The Engine

Originality

If the owner claims the engine is original, then look at the Engine Number and make sure it matches the VIN.

The engine should be checked for excessive smoking due to oil burning, excessive valvetrain noise, and sludge build up when looking under the oil filler cap. The aluminum bits inside should be clean and shiny, or maybe light brown. Beware of black or gummy parts inside.

White, sweet smelling steam

White or sweet-smelling steam coming from the tailpipe -- upon initial start-up or while driving the car – indicates water with coolant is getting into the engine. The Water/Coolant indicates a cracked cylinder head or a leaking (“blown”) head gasket.

Blue smoke on deceleration

A common problem is blue oil smoke coming from the tailpipe while decelerating from high engine RPMs. Typically, blue smoke is oil burning and indicates bad valve seals and worn valve guides. You can live with this problem as long as you check the oil level regularly. Rocker arms and shafts suffer from wear and usually need replacement if the head has over 100,000 miles on it. Valve guides almost always need replacement as well.

Blue smoke on acceleration

Blue oil smoke from the exhaust while accelerating comes from crankcase blow by and is an indication of loose rings. The lower end of these engines is tough – usually, the head needs the most work during rebuild time.

2002 Engine Types

The 1-barrel Solex carb on the 1971 and earlier 2002s are very simple to work on, and are also very reliable. Any problems here are usually caused by dirty jets and worn throttle shafts.

The 2-barrel Solex found on 1972 and later 2002s are a different story. The 2-barrel Solex is prone to parts working loose, poor drivability, and general fuel delivery problems. The 2-barrel Solex can be made to work properly, but usually require more effort than they are worth. A popular conversion is to replace the 2 barrel with a Weber 32/36 DGV (available with manual, electric, or water choke). The conversion requires minor modification to the manifold to match the ports, but the result is slightly increased performance and improved reliability.

2002tii Engine Types

The 2002tii and 2002 Turbo were factory equipped with fuel injection. All of these cars were equipped with a Kugelfischer mechanical fuel injection system, which uses an engine driven injection pump to pressurize the fuel to extremely high pressures and inject it behind each intake valve, much like a diesel injection system.

The Kugelfischer injection system on the 2002tii is a very robust and very well engineered system. Often, the pump will be blamed for performance problems, but the distributor and injectors are usually the cause. Also, if it's running well, don't mess with it!

All 2002tii models use the same basic Kugelfischer system. Two versions of the injection pump were used. All european and the '72-'73 US models used pumps equipped with the V7 fuel control cone, and the '74 US only tii used a pump with the V6 fuel control cone. Both pumps are identical in appearance and function other than the mixture curves.

There were two different styles of intake manifolds used. All cars equipped with the 121 or 121TI cylinder head used a manifold with the rubber/plastic intake runners. All later cars equipped with the E12 head used a manifold with aluminum intake runners. The plastic runners were prone to cracking and poor sealing, hence the switch to the more reliable aluminum runners.

Two different, but completely interchangeable throttle bodies were also used. The later version used a redesigned CO adjustment screw location that made mixture adjustment easier and less touchy.

Cylinder Heads

The 2002 engine was offered with four different cylinder heads. When building a high performance 2002, there are certain heads that may lend themselves to higher horsepower applications. Choosing among the various available options is dictated primarily by the intended application. All 2002 cylinder heads are designated by a number (either 121, 121TI, E12, or E21 2.0) which is cast into the head. The location of this number is on the intake side of the cylinder head, above the number four intake port. It is easily visible upon opening the hood.

Distributors

Vacuum Advance Distributor

Mechanical Advance Distributor

Basic Specification Information for the 2002 and 2002tii engines

Model	2002tii
Years	1972	1973	1974
Intake	Plastic Plenum Tubes Kugelfischer Mechanical Fuel Injection V7 Fuel Control Cone	Metal Plenum Tubes Kugelfischer Mechanical Fuel Injection V6 Fuel Control Cone	Deceleration/Anti-backfire valve, smog equipment? Kugelfischer Mechanical Fuel Injection V6 Fuel Control Cone
Head	121 or 121TI	E12	E12
Pistons	9.0:1 CR U.S. "Spec" piston used on '72 US-model 2002tii's	9.0:1 CR U.S. tii pistons	9.0:1 CR U.S. tii pistons

Model	2002
Years	1968-72	1972-73	1974	1975	1976 (non-CA)	1976 (CA)
Intake	Single Barrel Solex	Dual Barrel Solex
Head	121 or 121TI	E12			E21 2.0
Pistons	8.5:1 CR U.S. "Spec" piston on 1968-1972 2002's 42.3 mm pin-to-deck, flat top	8.3:1 CR U.S. "Spec" piston on mid 1972-1974 cars	8.3:1 CR U.S. "Spec" piston on mid 1972-1974 cars	8.1:1 CR flat-topped piston (much like the 8.5:1 CR used on the 121 heads)	8.3:1 CR flat-topped pistons

Cooling System

All '02 models use the same basic cooling system. All models use an engine driven water pump and cooling fan with a vertical flow radiator and dual action thermostat.

Operation

Starting at the water pump, the coolant is pumped into the engine block and up through the cylinder head. Most of the coolant exits the engine at the top of the cylinder head, at the hose flange next to the intake manifold. From here, the coolant flows either to the thermostat or to the radiator. If the engine is below the thermostat opening temperature, the coolant flows to the thermostat to warm it up, and from the thermostat it flows back to the water pump and into the engine. If the engine is hot, the thermostat shuts off the flow from the top of the head back into the engine, instead forcing the coolant to flow to and through the radiator. The coolant is cooled as it flows through the radiator and emerges from the bottom hose of the radiator to the bottom half of the thermostat. This cooled coolant then flows to the water pump and into the engine. By using this system, the thermostat controls the temperature of the coolant entering the engine, instead of the temperature of the coolant exiting the engine. This allows for better temperature control and prevents having ice cold coolant from a radiator on a cold day hitting a hot motor when the thermostat opens.

The heater takes hot coolant from a fitting on the back of the cylinder head, passes it through the heater core, and returns it through a pipe or through the bottom of the intake manifold to the water pump, where it is cycled back through the engine.

Carburetor cars equipped a water temperature based automatic choke takes hot coolant from the back of the block and returns it into the manifold to go back to the water pump. The warm-up device on the tii and the manifold heater on a downdraft carburetor car use hot coolant from the flange on the head and returns it to the water pump as well.

Water Pumps:

There are only 2 types of water pumps used on the '02. All non-tii and non-Turbo models use one pump, with the heater/manifold return pipe offset 180 degrees from the thermostat inlet fitting. The tii models and the Turbo have a water pump with the heater return pipe fitting offset 90 degrees from the thermostat inlet fitting. This was done because the location of the injection pump does not allow the use of the standard pump.

Cooling Fan/Fan Shroud/Pulley:

There were three types of cooling fans used. Very early US cars and most pre-'71 non-US cars came with a 4-blade fan. '71-up non-US cars and '75-'76 US cars came with a 5-blade 360mm diameter fan. '69-'74 US cars and available as special equipment on non-US cars was the 5-blade 400mm diameter "tropical" fan.

A fan shroud was installed on '75-'76 US 2002s. This shroud only works with a radiator equipped with mounting ears and the 360mm fan.

Most 2002s use the same sized pulleys, but the '75-'76 US 2002 had an overdriven water pump/cooling fan. The crankshaft pulley was larger than standard, and the water pump pulley was smaller than standard. This was done, in addition to the fan shroud, in an attempt to keep the engine cool with the addition of major emissions controls. This is also why '75-'76 US 2002s tend to have more fan noise than the earlier cars.

Thermostats:

The stock thermostat is an 80 deg C unit. 71 and 75 deg C units are available from the aftermaket. These can help the engine run cooler in extremely hot weather and help marginal cooling systems.

Upgrades/Retrofits

The main component in an '02 cooling system that is worthy of upgrading is the radiator. While a fresh, clean stock radiator will typically be adequate for most circumstances, extremely hot climates, lots of stop and go driving, the use of air conditioning, or a hopped-up engine may overwhelm the stock radiator. Several upgrades are available.

Recore the stock radiator using a thicker, high-efficiency core with a greater tube and fin count. This keeps the stock look yet is sufficient for just about every situation.
Retrofit a 320i radiator. The 320i radiator is larger, and the use of a plastic/aluminum or plastic/brass unit reduces weight. This is also sufficient for most setups. The drawbacks to this installation is the need for custom brackets or the drilling of extra holes in the body, and the need for different hoses.
Install a Ford Pinto or Volvo 240 radiator. These installations will work, and improve cooling capacity, but involve modifications to the body. Other similar-sized radiators can also be installed with modifications.

Other cooling system tips:

The 400mm cooling fan theoretically moves more air, and can help if you have overheating problems in traffic, but more often than not, the 360mm fan works better, as it is quieter, uses less power, and is typically adequate in most circumstances. The same applies to the overdriven pulley setup.

Removing the engine driven cooling fan entirely and replacing it with an electric fan improves engine performance, reduces engine noise, and can reduce engine temps in traffic, given an adequately sized fan. The drawbacks to this setup are the need to drill holes in the car to mount the fan, installing wiring to operate the fan, and the reliability of an electric fan vs. the engine driven fan.

All '02s use the same basic cooling system with a few component differences.

Radiators:

All '02s except for the Turbo use the same sized radiator. All early models and most non-US models use a radiator with a bottom hose fitting that extends straight back from the bottom tank and connects to a simple 90 degree bend lower hose. This lower hose setup does not clear air conditioning compressors. Most US models and all others equipped with air conditioning use a radiator with a bottom hose fitting that protrudes from the right side of the bottom tank and curves towards the back and upwards. This allows the lower hose to clear an A/C compressor.

Some 2002A's have a transmission oil cooler built into the bottom tank of the radiator. '75-'76 2002 radiators also have mounting ears for a fan shroud. There are also variations in core structure and thickness depending on the year and version of the radiator.

The 2002 Turbo came with a wider radiator for extra cooling capacity. The left side of the radiator is extended approximately 2 inches such that the edge of the radiator is next to the battery tray. This radiator can be fitted into any other '02, but the radiator support opening needs to be enlarged and the mounting holes redrilled.

Exhaust and Headers

Return to Top