BMW N43 Four-Cylinder Petrol 2007-2013


Not seen in North America – for that, you may be eternally grateful…

The BMW N43 engine is a technological masterpiece. Delivering 170 bhp with no turbocharger in a 2-liter four-cylinder engine was fairly an achievement. BMW designed this engine with one arm behind their again – dealing with ever stricter emissions rules on one hand, and the problem of creating an engine tractable and economical on the opposite.

The N43 was spectacular for its time in 2007, that includes an all-alloy building with a ladder-type crankcase, the place the principle bearing caps are constructed right into a ‘ladder’ kind body for critical energy. It had Double Vanos cam timing, 16 valves with chain-driven camshafts, however lacked Valvetronic – BMW’s intelligent concept that altered the carry of the inlet valves to regulate engine pace and cargo, however was incompatible with direct injection.

The timing chain setup used a cassette-type chain meeting, lowered down into the engine with the cylinder head fitted as an entire unit with the chain, the plastic information rail, and pivoting tensioner blade, crank sprocket, and the 2 Vanos items. Apparently, the crank had no nostril onto which the crank sprocket would match, and the tip bolt was tightened to 300nm, counting on the torque of the bolt to maintain it collectively – a design that works properly. Equally, the Vanos items weren’t keyed to the camshafts both, and stretch bolts had been used, activated by oil stress and managed by digital oil stress solenoids.

The generator and AC pump ran off one auxiliary belt, and to save lots of gasoline and assist emissions, an electrical water pump and electrical energy steering rack had been used, with a camshaft-driven brake servo vacuum pump. The oil pump is integral with the stability shaft unit within the sump, chain-driven from the crank. An ECU-controlled thermostat regulates engine temperature, and for final effectivity, the oil stress is regulated by an digital solenoid in the principle oilway to supply the engine with simply the oil stress it wants, lowering the load on the pump.

There are two engine capacities used on the N43: a 1.6-liter unit for the 116i and 316i, and a 2-liter within the later 116i, 118i, 120i, 318i, 320i twins, and an E60 520i. The principle change for the N43 over the N46, from which it was derived, was the introduction of direct injection. This required a brand new head casting to just accept the massive metallic Piezo injectors, in addition to a camshaft lobe-operated high-pressure gasoline pump. EGR (exhaust fuel recirculation) was used, together with a set of exhaust fuel sensors. Along with the three Lambda probes, there’s additionally a NoX (nitrogen oxide) sensor.

What about PIEZO?

No, it’s not an Italian dish, though these injectors had been made within the VDO Siemens Italian manufacturing facility. These injectors comprise Piezo crystals that broaden and contract when given {an electrical} pulse, permitting for an extremely quick and correct gasoline spray. These injectors are astonishing and contribute to the engine’s energy output of 170 bhp.

What Goes Fallacious?

The N43 was beset with misfires and working issues ten or fifteen years in the past. Troubled Piezo injectors, in addition to failing coil packs, made many an N43 proprietor’s life a nightmare. In fact, these points may be fastened, however at a value – new injectors are round £400 every, plus becoming and coding, and also you’d hope you don’t want to exchange the opposite three since they can’t be reconditioned.

The timing chain has a fame, nevertheless it’s extra the chain guides than the chain itself – precise chain breakage is uncommon. If the plastic guides have damaged up, the oil pan will have to be dropped to get the bits out. Bits of chain information blocking the oil pick-up strainer are in all probability the most important killer of N43 motors. N43 Vanos items are higher than the older N46 ones and don’t fail that always.

The N43 had a poor fame for being a misfire nightmare. It’s not BMW’s fault both as a result of they had been compelled down the direct injection route by Euro emissions legal guidelines. The unique Piezo injectors have largely been changed with new ones by now. NoX sensors can fail and trigger the automobile to run massively wealthy, and used ones are very uncommon. A NoX emulator from Bimmerprofs is a greater thought as they are often tuned to the engine and never vice versa. The three Lambda probes are dependable, nevertheless.

The N46 may be smoky in previous age, however the N43 appears significantly better. The brake vacuum pump can fail, that means the servo gained’t work (heavy brakes), and it’s not really easy to exchange. Low oil stress may be attributable to three issues – worn stability shaft bearings, a defective stress solenoid, or a defective thermostat ensuing within the engine working too sizzling.

Is The N43 Dependable?

Total? The N43 is a dangerous proposition, and the N46 – significantly the later variations – is a greater thought. On one hand, it performs properly and might obtain 40 mpg with care, however so do many different vehicles. Reliability is actually a problem, however these are actually of a worth low sufficient to not fear an excessive amount of. If nothing else, one is an interesting engine… it’s simply ironic that this and the direct injection N53 straight six had been denied entry into the US.”


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