The M30 engine is a large in-line 6-cylinder engine that comes in 2.5, 2.8, 3.0, 3.2 and 3.5 liter displacements. It can be found on the 5 Series (E12, E28 and E34), 6 Series (E24) and 7 Series (E23 and E32), as well as the famous BMW M1.

The engine turned out to be very successful, both in design and in survivability. Of course, part of the survivability of the engine was provided by its high power. Due to the fact that more powerful engines and load less.

Only the M30B35 modification with a cylinder diameter of 93.4 mm was unsuccessful - it turned out to be too energy loaded. But do not confuse it with the M30B34, which was installed on almost all 3.5 liter cars.

The M30 is an engine for a quiet ride, it has a too heavy piston and too large piston strokes, which do not allow it to spin up quickly and create heavy loads on the bearings (liners).

Also, due to the high mass of the piston system, the engine is very demanding on oil, if you feed it with mineral oil and at the same time keep it constantly in the 4-6 thousand rpm range, you will have to grind the crankshaft after a few thousand. Only synthetic oil should be poured into this engine, and if you like to turn it, then on volumes of more than 2.8 liters, an oil cooler must be installed.

On the other hand, the advantages of straight-six balance and high power at low revs more than compensate for these shortcomings.

Also, the M30 was the second and last engine to be turbocharged as standard - turbocharged M30 modifications were used only in E23 745i models. In fact, their volume was 3.2 and 3.4 liters, depending on the modification. But both options were marked M102. The power is the same - 252 hp. The main difference is the ignition and power system.

The engine was installed on cars of the third, fifth, sixth and seventh series.

3rd series:
E30- 333i - 3.2. liters, with Motronic injection system. Supplied only in the UAE.
5th series:
E12- 525 - 2.5 liters with carburetor, 528 - 2.8 liters. with carburetor and injector, 535i - 3.5 liters, with injector only.
E28- models 525i, 528i, and since 85 535i and M535i. Starting with the E28 body, only injection modifications were installed.
E34- 530i - 3 l., 535i - 3.5 l. Also, only the injector with the Motronic injection system and with the crankshaft position sensor located on the crankshaft damper, and not on the gearbox.
6th series:
E24- 628CS with carburetor and injection (628CSi), 633CSi, 635CSi - injector only.
7th series:
E23- 728 injector / carburetor, 730 carburetor, 732i / 733i, 735i, 745i - a turbocharged version of the engine was installed on the 745i model.
E32- 730i, 735i - 3.0 and 3.5 liters respectively.

BMW M30 engine block heads.

The cylinder head of the BMW M30 engine is perhaps the most unified of all existing ones.

Only carburetor and injection heads have cardinal differences, and the difference is so strong that it is impossible in principle to interchange them.

Otherwise, the block heads are completely identical, up to the valve timing (camshafts).

Otherwise, in the design of the cylinder head there are no fundamental differences from other BMW engines. The movement of gases through the engine is transverse, the combustion chambers have a trispherical shape, a V-shaped arrangement of valves with an overhead camshaft.

Valve plate diameter:

inlet outlet

The height of the cylinder head of the M30 engine: 129 ± 0.1 mm. Reducing the height of the cylinder head during grinding is allowed by an amount not more than: 0.5 mm (at the same time, it is necessary to grind the timing cover by the same amount). Minimum permitted cylinder head height from model year 1980: 128.6 mm.

piston system

Distinctive characteristics of pistons.
Engine pistons have their own distinctive marks:
Marking on the bottom of standard pistons: engine type / compression ratio (for example 2.8 / 9.3); piston skirt diameter (for example, 85.97); as well as an arrow for orienting the piston in the cylinder during installation.

Specifications

For all M30:

	Volume	Diameter cylinders		St.Szh.	Power (hp)	Max. moment (H*m)

Detailed technical information about the engine.

Main technical data
Type: M86, M30	petrol
Number and arrangement of cylinders
Number of valves	2 per cylinder
Fuel system types
	Carburetor (E12 only) L-Jetronic (only on E28)
	Carburetor L-Jetronic
	Carburetor L-Jetronic (USA only) Motronic 1.3 (E32, E34)
	L-Jetronic (up to 9/79 and up to 09/80 for Sweden) Motronic 1.0 (from 09/79)
	L-Jetronic Motronic 1.0 Motronic 1.0 Adaptive Motronic 1.3 (E32, E34)
Cylinder diameters
Piston group
	Unique for each type
	Same for all engine types
Crankshaft: Stroke:
Working volume, cm 3
Interchangeability	Fully interchangeable, but without changing the carburetor-injection
valve seats	pressed into the cylinder head
Valve guides
Cylinder head height
The maximum allowable reduction in the height of the cylinder head when grinding	0.5 (at the same time, it is necessary to grind the cover of the timing mechanism by the same amount)
Movement of gases	transverse
	Trispherical CS
Cylinder head gasket
The cylinder head gasket only installs in one position, dry, except for the front (camshaft drive side) where sealant must be applied.
It is not allowed to install the cylinder head gasket of a carburetor engine on an engine equipped with a fuel injection system.
Valve seats.
Valve guides
The valve guides are cast iron and pressed into the cylinder head. The dimensions of the guide sleeves for the intake and exhaust valves are the same.
Length up to 80g from 80g
Outside diameter	14 +0,033 +0,044
Inner diameter
Cylinder head bore diameter
Repair dimensions:
	increased by 0.1
	increased by 0.2
Preload when pressing the valve guides into the cylinder head: up to 78 since 78	0,033-0,069 0,015-0,044.
Protrusion of the valve guides relative to the plane of the cylinder head
Heating temperature of the cylinder head when pressing in the valve guides, 0 С
valve springs
Valve springs are the same for intake and exhaust valves. The springs are installed with the color mark down and towards the cylinder head.
Spring diameter
M86, M30 until 06.86
M30 from 06.86 External Internal	31.2 mm 21.2 mm
valves
Steel valves, chrome-plated stems.
Valve disc diameter
The total angle of the open state of the intake and exhaust valves, degrees:
Lifting height of the camshaft cams of the engines
From the 82nd year:
Gas distribution mechanism (GRM)
Chain tensioner plunger length
Number of teeth:
crankshaft sprockets
Camshaft sprockets
Number of chain links
Number of chain rows:
Pistons
Maximum allowable clearance in operation between piston and cylinder
The difference in the mass of pistons in the assembly of one engine	no more than 10 g
connecting rods
Permissible mass deviation:
For one engine
bottom head
top head

Engine	Disassemble and assemble
Engine only	Remove and install
Engine only (with automatic transmission installed)	Remove and install
Engine. Unit replacement	Remove and install
Engine repair. "Short" block	Remove and install
Compression pressure	Check
Valve cover and gasket	Remove and install
Valves. gaps	Check and adjust
Valves. stem seal	Remove and install
cylinder head	Disassemble and assemble
Cylinder head and gasket	Remove and install
Camshaft	Remove and install
Camshaft. Belt/chain drive	Remove and install
Crankshaft. Rear oil seal	Remove and install
Crankshaft. Rear oil seal (with power steering installed)	Remove and install
Crankshaft. main bearings	Remove and install
Crankshaft. Front oil seal	Remove and install
Piston rings	Remove and install
Connecting rods and pistons	Remove and install
Oil pressure	Check
oil pan	Remove and install
oil cooler	Remove and install

BMW M30 engine(in early models sometimes called M06) a six-cylinder piston engine with a single overhead camshaft (SOHC), which was used for 28 years in many BMW cars. The BMW M30 engine was voted "Best Engine of the 20th Century", and was nicknamed the "Big Six".

The volume of the engine is from 2.5 to 3.5 liters. The cylinder firing order for all M30 engines is 1-5-3-6-2-4.

This engine was designed to differentiate it from the less powerful 6-cylinder engine for the new BMW Neue Klasse luxury car series and is informally known as the Big Six.

In 1973, the Zenith 35/40 carburetor was replaced with a 32/40, the M68 engine power was reduced to 145 hp. and in this configuration the motor was installed from 1973 to 1976 on.

From 1976 to 1981, the E12 525 was equipped with an engine M68. Instead of the previous two Zenith INAT carburetors, a 4A1 was installed. This carburetor avoided the timing problems previously experienced with the dual system. Replacing the power system results in higher torque and 150 hp. at 5800 rpm.

From 1981 to 1987 2.5-liter engine with internal designation M107 was equipped with a Bosch Jetronic electronic injection system. The motor was installed under the hood and.

In 1972, the engine was tested M54 2400 cc, but the engine was too heavy and expensive to manufacture, resulting in the project being cancelled.

Characteristics of the BMW M30B25 engine

BMW M30B28 engine

The 2.8-liter BMW M30 engine debuted in 1968. The engine used a Zenith 35/40 INAT carburetor and a Jetronic fuel system. The volume of the power unit was increased by increasing the piston stroke to 80 mm.

From 1968 to 1976 2.8-liter 170-horsepower engine M06(M30B28V) installed on:

From 1976 to 1979 already as M68 this motor was supplied with a Solex 4A1 carburetor and fitted to the E12 528. The power ratings remained unchanged and, like the 2.5-litre version, this carburetor eliminated dual system timing issues.

1976 to 1979 3 liter engine M68 with one two-chamber Solex 4A1 carburetor was installed on and.

M49 unlike the M21, it was equipped with a D-Jetronic injection system and developed a maximum power of 197 hp. This engine was produced until 1977 and was installed on (only for South Africa).

From 1977 to 1979, a motor was produced for export cars to Japan and the USA. M73 with mechanical injection (K-Jetronic) and electronic fuel injection system (L-Jetronic, Motronic).

In 1986, the 3-liter M30 engine was updated: the power system was changed. Bosch DME electronic fuel injection is installed this time. This version of the engine was produced until 1994 and was the last in the chronological table of the M30 engine family.

The power unit was installed on the following models:

Specifications of the BMW M30B30 engine

BMW M30B32 engine

This engine is also known as M69» (M30B32LE) debuted in 1976 and was based on the 3 liter. Compared to the B30, the stroke has been increased from 80mm to 86mm, resulting in an increase in displacement to 3210cc. The cylinder bore remained unchanged, and the D-Jetronic injection system was replaced with L-Jetronic. In 1979, L-Jetronic was replaced by Motronic.

The 3.2-liter M69 was installed on:

• (North America only)
• (South Africa only)

BMW M30B35/M30B34 engine

Characteristics of the M30V35 engine

Production	Munich Plant
Engine brand	M30
Release years	1982-1992
Block material	cast iron
Supply system	injector
Type	in-line
Number of cylinders	6
Valves per cylinder	2
Piston stroke, mm	86
Cylinder diameter, mm	92
Compression ratio	8.0 9.0 10.0 (see description)
Engine volume, cc	3430
Engine power, hp / rpm	185/5400 211/5700 218/5500 (see description)
Torque, Nm/rpm	290/4000 305/4000 310/4000 (see description)
Fuel	92
Environmental regulations	-
Engine weight, kg	~145
Fuel consumption, l/100 km (for E34 535i) - city - track - mixed.	17.3 8.0 9.8
Oil consumption, g/1000 km	up to 1000
Engine oil	5W-30 5W-40 10W-40 15W-40
How much oil is in the engine, l	5.75
Oil change is carried out, km	7000-10000
Operating temperature of the engine, hail.	~90
Engine resource, thousand km - according to the plant - on practice	- 400+
Tuning, HP - potential - no loss of resource	800+ n.a.
The engine was installed	BMW M535i E28 BMW 535i E34 BMW 635 CSi E24 BMW 735i E32 BMW M535i E12 BMW 735i E23

Reliability, problems and repair of the BMW M30B35 / M30B34 engine

Before the introduction of the M60 series in 1992, with a V8 configuration, its place was occupied by large-volume inline-sixes called the M30. Despite the fact that the M30 was produced simultaneously with the M20 (also an in-line 6-cylinder), the 30th model has more in common with the younger M10 four. The first M30s appeared almost 50 years ago and have been constantly refined and modernized over time. One of the top options called M30B35 / M30B34 was released in 1982 and was intended for BMW cars with the 35i index.

The BMW M30B35 / M30B34 engine is an inline six in a cast iron cylinder block, the same as the M30B30, but the crankshaft has a piston stroke of 86 mm (against 80 mm for the M30B30), the cylinder diameter is increased from 89 mm to 92 mm. The height of the cylinder block does not differ. The length of the connecting rod is 135 mm, the compression height of the piston is 39.85 mm.
Cylinder head M30B34 / B35 single-shaft with 12 valves,without hydraulic lifters, so every 10 thousand km it is advisable to adjust the valves. Clearances (cold engine) for intake and exhaust - 0.3 mm. M30B35 camshaft specifications: 248 phase, 8mm lift.
The intake manifold has been changed, nozzles with a capacity of 214 cc are used.
Timing chain drive. The fuel supply system is injector.
Various versions of this engine were produced: with a catalyst, pistons for a compression ratio of 8 and Bosch Motronic 1.0, developing 185 hp. at 5400 rpm; without a catalyst and with pistons for a compression ratio of 10, their return is 218 hp. at 5500 rpm; as well as a catalyst version with pistons for a compression ratio of 9 and with Bosch Motronic 1.3, the power of such M30B35 reached 211 hp. at 5700 rpm.
In 1992, the M30B35 engine was replaced by a more modern V8 - M60B40.

Problems and disadvantages of BMW M30B35 engines

1. Overheating. This problem is inherent in many in-line 6-cylinder BMW engines and it is not worth starting it - the cylinder head will lead. The cause of the malfunction is a dirty radiator, pump, thermostat, or air locks in the cooling system.
2. Cracks in the cylinder block. They form around the threads for the cylinder head bolts, due to not removing oil from the threaded wells after disassembling the engine. Symptoms indicating the appearance of cracks in the M30: antifreeze leaving, emulsion in oil. You can try to solve the issue by repair, but it is safer and more correct to buy a used cylinder block without cracks.

Given the very advanced age of the BMW M30 engines, the wear of everything that is possible is added to the above: most often problems arise in the gas distribution mechanism, with the subsequent inability to adjust the valve, this is solved by replacing eccentrics, worn valves, guide bushings. There are also frequent malfunctions associated with the DMRV.
At the moment, all BMW M30 engines have worn out their life, despite the fact that it can easily exceed 500,000 km. Also, often cars with the M30 are operated quite harshly (especially the E34), this additionally leaves its mark.
By itself, the BMW M30B35 is a great engine for its time, but age is taking its toll. If you want to buy a BMW and have a choice between the M30 or M50 (and other engines in this series), you should take the more recent M50.

BMW M30B35 engine tuning

M30B35 Atmo. Stroker

There are a lot of tuning parts for the M30, and if you have money, you can remove some horses from it, but first, bring your engine back to normal, if the engine asks for capital, then no shafts will help you. After restoring the M30B35, there are two ways: make a stroker or aspirated on the shafts.
The first option involves installing a crankshaft with a piston stroke of 98 mm, short connecting rods and boring cylinders for forged pistons 93.4 mm. This will provide 4.0 liters of displacement, bored out to 95 mm, you get 4.2 liters, no more. The cost of such whales is higher than the cost of the entire car.
The second way: you need to mill the cylinder head to increase the compression ratio to ~11, modify the channels and combustion chambers, you will also need a sports intake, Schrick 284/280 camshaft (or similar) with springs, reinforced rockers, 76 mm direct-flow exhaust and brain tuning . All this will allow you to remove about 240-250 hp, but the piston is old, heavy, reluctant to turn, and it is better to replace it with light forging, add a throttle from S38. As a result, it's cheaper to buy a BMW S38 on throttles with 340 hp. and make a swap.

Turbo M30B35

BMW M30 engines from the factory have a very low compression ratio, so you don’t need to depressurize, which means it’s much easier to inflate than to make an aspirated one. Buy a cheap Chinese turbo kit for BMW M30 on eBay and install it on a stock motor. Or separately buy a Chinese Garrett GT35, with a manifold, 3 inch pipes, intercooler, wastegate, blow-off, 630 cc injectors and a Megasquirt control unit. Inflate 0.8-1 bar and get under 400 hp. Chinese turbines do not live long, several thousand km and need to be changed. The original 35th garrett is much better and more efficient, but the price is different at times.
Something similar can be assembled using a compressor, but with a turbine it will be more efficient.

Engines of the BMW M30 series are a representative of the old men. This is a large straight-six that the world saw in 1971. From 1971 to 1975, the engine was equipped with carburetors, after which the injection system became injection.

Characteristics and features of motors

The M30 engine received a volume of 3.0 liters. A cast iron block paired with an aluminum head, no modern bells and whistles. The gas distribution mechanism has a chain drive.

BMW E21 with M30 engine

The carburetor model M30B30 appeared along with the injection in 1971, had a compression ratio of 9 and developed 180 hp. at 6000 rpm. The injection model came with Bosch D-Jetronic injection and a compression ratio of 9.5, which made it possible to remove 200 hp. at 5500 rpm.

Since 1976 Solex Zenith 35/40 INAT carburetors have been replaced by Solex DVF-4A1. The power of such motors has increased to 184 hp. at 5800 rpm, and since 1979, instead of the carburetor M30B30, they began to install injection M30B28.

M30 engine

In 1975, the fuel injected M30B30s were modified: the compression ratio was reduced to 9, the injection was replaced by Bosch L-Jetronic and this was reflected in the power, which dropped to 195 hp. at 5800 rpm.

In 1986, the M30B30 engine began to be installed on a new, at that time, BMW 730i E32. Such a motor had a compression ratio of 9.2 and developed 197 hp. at 5800 rpm. A version with a catalyst and a compression ratio of 9 was produced, its power was 188 hp. at 5800 rpm.

Consider the main technical characteristics of the M30 series motors:

Service

Maintenance of M30 motors is no different from standard power units of this class. Maintenance of motors is carried out at intervals of 10,000 km. Recommended maintenance should be carried out every 7,500 km. So, consider a detailed technical service card:

TO-1: Oil change, oil filter replacement. Carried out after the first 1000-1500 km of run. This stage is also called break-in, since the elements of the motor are lapped.

TO-2: The second maintenance is carried out after 10,000 km of run. So, the engine oil and filter are changed again, as well as the air filter element. At this stage, the pressure on the engine is also measured.

TO-3: At this stage, which is performed after 20,000 km, a standard oil change procedure, fuel filter replacement, and diagnostics of all engine systems are carried out.

TO-4: The fourth maintenance is perhaps the easiest. After 30,000 km, only the oil and the oil filter element change.

TO-5: Fifth TO for the engine, like a second wind.

Typical malfunctions

In principle, all motors are similar in design and characteristics. So, let's look at what common problems can be found on the M30:

BMW M30 engine repair process

1. Oil leak. Occurs as a result of the breakdown of one of the gaskets.
2. Overheat. A common cause of failure in BMW. In this case, it is worth diagnosing the cooling system - thermostat, water pump or radiator.
3. Does not start. The problem may be hiding in the fuel pump or spark plugs. It is worth checking the rest of the fuel system.

Conclusion

The M30 engine is an old man worthy of respect. Maintenance and repair of the power unit can be carried out independently. Many motorists of the late 80s and early 90s remember this power unit and know about its reliability.

Initially, based on the M30 engine, a model was developed with two camshafts and a two-row chain, as well as 4 valves per cylinder. The cylinder head consisted of two parts: the lower one formed the combustion chambers and the "cooling jacket", and the upper one was the gas distribution mechanism. Fuel injection was carried out individually into each cylinder, through a special Kugelfischer intake manifold, 6 distinctive intake pipes were present on the cylinder head. This version of the engine was installed from 1978 to 1981 on BMW M1 supercars and had a power of 277 hp.
Later, during the fuel crisis, the same engine, with minor modifications and M88 / 3 coding, was installed on the BMW M635CSi, and later received the S38 B35 marking.
The modification of the M88 engine of the M1 sports car, which was intended for racing in the Procar series, was boosted to 470 - 490 hp. This unit was distinguished by new camshafts, larger valves, forged pistons, and electromagnetic valves were used in the intake system (instead of throttle valves), in addition, a modified exhaust manifold was installed.
For participation in Group 5 races, the engine power was increased to 850 - 900 hp. by additional installation of two turbochargers. Such a power plant received an index - M88 / 2.
From 1985 to 1987, the M88 was used in the BMW M5 and from 1983 to 1989 in the BMW 6 Series, the M635CSi. This modification of the engine had the index M88 / 3 and developed a power of 286 hp.

So the options were:

BMW M88/1 engine

The M88/1 engine was the first iteration of the M88 and was installed in the BMW M1. Engine capacity 3453 cc It produced 277 hp. (207 kW) at 6500 rpm and 324 Nm at 5500 rpm. Produced from 1978 to 1981.

BMW M88/2 engine

Engine capacity 3453 cc For Group 5 racing, the M88 engine was turbocharged and became known as the M88/2. This racing engine produced up to 900 hp. (670 kW).

BMW M88/3 engine

The M88/1 engine also known as the S31B35ME was modified for use in the BMW E24 M635 CSi and BMW E28 M5, this engine was known as the M88/3. Engine capacity 3453 cc Kugelfisher fuel injection was replaced with Bosch Motronic and the engine produced 286 hp. (213 kW) at 6500 rpm, and the torque was 340 Nm at 4500 rpm. The M88/3 engine was also fitted to the South African BMW E23 745i, due to packaging issues with the turbocharged M102 engine used in other markets. The BMW M88 / 3 engine was produced from 1983 to 1989.

BMW M90 engine

A smaller power M90 engine with a 3453 cc single overhead camshaft (SOHC) that was based on the BMW M88 engine. It uses the same block from the M88 and maintains the same bore and stroke, but uses Bosch Motronic for fuel injection instead of Bosch L-Jetronic. Produced from 1978 to 1982. Used on BMW E24 635CSi, BMW E12 M535i and BMW E23 735i.

Specifications:
Modification: M88/1
Volume 3453 cm3
Bore, 93.4 mm
Stroke 84 mm
Compression ratio 9.0:1
Power @RPM [email protected]
Max. Torque @RPM [email protected]
Injection type: Kugelfischer