I don't understand the formula?
To calculate a rectangle with radiused corners you need the corner radius.
What I remember, where "r" is the corner radius:
A = H × W - (П × r^2)
Example:
If H = 2.00", W = 4.00", r = .125"
A = 7.95"
Be very sure to inspect the O-ring on the pickup, an air leak there is fatal.
440Jim was figuring the EQUIVALENT diameter to the area of the rectangle. He plugged in the Area of the rectangle (H x W) into the area of a circle and solved for D. Making the assumption you want the two to be the same. That gets you the diameter to make the same area. You are correct, technically the radii on the corners take away some area on the rectangle though.
Which O-ring are you referring to? At the face seals to the pan, or is there an internal one? I have the 440 Source pickup in my motor and had an odd bearing failure. Trying to rule out all possible causes so this thread has me thinking a bit.
