1974 BMW 2002

The 1974 BMW 2002’s M10 inline-four and ZF 3-speed auto have a few well-known quirks, but nothing that’ll scare off an experienced wrench-turner.

Engine (M10 2.0 L)

• Timing-chain tensioner can collapse if sludge blocks the oil feed—listen for a diesel-like rattle on start-up. Budget $80-120 for a fresh tensioner and 30 min of labour.
• Timing-chain guides get brittle past ~120k miles; replace them with the tensioner. Parts are $40-60.
• Oil leaks: valve-cover gasket, front crank seal, and the oil-pan cork strip. Gasket set is $35-50.
• Carb models (Solex 32/32 on your ‘74) suffer from clogged idle jets and vacuum leaks. A rebuild kit is $60-90 and a weekend of fiddling.
• Points ignition—keep spare points/condenser in the glovebox or swap to a Pertronix electronic module ($80).
• Cooling: radiator lower tank cracks and the mechanical fan clutch seizes. Radiator recore ≈ $250; clutch ≈ $70.

Transmission (ZF 3HP12 3-speed auto)

• Parts are getting scarce—most rebuild kits are listed for ‘75-76 only, but internals are the same ‘66-76. A full kit runs $350-450 if you can find it.
• Front pump bushing and sealing rings wear → delayed engagement and soft shifts. Fix is a pump rebuild while the box is out.
• 2-3 shift flare is common; it’s usually the direct-clutch drum sealing rings. Address during overhaul.
• Governor valve sticks → erratic shift points. A new valve is $60 and lives inside the pan.
• Vacuum modulator diaphragm fails → harsh or mushy shifts and ATF gets sucked into the intake. Modulator is $40-55.
• Heat is the enemy—small cooler, no lock-up in 1-3rd, so change ATF every 20k miles and add an auxiliary cooler if you’re keeping the auto.

Because your shell is missing both drivetrain pieces, you get to pick the healthiest used M10/auto you can find and refresh them on the bench before dropping them in. Good luck—plenty of parts vendors still support these cars, and the 2002 community is huge. Want help tracking down a solid used engine/trans combo or finding comparable project cars?