Burnishing Inserts Rod Bearing

3

31/S/W

Junior Member
Can anyone tell me how to burnish the rod bearing and what to use for compound? Does it help the motor will it make the bearing last longer? A round surface is better than one that does not touch 100%? Has anyone done this, How do you hold the piston when turning the crank. Do you do the mains the same way? Any feed back will be helpful. If this was a modern race engine then I would think it would be polished?
Thanks
 
Sir,

You really don't want to do that! The insert bearing is not as forgiving as a
poured bearing. An oil film between the bearing and the journal, suspends the
rod from touching the crank. If the crank is ground and polished with the
correct clearance, it will not touch.
The mains(block) and rods are done first, to generate the numbers needed
to grind the crank!

Dudley
 
DJ, after thinking about your reply. This is what my thinking is. If one polished the rod or main journals - they would be perfectly round with the same amount of clearance all the way around the journal thus the oil would have a better film thickness! Am I off bace? The rods and mains ride on a bed of or layer of oil-also the oil would flow better around the bearing? They sell a kit to do this for the model T's I have been told-but I do not know how they do it. Any suggestions? Pleas all give any advise you have, this is all new to me, I am just wanting to build the best motor I can.
Ken
 
Ken,

You can't polish a journal round..it has to be ground. Heavy polishing leaves
a " swahle "(sp), low in the center and may be tapered. The crank needs to
be measured with a micrometer that reads in tenths( .0000 ).

I think we need more info from you....what have you got and whats been done.

Dudley
 
Poured babbit bearings are old-school technology (nothing wrong with that) and are labor intensive, what with the needed skills to pour, machine, burnish, etc. Your insert bearings , on the other hand, are precision machined at the factory and are not to be messed with. You will only screw up the surface. Nothing you can do in your garage or at the average machine shop will help (unless you have some old semi-finished inserts). If you need to burnish, something is majorly wrong.
 
You must log in or register to reply here.
Back
Top