The world-renowned BMW M52B28 engine launched in early 1994 in the E36 3-series continued production until late 2020. The following was the M50 engine and succeeded by the M54 in the same year.
There are three M53 versions manufactured since its release: a 2.0L (M52B20), 2.5: M52B25, and 2.8L M52B28. However, in 1998, the three versions received a mandatory technical update to improve these engines.
The fundamental change was adding the VANOS system, or the variable valve timing, an electronic throttle control, and a DISA intake manifold.
All of which fit the profile and distinct taste of M52 engines.
The M52 is famous for its role in the E39 5-series as well as in the E36 3-series, which we mentioned earlier too. Further, the engine also powered various BMW vehicles apart from what we said, including late 909’s E46, E38 7-series, and E36/E37 Z3.
What Are BMW M52B28 Engines?
The BMW M52B28 engine is a 2.8-liter inline-six, naturally-aspirated engine from the M52 engine family. The engine production was commenced in Munich, Germany, from 1995 to 2001.
The M52 family featured a cast-aluminum alloy cylinder block with Nikasil coated cylinder liners. Though early cylinder blocks of M52 are cast-iron. BMW switched to Nikasil aluminum to save weight and more excellent stability.
However, the M52 engine received negative comments regarding high levels of sulfur in various countries, especially in the late 1990s. M52’s aluminum-made block, is susceptible to corrosion leading to many early M52 and M60 engines having premature bore-liner wear.
With that, countries with higher sulfur levels in their fuel received an iron-block version of the M52, so Nikasil problems are not that much of a problem in these countries. In addition, BMW found out that the problem was the Nikasil coating; instead of using Nikasil coating, BMW used steel cylinder liners.
Thus, the M52TU versions are not affected by the Nikasil issue.
Moreover, M52B28 engines feature a distributor-less ignition system with individual ignition coils for each cylinder. It is also equipped with Siemens MS 41.0 and Digital Motor Electronics System (DME).
Engine Specifications and Design:
- Production Run: 1995 – 2001
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Nikasil-coated Aluminum
- Configuration: Inline 6
- Bore: 84 mm
- Stroke: 84 mm
- Valvetrain: DOHC four valves per cylinder
- Displacement: 2.8 L (2793 cc)
- Compression Ratio: 10.2
- Weight: 360 lbs.
- Maximum HP: 190 HP at 5,300 RPM
- Maximum Torque: 207 lb-ft at 3,950 RPM
The BMW M52B28 engine is a square engine, having the exact bore/stroke dimensions. It has a cylinder bore and piston stroke of 84 mm. The machine has a redline of 6,500 RPM and a compression rating of 10.2.
The engine has a maximum output of 190 HP and 207 lb-ft of torque at 3,950 RPM.
The cylinder block is made from cast-aluminum alloy with Nikasil coating coated cylinder liners. As for Nikasil is a trademarked electrodeposited lipophilic nickel matrix silicon carbide coating specially made for engine component applications.
But, the nickel material has its disadvantages. It has a high sensitivity to sulfur-containing gases. That is why some markets refused the application of Nikasil and opted for the alternate BMW M52B28 aluminum cylinder block with cast-iron sleeves.
The cylinder has a great design exposing them on all sides to maximize coolant flow in every way. The engine used seven main bearings supporting the counterweighted crankshaft. The crankshaft rotates in a replaceable split-shell main bearing.
The forged steel connecting rods has the same split-shell bearings at the crankshaft’s end and solid bushings at the piston end. Three-ring type pistons with two upper compression rings and a lower one-piece oil scraper ring; circlips hold the full-floating piston pins.
The BMW M52B28 cylinder head is made from an aluminum alloy. That alone provides an excellent cooling efficiency and better ventilation. The engine also uses chain-driven dual overhead camshafts with a single VANOS system (Variable Camshaft Timing) and four valves per cylinder.
The standard head height is 140 mm. Apart from that, the cylinder head utilizes a crossflow design for better efficiency and power. Intake air enters the combustion from one side, and exhausts gas exits on the other.
Intake valve sizes are 33 mm in diameter, and exhaust valves are 30.5 mm. Valve clearance adjustments are through self-adjusting hydraulic lifters to eliminate routine valve adjustment and reduced valve noise.
Engine Tuning, Upgrades, and Modifications
1. Stroker and Manifold – Naturally Aspirated
The most typical and the easiest way to increase the engine’s power output is to install the M50B25 intake manifold and cold air intake. With that, you need to upgrade the camshaft and tune the ECU to complement the improvements.
S52B32 camshaft will be a better option for this setup and will serve its purpose. These upgrades can gain you as much as 250 HP, a good range for a city drive excursion.
However, there is another alternative to ramp up your engine displacement into 3-liter M52B30. You need to buy an M54B30 crankshaft to commence this project, though.
Standard pistons should be milled down to at least 1.6 mm. The M50B25 intake manifold is suggested for HP improvement.
If you want another setup or build, you can also install a turbocharger. The recommended turbocharger is the Garrett GT35 turbo kit using M52B28 stock internals. After the tuning is completed, the M52B28 turbo can reach 400 HP when the boost is ten psi.
It will be followed with a smooth acceleration perfect for an everyday drive and has impeccable reliability.
Further, the M52B28 stock bearings can handle large amounts of pressure up to 14 psi. But that is borderline critical, and for some cases, that pressure can go higher. So it greatly depends on the ability of your internals too.
So, if the rate is higher than 500 HP, the stock pistons must be replaced by forged pistons with an 8.5 compression ratio to secure the longevity and reliability of the engine.
On another note, a supercharger can also be applied to this engine. You can benefit from the positives of the ESS TS2 supercharger kit produced on the base of the Lysholm supercharger.
This kit can upgrade your machine up to 300 HP and more even without replacing the stock pistons.
Problems Surrounding BMW M52B28 Engines:
1. Radiator and Expansion Tank Leaks
The cooling system of the M52 might be the weakest point of this family. Many radiator support parts are plastic made, meaning that they easily break, if not correctly made, to fluctuating temperature and unstable behaviors leading to cracking and leaking.
Radiator leaks commonly stem from the top radiator pipe and the thermostat housing.
So, if you experience regular overheating, you either have a leak in the cooling system or a failed radiator.
2. Idle Control Valve Failure
The idle control valve picks up dust and dirt over time, resulting in a dysfunctional component. The idle control valve controls the car’s idle by regulating air to fuel ratios at idle. A frail valve will lead to irregular and rough idling.
3. Water Pump Failure
The BMW M52B28 engine uses a plastic impeller, an integral part of the engine that sends the coolant through the machine. The plastic impeller commonly breaks from normal wear and tear, causing the water pump to stop functioning. The water pump usually lasts around 80,000 – 100,00 miles.
4. VANOS Failure
The M52 family has a dual-VANOS system; the M52B28 has a single VANOS only. Whether the engine has one or two, this system, VANOS, tends to be faulty even in modern BMW engines. But it is far more rampant in the early BMW engines, which were the first to use the system.
If you experience rough idling, cold start issues, loss of drivability, the appearance of P1520, P1523, and P1397 engine codes.
5. Valve Cover Cracks and Oil Leaks
Another point of concern, if you’re a new BMW owner, is the valve covers. However, if you’ve owned a BMW before, this issue might not bother you anymore. Well, these valve covers tend to crack over time due to sustained heat.
Because they are made of plastic, these valve covers do not have much resistance in such conditions. Even the most minor cracks can result in an oil leak. In addition, valve cover gaskets often cause oil leaks from the normal wear and tear because they are made from rubber.
To know if you have a cracked cover or just a plain old gasket, check if there is a leak. If there is a leak, pull off the lid and assess it for any cracks or irregularities. If all looks good, start by replacing the gasket. Make sure to check the spark plugs too.
The BMW M52B28 engine, as we discussed above, is a great engine overall and the internals are sturdy and reliable. But as the car accumulates miles and ages, maintenance becomes a critical part of the longevity process.
The supporting engine parts must also be maintained and be appropriately taken care of.
Furthermore, the engine served its purpose and continuously impressed many engine enthusiasts. Though it is a little bit expensive, this BMW M52B28 engine can give you satisfaction; it is also a great engine to drive.