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IA Technical Bulletin

BMW M10 Engine Guide

Engine: M10

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The M10 is a SOHC inline-4 petrol engine that Wikipedia says BMW built from 1962 to 1988. It began in the New Class sedans and was phased out after the BMW M40 arrived in 1987.

Wikipedia says the engine was first known as the M115, took the name M10 in 1975, and got the standardised code M10B18 for the 1.8 liter version in 1980.

BMW sold the M10 in US-market cars. BMW's parts data lists it in five US models: the 1602, the 2002, the 2002tii, the E21 320i and the E30 318i. The dates are in Where you find it.

Wikipedia lists several versions of the M10, so which one a given car has depends on model and year. This guide covers only what we could prove.

Quick read

Ownership position: Not established yet. We are still researching this engine.
Reliability: Not established yet. We are still researching this engine.
Cost to own: Not established yet. We are still researching this engine.
Power potential: Not established yet. We are still researching this engine. Factory outputs Wikipedia lists are in Technical Specifications.
Main watch item: Not established yet. The two NHTSA recalls under Known Failure Points are the only BMW-backed items we found.

M10 At a Glance

Question	Practical answer
Sold in US-market BMWs	Yes. BMW's parts data lists the M10 in the 1602, 2002, 2002tii, E21 320i and E30 318i for the US market.
Years built	Wikipedia says 1962-1988 worldwide. US-market cars in BMW's parts data were built from 09/1967 to 09/1985.
Layout	SOHC inline-4 petrol with a cast iron block, an aluminum alloy head, two valves per cylinder and a chain-driven camshaft, according to Wikipedia.
Displacements	Wikipedia lists versions from 1,499 cc to 1,990 cc. Wikipedia's application lists give 1,573 cc for the 1602, 1,990 cc for the 2002 and 2002tii, 1,990 cc (1975-1979) and then 1,766 cc (1980-1983) for the US E21 320i, and 1,766 cc for the E30 318i.
Engine oil capacity	Not established for US cars. BMW's fill-quantity data lists 4.0 liters (about 4.2 US quarts) for the M10 B18 in the E30 316i and E28 518i, which are not US-market models in the parts data.
Reliability profile	Not established yet. We are still researching this engine.
Before buying	Confirm the exact version, because Wikipedia lists two M10 versions for the US E21 320i, a 1,990 cc M43/1 and a 1,766 cc M10B18.

Where you find it

BMW's parts data (the data we hold ends in December 2019) lists these US-market cars with the M10. Dates are BMW build dates.

US model	Built
1602	09/1967-03/1971
2002	02/1968-07/1976
2002tii	08/1971-12/1974
320i (E21)	07/1976-12/1982
318i (E30)	12/1982-09/1985

BMW's parts data lists the US E21 320i from 07/1976, while Wikipedia lists the 1,990 cc M43/1 in the US 320i from 1975. The tables here use the BMW dates.

Technical Specifications

Specification	Detail
Configuration	SOHC inline-4 petrol
Block and head	Cast iron block, aluminum alloy head
Valvetrain	Two valves per cylinder, chain-driven camshaft, rocker arm valve actuation
Crankshaft	Forged crankshaft with counterbalance weights and five main bearings
Bore x stroke by displacement	1,499 cc is 82 x 71 mm. 1,573 cc is 84 x 71 mm. 1,766 cc is 89 x 71 mm. 1,773 cc is 84 x 80 mm. 1,990 cc is 89 x 80 mm.
E30 318i	Wikipedia lists the 1,766 cc M10B18 at 77 kW and 10.0:1 compression with Bosch L-Jetronic fuel injection. US-trim output is not established.
E21 320i, US versions	Wikipedia lists a US-only 1,990 cc M43/1 with K-Jetronic, 81 kW and 8.1:1 compression for 1975-1979, and a US-only 1,766 cc M10B18 with K-Jetronic, 75 kW and 8.8:1 compression for 1980-1983.
2002tii	Wikipedia lists the M15 version with Kugelfischer mechanical fuel injection at 130 PS.
Engine management	Not established yet.
Engine oil	Capacity not established for US cars; see At a Glance. BMW of North America's oil chart (SI B11 01 15, February 2017) lists 5W-30 LL01 or 0W-30 LL01FE for all BMW gasoline engines of model year 2011 and older; it does not name the M10 by code.
Firing order	1-3-4-2, per BMW's Engine Technology training chart
Coolant	Not established yet.

Factory Deep Dive

Block and head

Wikipedia describes a cast iron block and an aluminum alloy head with hemispherical combustion chambers, two valves per cylinder, a forged crankshaft and five main bearings.

Valvetrain

Wikipedia describes a chain-driven camshaft with rocker arm valve actuation, a layout it also lists for the M30. Wikipedia says the M20 six uses a timing belt instead.

Fuel and induction

Wikipedia lists carburetors on the early cars, Kugelfischer mechanical fuel injection on the tii engine, Bosch K-Jetronic on the US E21 320i and Bosch L-Jetronic on the E30 318i.

Family

Wikipedia says the S14 used in the E30 M3 was based on the M10 block.

Service Parts at a Glance

These numbers come from BMW's US parts data (December 2019). Dates are BMW build dates. Check the exact car before ordering.

Part	BMW part number	Note
Oil filter	11421276850	Fits the E30 318i (12/1982-09/1985) and the E21 320i (07/1976-12/1982).
Oil filter	11421258038	Fits the 2002 (03/1971-07/1976), 2002tii (08/1971-12/1974) and E21 320i (07/1976-12/1982).
Oil filter insert	11429061088	Fits the 1602 (09/1967-03/1971), 2002 (02/1968-07/1976) and 2002tii (08/1971-12/1974).
Thermostat	11531253249	Fits all five US M10 models. BMW's data links it to 11531253248 and 11531468056, both current.
Air filter element	13721278138	Fits the E30 318i (12/1982-09/1985) and E21 320i (09/1979-12/1982).
Spark plug, Bosch WR9DS	12121272128	Four per engine. Fits the E30 318i (12/1982-09/1985) and E21 320i (09/1979-12/1982).
Spark plug, Bosch W6DC	12121338145	Four per engine. Fits the 1602 (09/1967-03/1971), 2002 (02/1968-07/1976) and 2002tii (08/1971-12/1974).
Ignition coil	12131359637	Fits the 1602 (09/1967-03/1971), 2002 (02/1968-07/1976) and 2002tii (08/1971-12/1974).
Exchange water pump	11519056401	Fits the 1602 (09/1967-03/1971) and 2002 (02/1968-07/1976).

Known Failure Points and Service Items

Not established yet. We found no BMW service bulletin or training document for the M10. NHTSA lists two recalls on the US E21 320i, which BMW's parts data lists only with the M10. NHTSA records list vehicles by model and model year, not by engine, and we cannot say whether a given car had the remedy done.

01 Fuel vapor bubbles, 320i, model years 1977-1978

NHTSA recall 78V-061 was received on 24 March 1978 and covers the 1977 and 1978 320i. The record says a high fuel flow rate in the fuel system can lead to fuel vapor bubbles under extreme altitude, temperature or fuel contamination. The remedy was an additional fuel pump in the right side of the fuel tank.

Watch for: rough engine running or stalling, which the record names as the possible result.

02 Accelerator return springs, 320i, model year 1977

NHTSA recall 77V-092 was received on 16 June 1977 and covers the 1977 320 and 320i. The record says the two accelerator return springs on top of the engine may oscillate at high engine speeds, causing vibration noise and early spring fatigue, and that breakage could make it impossible for the accelerator system to return to idle. The remedy was to inspect the springs and, if necessary, fit rubber sleeves over them.

Watch for: vibration noise from the top of the engine at high speed, and an accelerator that does not return to idle.

Reliability Verdict

Not established yet. We are still researching this engine.

Power Potential

Not established yet. We are still researching this engine.

Cost of Ownership

Not established yet. We are still researching this engine.

Common Questions

Which US-market BMWs had the M10 engine?

BMW's parts data lists the M10 in five US-market models: the 1602 (built 09/1967-03/1971), 2002 (02/1968-07/1976), 2002tii (08/1971-12/1974), E21 320i (07/1976-12/1982) and E30 318i (12/1982-09/1985).