BMW M30B35 Engine

  1. Specifications
  2. Overview, problems
  3. Performance tuning

BMW M30B34 / M30B35 engine specs

Manufacturer Munich Plant
Also called BMW M30
Production 1982-1992
Cylinder block alloy Cast-iron
Configuration Straight-6
Valvetrain SOHC
2 valves per cylinder
Piston stroke, mm (inch) 86 (3.39)
Cylinder bore, mm (inch) 92 (3.62)
Compression ratio 8.0
Displacement 3430 cc (209.3 cu in)
Power output 136 kW (185 HP) at 5,400 rpm
155 kW (211 HP) at 5,700 rpm
160 kW (218 HP) at 5,500 rpm
Torque output 290 Nm (210 lb·ft) at 4,000 rpm
305 Nm (225 lb·ft) at 4,000 rpm
310 Nm (230 lb·ft) at 4,200 rpm
Redline 6,200
HP per liter 53.9
Fuel type Gasoline
Weight, kg (lbs) 145 (320)
Fuel consumption, L/100 km (mpg)

for E34 535i
17.3 (13.6)
8.0 (29.4)

9.8 (24)
Turbocharger Naturally aspirated
Oil consumption , L/1000 km
(qt. per miles)
up to 1.0
(1 qt. per 750 miles)
Recommended engine oil 5W-30
Engine oil capacity, L (qt.) 5.75 (6.05)
Oil change interval, km (miles) 5,000-10,000
Normal engine operating temperature, °C (F) ~90 (195)
Engine lifespan, km (miles)
-Official information

400,000+ (250,000)
Tuning, HP
-Max HP
-No life span loss


The engine is installed in BMW M535i E28
BMW M535i E12
BMW 535i E34

BMW 635 CSi E24
BMW 735i E32
BMW 735i E23

BMW M30B35 engine reliability, problems and repair

Before BMW M60 series (V8) in 1992 its place occupied by large inline 6-cylinder M30 engine. In spite of the fact that M30 produced along with M20 (straight-6), M30 has more common with younger 4-cylinder M10. The first M30 motors appeared nearly 50 years ago and since then were constantly improved and modernized. One of the top variants called M30B35/M30B34 released in 1982 and intended for BMW cars with 35i index.
BMW M30B35/M30B34 uses the straight-6 cylinder block made of cast iron. It is the same as at M30B30, but the crankshaft has a piston stroke of 86 mm, bore size increased to 92 mm. Height of the cylinder block doesn’t differ. M30B35 rod lengths – 135 mm, piston compression height – 39.85 mm.
Cylinder head M30B34/B35 with one camshaft (SOHC) and with 12 valves. There are no hydraulic lifters on this engine so you have to adjust the valves every 5,000 – 7,000 miles (10,000 km) of mileage. The clearances of the valves (cold engine): inlet and exhaust – 0.3 mm.
Specs of M30B35 camshaft: duration 248 deg, lift 8 mm. The intake manifold was changed. The size of fuel injectors on M30B35: 214 cc/min. The firing order on BMW M30: 1-5-3-6-2-4. The camshaft is set in motion by timing chains. Fuel system is injector.
Produced different versions of this engine:
1. Motors equipped with catalytic converter, low compression pistons (CR=8) and Bosch Motronic 1.0. Power of M30B35 is 185 HP at 5,400 rpm.
2. Motors not equipped with catalytic converter and with new pistons (compression ratio is 10:1). Their power is 218 horsepower at 5,500 rpm.
3. The version with catalytic converter, with different pistons (compression ratio is 9:1) and with Bosch Motronic 1.3. Such engines have the power 211 HP at 5,700 rpm.
In 1992 the BMW M30B35 was changed by more modern V8 – M60B40.

BMW M30 engine problems and malfunctions

1. Overheat. This problem is common to many inline 6-cylinder BMW engines. If don’t rectify a problem the cylinder head is deformed. Causes of defect: a dirty radiator, a water pomp, the thermostat or an air-bound cooling system.
2. Cracks in the engine block. They are formed around the threads of bolts in cylinder head. The reason – oil doesn’t take from threaded sets, after disassembly of the engine. The symptoms indicating on cracks in M30: a high coolant consumption, the appearance of the emulsion in the engine oil. You can try to repair, but in such cases you just need to buy the cylinder block without cracks.
Speaking about BMW M30 can be everything because of their age. Most often problems are in the valvetrain. You won’t be able to adjust valves. If it happened, then you need to buy guide bushing set, to replace rocker arm eccentrics and worn-out valves. Sometimes there are problems with MAF-sensor.
For its time BMW M30B35 is the magnificent engine, it can to pass more than 300,000 miles (500,000 km) of mileage without overhaul. But it would be better to buy M50.

BMW M30 tuning

M30B35 stroker

There are many different aftermarket performance parts for BMW M30. If you have a desire to make powerful M30B35, then for a start bring the motor into a normal state. After that there are two ways: to buy stroker kit or aggressive cams.
To make a M30B35 with a 4 liter capacity, you need to buy a crankshaft with a stroke of 98 mm, short rods, increase bore to 93.5 mm and forged pistons. If you increase bore to 95 mm, you will get a 4.2 l. The price of stroker kit is higher than the cost of all vehicle.
Second way. You need to shave the cylinder head to increase the compression ratio to ~11. After that you need to do head porting, buy a cold air intake, Schrick camshaft 284/280 deg. (or something similar) with springs, reinforced rocker arms, headers, performance exhaust system 3” (or straight pipes).Then ECU need to adjust, it will give about 240-250 horsepower. Extra power you will get by buying forged pistons, lightweight connecting rods and S38 individual throttle bodies kit.The result is an interesting engine, but it is cheaper to buy a BMW E34 M5 with powerful S38.

M30B35 Turbo

Stock BMW M30 engines have very low compression, so you can install a turbocharger without using forged pistons. Buy on eBay cheap Chinese turbo kit for BMW M30 and install it on stock internals. You can assemble a kit by yourself. Just buy Chinese Garrett GT35, turbo manifold, 3” pipes, intercooler, wastegate, blow-off, fuel injectors 630 cc/min and Megasquirt ECU. Don’t forget about ARP head studs and MLS head gasket. After that you can increase boost to 11-14 psi (0.8-1 bar), it will give about 400 horsepower. The Chinese turbocharger serve not too long, probably after a few thousand miles it will be necessary to buy the new. Instead of the Chinese performance parts, you can buy original Garrett GT35, it will be more expensive, but much more effective. Besides single turbo you can make twin turbo M30B35. Something similar can be constructed, using supercharger, but with a turbocharger the effect will be higher.