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| Joined: | 06-25-2013 |
| Location: | Thousand Oaks, California USA |
| Posts: | 17 |
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O-Ring Counterbore Details:
.......... SPEC METRIC / Calc'd Inch Decimal / approx inch fraction
Dia. 12.30 -12.44 mm / 0.48425" - 0.48976" / ~31/64" (.484375")
Depth 1.20 - 1.30 mm / 0.04724" - 0.51181" / ~3/64" (.046875")
My groove is a little smaller at .475 diameter x .044 deep. So I calculated the volume of a hollow cylinder (the groove less the roll pin) at .0043 cubic inch and the volume of a torus (the McMaster Carr o-ring) at .0037 so the o-ring does just barely fit into the groove when compressed.
The sloppy fit -012 o-ring is too large for the groove at .0052 cubic inch and the -011 o-ring which has to be stretched to fit over the roll pin is good at .0045 cubic inch but has to be stretched .016 diameter which is quite long at the circumference. I'll go with the metric one.
I'll order the o-rings today in Viton since Buna-N is good to 250 degrees F and Viton is good to 400 degrees F. They come in a pack of 25 (not 100 as previously written) and I only have two engines so there are plenty left. If anyone wants a couple, send a stamped, self-addressed envelope to:
Claus Groth
1795 Sweet Briar Place
Thousand Oaks, CA 91362