Remember that the load on a 2 stroke connecting rod is primarily TOWARDS the crank. Very little force is used to pull the piston towards the rod (ie; the rod is primarily in compression, not tension).
Check out a con rod from an EMD 2 stroke railroad diesel and you'll see what I mean: There's virtually no bearing material on the bottom of the rod.
Jeff
"We live at the bottom of an ocean of air." - General Marvage Slatington
1018 is a low carbon steel, the only thing you could do with it would be to carburize it anyway, not worth the trouble. I saw the drawn cup and yes that's a good way to do it, that gives you a good bearing surface without any unknowns. The strength of the weld zone isn't very good, about 53ksi is what you can expect from normalized 1018, the area above the heat effected zone is good for about 70 ksi and that's probably ok given, as Jeff noted the loads are compressive anyway. If the bearing can handle the load then it should work pretty well. Not sure what the bearing loads are, but that's probably the life limiting factor on it right now. Within the limitations of the stock crank cases you've done about as well as could be done.
Tim
Would it not be better to use a drawn cup bearing in the wrist pin end of the new rod without washers and let the OEM rod control the rod centering on the crank. Let the link rod piston float. If I remember correctly, the wrist pin is 9/16 and a bearing should be available.
How does the pin with the needle bearing that connects the two rods stay in its hole?
He mentioned that he's going to tack weld the pin. Tack welding on things with bearings is dangerous. I know they do it with cranks all the time, but one needs to be careful since one can ruin a bearing doing it. The capacitance in the system can cause an arc to jump across the bearing even if that is not the primary path (ground clamp is on the same part as the pin. Good practice is to provide a good ground strap around the bearing to make sure that there is no potential across the bearing ever.Originally Posted by BJuby
Lubing the roller bearings helps as well.
Jeff
"We live at the bottom of an ocean of air." - General Marvage Slatington
Thanks to all for your input. An update with images was attempted, but an internal server error precluded the post. I'm hoping this quick reply gets through. Another attempt will be made later today.
Can't wait, as usual!
Jeff
"We live at the bottom of an ocean of air." - General Marvage Slatington
Need my fix of info from this thread. Hard to wait for an update. Such amazing work..........
Progress update 888
Several attempts to update failed. This one is by iPhone in hopes of getting through. Thanks all for your interest and patience. Master and link rods are complete. Crank train fitting begins this week. If this update gets through, images will follow. Tim
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