I haven't did anything but take a picture, maybe when I take it apart it'll be obvious what exactly this does.
More than likely, it auto adjusts either the thrust or the radial bearing clearance.
But with that coil spring on there... I would say it's a band lint filter!! ;)
Something new every day! At least, I've never seen anything like it.
So the spring, which is now mostly relaxed, let's assume was originally much more extended. That would put a torque on the bolt (upper in the picture) which would tend to tighten it.
So, my best guess is some kind of automatic gadget to take up the slack on a bearing cap, as the babbitt wore down.
Of course, I can think of at least three ways that gadget introduced a potential disaster into the engine, but we can assume the folks who made it had a slick way of advertising it, with no mention of the "un-intended consequences."
A cute idea, though.
Crankshaft end play auto-take up. jb
a device to keep tension on bolts to keep them from backing out.?
James has it. It has nothing to do with the main bearing bolts. It has an inner thrust bearing/bushing that is used to take up end play caused by an excessively worn rear main bearing cap thrust surface.