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Summary on case through-bolt o-rings:
1) You should chamfer your through bolt holes, if they were not machined previously.
2) With regard to installation grease, it is fact that although more expensive, Krytox GPL-207 retains approximately double the tensile strength of the o-ring relative to Dow 55 when used on the green viton o-rings measured after 70hrs of operating use. DC 55 trades strength for swelling of the ring intentionally.
3) Green viton through bolt o-rings still seem to be the best.
4) It is fact that DuPont Krytox GPL 207 is non-reactive. It is also fact that DOW publishes warnings for thoroughly testing DC 55 on certain elastomers including silicone rubber, which are found in off the shelf 911 seal kits, due to chemical reaction. It is further fact that although Viton loses half of strength after 70hrs, other elastomers experience even more profound losses of strength when exposed to DC 55. End user confirming compatability with materials is advised.
5) It is fact that the chemical reaction with DC 55 that reduces tensile strength advances over time and operating temperature. Engines that are frequently rebuilt or used less frequently (race car, garage queen, collector storage etc) will therefore experience slower advancement of seal weakening and than would daily driver or heavy use vehicles when using DC 55.
End of summary.
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“Of the value traps, the most widespread and pernicious is value rigidity. This is an inability to revalue what one sees because of commitment to previous values. In motorcycle maintenance, you MUST rediscover what you do as you go. Rigid values makes this impossible.”
― Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values
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