M6x engine swap for E30 chassis is a pretty interesting setup. A budget swap is based on M60B40 engine, mostly due to its simplicity with both wiring harness and ECU. The other low cost option is to go with stock M62B44 engine. M62B46, and M62B48, and S62 are viable, but these options are expensive, and their availability is also scarce.

So how about installing M60B44 engine? Hey, wait a minute! There is no official engine type such as M60B44 from the factory line. The aforementioned code simply refers to a custom built engine, utilizing the best components from both M60 and M62 engine generations. This unique combination creates a high compression engine, a ratio typically found only in S-series of engines. In the land of “what ifs”, this engine could have been rolled out from the factory as hypothetical, high power S-variant for M60 engine family. This homebrew engine modification is also know as M60B44 hybrid motor, or M60B44 frankenmotor.

The base recipe for M60B44 consists of:

M62B44 bottom end,

M60B40 cylinder head,

M60B40 robust timing assembly with duplex chain,

M60B40 wiring harness, sensors and ECU.

Benefits of building M60B44 engine:

• Increased 11:1 compression ratio,
• Almost ideal stroke-to-bore ratio. In comparison, Ferrari 458 engine with 4,5 litres capacity has 94mm x 81mm (Bore x Stroke) whereas M62B44 engine is 92mm x 82,7mm,
• 4,6 litres and bigger M6x bottom ends increase stroke, which leads into increased piston speed, and compromised high rpm performance,
• Wide selection of high quality M60 engine cams from Cat Cams,
• 32 valve cylinder heads are capable to flow over 600hp,
• Very robust duplex timing chain that can take the beating,
• Stiffer dual spring valve train. To gain real benefits from the M60 springs, you must assemble lighter lifters, see my other article here,
• 600 grams of weight saving with aforementioned lifters, allowing the top end to sustain revs up to 8400 rpm,
• Durable Alusil block,
• Lighter forged crankshaft, thanks to revised design with the central hollow cavity,
• Oil spray nozzles for pistons,
• Gaining the benefits of using M62B44’s MLS-type cylinder head gasket.

Building tips for M60B44 engine:

• Remember to block the obsolete oil channel for M62 cam tensioner,
• Take home points from lightweight lifters, see my other article about them here,
• 3,8 kg weight reduction from rotating masses with hollow, gun drilled Cat Cams -cams,
• up to 7 kg weight reduction from rotating masses with solid flywheel,
• Custom 4-1 headers with 2,25″ collector size for optimal torque delivery,
• The 1992 model year has the best “Trumpet” or “Horn-style” intake manifold, see my other article about the aforementioned here,
• The 1996 model year has the best flowing 80mm throttle body (No additional wedges),
• Remember to use the better crankcase ventilation system,
• Properly built, Corvette -style cold air intake with RAM-air effect, see my other article about naturally aspirated engine tuning about reducing pressure losses,
• Use of other lightweight components, see my comparison chart of light weight engine components here,
• With all above tips utilized, your engine is capable of producing amazing torque, up to 113 nm per litre!