Notching cylinder for 4” merc crank in a 221

[39fordtruck]

I have a 40 221 24 stud block that’s has been bored 3-3/16”. Plan to use 4” Merc crank. I have gathered up almost everything I need for assembly.
It was noted there might be interference between the rods and bottom of the cylinder. I would need notch it 1/16” x 1”
My questions are:
Does this only apply if the bore is 3-1/16”?
Should I do it before assembly just to be on the safe side?
What exactly does this notch look like? Anyone have pictures?
Thanks.

[cas3]

An example of the notches in this thread, click on the video's https://www.fordbarn.com/forum/showthread.php?t=306546

[Mart]

I can't say whether you need notches or not, but can you not set the crank, a rod and piston in place and go through a dummy run looking for interference? If material removal is needed, it could be kept to a minimum.

[bobH]

Originally Posted by Mart

I can't say whether you need notches or not, but can you not set the crank, a rod and piston in place and go through a dummy run looking for interference? If material removal is needed, it could be kept to a minimum.

IMO, Marts approach makes more sense than trying to duplicate whatever someone else has done, and from a picture or sketch, no less. Dummy it up, and determine what is needed. Just saying...

[39fordtruck]

I don’t have the pistons yet and nothing that will fit 3-3/16 except maybe 221 pistons. I think Walt mentioned 1/16 x 1” and I was wondering what it would look like. That notch in the video looks pretty big. It is only on one side where the rod would be going up into the cylinder. Interesting that it is not needed on both sides. What am I missing here?

[39fordtruck]

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I see it now inside on the drivers side a outside on the passenger side

[rotorwrench]

There is a crank centerline offset on Ford engines. This was a part of the Desaxe Principle.

[Mart]

Could you wrap something like masking tape around the existing pistons to make them fit the bore and run through the clearance tests. You would only need one, and move it from bore to bore as they might not all be the same. Logic would say one bank should all be the same and the other bank should all be the same but not necessarily the same as the first bank.
Just have a play with it and see what you find.
Mart.

[39fordtruck]

Originally Posted by Mart

Could you wrap something like masking tape around the existing pistons to make them fit the bore and run through the clearance tests. You would only need one, and move it from bore to bore as they might not all be the same. Logic would say one bank should all be the same and the other bank should all be the same but not necessarily the same as the first bank.
Just have a play with it and see what you find.
Mart.

Thanks Matt good idea.
If the length of the cylinder is the same as the 59AB block and the bore is the same, there is a good chance it will not make contact. A 221 block would 1/8 or 1/16 smaller on each side.
Are the later rods beefier than the early ones?

[V8COOPMAN]

Originally Posted by rotorwrench

There is a crank centerline offset on Ford engines. This was a part of the Desaxe Principle.

You can clearly see that this offset is 0.265" toward bottom of this drawing. DD

[flatjack9]

I don't see a problem with a 3 3/16 bore.

[39fordtruck]

Originally Posted by V8COOPMAN

You can clearly see that this offset is 0.265" toward bottom of this drawing. DD

Would not that effect how far the pistons travel up the bore from one side to other or would the different not be very much?
Are all v8s designed that way.
I learn new things all the time on the Ford Barn.

[VeryTangled]

Originally Posted by 39fordtruck

Would not that effect how far the pistons travel up the bore from one side to other or would the different not be very much?

I hope saltracer doesn't mind me drawing on a screen grab from his videos. (See post #2)

[Mart]

The motor above may have been running more than a 4" crank, and may have had non stock rods. Those reliefs may be more than is needed in this application.
Mart.

[Juergen]

In previous discussions, someone pointed out that no relief was required with a 3 3/16 bore in a 221 inch engine. I did not require it in my 37 Ford (21 stud) 221, although I had to massage the center block saddle as the earlier block has a wider center saddle.

[rotorwrench]

The crank offset was retained through all of the flathead V8 production. After the war, the valve angles were changed so that change made using early heads on a post war motor more complicated but it is doable. The Desaxe principle allows more down force efficiency with the normal direction of rotation.

During the run of "59" series engine blocks, there were two different design castings. They made both 221 replacements and 239 production blocks and the two are not the same, so not all "59" blocks are the same. The 221 blocks have characteristics of the prewar 221 blocks like the ledge above the timing cover.

[Brian]

I agree with Juergen...I fitted a 4" crank into a 221 with 3 3/16 bore and 21A con rods..no notching was required

[deuce_roadster]

As suggested, put your crank, with the rods you are going to use in the block and check it. I would put 2 rods on the same crank throw and check both sides of the engine for whether you need to notch it or not. What others have done is irrelevant to you. My guess is you will not need to notch anything.

[Pete]

Originally Posted by deuce_roadster

As suggested, put your crank, with the rods you are going to use in the block and check it. I would put 2 rods on the same crank throw and check both sides of the engine for whether you need to notch it or not. What others have done is irrelevant to you. My guess is you will not need to notch anything.

This is the best advice you can get about this, especially the line
that says, "What others have done is irrelevant to you".