Motore Monoalbero FIAT: differenze tra le versioni
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Riga 1:
Progettato inizialmente da [[Aurelio Lampredi]], padre anche dei ben più noti propulsori b[[Motore bialbero FIAT|ialbero FIAT]], fu costantemente aggiornato negli anni vedendo la sua cubatura crescere dagli originali 1116 cc (nella [[Fiat 128]]) fino a 1839 cc (nella [[Fiat Linea]]) pur essendo sostituito prima dal propulsore [[FIRE]] oltre che successivamente dalle famiglie di motori [[Motori modulari FIAT Pratola Serra|Pratola Serra]] ed [[Motori Fiat E.torQ|E.Torq]].
Riga 10:
Una caratteristica prominente nel motore SOHC Fiat era il suo design [[Rapporto alesaggio/corsa|a corsa corta]], scelta tecnica effettuata poiché permetteva di utilizzare valvole più grandi rispetto alla concorrenza a parità di cubatura e, per la naturale conformazione dei motori superquadri, permetteva di ridurre le forze di inerzia e quindi di permettere al motore di raggiungere regimi particolarmente elevati.
The engine was developed for forced-induction use in the [[Fiat Uno]] Turbo. It was then further refined for the Uno Turbo Mark II, and later for the Punto GT.
As with its bigger brother the famous [[Motore bialbero FIAT|Fiat DOHC]] (aka Fiat/Lancia twincam) engine, the Fiat SOHC engine was shared with the Fiat subsidiary [[Lancia (azienda)|Lancia]] (appearing in 1,500 cc guise in the [[Lancia Delta]]/[[Lancia Prisma|Prisma]] of the 1980s) as well as being used in the Fiat 128 derived [[Zastava Koral|Yugo]].
The final incarnation of the 128 SOHC engine was modified to utilise 16 valves and dual cam shafts. The engine (using the designation "Torque") featured the bore-spacing, bore and stroke of the 1580 cc 159/160 series engine with a new 16 valve DOHC cylinder-head. To incorporate the extra oil-return-paths and symmetrical head (as opposed to the asymmetrical SOHC head) the cylinder-block was slightly revised making the DOHC head non-interchangeable with the previous incarnations of the 128 engine. The "Torque" engine (178.B3 - 182.A4) powered the Brava/Bravo, Marea and Multipla Fiat{{Citation needed|date=April 2008}} automobiles as well as the second-generation Lancia Delta (never sold in the UK), finally ending production in 1999 for the European market. In Argentina it remained on production until 2002 mostly exported to be fitted into Brazilian-made versions of the Brava, Palio, Siena, Strada and Doblò.
== Engine specification ==
The Fiat SOHC engine was produced in a number of configurations differing in stroke and bore but maintaining a standard bore-spacing. The first generation of 128 derived engines used a stroke of 55.5 mm and a bore of 80 mm to produce a displacement of 1116 cc. The bore was increased to 86 mm (maintaining the 55.5 mm stroke) to give a displacement of 1290 cc for the X1/9. The original 1290 cc 128/X1/9 engine is the only one of the family to have used the 86 mm bore. The second generation used bores of either 80 mm or 86.4 mm with strokes of 55.5 mm or 63.9 mm giving four possible engine capacities. The final generation of SOHC engines standardised on a longer 67.4 mm stroke with either an 80.5 mm or 86.4 mm bore (giving 1372 cc and 1581 cc respectively).
{| class="" style="margin-bottom: 10px;"
|+ '''Valid engine bore/stroke combinations'''
|
{| class="wikitable" style="text-align:center"
! rowspan="2" width="50px" | Stroke<br>
(mm)
! colspan="4" | Bore (mm)
|-
! 80
! 80.5
! 86
! 86.4
|-
! 55.5
| style="background:#ccccff; color:black" width="50px" | 1116
| style="color:silver" width="50px" | ''1130''
| style="background:#ddddff; color:black" width="50px" | 1290
| style="background:#bbbbff; color:black" width="50px" | 1302
! rowspan="3" | Capacity<br>
(cc)
|-
! 63.9
| style="background:#bbbbff; color:black" width="50px" | 1285
| style="background:#bbbbff; color:black" width="50px" | 1301
| style="color:silver" width="50px" | ''1485''
| style="background:#bbbbff; color:black" width="50px" | 1499
|-
! 67.4
| style="color:silver" width="50px" | ''1355''
| style="background:#9999ff; color:black" width="50px" | 1372
| style="color:silver" width="50px" | ''1566''
| style="background:#9999ff; color:black" width="50px" | 1581
|}
|
{| class="wikitable" style="text-align:center"
! colspan="2" | Key
|-
| 1st Generation
|-
| 1st & 2nd Generation
|-
| 2nd Generation
|-
| 3rd Generation
|}
|}
{| class="" style="margin-bottom: 10px;"
|
{| class="wikitable" style="text-align:center"
|+ '''Engine specification (by engine-number)'''
! Engine Code
! Bore (mm)
! Stroke (mm)
! Capacity (cc)<br>
stated
! Capacity (cc)<br>
calculated
! Production<br>
(from - to)
! BHP
! Notes
|- style="background:#ddddff; color:black"
| 128.A.000
| 80
| 55.5
| 1116
| 1116
| 1969–1982
| 55-65
| 128
|- style="background:#ddddff; color:black"
| 128.A1.000
| 86
| 55.5
| 1290
| 1290
| 1971 - 78
| 75-85
| 128 Rally & Sport
|- style="background:#ddddff; color:black"
| 128.AS.000
| 86
| 55.5
| 1290
| 1290
| 1972–1978
| 75
| X1/9 1300
|- style="background:#ddddff; color:black"
| 128.A.064
| 80
| 55.5
| 1116
| 1116
| 1971–2008
| 55-64
|Zastava''' Koral/Tempo, Skala ''55 60 1.1'' (21 May (company))'''
|- style="background:#ddddff; color:black"
| 128.A1.064
| 80
| 55.5
| 1116
| 1116
| 1979–1983
| 64
| Zastava 101 SC-super (21 May (company))
|- style="background:#ddddff; color:black"
| 128.A2.064
| 80
| 55.5
| 1116
| 1116
| 1988–2008
| 60
| '''<nowiki>Zastava|YUGO 60</nowiki>''' Koral/Tempo 1.1 CW (21 May (company))
|- style="background:#ddddff; color:black"
| 128.AC.000
| 86
| 55.5
| 1290
| 1290
| 1989–1983
| 73
| Zastava 101 Specijal (21 May (company))
|- style="background:#ddddff; color:black"
| 128.A7.064
| 86
| 55.5
| 1290
| 1290
| 1981–1986
| 65
| Zastava 101 1300 1.3 (21 May (company))
|- style="background:#ddddff; color:black"
| 128.A6.064
| 86.4
| 55.5
| 1298
| 1302
| 1987–2008
| 65
| [[Zastava Koral|'''Zastava YUGO''' Koral, Skala, Florida ''65, 1.3'']] (21 May (company))
|- style="background:#ddddff; color:black"
| 11.E1.064
| 80
| 55.5
| 1116
| 1116
| 1986–1998
| 60
| [[Zastava Koral|'''Zastava YUGO''' Koral EFI 60]] (21 May (company)) Bosch Motronic MP3.1
|- style="background:#ddddff; color:black"
| 13.E1.064
| 86.4
| 55.5
| 1298
| 1302
| 1986–1998
| 65
| [[Zastava Koral|'''Zastava YUGO''' Koral EFI 65]] (21 May (company)) Bosch Motronic MP3.1
|- style="background:#ddddff; color:black"
| 13.E3.064
| 86.4
| 55.5
| 1298
| 1302
| 1988–1998
| 65
| [[Zastava Florida|'''YUGO''' Florida/Sana 1.3 EFI]] (21 May (company)) DMB) Bosch Motronic MP3.1
|- style="background:#ddddff; color:black"
| 11.MA.064
| 80
| 55.5
| 1116
| 1116
| 1998–2008
| 60
| [[Zastava Koral|'''Zastava|YUGO''' Koral/Tempo 1.1 i]] (21 May (company)) Bosch Motronic M4.6
|- style="background:#ddddff; color:black"
| 13.MA.064
| 86.4
| 55.5
| 1298
| 1302
| 1998–2008
| 65
| [[Zastava Koral|'''Zastava|YUGO''' Florida, Koral/Tempo 1.3 i]] (21 May (company)) Bosch Motronic M4.6
|- style="background:#ddddff; color:black"
|131.F4.016
|80.5
|67.4
|1372
|1372
|1995-2002
|82
|Tofaş Şahin 1.4
|-
|131.D2.016
|86.4
|67.4
|1581
|1581
|1995-2002
|92
|Tofaş Şahin S, Kartal
|-
|131.D1.016
|86.4
|67.4
|1581
|1581
|1992-2002
|96
|Tofaş Doğan and Kartal 1.6 S, SL, SLX (carb)
|-
|131.F3.016
|86.4
|67.4
|1581
|1581
|1998-2002
|96
|Tofaş Doğan and Kartal 1.6 S, SLX (i.e., cat)
|- style="background:#bbbbff; color:black"
| 138.A.000
| 80
| 55.5
| 1116
| 1116
| 1978–1985
| 60
| Ritmo 60
|- style="background:#bbbbff; color:black"
| 138.A1.000
| 86.4
| 55.5
| 1301
| 1302
| 1978–1982
| 75-65
| Ritmo 65
|- style="background:#bbbbff; color:black"
| 138.A2.000
| 86.4
| 63.9
| 1498
| 1499
| 1978–1982
| 75-85
| X1/9 1500, Ritmo 75
|- style="background:#bbbbff; color:black"
| 138.A3.000
| 86.4
| 55.5
| 1301
| 1302
| 1982
| 75
| Ritmo S75
|- style="background:#bbbbff; color:black"
| 138.A4.000
| 86.4
| 63.9
| 1498
| 1499
| 1980–1982
| 75-85
| X1/9 1500, Ritmo S85
|- style="background:#bbbbff; color:black"
| 138.A5.000
| 86.4
| 55.5
| 1301
| 1302
| 1982–1985
| 70
| Also 138.AS.000
|- style="background:#bbbbff; color:black"
| 138.B.000
| 80
| 55.5
| 1116
| 1116
| 1983–1985
| 55
| Uno 55
|- style="background:#bbbbff; color:black"
| 138.B1.000
| 80
| 55.5
| 1116
| 1116
| 1982–1985
| 55-58
| Ritmo Mk II
|- style="background:#bbbbff; color:black"
| 138.B2.000
| 86.4
| 55.5
| 1301
| 1302
| 1983–1986
| 68-70
| Uno 70
|- style="background:#bbbbff; color:black"
| 138.B3.000
| 86.4
| 63.9
| 1498
| 1499
| 1982–1985
| 70-85
| Regata 85S
|- style="background:#bbbbff; color:black"
| 146.A4.048
| 80
| 55.5
| 1116
| 1116
| 1985–1989
| 58,5
| Uno 60
|- style="background:#bbbbff; color:black"
| 146.A2.000
| 80.5
| 63.9
| 1301
| 1301
| 1985–1989
| 105
| Uno Turbo Mk I
|- style="background:#bbbbff; color:black"
| 146.A2.146
| 80.5
| 63.9
| 1301
| 1301
| 1987–1989
| 99
| Uno Turbo Mk I (cat)
|- style="background:#9999ff; color:black"
| 146.A2.246
| 80.5
| 63.9
| 1301
| 1301
| 1989–1991
| 101
| Uno Turbo Mk II (cat)
|- style="background:#9999ff; color:black"
| 146.A8.000
| 80.5
| 67.4
| 1372
| 1372
| 1989-1994
| 118
| Uno Turbo Mk II
|- style="background:#9999ff; color:black"
| 146.A8.046
| 80.5
| 67.4
| 1372
| 1372
| 1989-1993
| 111
| Uno Turbo Mk II (cat)
|- style="background:#9999ff; color:black"
| 146.C1.000
| 80.5
| 67.4
| 1372
| 1372
| 1989–1993
| 72
| Uno 70SXie
|- style="background:#bbbbff; color:black"
| 149.A7.000
| 86.4
| 55.5;
| 1301
| 1302
| 1986–1989
| 65
| Uno 70SX
|- style="background:#bbbbff; color:black"
| 149.C1.000
| 86.4
| 63.9
| 1498
| 1499
| 1988
| 75
| Uno 75 SX i.e. (cat)/Selecta
|- style="background:#9999ff; color:black"
| 159.A2.000
| 80.5
| 67.4
| 1372
| 1372
| 1990–1993
| 76
| Tipo/Tempra 1.4 (carb & i.e.)
|- style="background:#9999ff; color:black"
| 159.A3.000
| 86.4
| 67.4
| 1581
| 1581
| 1990–1996
| 75-78
| Tipo/Tempra 1.6 (carb & i.e.)
|-
|159.B9.000
|86.4
|67.4
|1581
|1584
|1996
|90
|Tempra i.e.
|- style="background:#9999ff; color:black"
| 160.A1.000
| 80.5
| 67.4
| 1372
| 1372
| 1988–1993
| 72
| Tipo/Tempra 1.4 i.e.
|- style="background:#9999ff; color:black"
| 160.A1.046
| 80.5
| 67.4
| 1372
| 1372
| 1992–1993
| 69
| Uno Selecta
|- style="background:#9999ff; color:black"
| 160.A2.000
| 86.4
| 67.4
| 1580
| 1581
| 1988–1993
| 83
| Tipo/Tempra 1.6 (carb & i.e.)
|- style="background:#9999ff; color:black"
| 835.C1.000
| 86.4
| 67.4
| 1580
| 1581
| 1993–1995
| 75
| Tipo/Tempra 1.6 i.e. (Typ 160)
|- style="background:#9999ff; color:black"
| 176.A4.000
| 80.5
| 67.4
| 1372
| 1372
| 1993–1995
| 136
| Mk I Punto GT (GT1), CR 7.8:1
|- style="background:#9999ff; color:black"
| 176.A4.000
| 80.5
| 67.4
| 1372
| 1372
| 1995–1997
| 133
| Mk I Punto GT (GT2), CR 7.8:1
|- style="background:#9999ff; color:black"
| 176.B6.000
| 80.5
| 67.4
| 1372
| 1372
| 1997–1999
| 130
| Mk I Punto GT (GT3), CR 9.0:1
|- style="background:#9999ff; color:black"
| 176.A9.000
| 86.4
| 67.4
| 1581
| 1581
| 1994–1997
| 88
| Mk I Punto Sporting & Cabrio
|- style="background:#9999ff; color:black"
| 835.C1.000
| 86.4
| 67.4
| 1581
| 1581
| 1989–1994
| 75-78
| Lancia Dedra Mk I (1.6 i.e.)
|- style="background:#9999ff; color:black"
| 835.A1.046
| 86.4
| 67.4
| 1581
| 1581
| 1989–1994
| 75-78
| Lancia Dedra Mk I (1.6 i.e.)
|- style="background:#9999ff; color:black"
| 835.A1.000
| 86.4
| 67.4
| 1581
| 1581
| 1995–1997
| 90
| Lancia Dedra Mk II (1.6 i.e.)
|- style="background:#9999ff; color:black"
| 182.A4.000
| 86.4
| 67.4
| 1581
| 1581
| 1995–2002
| 103
| DOHC 16v, Bravo/Brava/Marea/Multipla/Lancia Dedra 1.6 16v
|- style="background:#9999ff; color:black"
| 182.B6.000
| 80.5
| 78.4
| 1596
| 1596
| 2002–2005
| 103
| DOHC 16v, Marea/Multipla/Stilo
|- style="background:#9999ff; color:black"
| 310 A3.011
| 86.4
| 78.4
| 1839
| 1839
| 2008–2010
| 132
| DOHC 16v, Brazilian Linea 1.9 16v EcoFlex
|}
|
{| class="wikitable" style="text-align:center"
! colspan="2" | Key
|-
| 1st Generation
|-
| 2nd Generation
|-
| 3rd Generation
|}
|}
== Applications ==
List of vehicles utilising variations of the Fiat SOHC engine.
=== Fiat ===
* Fiat [[Fiat 128|128]]: 1969-1985
* Fiat [[Fiat Regata|Regata]]: 1985-1990
* Fiat [[Fiat Ritmo|Ritmo/Strada]]: 1978-1988
* Fiat [[Fiat Punto|Punto Mk I]]: 1993-1999
* Fiat [[Fiat Uno|Uno]]: 1983-1989
* Fiat [[Fiat Tipo|Tipo]]: 1988-1995
* Fiat [[Fiat Tempra|Tempra]]: 1990-1995
* Fiat [[Fiat X1/9|X1/9]]: 1972-1989
=== Lancia ===
* Lancia [[Lancia Delta|Delta]]: 1979-1994
* Lancia [[Lancia Prisma|Prisma]]: 1980s
* Lancia [[Lancia Dedra|Dedra]]: 1990-1998
=== Zastava ===
* Yugo [[Zastava Koral|55]]
* Yugo [[Zastava Koral|60]]
* Yugo [[Zastava Koral|65]]
* Zastava 101
* Zastava 128
* Zastava Florida
* Yugo sana 1.3 1.4
=== Tofaş ===
* Tofaş Şahin/Doğan/Kartal: 1992-2002
== Induction ==
=== Production ===
The Fiat SOHC used the full gamut of induction techniques through its long production run. The original 128 and 138 series engines originally used a single down-draught carburettor. The carburettor was normally of progressive twin-choke design (two asymmetric sized chokes operated progressively) such as the Weber DMTR and DATR of the X1/9. Multi Point fuel Injection (MPI) was introduced late in the 138 series to help meet lowered emission requirements in the US. The original MPI system comprised a large cylindrical plenum running parallel to the engine with individual runners to each inlet port and a single throttle controlling air-flow into the plenum. This plenum was pressurised in the Mk I Uno Turbo. The plenum was slightly redesigned to a more angular "box" shape for the 3rd Generation engines and was again pressurised for the Uno and Punto GT Turbo models. For the 3rd Generation engines the down-draft carburettor was replaced with a Single Point fuel Injection system (SPI) in the base-level models. The SPI system mounts on a manifold similar to that of the carburetted models and looks, as well as acts, much like a single-choke carburettor with a single throttle plate but no venturi and a centrally mounted single injector.
=== Tuning & modification ===
==== Carburettor ====
Traditionally both down-draft (DCNF & IDF) and side-draft ([[Weber (azienda)|DCOE]]) twin-choke carburettors have been used to extract more power from the 128 derived engines. IDFs are rarely used due to an incorrect orientation of the float-bowls (causing possible surge/starve issues under cornering), the correctly orientated DCNF being the preferred down-draft carburettor in this application (also having a much lower profile than the IDF). For ultimate power the DCOE carburettor is used even though the float-bowl direction matches that of the IDF (i.e. incorrect). The aforementioned carburettors are usually used in pairs (effectively giving one independently tuneable carburettor per engine-cylinder), though applications where a single DCNF/DCOE are used to feed a shared manifold do exist. DCNF's tend to be either 36 mm or 40 mm, the larger 44-DCNF is deemed too large for the engine. Both 40-DCOE and 45-DCOE are commonly used where space allows.<ref>To fit DCOE carburettors in an X1/9 a small amount of bodywork must be removed/reshaped</ref>
==== MPI ====
Tuning of the early MPI systems has previously been difficult as the electronic control systems are analogue making them difficult to "re-map". Low-cost DIY Fuel Injection (FI) controllers (such as MegaSquirt) have made it easier to alter the characteristics of the early MPI systems and release similar potential as the DCNF/DCOE carburettors. It is possible to "chip" the later digital MPI systems though aftermarket FI controllers again give greater flexibility.
==== Throttle bodies ====
Individual FI Throttle Bodies (TBs) are available for mounting to DCNF and DCOE manifolds as well as custom-built FI systems which, with aftermarket controllers, give the most flexibility and control over fuelling out of all the options.
==== Motorcycle carburettors ====
Motorcycle, or "bike" carburettors, being a modern and cost-effective alternative to DCOE/DCNFs, have been adapted to work with the 128-derived engines. They potentially offer better control over fuelling than DCNF/DCOE, but their use on the Fiat SOHC engine is still in its infancy.
== Camshaft profile ==
The camshaft was a main methods of varying the 128 series engines characteristics for different applications/markets. The high-revving oversquare design of the 128 engine lends itself to high-overlap high-duration cam profiles better than more traditional square/under-square engine designs without losing drivability.<ref>The standard European carburettord X1/9 used a camshaft more radical than many after-market "performance" camshafts offered for contemporary engines from other (non Italian) European manufacturers.</ref> Though a beneficial characteristic for sports orientated engine the high-overlap high-duration cam design gives poor emissions output which was unacceptable under the tightened US emissions regulations. To remedy this (in addition to the introduction of MPI) camshafts for emission-restricted markets featured asthmatic low-lift, low-duration, low-overlap profiles totally unsuited to the nature of the 128 engine.
{| class="wikitable" style="text-align: center; margin-bottom: 10px;"
|+ '''Standard production camshaft specifications'''
! Profile
! Duration<br>
(degrees)
! Overlap<br>
(degrees)
! Lift<br>
(mm)
! Clearance (mm)<br>
Inlet/Exhaust
! Application
|-
| 12/52-52/12
| 244
| 24
| -
| -
| 1.1 L 128 - European Specification
|-
| 10/54-54/10
| 244
| 20
| -
| -
| 1.1 L 128 - North-American Specification
|-
| 24/68-68/24
| 272
| 48
| 9.85
| -
| 128 Rally
|-
| 24/68-68/24
| 272
| 48
| 9.85
| -
| 1300 X1/9 - European Specification
|-
| 10/54-54/10
| 244
| 20
| -
| -
| 1300 X1/9 - North-American Specification
|-
| 12/52-52/12
| 244
| 24
| -
| -
| 1300 X1/9 - Australian Specification
|-
| 24/68-68/24
| 272
| 48
| 9.9
| -
| 1500 X1/9 - European Specification (carb)
|-
| 10/54-54/10
| 244
| 20
| -
| -
| 1500 X1/9 - North-American Specification (FI)
|-
| 10/54-54/10
| 244
| 20
| -
| -
| 1500 X1/9 - Australian Specification (carb)
|-
| 9/39-31/1
| 228-212
| 10
| 8
| -
| 1.3 L Uno
|-
| 0/30-40/10
| 210-230
| 10
| 8
| -
| 1.3 L Uno Turbo
|-
| 14/36-44/6
| 230
| 20
| 8.8
| -
| 1.4 L Uno Turbo
|-
|7/35-37/5
|222
|12
|8.8
|0.4/0.5
|1.6 Tipo
|}
=== Tuning and modification ===
{| class="wikitable" style="text-align: center; margin-bottom: 10px;"
|+ '''Fast-road/race camshaft specifications'''
! Manufacturer
! Profile name
! Profile
! Duration<br>
(degrees)
! Overlap<br>
(degrees)
! Lift<br>
(mm)
! Clearance (mm)<br>
Inlet/Exhaust
! Application
|-
| Kent
| FT7
| 35/67-67/35
| 282
| 70
| 10.33
| 0.20 / 0.20
| NA - fast road
|-
| Kent
| FT8
| 52/76-76/52
| 308
| 104
| 10.82
| 0.20 / 0.20
| NA - race
|-
| Piper
| BP270
| 33/67-67/33
| 280
| 66
| 9.80
| 0.20 / 0.20
| NA - fast road
|-
| Piper
| BP285
| 36/72-72/36
| 288
| 72
| 10.40
| 0.20 / 0.20
| NA - fast road
|-
| Piper
| BP300
| 39/71-71/39
| 290
| 78
| 11.18
| 0.25 / 0.25
| NA - race
|-
| Piper
| BP320
| 53/83-83/53
| 316
| 106
| 11.18
| 0.25 / 0.25
| NA - race
|}
== Footnotes ==
| |||