[yupetc]

Originally Posted by lforter

I don´t think metal on metal contact occurs on our cars because of the high horsepower. There are several high-horsepower n54 around with no problems to bearings, I dont know how neccesary are trimetal softness since our cars dont rev that high, however, in our case (n54 and n55) the babbit could help as an extra layer of protection, as long as it keeps it, it provides less chance of seizing, otherwise they will seize faster than a bimetal (theres a PDF from king where they show this on some test).

I believe the problem with our cars is oil starvation and contamination during high Gs and poor maintenance. So if you replace the rod bearings I would suggest going for some coating or WPC treatment or not do them (since if you just change them for normal bearings you are just as likely to failure, since the problem is not the bearing itself). Going for bi metal or tri metal is a personal choice, but I dont think it will matter much, maybe if you drag race it will be better for tri metal? or if you dissassemble your engine often. In any case, the main problem will persist (oil starvation) so other solutions must be proposed.

You're right, doesn't matter what bearings we use, the problem still persists with oil starvation and dirty oil. And bearing choice is more of a personal choice/preference. I just happen to be the guy who opens up the engine every 20-30k, so yea, which ever bearing I put in there, I have ample of time to react if some bad primitive wear were to happen. I went with trimetal bearings for my build, and opened it up after 20k miles of use and found zero scratch on that thing; henceforth the recommendation. Note that I also changed the oil 6 times during this 20k mile bout.