Do you have H beam rods? Also i would not use them unless you have H beam rods,,that's what the H stands for..you also are running a cast crankshaft and the h series bearings are too hard for the crank and will ware on it..The coated bearings, you best mic the crank first,the coating adds a .0001+ oil clearance,in other words they are tight and could cause issues.

I'm running the Eagle I-beam cap screw rods, not H-beam. I was under the impression that the H-series bearings were recommended for most of the aftermarket cranks because they have the larger chamfer for the bigger fillet radius that is common on the aftermarket cranks. As long as there is a good oil film why would it make a difference whether the crank is cast or forged? Can you elaborate? If a lot of junk went through the bearings, I could see where a softer bearing would spare the crank surface, but otherwise it doesn't make sense to me. Thanks.

The "H" stands for High Performance as you can see in the Clevite part number key on Jegs. Their the one you would want. They do have a "HK" which has a moly/graphite coating. Here's a cut/paste about them.

The exclusive Clevite® TriArmor™ engine bearings feature the industry’s only moly/graphite treatment. This sophisticated blend, in a low friction PTFe polymer base, offers extraordinary protection and lubricity. Enhanced wear characteristics increase bearing life in race engines and high performance street engines.

Now, high performance engine builders can enjoy the strength and durability of the legendary Clevite® TriMetal™ bearing construction coupled with the latest in coating technology - right out of the box.

For years, engine builders have experimented with coating engine bearings for race engines and high performance street engines, with varying degrees of success. Now, MAHLE engineers, after extensive research and development, have devised TriArmor™, a proprietary blend of molybdenum disulfide (MoS2) and graphite all carried in an inert polymer substrate.

Central to this breakthrough is the exclusive use of graphite and unique application and low temperature cure processes. These processes provide extremely uniform thickness coupled with unparalleled adhesion, all while protecting the metallurgical integrity of the bearing during the coating procedure.

The result? A .0003” thick protective coating that offers: * Reduced friction and drag, resulting in increased horsepower
* Protection during start-up
* Embedability to resist damage from debris
* Ability to withstand extreme temperatures and pressures
* Conformability for distressed or imperfect surfaces
* Extraordinary strength and durability

Looking back it sounds like the HK is what your builder was talking about.

This is old but has some good info in it.

http://stealth316.com/misc/clevite-7...n-bearings.pdf

Thanks for the info, Jim. Wow, those HK coated bearing are pricey! Cheapest set of mains I could find run $130. Is the extra money for the coating worth it?

Probably not for a 500-550hp engine that's only going to see 5500 rpm max on occasions. Just pointing out that's probably the ones your builder was refering to.

scratch my comment,,i was thinking of the alunimum rod's in the 740'' engine in the race car....those have location holes drilled in them..

your right, does not matter what rods, and does not matter forged vs. cast crank, I love when the non engine builder guys chime in since both of them answers were wrong... the oil film is between crank and bearing, in reality they never touch...I have cast cranks with coated H-series on rods and mains..my rods are also forged 420 rods.

I like the coated bearings and always use them, when you have fails they can save you, I had a fail, cracked a cylinder wall and contaminated the oil with lots of water, did ZERO damage to bearings and actually reused them and 5 years later all is well, they had looked like they were never ran...

YES when building the engine you really don't wanna save money in the wrong places...its worth the money should you have oil issues or contaminate with water...

I am not a pro but I thought the H stood for hardened? I am building a nice 4 bolt forged 454 now and will use the clevite H series bearings..... Our boat motors really need the extra toughness and resistance to fatgigue, heat, etc, as they are run under high loads for long times....... I think using the H series is cheap insurance for just a little more money...... I would certainly get the advice of an experienced marine engine builder..... TBF