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B28 —
the Swedish 2.8

The B28 is the 2,849 cc at Volvo — the displacement shared by the DeLorean's ZMJ-159, the 604 GTI's ZNJ and Renault's Z7W. Three letters for three fuelling systems and markets: B28A with an SU-HIF6 carburettor (126 bhp, 262C), B28E with CI K-Jetronic injection (155 bhp, 264 and 265), B28F for the United States (130 bhp).

2 849
CC
126–155
BHP
3
VARIANTS
The Swedish third

The most talkative manual in the Library

The B28 succeeds the B27 in the 260 series and takes the 2.7 to 2.8 litres — same block, same CI injection, same workshop practice: valve adjustment in two crankshaft positions with the pulley's “1” and “2” marks, oil pressure taken ahead of the filter and nowhere else, the chain tensioner finger read through the left rocker cover.

The three Volvo 260 manuals — repair and maintenance, overhaul, CI injection — are in the Library, and they are unusually precise: piston classes to the hundredth, colour-matched gudgeon pins, CO tables by market and model year. The 2.8 would then live on at Volvo under the B280 code, with LH-Jetronic injection, in the 760, 780 and 960.

B28
VOLVO CODE · 2,849 CC · CARBURETTOR OR CI INJECTION · 12 VALVES
2849
CC
155
BHP · B28E
12
VALVES
Identity

What makes a B28 a B28

Figures read in the constructor's documents held in our Library — repair manuals, Pub et Trade data sheets, period bulletins. Nothing here comes from a web fact sheet.

B28 2,849 cc · 12 valves · first generation · three Volvo manuals Engine overhaul →
91 × 73
2,849 cc — 91 mm bore × 73 mm stroke. Mahle pistons only on the B28 (the B27 accepts Demolin or Mahle): 455 ± 3 g, six grams' spread at most in one engine, classes A 90.970-90.980 · B 90.980-90.990 · C 90.990-91.000 mm.
Axes
Colour-matched pin bore — blue 23.510-23.513, white 23.507-23.510, red 23.504-23.507 — with a pin of the same colour. Ring gap: 0.40-0.60 mm for the two compression rings, 0.38-1.45 for the oil-control ring.
CO
B28E, uncatalysed: 2.0 % (check 1.0-3.0), idle 900 rpm, 1,000 with an automatic. B28F, catalysed: 1.0 % (0.7-1.3) with the Lambda sensor disconnected, and under 1.0 % once reconnected; idle 950 rpm on the 1980 B28F.
Compression
8 to 11 bar, engine warm, throttle wide open, starter at 250-300 rpm — and the wire of the coil's terminal 15 disconnected before starting.
Huile
At least 0.1 MPa at 900 rpm and 0.4 MPa at 3,000, at the left-hand tapping ahead of the filter — “if the pressure is measured anywhere else, the results will be invalid”.
Known variants

A, E and F

One letter for the fuelling and the market — the full code table is on the Engines page.

B28 126 to 155 bhp Every known code →
B28A126 bhp
SU-HIF6 carburettor12-valve
Volvo 262C — 126 bhp.
B28E155 bhp
CI K-Jetronic injection12-valve
Volvo 264 · 265 — 155 bhp, Europe.
B28F130 bhp
CI K-Jetronic injection12-valveRegulated markets
Volvo 264 (United States) — 130 bhp, Lambda sensor.
On the road

The cars of the B28

Volvo 264 · 265 · 262C →

The 260 series in 2.8 litre form: 155 bhp in Europe, 130 bhp in the United States, 126 carburetted bhp for the 262C coupé.

In the workshop

What the documents say about the B28

Answers taken from our FAQ, each one read in the Library. The full FAQ holds several hundred more, engine code by engine code.

The B28, in the documents The full FAQ →
Pistons
What are the piston dimensions of a Volvo B28?
Mahle pistons only on the B28 (the B27 accepts Demolin or Mahle). Weight 455 ± 3 g, with a maximum difference of 6 grams between pistons in the same engine. Overall height 62.8 mm on A and F engines, 65.3 mm on the E; from gudgeon pin centre to crown, 38.8 and 41.3 mm. Diameter measured 8 mm from the bottom edge and at right angles to the pin bore, by class: A 90.970-90.980 · B 90.980-90.990 · C 90.990-91.000 mm. The pin bore is colour-matched too — blue 23.510-23.513, white 23.507-23.510, red 23.504-23.507 — with a pin of the same colour. Ring gap, measured 15 mm from the bottom of the cylinder: 0.40-0.60 mm for both compression rings, 0.38-1.45 for the oil ring. Volvo reconditioning booklet, page 7.
CO
What CO content and idle speed on a Volvo B27 / B28?
It all depends on engine, model year AND market, and the manual gives two tables. E engines, no catalyst: B27E 1975-1977 Sweden and Australia 1.5% (check 1.0-4.0), other markets 2.0; 1978 to 1980 and all B28E: 2.0% (check 1.0-3.0). Idle 900 rpm — 1,000 with automatic transmission. F engines, catalysed: B27F 1976 1.7% (1.4-2.0) with the air pump disconnected; 1977 USA California 0.7% (0.4-1.0), USA Federal 1.0 (0.7-1.3), Canada and Japan 1.7; 1978, 1979 and B28F: 1.0% (0.7-1.3), Lambda sensor disconnected — and once the sensor is reconnected the CO must drop below 1.0%. Idle 900 rpm, 950 on the 1980 B28F. Two general rules: automatic transmission in neutral with the parking brake on, and if the CO is within the check values, do not adjust, even if it is not on the setting value. Volvo CI fuel system booklet, section 2 (23), page 5.
Huile
Where must oil pressure be measured on a B27 / B28?
On the take-off on the left-hand side of the engine, in front of the oil filter — and nowhere else. The manual is categorical: “if the pressure is measured anywhere else, the results will be invalid”. Adapter P/N 464592-5 lets you fit a gauge there. Warm engine and new filter, expect at least 0.1 MPa at 900 rpm and 0.4 MPa at 3,000 rpm. Volvo service manual, section 2, page 87.
Compression
What compression should a Volvo 260's PRV V6 give?
0.8 to 1.1 MPa, that is 8 to 11 bar (114 to 156 psi). And the manual boxes the conditions, without which the reading means nothing: warm engine, throttle fully open, and a starter turning speed of 250-300 rpm. Precaution before starting: disconnect the cable from terminal 15 on the ignition coil. Plugs go back in at 12 ± 2 N·m. Volvo service manual, section 2, page 29.

In the Library

The three Volvo 260 manuals, searchable page by page: Volvo B27 / B28 — engine repair and maintenance · Volvo B27 / B28 — engine overhaul · Volvo B27 / B28 — CI injection (K-Jetronic)

The rest of the family

Architecture, generations and every known engine code of the PRV V6 — on the main Engines page.

B27 — the Swedish 2.7 →B280 — the 760, 780 and 960 → All PRV engines →