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Hartley Enterprises specializes in custom high performance engines for sport and competition use.  The engines incorporate advance motorcycle engine technology to give unparalleled high horsepower and low weight. 



The BOLT4 is a 16 valve L4 engine.  It utilizes the Suzuki Hayabusa head and incorporates race car  features such as a high capacity alternator, flywheel with an automotive race clutch, adapter for Hewland and other gearboxes, robust crankshaft, advanced dry sump oiling system and low crankshaft center height . 
See BOLT 4 Specs. page for details. (CLICK HERE!)


The MAXI is the largest and most powerful compact V8 available.  This 90° V8 utilizes motorcycle technology for the heads, flat plane crank and a robust bottom end to insure durability. 

The unique cam drive reduces the engine length and it retains separate cylinders for flexibility in bore size and rebuild.  Presently it is available in displacements 2.5 to 3.3 liters, and a 3.5 liter version is planned.


See H1 MAXI V8 Specs. Page  for specifications details  (CLICK HERE!)

See H1 MAXI V8 MFG Page  for manufacturing details   (CLICK HERE!)




See the updated GALLERY page for examples of applications and technical details! 


Last update 12/2023



  Hartley Enterprises working on the following projects:

  • 2000cc V4 engine for race applications-  Prototype is complete and is the test phase.
  • 250cc supercharged high efficiency 2 cylinder engine- The 25 hp air cooled uniflow engine is focused on the drone market.  Also foreseen is a 4 cylinder version for the hybrid automotive market.