BMW M10 (M98) engine

The BMW M10 (M98) engine is a gasoline power unit from the Bavarians, which features a maximum output of 75 horsepower with a displacement of 1.6 liters. Such engines can be found under the hood of the BMW third series of the first generation in the E21 body.

M10 (M98) engine specifications

Advantages

The BMW M98 powertrain has been given a special approach by the Bavarian company’s engineers. The company’s managers set them the task of achieving maximum simplicity and practicality of the scheme and design as a whole. Therefore, all cylinders decided to place in the classic in-line layout. Thus, such engines are very easy to repair and the cost of this procedure is relatively small. At the same time, almost any service station can undertake such work, and the popularity of these motors has led to the fact that it is quite easy to find spare parts for them.

The common material used for casting the cylinder block is cast iron, while the cylinder head is made of a high-strength aluminum alloy. This combination is considered to be the most optimal, as minimal weight is combined with great reliability. Engineers have made every effort to make a motor that meets the needs of users as much as possible, and the goal has been achieved. Unlike the new cylinder blocks, which are made of aluminum, the cast iron elements are easily overhauled and can be easily turned.

The motor is tilted 30 degrees to the right of its axis. This solution from the Bavarian engineers has its positive qualities, as the negative impact from the forces arising during engine operation becomes relatively small. This makes it possible to preserve the original technical characteristics, which are combined with a normal working life. Only in order to maximize the need for major repairs, it is best to use the recommended lubricants in combination with high-quality gasoline.

The location of the exhaust and intake manifold has also not been neglected from the engineers. The engine has been designed so that both manifolds are located on opposite sides of the power unit. This arrangement gives full access to all necessary parts during repairs, which significantly reduces the cost of maintenance and repair work.

Disadvantages

M98 motors have become quite successful, as they turned out to be relatively reliable and unpretentious in operation, but despite this, certain shortcomings and characteristic faults in their design are present. Most often, owners of cars with such motors under the hood face the following problems:

• The weakest point of these motors is the cylinder block, which often develops cracks. As a rule, the cracks occur at the threaded connections made to fix the cooling jacket and the block head. Often, the cause of cracks is severe overheating of the power unit. The first signs of a defect are the formation of emulsion in the lubricating fluid, as well as a gradual decrease in antifreeze in the expansion tank. Through the crack, a portion of oil seeps through the motor crankcase. This negatively affects the wear of parts whose surfaces rub during operation, which also increases the likelihood of motor overheating. The defect is quite common, so today it is almost impossible to find a whole cylinder block.
• The cam-rocker pair and the eccentric washer also have a short service life. These elements of the timing mechanism should be replaced periodically, as it is possible to encounter a problem during valve adjustment. Incorrectly set thermal clearances result in a characteristic chattering noise during engine operation.
• Low-quality materials were used in the production of the cylinder head gasket, so it can burn out quickly. Coolant starts to enter the cylinders through the gasket, and nothing good can be expected from this.
• After passing about 150 thousand kilometers, owners of cars with such motors may have certain problems associated with increased consumption of lubricating fluid. This is a normal phenomenon, which is caused by increased wear of piston rings.
• Despite the fact that the motors have typical faults, the entire BMW M10 engine range has proven to be quite reliable. They are characterized by very simple repairs, inexpensive maintenance, and relatively low fastidiousness to the quality of the working fluids used. This can be evidenced even by the fact that despite the old age of the engines, they can still be found on domestic roads.

Technical specifications

The M98 is a limited version of the M10B16 engine, which has a maximum output of 75 horsepower. An alternative name for the engine is M10B15.

The motor was produced from 1981 to 1983, and was designed to fit under the hood of the BMW E21. This powertrain is the same motor that was fitted to the 1502 cars, but it has received certain upgrades that are specific to the M10B16 motors.

Despite all the positive qualities and relatively low cost, it is not recommended to buy such motors. They are quite old, and most often they are bought as donors, in order to restore rare cars of the German concern. The resource of these motors has long gone out, and to find today a whole block of cylinders, without cracks in characteristic places, is almost impossible. Therefore, the purchase of such motors is a losing decision in advance.

But despite this, the line of engines was on the assembly line for 25 years, which testifies to the high quality of the engines, and also confirms their reliability. The motor design is quite simple and well studied, the life of the motors is amazing, so it is very easy to repair them.