View source for Vauxhall Slant-4 engine

{{Use dmy dates|date=May 2017}}
{{Use British English|date=May 2017}}
{{Infobox engine
| name          = Vauxhall Slant-4 engine
| image         = File:Vauxhall viva 2300 (2).jpg
| manufacturer  = [[Vauxhall Motors]]
| aka           = 
| production    = September 1967 - July 1983<ref name="vauxhall"/>
| predecessor   = 
| successor     = [[Opel cam-in-head engine]]
| configuration = [[Naturally aspirated]] [[Straight-four engine|inline-four]]
| displacement  = {{ubl | {{cvt|1599|cc|cuin}} | {{cvt|1759|cc|cuin}} | {{cvt|1979|cc|cuin}} | {{cvt|2279|cc|cuin}}}}
| bore          = {{ubl | {{cvt|85.73|mm|in}}| {{cvt|95.25|mm|in}}| {{cvt|97.4|mm|in}}}}
| stroke        = {{ubl | {{cvt|69.24|mm|in}}| {{cvt|76.2|mm|in}}}}
| block         = [[Cast iron]]
| head          = Cast iron
| valvetrain    = [[SOHC]] 2 or [[Multi-valve#Four valves|4 valves x cyl.]]
| compression   = 7.3:1, 8.5:1, 9.2:1
| supercharger  = 
| turbocharger  = 
| fuelsystem    = [[Carburettor]]
| management    = 
| fueltype      = [[Gasoline|Petrol]]
| oilsystem     = [[Wet sump]]
| coolingsystem = [[Radiator (engine cooling)#Automobiles and motorcycles|Water-cooled]]
| idle          =
| redline       =
| power         = {{cvt|69.2-135|bhp|kW}}
| specpower     = 
| torque        = {{cvt|83-145.5|lbft|Nm}}
| length        = 
| width         = 
| height        = 
| diameter      = 
| weight        = 
| emissions level =
| emissions control =
}}

The '''Vauxhall Slant-4''' (or '''Slant Four''') is an [[Straight-four engine|inline four-cylinder]] petrol [[automobile|car]] [[engine]] manufactured by [[Vauxhall Motors]]. Unveiled in 1966, it was one of the first production [[overhead camshaft]] designs to use a [[Timing belt (camshaft)|timing belt]] to drive the [[camshaft]]. The Slant-4 block was used as a development mule for the [[Lotus 900 series]] of engines.<ref name="enthusiasts"/> Vauxhall used the engine in a variety of models until production ended in 1983.<ref name="vauxhall"/>

==History==
===Design===
The Slant-4 gets its name from the fact that its [[cylinder (engine)|cylinder]]s are inclined at an angle of approximately 45° from vertical.<ref name="vauxhall"/> This layout came about because Vauxhall had originally planned to develop a whole family of engines all built on the same production line. There were to be slant-4s and V8s in both petrol and diesel versions, designed under the guidance of Vauxhall's then chief engineer, John Alden. Although a V8 petrol prototype and several 4-cylinder diesel prototypes were built only the 4-cylinder petrol engine made it to series production.

The engine has a [[Overhead camshaft#Single overhead camshaft|single overhead camshaft]] driven by a timing belt. The Slant-4 was one of three engines using this method of driving the camshaft released the same year, the others being the [[Fiat Twin Cam engine]] and the [[Pontiac straight-6 engine#Overhead cam|Pontiac straight-6 OHC]]. Prior to 1966, belt-driven camshafts had only appeared in the [[Glas 1004]] series starting in 1962 and in the few [[Devin Enterprises#The Devin Panhard|Devin-Panhard]] cars built starting in 1956. The camshaft operated two [[Poppet valve|valve]]s per cylinder. An ingenious valve train design incorporating an inclined [[screw|socket head cap screw]] allowed valve clearances to be adjusted with a [[feeler gauge]] and an [[Allen key]]. The block and [[crossflow cylinder head|crossflow]] head are both of [[cast iron]]. The layout lowers the overall height of the engine, which allowed for more [[aerodynamic]] vehicle bodies to be achieved by lowering the [[hood (vehicle)|bonnet]] line. It also means most of the engine is very easy to access for maintenance, with the exception of the [[exhaust manifold]] and [[spark plug]]s, which are "underneath" the slanted cylinders.

===Applications===
Prototype engines were fitted to the [[Vauxhall Victor#FC Series Victor and VX4/90|FC Victor]], and the engine also appeared in the [[Vauxhall XVR]] [[concept car]].<ref name="xvr1"/> The first production car to use the engine was the 1967 [[Vauxhall Victor#FD Series Victor, VX4/90 and Ventora|FD Victor]]. The original engine capacities were {{cvt|1599|cc|cuin|1}} and {{cvt|1975|cc|cuin|1}}. For the 1972 launch of the [[Vauxhall Victor#FE Series Victor, VX4/90, Ventora, VX1800 and VX2300|FE Victor]], the smaller engine was increased to {{cvt|1759|cc|cuin|1}}, and the larger to {{cvt|2279|cc|cuin|1}}. Blydenstein Racing developed a [[long stroke]] version with a capacity of {{cvt|2600|cc|cuin|1}} capable of producing almost {{cvt|250|hp|kW|0}}. Having been designed to withstand the stresses of diesel compression ignition, the block is immensely strong and able to handle large increases in power without modification. The crank was also designed to be shared with the diesel version, which meant its strength was assured for the petrol version. The larger displacement versions are known for their immense [[torque]], but also as not very smooth running or high-revving. A fuel-injected version of the 2.3-litre engine was planned for both the [[Vauxhall HP Firenza|HP Firenza]] and [[Vauxhall VX4/90|VX4/90]]. Running prototypes were tested before the project was abandoned due to cost and the impending merger of Vauxhall's design and engineering pool with that of Opel in Germany.

Apart from its use in passenger cars, the engine was also developed for [[marine propulsion|marine applications]]. It grew popular with tuners due to its great strength, tunability and simplicity. A 2-litre version of the Slant-4 powered the eight [[Costin Amigo]]s that were built between 1970 and 1972.<ref name="coomberbook"/>{{rp|165}} The engine remained in production well into the 1980s for the [[Bedford CF]] van.

Although arguably more technically advanced, the Slant-4 was considered less reliable than its continental GM counterpart, the [[Opel cam-in-head engine|Opel CIH]] (Cam In Head) engine. The Slant-4 was replaced by the CIH in the [[badge engineering|badge-engineered]] Vauxhall [[Vauxhall Cavalier|Cavalier Mk.1]]s from the mid 1970s onward, whilst the Bedford CF van lost the Slant-4 in favour of the CIH when revised in 1983.

==Engine specifications==
{| class="wikitable"  style="align:center; text-align:center" 
! Displacement
! Bore x Stroke
! Compression ratio
! Power (net)<ref name="vauxhall"/>
! Torque
! Year(s)
! Notes
|-
! " rowspan="2"|{{cvt|1599|cc|cuin}}
| " rowspan="2"|{{cvt|85.73x69.24|mm|in}}
| " rowspan="2"|8.5:1
| {{cvt|72|bhp|kW}}<br/>at 5600&nbsp;rpm
| {{cvt|83|lbft|Nm|0}}<br/>at 2200&nbsp;rpm
| 1967 to 1972
| 
|-
| {{cvt|69.2|bhp|kW}}<br/>at 5100&nbsp;rpm
| {{cvt|90|lbft|Nm|0}}<br/>at 2500&nbsp;rpm
| 1970 to 1972
| Low-lift camshaft.
|-
! " rowspan="2"|{{cvt|1759|cc|cuin}}
| " rowspan="2"|{{cvt|85.73x76.2|mm|in}}
| " rowspan="2"|8.5:1
| {{cvt|77|bhp|kW}}<br/>at 5100&nbsp;rpm
| {{cvt|97|lbft|Nm|0}}<br/>at 3000&nbsp;rpm
| 1972 to 1975
| 
|-
| {{cvt|88|bhp|kW}}<br/>at 5800&nbsp;rpm
| {{cvt|99|lbft|Nm|0}}<br/>at 3500&nbsp;rpm
| 1976 onwards
| 
|-
! " rowspan="3"|{{cvt|1975|cc|cuin}}
| " rowspan="3"|{{cvt|95.25x69.24|mm|in}}
| 8.5:1
| {{cvt|88|bhp|kW}}<br/>at 5500&nbsp;rpm
| {{cvt|102|lbft|Nm|0}}<br/>at 3200&nbsp;rpm
| 1967 to 1972
| 
|-
| 7.3:1
| {{cvt|77.5|bhp|kW}}<br/>at 5100&nbsp;rpm
| {{cvt|100.5|lbft|Nm|0}}<br/>at 2800&nbsp;rpm
| 1971 to 1972
| Canadian spec.
|-
| 8.5:1
| {{cvt|104|bhp|kW}}<br/>at 5600&nbsp;rpm
| {{cvt|117|lbft|Nm|0}}<br/>at 3400&nbsp;rpm
| 1968 to 1972
| Dual carburettors
|-
! " rowspan="6"|{{cvt|2279|cc|cuin}}
| " rowspan="6"|{{cvt|97.4x76.2|mm|in}}
| " rowspan="4"|8.5:1
| {{cvt|100|bhp|kW}}<br/>at 5200&nbsp;rpm
| {{cvt|139|lbft|Nm|0}}<br/>at 3000&nbsp;rpm
| 1972 to 1976
| 
|-
| {{cvt|109|bhp|kW}}<br/>at 5000&nbsp;rpm
| {{cvt|140|lbft|Nm|0}}<br/>at 3000&nbsp;rpm
| 1976 to 1978
| 
|-
| {{cvt|112|bhp|kW}}<br/>at 5400&nbsp;rpm
| {{cvt|140|lbft|Nm|0}}<br/>at 3000&nbsp;rpm
| 1972 to 1974
| Dual carburettors
|-
| {{cvt|116|bhp|kW}}<br/>at 5000&nbsp;rpm
| {{cvt|145|lbft|Nm|0}}<br/>at 3000&nbsp;rpm
| 1974 to 1978
| Dual carburettors
|-
| 9.2:1
| {{cvt|131|bhp|kW}}<br/>at 5500&nbsp;rpm
| {{cvt|145.5|lbft|Nm}}<br/>at 3500&nbsp;rpm
| 1974 to 1975
| Dual carburettors, HPF
|-
| 8.5:1
| {{cvt|135|bhp|kW}}<br/>at 5500&nbsp;rpm
| {{cvt|134|lbft|Nm|0}}<br/>at 4500&nbsp;rpm
| 1978 to 1982
| Dual carburettors, 16-valve head, HS/HSR
|-
|}

==Lotus 900 series engines==
{{main article|Lotus 900 series}}
It is said that when Vauxhall unveiled its new slant-four engine at the 1966 [[Earls Court Exhibition Centre|Earls Court]] [[British International Motor Show|Motor Show]] its bore centers were exactly the same as those proposed by [[Lotus Cars|Lotus]] for their new all-alloy engine. Lotus boss [[Colin Chapman]] immediately negotiated a deal with Vauxhall to buy some of their cast-iron blocks so that development of Lotus’ own aluminum [[Lotus 907|907]] engine could be sped up. For racing the hybrid engines were called LV220 and LV240, with LV standing for Lotus/Vauxhall and the numbers standing for the reported horsepower developed by each version.<ref name="ggmk62"/> Lotus tested the production intent hybrid engine in a Vauxhall Victor and a Vauxhall Viva GT (registration number RAH 713F), as well as in a converted Bedford CF van.

The Lotus 900 series engine block was cast in [[aluminium alloy]] instead of iron, which made it considerably lighter than the Slant-4. The Lotus engine also used a [[cylinder head]] of light alloy that featured [[Overhead camshaft#Dual overhead camshaft|double overhead camshafts]] and [[Multi-valve#Four valves|four valves per cylinder]]. With a few modifications the Lotus head could be fitted to the Vauxhall block. Engines with Lotus heads were used in Vauxhall's dealer team race and rally programmes until the late 1970s.<ref name="dsg1"/>

==Vauxhall 16-valve engines==
After experimenting with an 8-valve twin cam cylinder head, Vauxhall began development of a 16-valve, twin cam head for the Slant-4 in the early 1970s. The first test engine, 'Old Number 1', was running by 1973. The cylinder head was similar to the Lotus head in principle, but different in detail; in particular the cam carriers on the Vauxhall engine were angled upwards so that the covers were both horizontal (those on the Lotus engine were equal about the cylinder centreline).

The 16-valve was announced for use in the [[Vauxhall Chevette#Chevette HS|Chevette 2300 HS]], which was immediately homologated for racing by the RAC MSA. Vauxhall's own 16-valve head had passed beyond the design stage, but initially was in such short supply that the rally team continued to use the Lotus heads.<ref name="coomberbook"/>{{rp|248}} To address the production shortfall Vauxhall approached [[Cosworth]] and had them produce the 400 cylinder heads needed for the racing homologation requirements.<ref name="cosworthbook"/>{{rp|83, 84}} When the new Vauxhall heads appeared in the Chevette 2300 HST the other teams complained, which led to a homologation scandal. This in turn led to the cars being prevented from starting the 1978 [[Rally de Portugal|Rally of Portugal]]. As a result, all cars competing in international rallies were forced to use the Vauxhall head.

==Motorsports==
Lotus raced the hybrid LV engine in two [[Lotus 62]]s for a single season.

While Vauxhall's [[General Motors]] parent company had a "no racing" policy, the Slant-4 was campaigned in various cars by the independent [[Dealer Team Vauxhall]] (DTV) organization. Development of the cars was handled by different groups, including Bill Blydenstein Racing, who ran the rally team and both raced the Lotus-head cars and improved the Vauxhall head to a point where it performed better than the Lotus head. Chris Coburn's ''Coburn Improvements'' also raced under the DTV banner.<ref name="coomberbook"/>{{rp|248}}

==References==
{{Reflist|refs=

<ref name="enthusiasts">{{cite book |last=Vale |first=Matthew |date=6 January 2016 |title=Lotus Elite, Eclat and Excel: An Enthusiast's Guide |publisher=The Crowood Press Ltd |isbn=978-1785000782 }}</ref>

<ref name="vauxhall">{{cite web|url=http://vauxpedianet.uk2sitebuilder.com/vauxhall---the-slant-4-engine|title=VAUXHALL - THE SLANT FOUR ENGINE STORY|work=vauxpedianet.uk2sitebuilder.com}}</ref>

<ref name="xvr1">{{cite web|url=http://vauxpedianet.uk2sitebuilder.com/vauxhall-xvr-concepts |title=1. Vauxhall XVR Concept - Background |website=vauxpedianet.uk2sitebuilder.com }}</ref>

<ref name="ggmk62">{{cite web|url=http://www.gglotus.org/ggtech/type62-specsheet/t62spec.htm|title=Lotus 62 Specification Sheet|work=gglotus.org}}</ref>

<ref name="dsg1">{{cite web|url=http://www.droopsnoot.co.uk/cars.htm|title=The Slant Four engine |work=www.droopsnoot.co.uk}}</ref>

<ref name="coomberbook">{{cite book |last=Coomber |first=Ian |date=5 December 2017 |title=Vauxhall: Britain's Oldest Car Maker |publisher=Fonthill Media |isbn=978-1781556405 }}</ref>

<ref name="cosworthbook">{{cite book |last=Robson |first=Graham |date=15 May 2017 |title=Cosworth: The Search for Power - 6th Edition |publisher=Veloce Publishing |isbn=978-1845848958 }}</ref>

}}
[[Category:Slant-four engines]]
[[Category:Vauxhall engines]]
[[Category:Gasoline engines by model]]