From the
F1 fanatic website re engine freezes.
Planned FIA engine development freeze, 2015-2020
As per the current 2014 Technical Regulations:
2015
New items included in development freeze
Upper/lower crankcase: Cylinder bore spacing, deck height, bank stagger.
Crankshaft: Crank throw, main bearing journal diameter, rod bearing journal diameter.
Air valve system: Including compressor, air pressure regulation devices.
2016
Upper/lower crankcase: All dimensions including cylinder bore position relative to legality volume, water core.
Valve drive – camshafts: From camshaft lobe to gear train. Geometry except lift profile. Includes damping systems linked to camshaft. Exhaust and Inlet.
Valve drive: Position and geometry. Gear train down to crankshaft gear included, and dampers.
Covers: Covers closing the areas in contact with engine oil cam covers, cam-timing covers.
Ancilliaries drive: From ancillary to power source. Includes position of the ancillaries as far as drive is concerned.
2018
Valves axis position: Includes angle but excludes axial displacement.
Valves drive: From valve to camshaft lobe. Position and geometry. Exhaust and inlet. Includes valve return function inside the head.
Crankshaft: Except crank throw, main bearing journal diameter, rod bearing journal diameter. Includes crankshaft bearings.
Oil pressure pumps: Including filter but excluding internal if no impact on body.
Oil scavenge systems: Any scavenging system.
2019
Cylinder head: Except modifications linked to subsequent modifications.
Combustion: All parts of parts defining combustion including ports, piston crown, combustion chamber, valves geometry, timing, lift, injector nozzle, coils, spark plug but excluding valves position.
Con rods: Including small and big end bearings.
Pistons: Including bearings and pin. Excluding crown.
Oil recuperation: Oil/air separator, oil tank, catch tank.
Engine water pumps: Include power unit mounted water pipes.
Injection systems: Power unit-mounted fuel system components e.g. high pressure fuel hose, fuel rail, fuel injectors, accumulators but excluding injector nozzle.
Inlet system: Plenum and associated actuators. Excluding pressure charging, trumpets and throttle associated parts and actuators. Trumpets and associated parts and actuators. Throttles and associated parts and actuators.
Pressure charging: From compressor inlet to compressor outlet. From turbine inlet to turbine outlet. External actuators linked to pressure charging.
Ignition system: Ignition coils, driver box.
Lubrication: All parts in which circulates oil under pressure (oil pump gears, channels, piping, jets) and not mentioned elsewhere in the table.
Friction coatings
Sliding or rotating seals
Complete Motor Generator Units for Heat and Kinetic energy – all internals including bearings, casing, etc…, their position, transmission and power electronics.
Energy Store: Cells.
Energy Recovery System – Cooling/lubrication: Including energy store jackets, pipes, pumps, actuators.
Edit: I have just seen the date on the article which was mid September 2013 so might have changed since then