Volvo Penta MD21A, MD32A, AQD21A, AQD32A Workshop Manual
Volvo Models Covered & Key Technical Specifications
Models: Volvo Penta MD21A, MD32A, AQD21A, AQD32A
Sub-models / Variants: 4-cylinder variants (MD21A, AQD21A), 6-cylinder variants (MD32A, AQD32A), inboard engines, outboard drive 270D units
Model Years: 1975
Technical Data:
- Engine Types: Indenor XDP 4/90 (4-cyl), Indenor XDP 6/90 (6-cyl)
- Power Output: 55.2 kW (75 HP) for 21-series, 78 kW (106 HP) for 32-series
- Compression Ratio: 22.1:1
- Fuel System: CAV Roto-Diesel/DPA injection pump
- Firing Order (MD21): 1–3–4–2
- Firing Order (MD32): 1–5–3–6–2–4
- Crankshaft Pulley Torque: 170 Nm (MD21), 210 Nm (MD32)
- Cylinder Head Bolt Torque: 70 Nm (stage two)
- Lubrication System: Gear-type pump, 5.5 liters capacity (MD21) or 8 liters (MD32)
Volvo Manual Features & Content Preview
- Official 40-page Volvo Penta OEM workshop publication (Pub. No. 2769 B, December 1975 edition)
- Covers 1975 Volvo Penta MD21A, MD32A, AQD21A, and AQD32A marine diesel engines, including 4-cylinder and 6-cylinder configurations
- Outlines specifications for 12 specialized diagnostic tools, torque values for internal components, and comprehensive electrical wiring schematics
- Available as an instant download immediately after purchase
- Fully indexed PDF allowing you to search every chapter and appendix to speed up your repair workflow
- Stored safely in your account for easy retrieval if you lose your files
- Documents specific timing sequences and injection pump settings for the Indenor-based marine diesel engine family
Internal Mechanical Details
This factory publication details technical procedures for engine disassembly, fitting, and component inspection. You receive complete reference data for removing the electrical system, heat exchangers, cylinder heads, and timing gear assemblies. Dedicated sections provide the necessary tolerances to properly inspect the crankshaft, connecting rods, and piston assemblies. It outlines exact clearances for fitting new cylinder liners and verifying valve seat geometry. Accessing these factory measurements for the lubricating oil pump and cooling systems is essential for an accurate marine engine repair. Always consult a certified marine technician before performing service on this equipment to ensure safe operation.
Engine Specification Highlights
The manual delivers crucial reference values directly to your workbench. Cylinder head bolt torque is specified at 70 Nm within the multi-stage assembly data. For the Indenor XDP 4/90, engine timing gear backlash is documented at 0.04–0.14 mm in the tolerance tables. The cooling system capacity for the MD32A engine is listed at 8 liters. Clear wiring diagrams map out both early and late production instrument panels. Fuel injection parameters, including advanced injection angles and test bench procedures, are clearly documented for the 4-cylinder and 6-cylinder models.
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