The cylinder head is one of the key engine components that ultimately determines the power of an engine. The head is designed to perform to a level determined by the manufacturer which is fine whilst the engine remains in standard specification. However, once you start to modify an engine with performance camshafts, twin carburettors, etc, the head soon becomes the bottleneck to releasing extra horsepower. All heads have a maximum amount that their ports will flow in standard production form. To increase the flow capacity of the head, we need to look at the port sizes and valve sizes. For most heads, a mild improvement can be made through altering the inlet and exhaust ports alone (a typical stage one modification) but eventually the restriction will be moved to the diameter of the valves which must be increased before seeing further improvements through port modifications.
So surely all you need to do is buy some grinding stones and attack your own head, saving a fortune? Theoretically yes but how much to take off and where? Porting or gas flowing a head is a highly skilled job that requires years of development to perfect which initially includes trial and error to find the limitations of the castings. The ports are surrounded by water jackets by a wall thickness of an unknown size so an amateur would do well to complete the job without breaking through the port wall and ruining the head! The other equally important goal to successfully gas flowing a head, and this is obvious, is to make sure that the port modifications do actually improve the flow of the head. Gas flowing a port to its maximum size will not always mean it flows better, if the port is made too large then the gas flow will slow down resulting in loss of efficiency and loss of torque. Some of the head designs work well with extensive porting because the originals are relatively small. Others have ports that are considered almost too large so these designs benefit from attention to port angles and valve throat modifications. It is this experience and knowledge that goes into every Burton Power cylinder head.
Now CNC Machined!!!
Using the benefits of the latest technology and machinery, all Burton Power performance heads are now CNC machined. This increases the accuracy to which each head is modified and ensures that each cylinder port performs the same as the others. Each design has been copied from an optimised head using scanning technology which means every head performs identically and eradicates any variations due to hand machining.
CNC machined stage 1 cylinder head for 2.0 SOHC Pinto:
Each casting is cleaned and crack tested prior to modification. Original valve guide area of the head is machined out to accept our loose cast iron guides. Spring seats are deepened to suit HD valve springs and allow higher camshaft lifts. Inlet and exhaust ports are CNC profiled to suit the valve sizes. Cylinder head face is skimmed to lower chamber volume to 47cc. Chambers are CNC machined to equalise them. Inlet and exhaust faces are skimmed to clean. External casting faces are painted black. Head is fitted and assembled with:
• 42.1mm inlet valves
• 34.9mm exhaust valves
• Cast iron valve guides
• Heavy duty single valve springs
• New steel retainers
• New valve cotters
• Bronze cam bearings
• Stem seals
• Core plug
Maximum cam lift .400"(10.2mm).
Surcharges - all cylinder heads are priced on an exchange basis and an old core surcharge will be applied to all cylinder head orders placed on this website. This is subject to the availability of old core, where this is not available, the customer will have to supply a unit suitable for modification. The surcharge is refundable subject to returning a suitable old core unit. Old core units must be crack-free, in a serviceable condition, unmodified and supplied stripped. If you wish to avoid the paying the surcharge by supplying an old core unit in advance then please contact a member of our sales team.