VW Type 4 Cylinder Heads and Crankcases
VW Type 4 Engine: Cylinder Heads & Crankcases
This article provides detailed reference information on Volkswagen Type 4 cylinder heads and crankcases, including part numbers, specifications, and identification tips.
Cylinder Heads
Type 4 cylinder heads are cast‐aluminum, compact-wedge combustion‐chamber designs with dual intake ports (similar location to Type 1) and exhaust ports exiting through the bottom between pushrod tubes. While most Type 4 heads interchange across series, port sizes, chamber shapes, and ancillary provisions (breather, EGR, air‐injection bosses) vary and may require minor machining or plug‐off work.
Valve Sizes & Part Numbers
| Engine Series | Part Number | Valve Sizes (Intake × Exhaust) | Notes |
|---|---|---|---|
| 1.7 (1679 cc) | 021‑101‑371B/J/Q, 021‑101‑372 | 39.3 × 33 mm | Some have breather pipe or CHT boss; EGR port on carb models |
| 1.8 (1781 cc) | 021‑101‑371H/S | 41 × 34 mm or 39.3 × 34 mm | EFI models have smaller intakes; some have EGR/CHT ports |
| 2.0 (1971 cc) | 022‑101‑372G, 071‑101‑371A/B | 37.5 × 33 mm | Sodium‐filled exhaust valves; Vanagon heads have unique port shape |
| 914 / 912E (Porsche) | 039‑101‑371A | 42 × 36 mm | 3 intake studs, steeper plug angle; highest HP potential |
Crankcases
Type 4 crankcases are split die-cast aluminum with increased cylinder spacing and a larger stud pattern, allowing for larger bore sizes resulting in increased displacement. They feature case through (thru) bolts across the main journals, unlike the Type 1 crankcase that has fasteners that thread into the opposite case half (a much weaker design). Each series is identified by a prefix cast into the case.
Case Prefixes & Specifications
| Prefix | Series (cc) | Application | Compression Ratio | HP / Torque | Notes |
|---|---|---|---|---|---|
| V | 1.7 (1679) | ’69 VW 411 | n/a | 68 hp | Rare; not magnesium (VO is Mg) |
| W / Z | 1.7 (1679) | ’71 VW 411 / ’69–70 VW 411 | 8.2 : 1 / 7.8 : 1 | 80 hp / 68 hp | Fuel‐injected / dual carb; auto trans Z has lower output |
| CB / CD | 1.7 (1679) | ’72–73 Bus | 7.3 : 1 | 63 hp / 59 hp | Carb; auto trans CD has lower hp |
| EA / EB | 1.7 (1679) | ’73–74 411/412 / ’73 914 | 8.2 : 1 / 7.3 : 1 | 80 hp / 72 hp | EFI types (D‑Jet / L‑Jet); California EB |
| EC / ED | 1.8 (1795) | ’74 412 / ’75 Bus | 7.3 : 1 | 76 hp / 67 hp | EFI; California only / fuel‐injected Bus |
| AN / AP / AT | 1.8 (1795) | ’74 914 / Bus (& Euro) | 8.6 : 1 / 7.3 : 1 | 85 hp / 68 hp / 75 hp | 914 EFI / Euro carbs |
| AW / GE / CJ / CU / CV | 1.8 (1795) / 2.0 (1971) | ’73 Bus / ’78–83 Bus / Vanagon | 7.3 : 1 / 7.5 : 1 | 65–92 hp / 92 ft‑lb | Late Bus: unique ports, E‑pump; CV needs 911 fan tower mod |
| GA / GB / GC / GD | 2.0 (1971) | ’73–76 914 / ’76 912E / Bus | 7.6–8.0 : 1 | 95–100 hp / 101 ft‑lb | 3 stud intake; D‑Jet / L‑Jet; solid lifters on GD |
Common Misidentification
CT / CZ (1.6 L): Euro Bus 1980–82; modified Type 1 case, not true Type 4. Uses Type 1 heads, cast‑in filter boss. Limited interchangeability.