Alfa Romeo1990–1994Technical specifications

33 1.5: Technical specifications

Workshop data for the 1.5-litre petrol (engine code 307.50). Covers engine, fluids, brakes, service, torques and air conditioning: the figures to check before a job or a parts order.

Summary

Match the engine code (307.50) to the vehicle before ordering parts or applying these figures.

Vehicle specifications

Overview

Make: Alfa Romeo
Model: 33
Years: 1990–1994
Fuel: Petrol
Engine code: 307.50

Performance & efficiency

Power: 71 kW (97 hp)
Engine size: 1,490 cc
Cylinders: 4 · OHC
Compression ratio: 9.5:1
Fuel system: Bosch

Fluids & capacities

Engine oil (with the filter): 4.0 litres

All 133 specifications below

Engine & identification

Vehicle identification

No. of cylinders Type	4/OHC
Capacity (Fiscal) cc	1490 (1474)
Compression ratio :1	9,5
Suitable for unleaded petrol	Yes
Minimum octane rating RON	95
Ignition system Make	Bosch
Ignition system Type	TSZ-i
Ignition system Description	Trans-i
Trigger location	Distributor
Fuel system Make	Bosch
Fuel system Type	L3-Jetronic
Fuel system Description	MFI-i
Air metering Type	Flow
Combined ignition and fuel ECM	No
Diagnostic socket	No

Ignition system

Ignition coil Make	Bosch
Ignition coil Type	0 221 600 002
Ignition coil supply voltage + with ballast V	11,0
Primary resistance Ohm	0,7-1,0
Secondary resistance Ohm	6700-9600
Distributor (ECM) Make	Bosch
Distributor (ECM) No.	0 237 507 009

Firing order

The firing order for the Alfa Romeo 33 1.5 (1990–1994) is 1-3-2-4.

Firing order	1-3-2-4

Valve clearances

Valve clearances on the Alfa Romeo 33 1.5 (1990–1994) are hydraulic — they self-adjust, so no manual clearance figure applies.

Valve clearance - INLET mm	Hydraulic
Valve clearance - EXHAUST mm	Hydraulic

Engine oil & fluids

Engine oil

The Alfa Romeo 33 1.5 (1990–1994) takes 4.0 litres of engine oil with the filter.

A listed engine oil option is SAE 10W-30 for cold climates, with API/ACEA classification SH/A2.

A listed engine oil option is SAE 10W-40 for moderate climates, with API/ACEA classification SH/A2.

A listed engine oil option is SAE 10W-40 as an alternative for moderate climates, with API/ACEA classification SH/A3.

A listed engine oil option is SAE 20W-50 for hot climates, with API/ACEA classification SH/A2.

Manual gearbox

The manual gearbox has a listed capacity of 2.6 litres. The specified oil is SAE 75W-90.

Coolant

The listed total cooling-system capacity is 7.8 litres.

Grades, filling conditions and capacities

Lubricants and capacities — complete reference
Engine oil options
Ambient temperature range	Cold climate
Engine oil grade SAE	10W-30
Engine oil classification API/ACEA	SH/A2
Ambient temperature range	Moderate climate
Engine oil grade SAE	10W-40
Engine oil classification API/ACEA	SH/A2
Ambient temperature range	Moderate climate alternative
Engine oil grade SAE	10W-40
Engine oil classification API/ACEA	SH/A3
Ambient temperature range	Hot climate
Engine oil grade SAE	20W-50
Engine oil classification API/ACEA	SH/A2
Engine with filter(s) litres	4.0
Other lubricants and capacities
Manual transmission oil grade SAE	75W-90
Manual transmission litres	2.6
Differential oil grade - rear SAE	80W-90
Differential rear litres	1.0
Cooling system - total capacity litres	7.8
Brake fluid Type	ATE S

Brakes & wear limits

Brake disc thickness

Brake discs on the Alfa Romeo 33 1.5 (1990–1994) are replaced at a minimum thickness of 9 mm (solid) or 20,2 mm (ventilated) front and 9,2 mm rear.

Minimum disc thickness for replacement - solid Front	9 mm
Minimum disc thickness for replacement - ventilated Front	20,2 mm
Minimum disc thickness for replacement Rear	9,2 mm
Maximum drum diameter for replacement Rear	229,6 mm

Brake disc and drum dimensions

Maximum rear drum diameter
Disc runout Front	0,03 mm
Minimum pad thickness Front	7 mm
Minimum pad/shoe thickness
Minimum shoe thickness Rear	0,5 mm
Parking brake travel No. of notches	1-3

Service & electrical

Ignition timing

Basic ignition timing for the Alfa Romeo 33 1.5 (1990–1994) is 8°±1° BTDC at 900 rpm.

Ignition timing
Ignition timing	Without vacuum
Ignition timing - basic BTDC °Engine/rpm	8±1/900

Battery

The Alfa Romeo 33 1.5 (1990–1994) uses a 12 V, 50 Ah battery (reserve capacity 80 minutes).

Battery V/RC(Ah)	12/80 (50)

Spark plugs

The Alfa Romeo 33 1.5 (1990–1994) uses Lodge 25HL spark plugs with a 0,7 mm electrode gap.

Spark plugs Original equipment	Lodge
Spark plug Type	25HL
Electrode gap mm	0,7
Spark plugs Make	Autolite
Spark plug Type	APP62
Electrode gap mm	0,6
Spark plugs Make	Beru
Spark plug Type	14-6DTU
Electrode gap mm	0,8
Spark plugs Make	Bosch
Spark plug Type	W6DTC
Electrode gap mm	0,8
Spark plugs Make	Champion
Spark plug Type	N6YC
Electrode gap mm	0,6
Spark plugs Make	NGK
Spark plug Type	BP6E-VG
Electrode gap mm	0,7

Tuning and emissions

Ignition timing
Tuning conditions	—
View more information	—
Ignition advance	Without vacuum and basic timing
Ignition advance checks °Engine/rpm	0-2/3000
Ignition advance checks °Engine/rpm	4-10/4000
Ignition advance checks °Engine/rpm	16-20/6000
Vacuum check	Ignition timing advances
Vacuum range °Engine	16-20
Vacuum starts mbar	100
Vacuum ends mbar	400
Idle speed rpm	800-900
Oil temperature °C	80
CO level at idle speed - tailpipe Vol. % CO	0,8-1,7
HC level at idle speed ppm	300
HC level at idle - alternative ppm	Kat=50 Max
CO2 level at idle speed Vol. % CO2	13-16
O2 level at idle speed Vol. % O2	0,5-2,0

Starting and charging

Starter motor Make	Bosch
Starter motor Type	0 001 113 004
Maximum cranking amps A	135-165
Alternator Make	Bosch
Alternator Type	0 120 488 118
Alternator output A/V/rpm	65/13,5/3000
Regulated voltage V	13,7-14,5

Service checks and adjustments

Compression pressure bar	10,3 Min
Radiator cap bar	0,90-1,10
Thermostat opens °C	84-88

Fuel system

System pressure bar	2,8-3,2
Regulated pressure with vacuum bar	2,3-2,7
Engine coolant temperature (ECT) sensor Ohm/°C	300/80
Injector Ohm	14,0-16,0
Injector opening duration (hot) ms/rpm	2-10/900
Idle air control (IAC) valve/idle speed control (ISC) actuator Ohm	40,0-75,0
Lambda sensor (Oxygen) heater Ohm	3,0-20,0

Tightening torques

Cylinder head bolt torque

The cylinder head bolts on the Alfa Romeo 33 1.5 (1990–1994) are tightened in 3 stages: 40-60 Nm, then 81-87 Nm, then a final 81-87 Nm.

Cylinder head
Renew bolts	No
Tighten	40-60 Nm
Tighten	81-87 Nm
Run engine	15 minutes
Wait	120 minutes
Individually slacken off	360°
Tighten	81-87 Nm

Other engine tightening torques
Cylinder head instructions	—
Main bearings Renew bolts/nuts	No
Main bearings Stage 1	—
View more information	—
Main bearings
Big end bearings Renew bolts/nuts	No
Big end bearings Stage 1	22-24 Nm
Big end bearings Stage 2	43-48 Nm
Sump bolts	8-10 Nm
Flywheel/driveplate	94-105 Nm
Clutch pressure plate	12-23 Nm
Crankshaft pulley/damper centre bolt	118-144 Nm
Camshaft sprocket/gear	63-70 Nm
Inlet manifold to cylinder head	19-24 Nm
Spark plugs	25-34 Nm
Chassis tightening torques
Front hub	427-472 Nm
Rear hub	—
Rear hub
Steering track rod end	39-48 Nm
Brake caliper/carrier to hub Front	66 Nm
Brake caliper to carrier Rear	33 Nm
Brake caliper/carrier to hub Rear	47 Nm
Back plate to hub Rear	39-48 Nm
Backplate to hub
Road wheels	88-108 Nm

Air conditioning

Air conditioning refrigerant Type	R12
Air conditioning refrigerant quantity grams	1150
Air conditioning oil Type	Suniso 5GS

Frequently asked questions

What is the firing order of the Alfa Romeo 33 1.5?

The firing order for the Alfa Romeo 33 1.5 (1990–1994) is 1-3-2-4.

What spark plugs does the Alfa Romeo 33 1.5 use?

The Alfa Romeo 33 1.5 (1990–1994) uses Lodge 25HL spark plugs with a 0,7 mm electrode gap.

How much oil does the Alfa Romeo 33 1.5 take?

The Alfa Romeo 33 1.5 (1990–1994) takes 4.0 litres of engine oil with the filter. A listed engine oil option is SAE 10W-30 for cold climates, with API/ACEA classification SH/A2. A listed engine oil option is SAE 10W-40 for moderate climates, with API/ACEA classification SH/A2. A listed engine oil option is SAE 10W-40 as an alternative for moderate climates, with API/ACEA classification SH/A3. A listed engine oil option is SAE 20W-50 for hot climates, with API/ACEA classification SH/A2.

What are the valve clearances for the Alfa Romeo 33 1.5?

Valve clearances on the Alfa Romeo 33 1.5 (1990–1994) are hydraulic — they self-adjust, so no manual clearance figure applies.

What is the cylinder head torque for the Alfa Romeo 33 1.5?

The cylinder head bolts on the Alfa Romeo 33 1.5 (1990–1994) are tightened in 3 stages: 40-60 Nm, then 81-87 Nm, then a final 81-87 Nm.

What is the ignition timing for the Alfa Romeo 33 1.5?

Basic ignition timing for the Alfa Romeo 33 1.5 (1990–1994) is 8°±1° BTDC at 900 rpm.