The BMW M30 engine has the unique distinction of being the BMW engine with the longest production run. This inline-six petrol engine was produced for nearly 27 years, from 1968 to 1995, and powered several of the manufacturer’s cars, many of which still run strong today. If you were in the market for a straight-six-powered Bimmer a few decades ago, you’d likely end up with one that features a BMW M30 engine.
Over its elaborate lifetime, the Bavarian manufacturer made several updates and refinements to the platform to ensure it stayed relevant. The M30 engine debuted on the BMW 2500 and 2800 sedans (from the BMW E3 or New Six series), but its iterations would go on to power the first generation of the BMW 5-Series (E12), the first BMW 7-Series (E23), and several other iconic models.
BMW is renowned for producing some of the best inline-six engines out there. This M30 engine plays a pivotal and significant role in that claim. In its prime, it was a symbol of reliable German engineering, and now, over 50 years after it was first introduced, it lives on as a crucial founding pillar to the famed BMW straight-six legacy.
Photo credit: autowp.ru
BMW M30 Engine — A Brief History
The BMW M30 engine draws its roots from the BMW M10 inline-four engine used on the BMW New Class sedans and coupes. Both engines shared features like a profile lowering 30° slant, a crossflow cylinder head, and a chain-driven camshaft with rocker arm valve actuation.
Another similarity was the construction materials: a cast-iron block with an aluminum head and a forged overhead crankshaft with two valves per cylinder.
A few years after the M30 engine made its debut, BMW introduced a smaller capacity M20 engine, earning the former the nicknames of ‘Big Six’ and ‘Senior Six.’ In fact, until the V12 BMW M70 engine came about in 1987, the M30 was BMW’s largest and most powerful production engine.
BMW M30 Engine — Available Versions
The BMW M30 engine was first introduced in two displacement options — 2.5 liters (2,494 ccs) and 2.8 liters (2,788 ccs). However, over its 27-year-long run, several other engine iterations were made available, with the largest version displacing 3.5L (3,430 ccs). You’ll also see that multiple engines initially introduced with carburetors were updated with fuel-injection systems down the line. These updates were seldom accompanied by any other major mechanical changes, but the introduction of fuel injection did bump up peak output figures.
M30B25V
The M30B25V was one of two initially introduced versions of the engine in 1968. With a bore of 86 mm and a stroke of 71.6 mm, this engine displaced 2,494 ccs. Peak output figures were rated at 150 hp at 6,000 rpm and 156 lb-ft of torque at 3,700 rpm, making this the least powerful iteration of the M30 engine.
BMW equipped this iteration of the engine with two Solex Zenith 35/40 INAT carburetors, which is where it gets the ‘V’ suffix in its name from — Vergaser is carburetor in German.
M30B25
In 1981, BMW replaced the carburetor on the previous engine version with a Bosch L-Jetronic electronic fuel injection system. While peak power remained identical at 150hp, peak torque increased slightly by 3 lb-ft to 159 lb-ft at 3,700 rpm.
M30B28V
The M30B28V was introduced alongside the M30B25V in 1968. Like its lower capacity sibling, it features two Solex Zenith 35/40 INAT carburetors, earning it the ‘V’ suffix for the same reason. With a bore of 86 mm and stroke of 80 mm, it displaced 2,788 ccs. Peak output figures were initially rated at 170 hp at 6,000 rpm and 173 lb-ft of torque at 3,700 rpm, but this changed slightly as the engine made its way to different markets.
M30B28
In 1977, BMW updated the 2.8L M30 engine with a Bosch L-Jetronic electronic fuel injection system. This bumped peak output figures to 181 hp at 5,800 rpm and 177 lb-ft of torque at 4,200 rpm.
M30B30V
The M30B30V was primarily based on the M30B28V. Owing to a 3 mm larger bore, displacement was increased to 2,986 ccs. The added capacity also increased power and torque, with 178 hp at 6,000 rpm and 188 lb-ft of torque at 3,700 rpm.
M30B30
The fuel-injected version of the 3.0L M30 engine made its debut in 1971 with a Bosch D-Jetronic mechanical fuel injection system. Five years later, in 1976, BMW updated this unit with a Bosch L-Jetronic electronic fuel injection. While peak output figures varied depending on which car it was used on and model year, the M30B30 produced 197 hp at 5,500 rpm and 201 lb-ft of torque at 4,300 rpm over most of its lifespan.
M30B32
The M30B32 was introduced in 1976 and displaced 3,210 ccs. In the U.S. market, the engine came equipped with a Bosch L-Jetronic electronic fuel injection system until 1981. It was then replaced with Bosch Motronic digital fuel injection, making it BMW’s first car to feature the system.
Peak power and torque were rated at 197 hp at 5,500 rpm and 210 lb-ft of torque at 4,300 rpm.
M30B33V
The M30B33V is a carbureted iteration of the engine introduced in 1973. With a bore of 89 mm and stroke of 88 mm, this version of the engine displaced 3,295 ccs. It produced 186 hp at 5,500 rpm and 213 lb-ft of torque at 3,500 rpm.
M30B34
With a bore of 92 mm and stroke of 86 mm, the M30B34 engine displaced 3,430 ccs, making it the largest iteration of the M30 engine (alongside the M30B35 discussed below.)
In most international markets, including Europe, the M30B34 used a 10.0:1 compression ratio. This enabled the engine to produce 215 hp at 5,800 rpm and 229 lb-ft of torque at 4,200 rpm. Interestingly, the North American and Japanese markets got a detuned engine version with an 8.0:1 compression ratio, producing just 182 hp.
M30B35
Despite having a capacity of 3,430 ccs, this engine version uses a “B35” model code. Peak output figures were 208 hp at 5,700 rpm and 225 lb-ft of torque at 4,000 rpm. In specific markets, the engine was sold without a catalytic converter, slightly increasing peak output figures to 217 hp and 232 lb-ft of torque, produced at the same points in the rev band.
Which BMW Cars Have an M30 Engine?
Photo credit: autowp.ru
The BMW M30 engine powered several machines that the manufacturer produced between 1968 and 1995. The BMW 2500 and 2800 sedans from the BMW E3 series were the first cars to feature the engine. Eventually, the M30 engine would make its way onto the E9 series, E12 5-Series, E24 6-Series, and E23 7-Series, among other models.
M30B25V
The M30B25V debuted on the E3 2500, produced from 1968 to 1977. It also powered the E9 2.5 CS from 1974 to 1975, BMW E12 525 from 1976 to 1981, and BMW E23 725 from 1977 to 1979.
It was also used with a Solex 4A1 carburetor on the BMW E12 525 from 1973 to 1976, producing 143 hp (compared to 148 hp on the other cars.)
M30B25
The fuel-injected M30B25 was used on the BMW E28 525i from 1981 to 1987 and the BMW E23 725i from 1981 to 1986.
M30B28V
The M30B28V was used on several models between 1968 and 1979. It was introduced on the BMW E3 2800 that was produced until 1977. Simultaneously, it also powered the BMW E9 2800 CS until 1971.
Some of the other models it powered include the U.S. market-specific 1971 BMW E3 Bavaria and the following:
- 1974-1976 BMW E12 528
- 1976-1978 BMW E12 528 (with dual Zenith INAT carburetors)
- 1977-1979 BMW E23 728 (with Solex 4A1 carburetor)
M30B28
The M30B28 powered the following cars::
- 1977-1978 BMW E12 528i (only sold in the North American market)
- 1978-1981 BMW E12 528i
- 1979-1986 BMW E23 728i
- 1979-1987 BMW E24 628CSi
- 1981-1987 BMW E28 528i
M30B30V
The M30B30V was based on the M30B28V and used two Zenith 35/40 INAT carburetors in most models. However, there are some exceptions. The following cars featured this iteration of the engine:
- 1971-1975 BMW E9 3.0 CS
- 1971-1972 BMW E9 3.0 CSL
- 1971-1974 BMW E3 3.0 S / 3.0 L / Bavaria
- 1976-1979 BMW E24 630 CS (with Pierburg 4A1 carburetor)
- 1977-1979 BMW E23 730 (with Solex 4 A 1 carburetor)
M30B30
The M30B30 was one of the more widely used iterations of the BMW M30 engine. It was sold in multiple international markets, and its specifications varied slightly based on where it was sold and on which car.
- 1971-1975 BMW E9 3.0 CSi
- 1972-1973 BMW E9 3.0 CSL
- 1972-1975 BMW E3 3.0 Si
- 1975-1978 BMW E12 530i (North American market only, producing 176 hp)
- 1976-1976 BMW E12 530 MLE (South African market only, producing 197 hp)
- 1977-1978 BMW E24 630CSi (North American market only, producing 173 hp)
- 1986-1995 BMW E32 730i
- 1988-1990 BMW E34 530i
M30B32
The M30B32 was another iteration of the engine that was used on several BMW models between 1973 and 1986. Its applications include:
- 1973-1975 BMW E9 3.0 CSL
- 1976-1984 BMW E24 633CSi (producing 194 or 197 hp in Euro-spec and 172 or 174 hp in U.S.-spec)
- 1976-1979 BMW E3 3.3 Li
- 1977-1984 BMW E23 733i (producing 197 hp in Euro-spec and 174 or 194 hp in U.S.-spec)
- 1979-1981 BMW E12 533 (North American market only, producing 181 hp)
- 1979-1986 BMW E23 732i
- 1982-1984 BMW E28 533i (North American market only, producing 181 hp)
- 1984-1986 BMW E30 333i (South African market only, producing 194 hp)
M30B33V
The carbureted M30B33V was used solely on the BMW E3 3.3 L from 1973 to 1975.
M30B34
The M30B34 engine was sold in a different spec in Europe and most other markets compared to North American and Japanese markets. Here are the cars that the M30B34 was used on:
- 1982-1987 BMW E23 735i / L7
- 1982-1987 BMW E24 635CSi / L6
- 1985-1988 BMW E28 535i / 535is / M535i
M30B35
The M30B35 was one of the last iterations of the M30 engine. It powered multiple BMW models, including the BMW E24 635CSi in 1988 and 1989, the BMW E32 735i from 1989 to 1992, and the BMW E34 535i from 1987 to 1992. It was also featured on the Italian-designed and built luxury off-roader Rayton Fissore Magnum 3.5 in 1988 and 1989.
Special Iterations of the BMW M30 Engine
Photo credit: autowp.ru
Over its production run, BMW experimented with the M30 engine to develop several special versions. The BMW M30 engine acted as the base for BMW’s first turbocharged inline-six engine, the world’s fastest production sedan at the time, and a lower-spec version of the iconic M88/1 engine that powered the BMW M1.
BMW M102 engine
The M20 engine acted as the base for the turbocharged M102 engine. Produced from 1980 to 1982, it was BMW’s first turbocharged six-cylinder engine. It displaced 3,210 ccs and produced 252 hp aboard the only car it was used on — the BMW E23 745i. The engine was equipped with a KKK K27 turbocharger that produced 9 psi of boost.
BMW M106 engine
The M106 (also dubbed the M30B34MAE) replaced the M102 and was produced from 1982 to 1986. It featured some notable updates like the inclusion of Bosch Motronic engine management and an increase in displacement to 3,430 ccs. While peak output was the same at 252 hp, it was produced lower in the rev band. Meanwhile, boost pressure was reduced from 9 psi to 6 psi.
The BMW M106 would turn out to be the last turbocharged petrol engine for a long time — its successor, the BMW N54, arrived only two decades later in 2006.
The M106, like the M102, was used on the BMW E23 745i from 1982 to 1986.
Alpina B10 Bi-Turbo
The Alpina B10 Bi-Turbo is a high-performance version of the BMW 535i from the E34 5-Series. The German manufacturer spent millions on development, and the car began production in 1989. It was powered by a specially tuned iteration of the M30 engine and, at the time of its introduction, was the fastest production sedan in the world.
An interesting fact in the history of the M30 is that the last 50 units of the M30 blocks were shipped to Alpina for use in the final 50 examples of the B10 Bi-Turbo.
Alpina ended production of the car in 1994 with just 507 examples produced.
M30B35LE
The M30B35LE engine, also called the M90, was a lower-performance version of the M88/1 engine. It features the same block as the M88/1 and borrows the cylinder head from the M30 engine.
It was used on multiple cars from 1979 to 1982, using both Bosch Motronic and Bosch L-Jetronic engine management systems. Some of its applications include:
- 1979-1981 BMW E12 M535i
- 1978-1982 BMW E24 635CSi
- 1978-1982 BMW E23 735i
Motorsport
The M30 is most famously known in motorsport for powering the BMW E9 CSL, arguably the German manufacturer’s most successful product in the racing circuits. The engine also powered multiple race-spec iterations of the BMW E24 6-Series, leading them to numerous victories in the European Touring Car Championship (ETCC) throughout the 1970s and into the mid-1980s.
Is the BMW M30 Engine Reliable?
The BMW M30 is one of the most bulletproof engines the German manufacturer has produced. The fact that it was in production for nearly three decades is a testament to that. Its reliability is further cemented in the fact that you can still find examples of these engines still running exceptionally well today.
Pre-Purchase Inspection and Common Problems
The BMW M30 engine is a highly reliable piece of engineering, but there’s no denying that it’s been around for multiple decades. Even the latest iteration of this engine has been around for 27 years, with the very originals having breached the 50-year mark. It’s also unlikely you’ll find a pre-owned example that’s done less than 100,000 miles.
Understandably, over this kind of mileage, things break, fail, and cause problems. This is expected of any machine, and the M30 engine, despite its dependability, is no exception to the laws of physics.
If you’re getting your hands on an M30-powered car, here are some of the common issues you may have to deal with:
Water Pump Failure
The M30 engine, and even other BMW engines that followed, came with a water pump with a plastic impeller. Plastic, as you may know, does not fare well against the test of time. The water pump was designed to last over 100,000 miles, but the impeller will likely fail much sooner. Given the age of an M30-powered car, it’s very likely that one of the previous owners has had them replaced at least once, if not multiple times, in the past.
A failed impeller results in an inefficient water pump that will cause your engine to overheat. If you’re getting a new impeller for your car, consider replacing the plastic unit with an aftermarket metal one that will last you longer.
Cooling System Problems
By today’s standards, the BMW M30 is a simplistic piece of machinery. While its cooling system was relatively rudimentary, some of its elements were known to fail, and you’ll likely run into problems with the system at some point in your ownership.
Multiple owners on Bimmer forums have reported that their M30 engines overheat, and they can’t seem to narrow down on the issue. Sometimes, the only solution is to replace the cooling system’s components until the issue is resolved. The most common culprits include the plastic coolant expansion tank, the fan clutch, and the thermostat.
The radiator housing is another problematic area since it’s made of plastic prone to breaking, resulting in a coolant leak.
Before purchasing an M30-powered car, let the engine run for a while from a cold start. If you don’t notice any inconsistencies with heat levels and the temperature reading settles at a normal level after a few minutes, the cooling system is likely in proper order.
Other Issues Worth Looking Into
On some M30-powered models, the return valve in the oil filter housing fails prematurely. This will cause oil to flow even after the engine has been stopped. While this may not cause any significant damage to the engine, it can prolong the time it takes the engine to build oil pressure once it’s started. BMW updated the part in 1991, so it’s less common in the cars produced after.
If you can have the car looked at by an experienced technician, you should have them look at the oil spray bar mounted above the camshaft. Sometimes, the bolts that hold the bar in place can loosen, resulting in the restricted flow of oil through the tube. This can result in inadequate cooling or lubrication of parts of the engine.
Other issues worth looking out for include rocker arm and valve spacing and the condition of the oil cover and gasket, which are bound to deteriorate with time.
M30 Engine Demands Proper Maintenance
The M30 engine is virtually indestructible by design, but age has likely worn down several examples you’ll find on the used market. As we mentioned above, the oldest examples of the engine have been around for over five decades, while the newer ones are creeping close to the three-decade mark. It’s improbable you’ll find too many examples of the former out there, but if you do, they can still be some excellent engines to own, maintain, and most of all, appreciate.
There are barely any reasons not to buy a post-1990 car with an M30 engine. They’re superbly built and offer tons of room for improvement. The main block is one of the most indestructible units that BMW has built, capable of handling stratospheric boost pressures, and you’ll find tuners working on them even today.
When you understand the significance the M30 engine has played in shaping BMW into the global automotive giant it is today, it’s clear why automotive analytics firm Ward’s Auto rated it as one of the “Top Engines of the 20th Century.”
Get Your BMW M30 Parts at Bimmers.com
Here at Bimmers.com, we offer one of the largest catalogs of BMW parts online. In there, you’ll see parts for the BMW M30, as well most other Bimmers that were sold in the US. To find what you’re looking for, head over to our online store, select your vehicle using our built-in tool and search for the parts you need. Our system will return only parts that are a guaranteed match for your car!
