For Full Competition Racing, CPR offer our customers a highly developed Stroker Motor, where we prefer to base the build on a 4G64 Hi-Deck Block.

Having raced Evo's for over 10 years, we have developed our approach to building extremely high hp endurance engines, capable of supporting 800hp+ levels for prolonged periods of time.

The 4G64 Hi-Deck Block offers a major advantage of the conventional 4G63 Block, with its 6mm Higher Deck. This allows CPR to specify a 2.4L 102mm Stroker Crank to be used with a 'Long-Rod' Option for the Con-Rod, at 156mm. This unique geometry means a Higher RPM bandwith, where a longer rod will reduce Piston Speed Acceleration / Force acting on the Engine, and therefore, a less stressed, higher revving engine setup is achieved.

All blocks start life as hand-picked running motors, before testing and strip down. The blocks are then examined & measured to ensure they meet our high standards of quality and meet all manufacturers tolerances. The blocks are then bored by our local machinists (who we have used for over 8 years), using a 'Bore Plate' to simulate the attachment of a Cylinder Head. This ensures the bores are bored parallel and straight to one another when the head is finally installed and torqued down. Without this Boring Plate, the bores can change shape when the cylinder head is attached. We use a Honing Process as advised by CP Pistons, and we find this is the optimum grade to ensure correct ring sealing, without any oil consumption issues whatsoever. Each bore is then examined and tested to ensure piston to bore clearance at our specification, before final assembly takes place.

Every Race Stroker Engine Build is carried out by our Head Engineer; Clive Seddon, who has been building and race on high HP Evo's for over 10 years. His attention to detail and skill in building engines that run at the highest levels of performance in European Competition, allows the highest quality of Race Motors to be produced for our customers.

For Full Race Applications, CPR choose their Full Race 2.4L Stroker Kit, for maximum reliability and horsepower capacity, with our kit being the most highly developed and used kit in Time Attack Racing over the last 5 years. The CPR 2.4L Stroker Kit supports 1000hp, and consists of;

For Stroker Competition Motors, it is imperative to install a Cylinder Head and valvetrain matched to the configuration of the engine, in CPR Race Motor case, the requirements of a Long-Stroke 2.4L Motor with custom geometry. CPR offer customers requiring the best quality of engine components the CNC Race Ported Cylinder Head from Cosworth.

The Cosworth 4G63 Head (MIVEC & NON-MIVEC) is based on a Brand New Casting, and is our prefered starting point when considering high hp applications, where used heads can have hidden weakpoints, deep with the casting, which are only exposed under High Boost/HP Conditions. CPR prefers to eliminate any risks of head / port cracking that can be associated with used heads of unknown history. When a customer insists that his original 4G63 Cylinder Head is in perfect condition, we are however able to offer a Race Porting Service for that particular head, but we will not be able to warranty any work carried out on used components.

Preferably, a Cosworth Head is used, where a Brand New Casting from high quality materials will ensure a Head free of imperfections and internals cracks.

Before final valvetrain assembly, CPR will carry out a Wire-Ring Machining Service to the Cylinder Head to ensure the highest possible level of Combustion Chamber Sealing

The Wire-Ringing is offered to customers seeking HP of 600hp+, and will help to reduce Cylinder Head Lifting and subsequent Headgasket failure at high boost applications. This Wire-Ring Process is as used on our own Time Attack Motors, ran in Circuit Trim at 3.0bar+ Boost Pressure on Race Fuel.

To achieve this enhanced Head modification, CPR will have thin grooves machined by our expert machinists around each Cylinder Head Top. We then lay a thin Wire Ring in this groove, which protrudes proud of the head face surface. Upon Installation, this Wire Ring will then add an extra layer of pinch on the Fire-Ring area of the Headgasket. This extra pinch will provide superior sealing.

A Multi-Layer Metal Headgasket is used on all of our competition engine builds, and the Head is finally installed and secured via one of two different sets of CPR Specification Cylinder Head Stud Kits based on final HP / Boost Specification;

The Cosworth CNC ported cylinder head features highly developed and researched flow bench proven ports, engineered for maximum usable power. Each new cylinder head is ported on a 5 axis machine to ensure consistency and perfect port shape every time. Additionally, larger intake (+1mm) and exhaust valves (+1mm) are utilized to help increased flow from high boost applications on longer stroker motors. Cosworth CNC ported Big Valve cylinder heads come with built Valvetrain (excluding Camshafts)

Specifications:
* CNC Ported/Machined finish port- New Castings
* Hand blended finish work
* Intake 20% (max) increased flow
* Exhaust 22% (max) increased flow
* 4-angle Inlet Valve job
* 3-angle & radius Exhaust Valve job
* Valves are lapped
* Back-Cut Inlet Valves
* Heads are Ultra Sonic cleaned prior to assembly
* Heads are Serialized and sport a machined Cosworth logo
* +1mm Stainless Steel Intake Valves (1800 degrees max.)
* +1mm Inconel Exhaust Valves (2400 degrees max.)
* Performance Valve Springs (Support 10,500 RPM max.)
* Titanium Retainers
* Hardened Steel Spring Platforms
* Knife edged port divider

CPR's specification of Pro-Camshaft completes the Competition Valvetrain package, and offers customers purchasing our Full Race Motors, the highest researched and developed Camshaft selection from any UK Evo Tuner, after many 100's of hours Dyno Testing to achieve the best possible balance between Extreme High HP and Maximum Response, the holy grail in Competition Evo Motor Tuning.

We have found that excessively high duration cams will increase turbo lag without increased power output potential. The CPR Pro Cam Set is ideal for Circuit Cars seeking the best possible response and least turbo lag as possible from their modified Evo's, suiting either our 2.3L Entry Level Competition or 2.4L Full Race Stroker Motors. These camshafts are designed to run on stock Mitsubishi Hydraulic Lifters, meaning old fashioned Solid Lifter conversions are no longer required, which will drastically reduce the risk of Solid Lifter failure. Superior quality, these camshafts are manufactured in the same factory as one of the top aftermarket parts manufacturers in Japan, ensuring excellent fitment and thorough quality control.

In conclusion; These cams idle smooth, aid response and make fantastic power, as proven with our 950HP/850LBFT Competition Engine in our Works Orange Evo 5, the quickest Mitsubishi Evo round a circuit in Europe.

Specification: UNDISCLOSED TO AVOID RIVAL COMPETITION COPYING!