Disagree. The
degradation of BEBs in some 1H-series of motors is well established.
It is speculation that the
cause of BEB degradation is due to a crank oiling problem. "Crank Oiling Problem" is a very broad explanation for BEB degradation.
Is
this the research paper you are referring to? That's a very interesting research paper and might be helpful to solving the BEB degradation. But I think it's important to keep in mind that the research paper:
- Is testing a generic inline 6 diesel engine with at least 7 main bearings. No specific mention of 1HZ, 1HZ-T, 1HD-T, 1HD-FT, 1HD-FTE, or any Toyota Diesel engine is made.
- Is discussing and testing the main journals of a diesel crankshaft. Not the BEBs.
- Is NOT testing for degradation of bearings due to cavitation or degradation for any other reason.
- Is testing for noise above 5kHz in the main bearings.
- The paper explains that the cause of the noise is from:
- (1) the cavitation of oil on the bearing surface; and
- (2) vibration of the main journal.
- The paper concludes that the noise can be prevented by adding grooves to the bearing surface, preventing the cavitation from reaching the edge of the bearing and causing the 5kHZ noise.
- Cavitation erosion is occurring during the tests, but the paper makes no mention for preventing cavitation/erosion on bearings of any type.
- A Toyota engineer was on the team.
I also reviewed
this article on the 1HD-FTE. Toyota added grooves to the
main bores of the FTE to transfer grooves into the bearing surface of the main bearings, presumably to reduce noise. There is no mention of BEBs or big end conrod modifications.
True. But how do we prevent BEB degradation? Is it due to cavitation erosion? Should we increase the oil pressure? Add aftermarket BEBs with grooves or chamfers? Reduce running clearance? Run harder bearings? Switch to 1HD-FT conrods?