Toyota SZ series engines

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Eugenio,77
mail@toyota-club.net
© Toyota-Club.Net
Jul 2021


K3-VE · 2SZ-FE EUR · 2SZ-FE JDM · 1SZ-FE · 3SZ-VE · Experience


At the very end of the 1990s, Daihatsu and Toyota created a new series of engines that combined classic solutions with new trends (cast iron cylinder block, timing chain, VVT). One of them had the designation 1SZ-FE and was used only for Toyota models (Vitz/Yaris/Platz). The second turned into a small family for Daihatsu's own models: basic K3-VE, forced K3-VE2, turbo K3-VET, simplified K3-DE.
In 2002, on the basis of the K3-VE, two completely dissimilar versions were created, which received the same Toyota designation 2SZ-FE: one for European (Yaris 10..90), the second for Japanese market (Vitz 10..90, Belta, Ractis).
In 2005, the third engine, 3SZ-VE, was introduced for Daihatsu models (including those bearing Toyota and Perodua nameplates).
Since 2000, the assembly of the SZ began at TMUK, over time production was deployed in China and Indonesia. Despite the fact that already from the mid-2000s SZ engines began to be replaced by KR and NR series, their production continued until the early 2020s.

EngineDisplacement, cm3Bore x Stroke, mmCompression ratioOutput, hpTorque, NmRON
1SZ-FE99869.0 x 66.710.068 / 600090 / 410095 (EEC)
1SZ-FE99869.0 x 66.710.070 / 600095 / 400091 (JIS)
2SZ-FE129872.0 x 79.710.087 / 6000122 / 420095 (EEC)
2SZ-FE129672.0 x 79.611.087 / 6000116 / 400091 (JIS)
3SZ-VE149572.0 x 91.810.0107 / 6000141 / 440095 (EEC)
3SZ-VE149572.0 x 91.810.0109 / 6000141 / 440091 (JIS)
3SZ-VE149572.0 x 91.810.097 / 6000134 / 440091 (JIS)
K3-DE129772.0 x 79.710.087 / 6000114 / 3600-
K3-VE129772.0 x 79.710.090 / 6000123 / 400091
K3-VE2129772.0 x 79.711.0110 / 7000126 / 440095
K3-VET129772.0 x 79.78.5140 / 6400177 / 320091
* engine weight: 1SZ-FE - 83 kg, 2SZ-FE - 95 kg

Applications:
1SZ-FE: Vitz/Platz/Yaris
2SZ-FE EUR: Yaris
2SZ-FE JDM: Vitz/Belta/Ractis
3SZ-VE: Terios/Be-Go/Rush, Boon/Sirion/Myvi, Coo/Materia/Bb, Gran Max/Luxio/Townace/Liteace, Boon Luminas/Passo Sette
K3-DE: Xenia/Avanza, Gran Max
K3-VE: Storia/Sirion/Duet, Terios/Cami, YRV, Atrai 7/Sparky, Boon/Sirion/Passo/Myvi, Coo/Materia/Bb, Copen, Xenia/Avanza
K3-VE2: Storia/Duet
K3-VET: Terios/Cami, YRV

K3-VE (1.3 EFI VVT)



Engine mechanical

The engine uses a classic cast iron cylinder block with a "closed deck". Together with the block some mounting elements, pump chamber, oil pump pressure relief valve chamber, dipstick hole etc. are cast.


1 - coolant pump, 2 - alternator bracket, 3 - pump chamber, 4 - coolant passage, 5 - cylinder block, 6 - water jacket, 7 - oil level gage hole, 8 - A/C compressor bracket, 9 - oil pump relief valve, 10 - oil pump chamber, 11 - oil pump

The axis of the crankshaft has been shifted by 8 mm relative to the cylinder axis lines ("desaxage"), thus reducing the lateral component of the force exerted by the piston to the cylinder wall, reducing wear.



The crankshaft has 8 balance weights, 5 journals and individual main bearing caps.



Pistons made of alloy, T-shaped with a rather wide skirt, with an alumite treating at head belt. A drawback - piston pins are non full-floating, but press-fitted into the connecting rods.


The design of the cylinder head is a traditional single-part. There are combined cap for the front camshaft bearings and separate caps for the rest. The head cover made of aluminum. The VVT solenoid is integrated into the timing chain cover.


1 - cover, 2 - gasket, 3 - camshaft journal cap 1, 4 - camshaft journal cap 2-5, 5 - cylinder head, 6 - oil gage, 7 - head gasket

The valve clearance is adjusted by a various-size lifters, without adjusting washers or lash adjusters.


1 - water jacket, 2 - ports, 3 - spark plug. a - intake, b - exhaust

Valvetrain - DOHC type, the angle between intake and exhaust valves is 29.7°. There is VVT (variable valve timing system) sprocket on the intake camshaft, the adjusting range is 42°. More about Toyota operation principles - see "Toyota Variable Valve Timing. VVT-i (gen.IV)".
Valve timing: intake open 30BTDC-12ATDC, close 10ABDC-52ABDC; exhaust open 30BBDC, close 2ATDC.


1 - VVT solenoid, 2 - VVT controller, 3 - intake camshaft, 4 - rotor, 5 - exhaust camshaft, 6 - valve lifter, 7 - valve spring, 8 - exhaust valve, 9 - intake valve, 10 - sprocket

Timing drive - by silent chain (pitch 6.35 mm) with a hydraulic tensioner.


1 - VVT solenoid, 2 - VVT filter, 3 - mounting bracket, 4 - timing chain cover, 5 - service hole, 6 - service plug, 7 - timing chain cover 2, 8 - VVT controller, 9 - intake camshaft, 10 - exhaust camshaft, 11 - chain guide, 12 - oil pump sprocket, 13 - chain guide 2 (skip prevention), 14 - oil jet, 15 - chain tensioner arm, 16 - chain tensioner

Auxiliary drive - by single serpentine belt, the tension is regulated by the generator mounting bolt. Early models could have a hydraulic power steering pump.


1 - idler 1, 2 - idler 2, 3 - A/C compressor, 5 - crankshaft, 6 - alternator, 7 - coolant pump

Lubrication

Trochoid oil pump is driven by timing chain. Oil bypass is internal to the pump inlet.


1 - intake camshaft, 2 - exhaust camshaft, 3 - oil filter, 4 - relief valve, 5 - oil strainer, 6 - oil jet, 7 - chain tensioner, 8 - VVT filter, 9 - VVT solenoid

The oil filter could have either a good classic or an unsuccessful separable structure. Over time, for ease of maintenance, filters on transverse motors began to be installed on a long bracket.


1 - filter element, 2 - filter cap, 3 - drain tube

Cooling


1 - coolant pump, 2 - throttle body, 3 - heater, 4 - thermostat, 5 - radiator

Cooling system is classic: pump drive by serpentine belt, "cold" (80-84°C) mechanical thermostat, heated throttle body, sinlge radiator fan.



Intake and exhaust

The location of the intake and exhaust manifolds - rear and front, respectively. The intake manifold is made of plastic. The exhaust manifold is made of stainless steel with an integrated catalyst.


1 - intake duct, 2 - surge tank, 3 - gasket

Fuel system / Engine control


1 - ECM , 2 - air cleaner, 3 - intake air temperature sensor, 4 - throttle position sensor, 5 - ISCV, 6 - throttle valve, 7 - EVAP VSV, 8 - vacuum sensor, 9 - VVT solenoid, 10 - injector, 11 - ignition coil, 12 - camshaft position sensor, 13 - VVT controller, 14 - EVAP canister, 15 - knock sensor, 16 - coolant temperature sensor, 17 - crankshaft position sensor, 18 - oxygen sensor (S1), 19 - catalyst, 20 - oxygen sensor (S2)

Engine control system - D-type EFI (with MAP sensor). Fuel system - without a return line, with the pressure regulator, and the fuel filter, and EVAP canister built in pump module.


1 - fuel delivery pipe, 2 - pulsation damper, 3 - injector, 4 - pressure regulator, 5 - fuel filter, 6 - fuel pump


1 - injector, 2 - fuel delivery pipe, 3 - pulsation damper, 4 - spacer, 5 - insulator

Injector - with a 4-point nozzle.



Crankshaft position sensor - induction type.


1 - crankshaft position sensor, 2 - rotor, 3 - crankshaft

Camshaft position sensor - induction type.


1 - camshaft position sensor, 2 - timing pin, 3 - rotor, 4 - camshaft

Simple EVAP system with purge VSV.



Knock sensor - flat piezoelectric non-resonance type.

The throttle valve is mechanically driven and has a classic idle speed control valve (R-ISCV). Oddly enough, but this principle remained until the end of the production.


1 - PCV port, 2 - coolant port, 3 - ISCV, 4 - throttle position sensor

Ignition system - DIS type, separate coil for each cylinder. Monitoring of combustion by ionization current is provided.


1 - battery, 2 - combustion ion current signal, 3 - ignition control signal, 4 - ion current detection IC, 5 - igniter, 6 - primary coil, 7 - secondary coil, 8 - spark plug

Spark plugs - iridium NGK IKR7D or Denso SXU22PR9.



2SZ-FE EUR (1.3 EFI VVT)

It would seem that this engine should be a complete copy of the K3-VE, but upon closer examination it has a number of minor and major differences...

• The crankshaft has 4 balance weights (as 1SZ-FE).



• Connecting rods with oil supply holes.
• Control system - L-type EFI (with MAF sensor).


1 - ignition coil, 2 - VVT solenoid, 3 - injector, 4 - ISCV, 5 - throttle position sensor, 6 - camshaft position sensor, 7 - coolant temperature sensor, 8 - knock sensor, 9 - crankshaft position sensor, 10 - oil pressure switch, 11 - oxygen sensor (B1S1), 12 - air flow meter, 13 - EVAP VSV, 14 - oxygen sensor (B1S2)

• Injectors with 10-point nozzle.
• Different missed teeth pattern of crankshaft position sensor rotor.


1 - crankshaft position sensor, 2 - rotor

• Spark plugs - Denso K16R-U or NGK BKR5EYA.
• '2005 version was equipped with electronic throttle (ETCS).


1 - throttle body, 2 - throttle position sensor, 3 - reduction gears, 4 - throttle valve, 5 - throttle motor, 6 - Hall sensor, 7 - magnetic yoke



2SZ-FE JDM (1.3 EFI VVT)



The Japanese version of 2SZ differs much from both the K3-VE and European 2SZ.

• The spacers in the water jacket installed for optimized coolant flow near cylinders.


1 - steel, 2 - resin, 3 - coolant pump, 4 - coolant flow



• The crankshaft with 8 counterweights (similar K3-VE).
• Increased compression ratio.
• Piston different shape and polymer coating on skirt.



• Combined caps for all camshaft bearings.



• Timing drive - by simple roller chain (pitch 8 mm) with hydraulic tensioner.
• The angle between intake and exhaust valves is 18.6°.


1 - exhaust port, 2 - intake port, 3 - spark plug

• Valve drive - by rockers. Clearance adjustment - by different size stem end caps.


1 - VVT controller, 2 - intake camshaft, 3 - rotor, 4 - exhaust camshaft, 5 - camshaft sprocket, 6 - rocker arm, 7 - pivot, 8 - stem end cap, 9 - lock, 10 - spring retainer, 11 - valve spring, 12 - valve

• If the valve timing of euro-2SZ-FE is similar to K3-VE, then Japanese timing is radically different: intake open 33BTDC-12ATDC, close 35-80ABDC; exhaust open 40BBDC, close 2ATDC. VVT operating range - 45°

• In the cooling system, the circuits for EGR valve and CVTF cooler were added.


1 - coolant pump, 2 - throttle body, 3 - cut valve, 4 - heater hoses, 5 - thermostat, 6 - CVTF cooler, 7 - EGR valve, 8 - radiator

• Control system - L-type EFI (with MAF sensor).


1 - ECM, 2 - air cleaner, 3 - throttle position sensor, 4 - air flow meter, 5 - throttle valve, 6 - throttle motor, 7 - accelerator pedal position sensor, 8 - EVAP VSV, 9 - fuel tank, 10 - canister, 11 - injector, 12 - VVT solenoid, 13 - ignition coil, 14 - camshaft position sensor, 15 - oxygen sensor (S1), 16 - knock sensor, 17 - coolant temperature sensor, 18 - EGR temperature sensor, 19 - EGR valve, 20 - crankshaft position sensor, 21 - catalyst, 22 - oxygen sensor (S2)

• Electronically controlled throttle valve.


1 - throttle motor, 2 - throttle valve, 3 - return spring, 4 - throttle position sensor

• Crankshaft position sensor rotor is similar to the euro version.



The engine received EGR system: the valve is driven by stepper motor, the feedback provided using temperature sensor.



1 - EGR valve, 2 - step motor, 3 - return spring, 4 - cooling path, 5 - EGR temperature sensor, 6 - valve

The exhaust gases are taken after the catalyst, pass to the EGR valve and then through cylinder head to intake manifold insulator, which distributes them more evenly between the cylinders.


1 - insulator, 2 - intake manifold, 3 - EGR input

• Spark plugs - Denso SK16HR11 or NGK ILFR5C11



1SZ-FE (1.0 EFI VVT)

Having slightly violated the chronological order, we can consider this engine as a reduced copy of euro-2SZ-FE.

The differences between 1SZ-FE of Japanese and European made cars were considered more fundamental at one time. For example, for TMC: Denso processor, camshaft position sensor - inductive, knock sensor - Denso resonant type, oxygen sensor - Denso, injector - Denso 10-point, spark plugs - Denso K16R-U / NGK BKR5EYA; for TMMF: Bosch processor, camshaft position sensor - Hall type, knock sensor - non-resonant Bosch flat type, oxygen sensor - Bosch, injector - 4-point Bosch, spark plugs - Bosch FR7KCU...

• Valve timing: intake opening 48BTDC - 12ATDC, closing 8ABDC - 52ABDC; exhaust opening 30BBDC, closing 2ATDC.
• Manifold ports of equal length for each cylinder. "Spider"-type exhaust manifold.


In 2003, with the introduction of Euro-IV, two Euro-modifications appeared, which had some difference from the first version:
• Aluminum oil sump instead of steel.
• Differently shaped manifolds.


• Modification for MMT received electronically controlled throttle valve (ETCS), accelerator pedal position sensor, 10-point nozzle injectors, 32-bit ECU processor.
• Three horsepower escaped and the engine mass increased to 89 kg.



3SZ-VE / 3SZ-FE (1.5 EFI VVT)



Mechanically and control system of 1.5 is as close as possible to K3-VE.


• The main difference is a conventional roller chain (pitch 8 mm )in the valvetrain.


1 - roller chain, 2 - intake camshaft, 3 - exhaust camshaft, 4 - rotor, 5 - valve lifter, 6 - valve spring, 7 - valve, 8 - VVT controller

• Pistons with polymer coating of skirts.



Rem. K3-VE and 3SZ-VE engines could be installed not only FF (light cars) or FR (Terios), but also longitudinally-horizontally under the front seats (Sparky, TownAce).


1 - ECM, 2 - camshaft position sensor, 3 - crankshaft position sensor, 4 - throttle position sensor, 5 - coolant temperature sensor, 6 - MAP sensor, 7 - oxygen sensor, 8 - knock sensor, 9 - injector, 10 - ignition coil, 11 - VVT solenoid, 12 - ISCV, 13 - EVAP VSV, 14 - fuel pump relay, 15 - main relay, 16 - starter relay, 17 - cooling fan relay, 18 - EVAP canister, 19 - DLC3, 20 - combination meter, 21 - fuel pump



Experience

From the point of view of journalism, the SZ/K3 engines are completely uninteresting - after all, in comparison with the problematic series of Toyota engines of those years, they simply did not have innate defects and typical malfunctions. The main enemies of SZ were the years, natural wear and thrifty owners.

Mileage over 200 t.km became the norm for them, and even 400+ were not rare cases (it is much more difficult to understand why the owners used far from the most comfortable models with insufficient thrust-to-weight ratio for such intensive and long-term operation).

• A certain stereotype makes use the lowest-quality oil that can be found and do not replace it as long as possible. Meanwhile, the SZ series does not differ from other modern engines in terms of piston rings and oil drain holes and is also easily prone to coking.
• On the Japanese version of the 2SZ-FE, the EGR system plays a huge role in engine poisoning and carbon deposits formation, so it should be plugged at the earliest opportunity.
• The crankshaft key can really be recognized as a weak point: although it works normally since factory production, but soon after the first intervention of local technicans it is broken off (causing piston/valve collision) too often - and if the same repairers remove and install pulleys on dozens of other engines without consequences - this means that the problem is not only in the under-tightened bolt.

• Tellingly, the potential maintainability of the cast-iron block of SZ was not in demand - the tortured engine is definitely more economically expedient, easier and faster to be replaced assembly with a second-hand one.

In the entire history of the series, there have been practically no official service campaigns (unique case for Toyota). Only recently, recall # 2944 appeared for Townace/Liteace 2018-2019 with 3SZ-VE - defective connecting rods can be broken during operation (prescription - preventive replacement of connecting rods).




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