Crank hub slippage
The S55 crank hub can slip, most often on tuned cars running above stock power, which can throw timing and cause serious engine damage.
If it slips and bends valves, one shop puts the repair at $3k to $6k; if it costs the engine, a used S55 is $5.5k to $11k before fitting. Source: Palenon Performance, a shop that sells the work, September 2026; used-engine asking prices on eBay, October 18, 2026.
How to check
Ask about tune history and whether a pinned or upgraded crank hub has been fitted. Treat heavily tuned cars without it as higher risk.

