The engine powering the Esprit is a Chevrolet LS6 race engine that was once used in the back of a Daytona Sports Prototype race car that raced in America in the Grand Am championship, these cars were badged as Pontiacs.
The Grand Am Championship rules stated the max capacity allowed for this engine was 5.5 litres, in this form they were very successful and as a result they were forced to reduce the capacity to 5.0 litres after 2005.
When I was looking to build my Chevy LS race engine I was originally going to keep it simple, however one day I spotted an advert on Ebay for a Daytona Sports Prototype short motor at a very good price, nobody else bid and it was mine.
Having bought the short motor I needed Cylinder Heads and a dry sump system, luckily for me the guy who sold me the engine was also selling a number of other Daytona Prototype (DP) engine parts including the dry sump (and a lot of spares) so that sorted that.
Trying to source cylinder heads took a bit more effort, I wanted to see if I could get some matching DP heads and was emailing and phoning race teams & engine builders in the US to see if anyone could help, well I got lucky one day when I phoned Bob Cronin at CRD race engines, it didn’t take long to work out that new heads were outside of my budget but Bob realised that I was an enthusiast club racer here in the UK preparing my own car …. ” I’ve got a couple of heads just come back from a customer, they have hardly used them, I will get the guys in the shop to give them a refresh, you hardly notice they have been used, how does $xxx sound ?” ….. I am still very greatful to Bob to this day.
So I had the bits, all I had to do was rebuild the motor, fortunately the short motor came with a build sheet from Fischer Race Engines who originally built the engine. A bit of further research and asking from advice from the States filled in the gaps.
Below are photos of the engine when first built when I fitted it with a FAST inlet manifold, for the New Esprit I have replaced this with a Kinsler manifold to improve throttle response and free up space behind the engine to fit dampers and springs.
The engine block and cylinder head castings are stock Chevrolet LS6, however are modified to produce big power and torque.
Engine Block: Fully Blueprinted LS6 block with a standard 3.910″ bore.
Crank : Callies Forged crank 3.500″ stroke, Std Main bearings, Small dia Honda big ends
Con Rods: Oliver Billet Rods 6.300″ length
Pistons : Mahle with graphite coating and thin piston rings
Camshaft : Comp Cams Roller cam, special grind 0.590″ lift, 283/287 duration 106 degree lobe centre angle.
Lifters: Crane solid rollers
Camshaft drive / timing: Jesel Belt drive
Crank Damper: ATI 6.25″ aluminium on aluminium hub.
Cylinder Heads: Rebuilt CRD Daytona Prototype Heads. LS6 CNC machined.
Inlet Valves: 2.000″ dia Xyledyne titanium valves
Exhaust Valves: 1.55″ dia Xyledyne titanium valves.
Valve Springs: 3 spring set up…Titanium retainers + collets
Valve guides: Phospher Bronze
Valve Seats: Copper Berylium.
Valve Gear: Crane 1.7″ sportsman rockers on special shaft mounting.
Rocker covers: Billet aluminium with spring oil cooling.
Dry Sump: Dailey engineering billet dry sump.
Water Pump: Meziere water pump.
Inlet Manifold: Originally FAST FX manifold and MSD Throttle Body, in 2021 fitted with a Kinsler independent runner system.