S2KI Honda S2000 Forums - Cylinder #2 rod bearing failure again :-(

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Cylinder #2 rod bearing failure again :-(

So my last post included a video clip which turned out to be confirmed as rod knock. Needless to say after the time and cost $,$$$ to rebuild after originally spinning the rod bearing on cyl #2, I am disappointed and contemplating letting go of my S2. All new OEM parts including pistons, con rods, rings / bearings, $2K machine shop work including freshened head........all lead to failure. The one component, the crank, I had reworked, spec'd, nitrided......I believe is the suspect cause of failure. Either the bearing was not properly spec’d (highly unlikely and shop checked everything) or the oil supply on that journal isn’t flowing. Inspection of bearings on cylinders 1, 3 and 4 all look great. The journal on #2 looks great, no scoring or marks. So now I believe I need to most likely replace the crank. Full tear down and cost of a crank is pushing the rebuild into stratospheric costs. Attached are pics. Bearing failed after 600 miles while using high end break in oil. Feedback on solutions or approach to fix would be immensely appreciated. A year and over $5K, I’ve reached a threshold.

My guess is that Billman could read this situation better than anyone under the circumstances. My God this situation sucks! I realize how huge it is financially, believe me. Best of luck!

There are some very good PDF Documents form Companys like MAHLE, CLEVITE out there that picture in detail every possible engine bearing damage and describe the reason.
Do a google search, this forum dont let me post the links to ths PDF Documents.

I would also send pictures from this bearing to this companys and ask for theyr opinion what causes the damage.

Improper crankshaft service. The crank needs to be beyond mirror perfect. Who built the motor without replacing the crankshaft?

So they reworked the original crankshaft?

must you always replace the crankshaft, or only if there is a reason to when rebuilding?

I've had a few crankshafts serviced. There is no issue as long as you dont go over .002". The biggest issue I usually see is the main journal bores on the block going out of round. If you only had one rod bearing go that badly and that early either the bearing clearance wasn't set correctly or the rod was over/under torqued causing the bore on the rod to be out of round.

Also possible the rod is not round on the big end, would plastgage ok but fail. Was common problem on CBX motorcycles that hydro locked from carb float issues.
just an idea no knowledge of this problem occurring on S2000

Once a motor has chewed up a bearing, I would have leaned towards a new crank. Surprised the shop did not, but its hard to judge not knowing what they found when they inspected everything.