M20 single mass flywheel on M50/M52

M20 single mass flywheel is great upgrade to M50/M52 engines if you want to reduce the rotational mass because they use twin-mass flywheels.

Parts and modifications that you will need:

• M20 flywheel – 228mm clutch disc diameter, single mass. Has the same flywheel/crank bolt pattern, but it has to be machined 4-6mm from the backside to clear the rear crank seal housing.
• Flywheel bolts – must use shorter M20 flywheel bolts or modify M50/M52 to fit.
• Starter/ring gear – M20 starter ring gear on the flywheel is different to M50/M52 so there are few options.
  1. Using M20 starter with M20 flywheel (starter doesn’t have threads in the housing so you will have to use bolt and nut to hold it in place).
  2. Replace the starter ring gear on M20 flywheel and fit the M50/M52 starter ring gear. Keep on using M50/M52 starter.
  3. Modify M50/M52 starter to fit M20 ring gear. Replace the bendix to M20 or BOSCH 1006209618/1006209693, OEM 12411722844.
• Throw out bearing – use E21 323 ’78-82 throw out bearing, 30mm height, part number SKF VKC2151, OEM 21511204525.
• Clutch – use M20 228 clutch disc and cover.