V-12 Cam bearings??

Is there any engine that has used aluminum cam bearings successfully?

Aluminum alloys are one of several types of heavy duty bearing material used in insert rod bearings. For several year just before and during World War TWO, aluminum rod bearing inserts were an "option" in the Packard Service Parts book for the Packard Twelve.<P>Aluminum alloy insert rod bearings were also popular in high performance piston aircraft engines.<P>I am going to GUESS and say they fell out of favor because they were subject to oxidation from the pollutants / by products of the combustion process. <P>GIven the superiority of modern oils, and the fact that modern automotive gasoline is so clean-burning, I see no reason why this shouldn't work for you!<P>Pete Hartmann

Thanks Peter I think I will try the aluminum. I understand Caterpiller uses aluminum in the cam bearings in its diesels. Sounds like it will hold up. Doug

Having several Pierce V-12 in my garage and having rebuilt several different classic engines I thought I would comment. First of all i wonder how you would cut the id on the bearings once they were installed. Most of the old style in line hand driven cutting equipment probably would make a mess of them. Most of a Pierce 12 oil pressure loss is at the cam bearings, many of the V-12 have low pressure and it usually can be traced to the cam bearings. Remember that with the early style lifters in this engine low oil pressure will cause lifter tick. Babbit cam bearings work fine in my engines, and with a carefull rebuild we have 30 lbs of pressure at idle on a hot engine. While inserts are fine and many people have no problem with them, I prefer to use the modern high pressure babbit. I drive my cars much more than most club members and tend to drive them VERY hard and I have never had a problem. Any problems related to the new type of cam bearings is not worth the risk to new or more engine damage that it could cause. The failure of a untried idea in thet engine could lead to a lot of grief.