KULTULZ (5/6/2024)

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What About The Rest of US ???

Considering that the latest crop of overhead cam engines being made by Ford do not use cam bearings on the camshaft journals, you have to question if bearings are required at all. Zero wear at those locations providing the engine had not been starved for oil. I have run into several instances where bearings were not available and I have simply made new bearings from brass for those engines. Many of the big diesel engines have brass cam bearings and they work for several hundred thousand miles. Early on, many of the oem engines did not use replaceable engine bearings and instead used 'poured babbit' for the interface between the moving parts. I was told early on that replaceable bearings were used to simply speed up the engine assembly process at the factory. Unless the oem's are able to control the machining tolerances to 0.0001", then replaceable bearings help to compensate for machining tolerances.

My engine building associates and I have had some interesting after-hours conversations regarding engine bearings. My thought process is as long as the clearance is suitable for the engine oil that's being used, then the quality of the bearing does not come to the forefront as the oil film is protecting both the journal and the bearing. If the oil film is doing its job, then there should be no metal-to-metal contact and thus no wear taking place. Hence those engines with 100K+ miles that show no bearing wear. Nitro methane or detonation does change that in that the dynamic oil wave gets pushed out of the way and then the quality or hardness of the bearing does come to the forefront. High compression engines tend to prefer a harder material for the bearings as a soft babbit will deform under extreme pressure loading. For most normally aspirated engine builds, the quality of the oil and the actual finish on the journals are much bigger considerations than the brand of the bearing being used. For some engines, there's not much choice in the brands of bearings but as a rule, I see very little difference in the wear attributes of the less expensive bearings versus those bearings that simply cost more.

Regardless of the bearing manufacturer that's being used, all engine bearings are checked with a ball micrometer for initial thickness before installation. It's also ideal that all the bearings being used within a set are the same lot number or were all manufactured at the same time. Measuring the bearings before actual short block assembly takes place will find those bearings that are not consistent in sizing. When the bearing clearances do not fall into the desired range with a particular set of bearings, that is sometimes alleviated by simply using the exact same brand of bearing and part number that was manufactured on a different day. Changing brands of bearings is also an option when a particular set of bearings does not fit the clearance criteria that's being targeted for.

While I have used the Engine Tech cam bearings in the Ford Y builds, I have not used their other bearings. I have used a variety of brands of bearings for the rods and mains and there are none that did not get the job done as designed.