BMW M10 Four Cylinder Engines

BMW M10 engine

1800Tisa twin carb performance engine.


In the early 1960's the German economy was recovering from the war at break neck speed. The middle classes were ready for a newer and larger car than BMW's 700 which used a modified motorbike engine in the rear. BMW responded with the ground breaking "Neue Klasse" saloons featuring such innovations as independent suspension and the engine which would eventually be known as the M10. This was the car that set the pattern for all modern BMWs and so did it's engine.

The Neue Klasse came to market in late 1961 with the single 1500cc option. This set new standards in it's class and demand was high. It wasn't long until BMW responded with a 1600, 1800, 2000 and a highly tuned twin carb version for the 1800Tisa.

Alpina's first products were released in an attempt to extract more power from the 1500cc engine.

A sportier two door version of the car was brought to market in the form of the 1600-2, soon to grow into the famous 2002 with its two litre engine in many variants. In the late '60s the predecessor of the E9 3.0CS came to market as the 2000C with a single carb or 2000CS with a twin carb M10.

Fuel injection came to BMW in the early 70's 2002tii with it's mechanical Kugelfischer system which also saw service for the first year (1973) of the new E12 520i. A normally aspirated M10 served in the 518 and 520.

It was perhaps unfortunate that BMW introduced the 2002 turbo at the same time as the early 70's fuel crisis started to bite, no doubt this hurt sales. The media of the time certainly had a very negative view of the car and BMW did few favours for itself by printing "turbo" in reverse on the front spoiler in great big letters to let driver's see it correctly in their rear view mirrors before being over taken. But none of this diminished the performance of the little car when a KKK turbo was mated with a two litre M10. This raised output from the normal 100bhp to 170 albeit with a good deal of turbo lag. It BMW's and indeed europe's first production turbo. A racing version was to follow.

All good things must come to an end and so did the 2002. But the E21 three series was a decent successor (not everyone thought so) and another big user of the M10 engine in both carb and Bosch Jetronic guises.

The 1980's brought new roles for the M10 in the E28 518i and E30 three series. The E30 used 1800cc M10s offered in carb (316) or injection (318i) versions until 1988 when the M40 replaced it. My first BMW was an E30 316 M10, in my opinion the M10 was superior to the M40 in most regards.

Finally we couldn't mention the M10 without talking about how it came to win Formula 1 in 1983. The racing versions were designate M12 and M13 and had an illustrious career in Formula 2. In the early 80's the Formula 1 rules said you could run a three litre normally aspirated engine or a 1500cc turbo. BMW built the latter and in one test it reportedly sent the motor sport division's dynamometer off the scale, quite an achievement as it was rated to 1250bhp! It reportedly ran at 8-900bhp for qualifying and 6-700 for races to increase durability. Legend has it that BMW preferred heat cycled blocks as the basis for their race engines and scoured europe's junk yards for old 1502's with "green" engines.

The M10 was also the basis for the 2.3 and 2.5 16 valve S14 engines used in the famous E30 //M3. 26 years, 30 if you count the S14. Quite a career. The M10 was the engine that BMW what it is today.

BMW M10 engine

1987 E30 316 with 1800cc Pierburg carb M10.


In the beginning M10s weren't called M10s. The initial 1500 was an M115, the 1600 an M116 and the 1800 an M118. They all shared a 100mm spacing between pistons which is larger than the 91mm spacing used on most BMW since. They were advanced engines for their time, in an era where competitors used pushrods the M10 had an overhead cam which made for better high rpm performance. In the high performance theme the crankshaft was forged, had counter balance weights and ran in five main bearings, again not the norm for the period. It was mounted at a 30 degree angle to reduce installation height, a trend that lasts to the present day. The production 1500 made 80bhp.

The 1.6 and 1.8 followed with a few tweeks in bore and stroke in the early years to enhance smoothness. Both were available in sportier twin carb "ti" variants. The M118 with twin Solex carbs made 110bhp, partly due to a higher compression ratio than the single carb version. For the 1800Tisa (which BMW would only sell to holders of a racing licence) larger carbs and an even higher 10.5:1 compression ratio gave an impressive 130bhp which wouldn't shame a modern 16 valve fuel injected 1.8.

The first two litre M10 appeared in 1965 and at the time was known as an M05. With a single carb it made 100bhp but as usual a twin Solex carb "ti" was on offer and gave 120bhp.

In 1966 a fundamental change was made to the cooling system and has been taken forward by BMW ever since. Beforehand the thermostat was located at the point in the cooling loop where the hot coolant exited the engine. This worked but could cause the temperature to fluctuate as engine load changed. The new design reversed this idea and put the thermostat at the cold coolant entry point into the engine. But a bypass allowed the warmer coolant to circulate around the thermostat too, this gave a more balanced operation less prone to fluctuations in temperature. It was a form of thermodynamic negative feedback into the control loop and is still used today.

In the late '60s BMW experimented with 16 valve heads and while this fed into the racing programme it never made its way to a road car. Similarly in 1970 a 2.2 was tested but it wasn't smooth enough.

The Kugelfischer fuel injection system was a mechanical alternative to the Jetronic-D used on the 3.0CSi. It made 130bhp using a complex mechanical metering system and made the 2002tii (touring international injection) into a legend. It was also fitted to the first year of the E12 520i before it was replaced with Jetronic-K. The Jetronic-K engine was available as an E21 320i making 130bhp and by all accounts was a real animal.

The 2.0 was turbocharged in 1974 using a KKK turbo which boosted output to 170bhp and had prodigious lag. The engine was designated M31 and had 177lb/ft or torque. BMW didn't release another petrol turbo engine until the 335i almost 30 years later.

After the mid-70s the engines were confusingly renamed the M41 (1600), M42 (1800) and M43 (2000). All received a new carburettor with an automatic choke. By 1979 the two liter was being replaced by the new M20B20 six cylinder unit, personally I prefer the M10.

The last M10 1.8 had Jetronic-L injection for the E28 518i and E20 318i until 1987/88. An E30 316 had an 1800cc with a horrid Pierburg carb which was prone to flat spots (I had one).

At some point the M10 got an electric fuel pump, I'm not sure when but my E30 316 certainly had one. The mechanical pump was driven by a lobe on the camshaft and had wasn't very powerful. In fact if your 2002 ran dry of petrol you sometimes had to suck fuel into the pipe which fed the carb, I've done it myself.

BMW M10 engine

E28 518i with Jetronic-L injection


Code Size Power
Manufactured Bore x
Timing Weight
VANOS Used in
M10 1.5







2.0 turbo

75 @ ?

85 @ 5700

90-98 @ 5250

105 @ ?

100 @ 5500

125 @ 5700

130 @ 5800

170 @ 5800


91@ 3000

108 @ 3000

106 @ ?

116 @ 3000

129 @ 4350

131 @ 4500

181 @ 4000


















66 - 69?

71 - 87

81 - 87

68 - 75

E21 320i / E12 520i

71 - 75

73 - 74









Chain 82 No 1502


1802, E21/E30 316

E28 518i, early E30 318i

2002, E21 320

2002 tii

2002 turbo


BMW M10 engine

Alpina A2 head and twin carbs for an early engine.


As these engines mainly had carburettors many problems can be traced to them. In particular the later Pierburg carb was not good. A Weber replacement gave more power and better economy the only down side being a manual choke.

These are lovely engines and I'd encourage any owner of a non-injection version today to fit twin Webers and electronic ignition.

The Kugelfischer system is a specialist bit of kit but there are books which describe how to fettle it's fuel delivery curve. Be very wary of fuel leaks due to dried out gaskets above the pistons, these really should be replaced for safety.

On the injection engines vacuum leaks are often the culprit. Best solved by stripping down the entire intake tract and checking all the old hoses carefully. Not a hard or time consuming job.

Not much went wrong with an M10 if it was looked after. They were tough as nails.

Lovely twin carb conversion in a 2002.