Originally Posted by hcompton
Yes all true but bearings are made out of a lot more metals than lead and tin. Usally they are zinc coated i was always taught not to even touch it or the caoting will react with the acids in your hands. It is also there for the rest of the life of the crank over years of wear these metals are taken off and that is when the crak begins to fail.
If you never had metal to metal crank contact you would never need to replace the bearings. They would never go bad with just oil touching them. But sadly that is not true they touch on start up and other times in an engines life when oil to that one bearing gets low or over powered and squished out this usally results in spun bearing.
I didnt think new bearings were made with lead in years since its not enviro freindly. When you pay extra for nice high performance bearings you are buying coatings, and they are alot more than flat metal that is the easy part.
I dont think I said anything about lead on inserts but I do buy old stock bearings that still contain it like from EGGE still on the shelves and use it for pouring Bobbitt's I just did a Whippet.
# 1: Bearing wear is caused mostly from dirt, carbon, acids, metal particles corrosion from contamination etc, etc, coming through the oil passages not from crank contact! A filter because of the bypass does not filter all the oil during the running of an engine only a percentage! The grooves in old bearings is not from crank contact! If you block the bypass like some do + me on race cars all your oil is filtered all the time , But most filters cant handle flow capacity or pressures!!! A lot of people think oil filters on domestic vehicles, filter all the oil all the time and contaminants cant escape! But they would be very, very wrong!!!!
Your entitled to an opinion wrong or right do what works for you!! But inserts are designed to be modified there is plenty of material to work with for slight increasing of clearances! You don't polish down 1 crank journal to get a .001 to .002 additional Clearance! Its silly!!! To me! It would be like honing a cylinder or deepening the ring land grooves to get your proper ring gap instead of filing the rings! Your the first person I ever heard say that! But to each his own do what works for you.