B16 Engine Breakdrown

[Cerberus]

There are 4 general classifications for B16A motors:

B16A SiR
B16A SiR II
B16A2
B16A3
It is often confused as to which motor is which. In this article, we will help you to pick out the clues as to which motor is which, and which one you should get for your B16 swap.

Although I just noted that there are 4 classes of B16A's, we can break that list down into two groups.

Our new grouping of B16A motors:

B16A SiR
B16A SiR II, B16A2, B16A3
Why this breakdown?

It all comes down to OBD. OBD, or on board diagnostics, are broken down into levels, based on the years they are instated. For more info on OBD, please read our article on OBD - Explained.) The B16A SiR, commonly and mistakenly called the B16A1, is an OBD-0 motor. This was the first level of OBD installed on motor ethicals. The other 3 are either OBD-1 or OBD-2 motors.

The SiR was designed for a 4th gen chassis. It works great with an 88-91 civic. However, try putting this motor in a 92+ civic and the problems will just start to flow. The tranny on the SiR is cable. the 5th gen chassis uses hydraulic actuation.

Why is the SiR cheaper?

It's cheaper for several reasons. First, it's older. Second, the A2/A3/SiR II have a higher demand, as they work in newer cars and have a higher output.

How to tell the difference between an SiR and an A2/A3/SiR II

SiR uses a cable tranny- 5th gens are hydraulic
SiR has a lower compression ratio, 10.2:1 and makes 160ps
A2/A3/SiR II have a higher compression ratio at 10.4:1 (10.2:1 A2/A3) and make 160hp (A2/A3) or 170ps (SiR II)
A2/A3/SiR II motors have a better cam profile
A2/A3/SiR II have better oiling functions, keeping things better lubricated
SiR has cast aluminum oil spray bars while the A2/A3/SiR II are made of extruded aluminum.
A2/A3/SiR II have a single- 4-wire O2 sensor instead of 2-single wire O2 sensors
A2/A3/SiR II MAP sensor is an integral part of the throttle body, not an external one with a tube.
A2/A3/SiR II harnesses are grey. SiR has cream colored ones.
SiR is PGM-F1, clearly labeled on the intake manifold, andA2/A3/SiR II are MPFI
SiR valve covers have "DOHC" written in a larger font size than "VTEC"
A2/A3/SiR II valve covers have "VTEC" written in a larger font size than "DOHC"


88-91 B16A's are known as the SIR 1. It uses OBD0 Ecu's, and cable tranny's. The engine serial number is usually 1xxxxxx.
92+ B16A's are known as the SIR 2. It uses OBD1 or OBD2(2b), and hydraulic trannys. The engine serial number is usually 5xxxxxx
The #'s at the end of the block code tell where the engine originated from. The Americas, Europe, Austraillia, etc.....
ALL Japanese engines, generally do NOT have a number after them. (** see below)
SO, if you have a B16A1,2,3,4, or 5. It is usually NOT a true JDM engine. Don't mistake a B16A1 as being a cable unit, because it could be a hydraulic. There are other ways to tell what year it is exactly.

**NOTE: There is ONE exception to this rule. In 90-91, the Civic/CRX SiR came with a B16A1, but they are SUPER rare, and came 160HP with 10.4:1 compression. Their counterpart of the same year was a 158HP, 10.2:1. They are very difficult to tell apart.