Originally Posted by
Yellowjacket
Not to throw cold water on the approach, but you need to think seriously about some kind of bearing and a much bigger area for the pin on the master rod. The stress in the pin is high and the contact stress is high even for something that isn't moving. No lubrication is going to stand up to that kind of pressure. You are going to bottom out the joint and it's going to gall and wear in no time at all. Cut away part of the counter weights to get some width and you can support proper size pin and bearing. You can make a new rod cap and make it out of high strength material (a high strength steel or nickel alloy like Inco 718). The full complement bearings that are used by Mercury are obsolete in many ways, but they can take really high loading and in this case that's not a bad thing. The stock wrist pins are good for over 9000 rpm in modified motors when proper lubricated so there is the capability to take a lot more load so I'd start with the stock small wrist pins and needle bearings and look at that kind of sizing if you want to run this at any speed over idle.