Saab H engine

The Saab H engine is a redesign of the Saab B engine. Despite the name it is not an H engine, but a slanted inline-4. The H engine was introduced in 1981 in the Saab 900 and was also used in the Saab 99 from 1982 onwards and the Saab 90. It continued in use in the 900/9-3, 9000, and 9-5. The 2003 "Epsilon" based 9-3 switched to the GM "Ecotec", leaving the 9-5 as the sole user of the H engine. The last model year for this family of engines will be 2009.

All versions feature a grey cast iron block and an aluminum head with a single or double overhead chain driven camshafts. SOHC engines use two valves per cylinder and DOHC versions use four valves per cylinder with a pentroof chamber; the valve angle being 22 degrees from vertical. All engines use flat inverted bucket type valve lifters, hydraulic in the case of DOHC engines.

The engines were given numbers, for instance B201 is a 2.0 litre (20) engine.

B201

B201 is the original H engine with two valves per cylinder and a single overhead camshaft. It was introduced in 1981 and unlike the B engine it didn't have the central shaft which used to power the distributor, oil- and coolant pump. Instead the distributor is directly driven by the camshaft on the flywheel side, while the integrated waterpump was made as a belt driven separate unit.

It was availible with 100 bhp (DIN) @ 5200 rpm using a single carburettor, 108 bhp (DIN) @ 5200 rpm using a dual carburettor, 118 bhp (DIN) @ 5500 rpm using fuel injection and a turbocharged, fuel injected version with 145 bhp (DIN) @ 5000 rpm. In 1986 an intercooled version of the turbo engine also became availible, it produced 155 bhp (DIN) @ 5500 rpm.

Bosch K-Jetronic was used on fuel injected versions.

B202 & B212

In 1984, Saab added a 16 valve cylinder head with double overhead camshafts. They retroactively renamed the 8-valve version the B201 and used B202 as the name of the new multi-valve unit. Another notable addition to the B202 was hydraulic valve lifters and Ecopower ("ep" in Italy, "(900)S" elsewhere), with a pre-heated catalytic converter for reduced emissions.

In 1991, Saab introduced a 140 bhp 2.1 litre normally-aspirated 16 valve engine, with an increased displacement of (2119 cc/129 in³). The intake manifold was enlarged and redesigned for better and greater flow.The intake manifold and the head from the 2.1 liter constitute a well-known replacement for 1985-1993 16 valve 2.0 liter turbo cars. Power increase is modest at stock boost but becomes much more evident at higher boost levels.

B204 & B234

A major redesign of the H engine came in 1990 in the form of the new B234. The B234 featured an increase in stroke from 78 mm to 90 mm, increasing the displacement to 2.3 liter. With this increased stroke also came a new engine block with increased deck height to make sufficient room for the increased stroke length without being forced to use shorter connecting rods, and in block counter-rotating balance shafts for reduced vibrations. Unlike the previous B202 the block was no longer angled, but straight, something that made it unsuitable for the 900 model with its gearbox under the engine, built into the engine oil sump.

The B202 was still being produced in 1993, but for the new generation Saab 900 being released in 1994 a new engine was required. This new engine was based on the earlier B234, but in order to make the engine fit in the 900 the engine had to be shortened. This meant that a new chain drive for the camshafts was required to reduce the length of the engine.

The B204 engine was available with natural aspiration in 900, 9000 and 9-3 in the form of 2.0i (B204I), with a low pressure turbo in the form of 9000 and 9-3 2.0t (B204E) or Saab 900 and 9-3 2.0T (B204L). B204R was briefly available in late 1999 9-3 SE models (with manual transmission). B204 was in production in Saab 9-3 until 2000, when it was replaced by B205. The longer stroke B234 was last produced in 1998, that being the last year for the 9000 model.

The B234 was selected as one of Ward's 10 Best Engines for 1995 and 1996.

Turbocharged engines used Garrett T25 turbochargers and the B234R used a Mitsubishi Heavy Industries TD04HL-15T-6

B206

The B206 is a version of B204 but without the double balance shafts. It was only offered as a naturally aspiranted engine B206I producing 133 hp. seemingly a Europe-only option, 94-96 non turbo 900 NGs. This engine is popular among Saab tuners in Sweden (e.g. Trollspeed) due to the lack of balance shafts with presumably equal strength to the turbo blocks with balance shafts.

B205 & B235

The B205 and B235 engines are an evolution of the B204 and B235 engines. They were introduced in 1998 with Saab 9-5 and offered extensive modifications aimed at reducing fuel consumption, improve emission control and reduce NVH. The changes included lightweight internal components (lighter valves, softer springs, longer conrods with lighter pistons and balance shafts), lighter block and cover, heavier flywheel and more. Another important development was the introduction of the Trionic 7 torque demand type engine management system. Trionic 7 equipped engine have the black direct ignition cassette on top of the engine rather than the red one on the Trionic 5

The B205 and B235 is considered to be less strong than its predecessor, and could be less suitable for performance tuning applications due to its lighter weight and weaker pistons, softer valvesprings and milder valve timing.

In 2005, it was announced that 1998-2003 B205 and B235 engines suffered from oil sludge-related failures. The failures are a result of a revised piston ring setup that was intended to reduce friction cause excessive blow-by into the crankcase and new positive crankcase ventilation (PCV) system used on these models that was not capable of handling this excessive blow-by. Due to the poor crankcase ventilation, combustion by-products contaminate the oil, causing its additives to break down prematurely. If the car is used for mostly short trips, not allowing the engine oil to heat up properly these contaminates (mostly water, various unburned hydrocarbons, and acids formed by nitrogen oxides and sulfur oxides and water) also won't be able to evaporate, making the situation even worse. Where the blow-by gases settle directly on the metal surfaces of the engine, a build up of "varnish" results.

The improper PCV also allows the PCV system itself to fall victim, as the poor ventilation of the blow-by gases allows them to condense into an acidic soup that attacks and dissolves the PCV hose rubber. This further compromising the effectiveness of the system and introduces fragments of hose rubber into the crankcase. Once the inadequately-vented combustion products have broken down the motor oil additives, the oil will start to oxidize rapidly and form a soft sludge material. The oxidized oil is also ineffective at properly lubricating the turbocharger without suffering thermal breakdown. This breakdown leads to the formation of hard carbon particles, in a process known as turbo coking.

As a result, the aforementioned oxidation byproducts (soft sludge, harder carbon deposits, and hose rubber fragments) will then start to agglomerate. If not caught in time, the agglomerate can clog the extremely fine wire mesh at the end of the oil pump pickup tube, resulting in a loss of oil pressure. This resulted in several cases of rod bearing failure as well as other lubrication-related failures. The sludge problems can be repaired under a special extended warranty for 8 years and unlimited miles. However, in order to take advantage of this warranty, SAAB requires their oil change intervals to be met and receipts presented to verify this.

A BioPower flexible-fuel variant capable of running on gasohol mixtures containing as much as 85% ethanol (E85) became available in 2006. Coupled with a turbocharger, the engine can take advantage of the higher octane rating of ethanol and boost power. A 9-5 with a 2.0t BioPower engine produces 150 PS (110 kW) on gasoline and 185 PS (136 kW) on E85. ref|popsci

B235R engines with manual transmissions also have an overboost function, providing 370 Nm (272 ft·lbf) during up to 20 seconds. In 2002 B235R was uprated to 250 hp (EEC) (184 kW), but since the engine already produced 250 hp during overboost in 2001 it had no effect on performance. The 2000 model was slightly less powerful, producing about 240 hp during overboost. In 2006 the B235R was uprated once again, this time also adding some new hardware, a new air inlet to the turbocharger and associating compressor housing, this increased the output to 260 hp. From 2008 all U.S. market 9-5 models are powered by this 260 hp B235R engine.

At the 2006 Los Angeles International Auto Show, Saab showed off a variant of the 9-5 SportCombi equipped with an ethanol fueled BioPower version of the 2.3 litre engine, producing 310 horsepower and 440 N·m (325 lbf·ft) of torque.

The base version was used on the first generation Saab 9-3 and Saab 9-5, with power output varying across the models and markets.

All engines use Garrett GT1752S turbochargers, except R models which instead use Mitsubishi Heavy Industries TD04HL-15T-5.

ee also

*Volvo Redblock Engine

References

# Matthew Phenix. [http://www.popsci.com/popsci/aviationspace/e65b89c49db84010vgnvcm1000004eecbccdrcrd.html Liquor Does It Quicker.] "Popular Science", July 2005.
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