narrower rod in place of another?

i'm kind of putting together a parts list for a goofy engine i'm thinking of.

the rod formerly in the engine (stock) has a BE bore of 2.008'', and is .935 wide, and the new rod i want to use is the same bore (2.008''), but is only .780 wide.

is there any way to get a "spacer" , or "thrust" washer for either side? has anyone ever read about this?

Some recent racing motors use a 'piston guided rod'. The rod is kept centered on the crankpin journal by the clearance between the rod and the piston. This apparently enables both a lighter crankshaft, and eliminates stress risers between the crankpin and web. Many folks will tell you that one of the most critical items on a crank is the journal fillet. The larger the fillet radius, the lower the stress, and the stronger the crank. On a conventional setup, the actual loading of the sides of the rod against the crank is rather low, else you could not get away with simple steel-steel bearing surfaces (see tribology links for more info). So if your pistons are well finished on the flats adjacent to where the pin fits, you could fit simple flat washers/shims of steel or brass/bronze to get a reasonable clearance. Do the math to see what dimensional changes the piston will have when it reaches operating temp. If you simply must have something on the big end, then a couple of brass buttons on the top and bottom should do the trick. For full house coverage, make brass half circles, and then pin them to the sides of the rod with countersunk flathead machine screws threaded into the sides of the rod, #4-40 or #6-32 ought to be big enough.

Carter

awesome ideas, kind of what we were thinking (piston bushings to center the rod. this will be a lower RPM engine too...with a torquey 1. 41 R/S ratio...

still might be thinking of going another way, but we'll see.

The brass (I would use sintered bronze myself) half circles sounds like the best bet. That said, drilling an tapping the rod is sure to weaken it.

Enough to matter? Dunno.

Another way; make a mold, and cast some Babbit metal onto each cheek of the big ends.

http://www.frymetals.com/pdf_uploads/referenceguide.pdf http://www.lindsaybks.com/bks4/babbitt/index.html http://freckleface.com/shopsite_sc/store/html/product189.html

Carter