The EMSCauto N12 Engine Rebuild Kit is a configurable rebuild package for R55, R56, R57, R58, and R59 MINI models equipped with the N12 engine. Designed for everything from a dependable stock-style rebuild to a stronger long-term street foundation, this kit lets you choose the piston, bearing, gasket, fastener, and timing components that best fit your engine condition and intended use.
Whether you are repairing a worn high-mile N12, addressing common timing and oil consumption issues, or rebuilding for long-term reliability, this kit helps you assemble the right combination of parts without guessing. For the N12 platform, piston options are offered exclusively through SneedSpeed, while bolt and bearing options still include SneedSpeed, ARP, and King where applicable. That gives you a cleaner, more focused package built around what actually makes sense for the engine.
From daily-driver rebuilds to stronger refreshed engines, this kit gives MINI owners and engine builders a solid starting point for restoring compression, improving reliability, and rebuilding the engine correctly the first time.
Build Path Options
| Build Path | Recommended Setup |
|---|---|
| Street Refresh | SneedSpeed pistons in STD size or rings-only option where applicable, Street Series bearings, Street head gasket, bolts, no rod bolt upgrade unless needed, SneedSpeed Cryo Hardened Timing Chain Kit, bearing size based on crank measurements |
| Light Performance / OEM+ | SneedSpeed pistons in STD or .5mm overbore as required, Performance bearings, Performance head gasket, Sneed Studs or ARP Studs, upgraded rod bolts as needed, SneedSpeed Cryo Hardened Timing Chain Kit, bearing size based on machine shop spec |
| Long-Term Reliability Build | SneedSpeed pistons in STD or .5mm overbore based on bore condition, King or performance bearing options, Performance or upgraded head gasket, Sneed Studs or ARP Studs, upgraded rod bolts where justified, SneedSpeed Cryo Hardened Timing Chain Kit, bearing size based on final crank machining |
| Full Rebuild Spec | SneedSpeed pistons in STD or .5mm overbore, King bearings or equivalent upgraded bearing strategy, upgraded head gasket, ARP Studs or Sneed Studs, upgraded rod bolts where needed, SneedSpeed Cryo Hardened Timing Chain Kit, bearing size based strictly on final crank measurements |
Which Build Is Right for You?
| Best For | Pistons | Bearings | Head Gasket | Head Fasteners | Rod Bolts | Timing Chain | Bearing Size | Summary |
|---|---|---|---|---|---|---|---|---|
| Street Refresh | Daily drivers, tired engines, stock rebuilds | SneedSpeed pistons in STD size if replacement is needed, or rings-only option if pistons are reusable | Street Series | Street | Bolts | None unless build justifies upgrade | SneedSpeed Cryo Hardened | Based on crank measurements: STD, .25mm under, or .5mm under |
| Light Performance / OEM+ | Stronger street cars, refreshed daily drivers, customers wanting extra durability | SneedSpeed pistons in STD or .5mm overbore as required | Performance bearings | Performance | Sneed Studs or ARP Studs | Upgraded as needed | SneedSpeed Cryo Hardened | Based on machine shop spec |
| Long-Term Reliability Build | High-mile engines, full rebuilds, customers planning to keep the car | SneedSpeed pistons in STD / .5mm based on final bore size | King or upgraded bearing options | Performance or upgraded gasket option | Sneed Studs or ARP Studs | Upgraded where justified | SneedSpeed Cryo Hardened | Based on final crank machining |
| Full Rebuild Spec | Complete engine rebuilds, machine-shop builds, strongest available N12 package | SneedSpeed pistons in STD / .5mm depending on bore size and build spec | King bearings or most aggressive bearing strategy appropriate to the build | Upgraded head gasket | ARP Studs or Sneed Studs | Upgraded where needed | SneedSpeed Cryo Hardened | Based strictly on final crank measurements |
