The home of the UK's greatest sportscar
26/07/2008
Racing Green TVR has finalised its specification for the rebuilding of the TVR Speed 6 engine and has followed the basic approach of working through all the engine components and reducing loads and increasing strength throughout the engine. All rebuilt TVR Speed 6 engines from Racing Green TVR will be built
Starting with the cylinder head Racing Green has specified ultra high quality parts throughout in order to resolve the known weaknesses. Inlet and exhaust valves, valve guides, valve stem seals, valve springs, finger followers and camshafts are all made to Racing Green TVRs enhanced specifications and are exclusive to Racing Green TVR.
The inlet and exhaust are both made from forged exhaust grade 214N Austenitic Stainless Steel and the exhaust has a welded Stellite 6 seat to handle the aggressive unleaded environment. Both inlet and exhaust are plasma gas nitrided to give an extremely hard surface finish and reduce valve stem wear. Valve stems are 7mm to keep valve weight down. Valve springs were originally too strong and have been reduced in strength in line with the upper rev limit of 7500rpm. Valve stem seal material has been upgraded to Viton which is probably the best material for stem seals. The valve guides have now been redesigned in Colsibro, an exotic Copper Nickel Silicon alloy which offers a remarkable blend of properties including high strength and high wear resistance and is ideally suited to the gas nitrided valve stems.
The finger follower has been redesigned and is now a high specification investment casting in steel hardened and coated. Given the original finger followers poor reputation Racing Green TVR has decided to over-engineer its finger followers to ensure they do not suffer the wear problems associated with the originals. With this aim in mind the finger followers are finished with a Diamond Like Coating. DLC is a Formula 1 derived aerospace quality coating increasing hardness whilst also reducing friction. This reduces loads both on the finger followers, camshafts and valve guides whilst virtually eliminating the wear associated with the standard original followers. Camshafts have been sourced in the correct grade of chilled cast iron. These high specification camshafts and finger followers are exclusive to Racing Green TVR. The oil supply has been enhanced to the rear of the exhaust finger follower shaft as this is the furthest point on the oil supply route and is also the hottest part of the valve train ensuring good oil supply to all finger followers.
The bottom end of the engine was similarly analysed and modified. New forged pistons in 2618 aerospace aluminium were designed and manufactured for Racing Green TVR. These pistons are both lighter and stronger than the standard cast pistons. Racing Green TVR has further enhanced the pistons by specifying a dry lubricant coating for the piston skirts. This coating, Dows D10, minimises bore wear both whilst running and also on cold starts as well as reducing frictional losses. Piston rings have been sourced from one of the foremost piston ring manufacturers in the world to give perfect sealing against the new bores and hence maximum power. Standard connecting rods were both heavy and not particularly strong nor matched in terms of weight. H beam section forged racing rods clearly present a number of advantages over the standard rod and these new rods have been designed by Racing Green in 4340 steel alloy for strength and lightness. The big end bolts have been replaced with racing standard ARP 2000 bolts. Correctly tightened during assembly by the stretch method these bolts ensure maximum bottom end integrity.
High quality head gasket has been manufactured to ensure perfect sealing of the combustion chamber and water and oilways. The Racing Green TVR sump baffle panel is fitted to rebuilt Speed 6 engines as standard to prevent any large components passing through the dry sump scavenge pump. All timing chains and oil seals are replaced as standard as are the half time bearings. The upper timing chain tensioner is replaced with the Racing Green TVR molybdenum disulphide impregnated version.
Prior to engine rebuilding all major components are ultrasonically cleaned to ensure absolute cleanliness throughout
All Racing Green TVR rebuilt Speed 6 engines come with the following components replaced as standard with high specification new components as seen throughout this website.
Relinered or rebored cylinder block with deck refaced
Reground crankshaft
New forged pistons with Dows D10 dry lubricant to skirts
New high specification piston rings
New forged H beam 4340 steel rods with ARP 2000 rod bolts
New main and big end bearings
New Racing Green TVR sump baffle panel
Cylinder head completely stripped with new Colsibro valve guides fitted and seats reground throughout.
New inlet valves
New exhaust valves
New valve stem seals
New DLC coated finger followers
New camshafts
New headgasket
New oil feed modification to rear of cylinder head
New high specification timing chains
New half time bearings
New molybdenum disulphide impregnated upper timing chain tensioner
Options available during engine build
Gas flowed cylinder head
Multi layer steel cylinder head gasket
ARP cylinder head stud kit
Fast road camshafts
Fully balanced pistons, rods, crankshaft, flywheel and damper.
Lightened flywheel
Tuned equal length exhaust manifolds
Hi flow catalytic converters
Lightweight billet crankshaft
Race type lightweight clutch
3.6 litre to 4.0 litre upgrade conversion