Clutch Masters Custom Steel Flywheel K-Eng to S2K Trans
Clutch Masters FW-K2F-SF is the steel flywheel for a Honda or Acura K20 or K24 engine bolted to the six-speed transmission from a Honda S2000. That rear-drive K-swap, which Clutch Masters catalogs as K Motor to F Trans, is popular in S2000 builds that have dropped the original F20C or F22C and in custom rear-drive chassis that want the S2000 gearbox behind a K-series. Stock parts were never made for this pairing, so the flywheel is the piece that makes the engine, the clutch and the transmission line up.
The flywheel bolts to the K-series crankshaft and carries the clutch that drives the S2000 input shaft. On a conversion like this it also has to put the clutch friction face and the pressure plate mounting in the right place for the S2000 release system. Clutch Masters designs its K2F clutch kits around its own K2F flywheels and states that those kits will only work with FW-K2F-SF or the aluminum FW-K2F-AL. In practice that means you choose the flywheel and the clutch as a matched pair from the same system.
The SF version is the lightweight steel option. Clutch Masters says it machines its steel flywheels from 1045 steel billet, zero balances them, black-oxide coats them against rust and certifies them to SFI 1.2 for motorsports. Steel keeps a little more rotating mass than the aluminum version, which helps the car pull away smoothly and cope with stop-and-go traffic, while still revving more freely than a heavy stock unit. The listed shipping weight is 15 lb. If the car is mostly a track or autocross build, the aluminum flywheel is the lighter choice; for a street-driven swap the steel one is easier to live with.
On a car that is already swapped, pull the transmission and inspect the flywheel face and the bolt holes before buying parts. Hot spots, heat cracks running toward the edge or a face that is out of flat mean the flywheel should be replaced rather than resurfaced again. If the clutch is slipping, log rpm against road speed in a high gear first; our slipping diagnosis guide explains how to read it. Also confirm which flywheel your current clutch was built for, because a K2F clutch kit will not work on another maker's swap flywheel and the reverse is also true.
Clutch Masters lists FW-K2F-SF for Honda and Acura K20 2.0L and K24 2.4L engines from 2000 on, mated to the F-series S2000 transmission. It is not a flywheel for an S2000 that still has its original F20C or F22C engine; that car uses an S2000 flywheel such as the ACT Streetlite 600355. It is also not for a K-series with a Honda front-drive gearbox or a Subaru box. For a K engine into a Subaru six-speed, Clutch Masters makes the FW-K721-SF flywheel instead. Swap kits vary by adapter and bellhousing, so tell us the engine code, the transmission and whose adapter you used, and we will confirm before you order. Browse more parts in our clutch and rebuild kits section.
| Brand | Clutch Masters |
| Part number | FW-K2F-SF |
| Fits | Clutch Masters Custom Steel Flywheel K-Eng to S2K Trans |
| Type | Flywheels |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
No. It is built for a Honda or Acura K20 or K24 engine bolted to the S2000 transmission. A car with its original F20C or F22C uses a standard S2000 flywheel.
Clutch Masters builds its K2F single-disc clutch kits for this flywheel and says those kits only work with FW-K2F-SF or FW-K2F-AL. Pick the kit level by how much power the K engine makes.
The steel SF keeps more rotating mass, so it is smoother pulling away and in traffic. The aluminum AL is lighter and suits a car driven mostly on track. Both fit the same K2F clutch kits.
No. Clutch Masters makes FW-K721-SF for a K engine into a Subaru six-speed. FW-K2F-SF is only for the S2000 F-series transmission.
No, it is an option. Clutch Masters says the hardened shim adds only about .010 to .012 in and helps stop fretting between the crankshaft and flywheel.
