First, you must realize that modern bearings STILL USE BABBITT MATERIAL!!! But the process of POURED babbitt using a rough form then machined vs more of a very thin 'plated' bearing which required minimum finishing.
Insert bearings were invented to take out all the work needed to repair a babbitt engine, and increase tolerances. Babbitt may last longer, or 'wear more gracefully' but the time and cost involved (even back in the day) would be significantly higher than inserts. Also motors that use babbitt bearing gave nowhere near the performance of later insert bearings.
For my 235 a set of bearings is less than $100. That's not even an hours time at a good machine shop.
"Babbit can imbed a lot more foreign material without totally destroying the bearing layer."
Well oil filters not being a big deal back then they yes, you will have a lot more crud in the oil as there was no filtering. But in the 40's engines starting getting oil filters and detergent motor oils so the amount of 'crud' would be significantly reduced. Also PCV systems taking a lot of moisture out of the oil decreased sludge. So thick babbitt bearings were really not needed.
If you read the service manuals and look at the amount of work to rebuild a babbitt bearing motor vs an insert motor its obvious that inserts, while not having ALL the supposed 'benefits' (again, this is more emotional than scientific, inserts solve every problem babbitts have) is a significant step forward in reliability and cost.
Is one 'better' than the other? Well, the purest will say that if the motor was poured babbit, then it should ALWAYS be poured. But for the cost of getting that work done vs 'failing gracefully' that makes no sense. For the cost of poured babbitting you could change your inserts every 50,000 miles, never see any significant wear, and still cost less than a babbitted motor getting ONE rebuild.
Last edited by pfarber; Sun Jan 01 2017 07:16 PM.
