Honda B20B engine (B20Z)

  1. Specifications
  2. Overview, problems
  3. Performance tuning

Honda B20B/B20Z engine specs

Manufacturer Honda Motor Company
Also called Honda B20
Production 1995-2002
Cylinder block alloy Aluminum
Configuration Inline-4
Valvetrain DOHC
4 valves per cylinder
Piston stroke, mm (inch) 89 (3.50)
Cylinder bore, mm (inch) 84 (3.31)
Compression ratio 8.8
Displacement 1972 cc (120.3 cu in)
Power output 94 kW (126 HP) at 5,400 rpm
106 kW (145 HP) at 6,200 rpm
110 kW (150 HP) at 6,200 rpm
110 kW (150 HP) at 6,300 rpm
Torque output 180 Nm (132 lb·ft) at 4,800 rpm
178 Nm (131 lb·ft) at 5,200 rpm
190 Nm (140 lb·ft) at 5,500 rpm
184 Nm (135 lb·ft) at 4,500 rpm
Redline 6,500 (1996+ B20B)
6,800 (1999+ B20Z)
HP per liter 64
Fuel type Gasoline
Weight, kg (lbs) 145 (320)
Fuel consumption, L/100 km (mpg)

Honda CR-V
11.9 (20)
8.4 (28)

9.7 (24)
Turbocharger  Naturally aspirated
Oil consumption, L/1000 km
(qt. per miles)
up to 1.0
(1 qt. per 600 miles)
Recommended engine oil 5W-30
Engine oil capacity, L (qt.) 3.8 (4.0)
Oil change interval, km (miles) 5,000-10,000
Normal engine operating temperature, °C (F) 90 (194)
Engine lifespan, km (miles)
-Official information

300,000+ (180,000)
Tuning, HP
-Max HP
-No life span loss


The engine is installed in Honda CR-V
Honda Orthia
Honda S-MX
Honda StepWGN

Honda B20B engine reliability, problems and repair

It is the largest engine of the Honda B-series, which also includes B16, B17 and B18. In this engine, an aluminum cylinder block with cast iron liners was used; its deck height was 211.84 mm. An 89 mm stroke crankshaft was installed inside, length of connecting rods was 137 mm, and pistons height was 30 mm. As a result, we have the displacement of 2 liters.
They installed a 16-valve non-VTEC DOHC head on the cylinder block. The size of intake valves was 31 mm, of exhaust valves – 28 mm, and the diameter of valve stem was 6.5 mm. Specifications of B20B camshafts: duration 278/276 deg, lift 10.08/9.7 mm.
Here a timing belt was used to be replaced after every 60,000 miles of mileage. If the belt breaks, most likely the valves will remain intact. This engine requires periodic valve adjustment after every 24,000 miles of mileage.
The valve clearances for B20B are 0.08-0.12 mm for intake valves, and 0.16-0.20 mm for exhaust valves.
The first modifications of the B20B engine had the compression ratio of 8.8 and the power of 126 HP 5,400 rpm, and the torque was 180 Nm 4,800 rpm.
In 1999 production of the B20Z series was launched, which had a new intake manifold, intake camshaft, increased compression ratio (CR = 9.6), a different oil pump, and an ECU. This increased the power up to 147 HP 6,200 rpm, and the torque was 190 Nm 5,500 rpm.
In Japan, B20Z I have the old designation B20B.
The size of B20Z and B20B fuel injectors was 240 cc. The size of B20 throttle body was 60 mm.
The firing order of B20B and B20Z was 1-3-4-2.
The B20Z and B20B engines were produced until 2001, when they were replaced with the modern K20A.

Honda B20B/B20Z engine problems and malfunctions

Like the entire B-series, this engine is considered to be one of the most reliable and durable. The most vulnerable components here are cam seals, head gasket, sometimes the water pump and the thermostat fail before time, which results in engine overheating. In any case, it is a very outdated engine, and one cannot expect too much reliability from it.
However if it is serviced right, and high-quality motor oil is used, the engine may run for a while.

Honda B20B engine tuning


There’s no sense making performance tuning of a regular non-VTEC B20B head, it is better to replace it with B16A/B16B VTEC. It will significantly improve efficiency, but creating a hybrid B20/B16 is a quite complicated task. You will need a fully assembled B16 or B18C head, ARP head studs, and a Hondata ECU, and all this should be adjusted. This will give you about 200 HP. However, the stock B20 cylinder block not too good for high rpm, so it is better to buy Darton (or similar) sleeves, install oil jets, an oil cooler and a Type R oil pump, to replace the standard pistons with Wiseco high compression pistons (CR = 12+), buy Eagle rods and ACL bearings. These mods will increase reliability of the B20 VTEC, and it will heat less.
Let’s go above 250 HP. You will need head porting, then you will need the following performance parts: a cold air intake system, a Skunk2 intake manifold, a Skunk2 70 mm throttle body, Skunk2 Stage 2 cams, adjustable cam gears, Supertech valves, valve guides, retainers, a TODA lightweight flywheel, 360 cc fuel injectors, a Walbro 255 lph fuel pump, NGK 7 spark plugs, a 4-2-1 header, a 2.5″ exhaust system, and a Hondata ECU.
In the end, all these performance upgrades will give 250+ HP.


Everything written above is good, but sometimes you want more. Getting 300 HP from a naturally aspirated B20B is almost an impossible task, a turbo project should be built.
Forget about installing a turbocharger on B20B stock internals, they are quite weak and you won’t have high reliability.
The basis of your turbo project may be what is written just above, but pistons are to be replaced with forged low compression pistons (CR ~8.5), Carrillo rods, and Stage 1 cams, 630 cc fuel injectors (or larger), an AEM fuel rail, an aftermarket fuel regulator, a wideband air/fuel o2 sensor, and a Hondata ECU are to be installed.
Then choose any turbo kit to your liking, and install it in your engine. It is optimal to use an Evo 8 turbocharger or something like that. An oil feed line and an oil return line are to be installed. In the end, you will easily get 300+ horsepower.


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