Alternatives To Babbitt

Stationary Engine List


| October/November 2000



Stationary Engine

The Stationary Engine Mailing List threw up some good discussions this past month to pass on GEM readers. As usual with a group of engine enthusiasts numbering around 300 on three continents, the discussion was lively to say the least, and flew off at several different tangents, including the ever faithful 'styles of restoration' argument, which I may one day bring to these pages. But I will cover myself right now by saying it is purely a matter of personal preference!! So, on to this month's subject:

Can anyone tell me if JB Weld is strong enough to make a bearing, instead of babbitt? I need new crank rod bearings on both my Renfrew Whatever and 2 HP Fuller Johnson. I am not a machinist. There is no one in my area to help me with babbitting, something I know absolutely nothing about. I do not have the equipment for grinding, finishing, polishing, etc. I want to get this engine running with the resources I do have, or with what is available.

I have read with much interest about using epoxies in place of babbitt for bearing material. While a marginally serviceable bearing could possibly be made of one of the numerable epoxies on the market, all of them would be inferior to babbitt. Babbitt's chief merit is in the fact that any dirt that will invariably find its way into your bearing will be forced into the soft bearing material and minimize the amount of scoring this dirt will do to your journal. A brass bearing or aluminum bearing is too hard to allow the dirt or grit to work its way into the bearing material where it will do little harm. JB Weld, Belzona and Devcon products are also too hard.

Pouring babbitt is really not difficult if you have any mechanical aptitude. I often pour my bearings around an undersize mandrel and bore them to size in the mill. Careful bluing and scraping would yield the same results, albeit much more slowly.

Making an insert is an option, although I fail to see any real advantage to it. The bearing boxes on many engines were rough cored, meant to be babbitted to situ. To machine the casting for an insert would be as much work as machining bearings cast in place. A bearing machined from a billet of babbitt would actually have less compressive strength than one cast and bored in situ. This is taken care of in modern engines by 'crush' as mentioned in another posting on the subject.

I am 31 years old and have been collecting engines since I was 12. I poured my first rod bearing when I was 14. If a kid can figure it out, any of you should be able to do it better. Someone expressed a concern about the paint being damaged; just accept the fact that the paint is going to need to be touched up but at least the engine will be repaired right. A rebabbitted bearing box should outlast all of us if done right and kept lubricated.