outer wall thickness of cylinders is thinner than a 239. Boring to 3 3/16 is generally considered safe, and leaves only a slight vestige of the stop ring. I have heard of 221's of this period being bored larger in old magazines, but doubt that it is safe to go beyond 3 3/16 plus a rebuild or two. Sonic testing, remember, is a spot check, not an overall view of the cylinder, Cylinder is a bit thicker at top than bottom, and considerably thinner than an early 239.
Thanks Bruce, I was waiting for you to find this post. Both my builder and I feel confident with a 3-3/16 bore. I am not willing to chance the block on the 3-5/16, so its out. But my problem is that I want to push this motor to 3-3/16 x 4-1/4 which they don't make pistons for. They make pistons for the 3-5/16 x 4-1/4, thus my question. So without spending the huge money on custom pistons, I am stuck with 4-1/8 stroke because Ross makes the pistons for this combo. They have a catalog piston for 3-3/16 x 4-1/8. I guess that 263CID is a hell alot better than 221CID. Would I see a hugh difference if I was to go with a 4-1/4 stroke over a 4-1/8 stroke? I know I am comparing apples and grapefruits here, I just don't know what to expect from the stroke combos. It will be a big difference from the 221 that it started as.
I only use cheap parts I scrounge, so my stroke limit is 4"... Flatdog's 12 second coupe had 4 1/4, and while seriously powerful, it used oil. Both of us were suspicious of side loading from the long stroke, and he was planning less stroke for next build. Issues involve both piston speed and side thrust from extra rod angle. Compute the inches in moving from 4 to 4 1/4...then decide if it is worth it. I regard a 4" stroke as rather long, myself. If you do decide to go wild, I am sure there is someone out there that can carve you a piston.
My very first motor that I put togeather and heard it run was a '40 Ford with sleeves. At least 50 years ago. Didn't know I'd still be at it now.
I have done this, I got a NOS Bren Gun Carrier engine. 24 stud, 221 ci, all cylinders sleeved. Pulled the sleeves and took it out to 3 3/16. After the bore job there was still a very small groove around the top of the cylinder. We put the sleeves down to that fact it would have been easily rebuilt in the field, considering it's intended military use.
i feel that long stroke small bore combo is not the best...the 239 would respond well to a light weight rotating assy and a cam that comes on in the higher rpm range . not much bottom end but would rev like a bunch of mad bees!
The sleeves were used on many '39-41 civilian motors...a simple kit of pullers allowed them to be changed easily for instant overhaul. I don't like real long strokes...there are multiple negative issues.
Hi- this is a little to the side of this issue but does anyone know what has to be done to the 4inch merc crank to put it into a 37 21 stud- wanting to build a 4 1/8 inch stroke 21 stud which is already .060 over and the bores are good- if the stroke was left at 4 inches can the newer rods be used and not cause interference with the block- thanks- Chuck
Ron on Fordbarn has done some of these. It is pretty much a matter of cutting down the bearing diameters, and I think mains may get slightly lengthened...front snout probably gets cut, although I think it could be left alone and used with a later pulley too. On the earlier babbitt main 221's, the job becomes very involved as oil holes have to be filled and redrilled. With the '36 LB--38 type crank, issues are much simpler. There is a service bulletin page showing all the cranks together with dimensionbs called out...maybe someone can post that. This is also a great way to recycle a crank that has reached minimum size for a big block, and the extra cutting allows you to strengthen it by adding radii to the journals.
Thanks Bruce- I am building this engine for a friend who has all the good parts for a 21 stud engine- Evans heads etc. I took the engine apart but am away from it and trying to get the pieces machined so when I go back I can build it-I was wondering about the snout as someone mentioned this before as well as the machinist at the machine shop- that is a good tip on the radius- I will try to find the bulletin page- thanks Chuck
What you meant to say was Ross doesn't have those pistons as a stock item. Believe me, they will make just about anything you want, but it won't be cheap for one set...
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