page_title: Crossplane
section_title: Firing intervals
hierarchical_section_title: Crossplane / Crossplane V8 crankshaft / Firing intervals
caption_attribution_description: The engine of a Ford GT40 (1960s Le Mans car) Replica on display at the 2008 Perth Motor Show
context_page_description: The crossplane or cross-plane is a crankshaft design for piston engines with a 90° angle between the crank throws. The crossplane crankshaft is the most popular configuration used in V8 road cars.
  Aside from the V8 already mentioned, other examples of configurations using such 90° piston phases include straight-2, straight-4, V2, and V4 engines.
  Crossplane crankshafts could feasibly be used with a great many other cylinder configurations, but the advantages and disadvantages described below may not apply to any or all of them and must be considered on a case-by-case basis.
context_section_description: Four stroke crossplane V8 engines have even 90 degree ignition intervals, but unevenly spaced firing patterns within each cylinder bank.
  The firing order on the Left and Right banks are generally LRLLRLRR or RLRRLRLL, with each 'L' or 'R' ignition being separated by 90° crank rotation for a total of 720° for eight ignitions.  As can be seen by counting four characters to the right of each 'L' or 'R' (4 x 90° = 360°), the cylinders that fire (and thus exhaust) at 360° phase difference reside in opposite banks in a crossplane V8. 
  The actual intervals in each bank are 180-90-180-270 crankshaft degrees, in various orders depending on the engine, and not usually in the same order in each bank.  The exact combinations depends on the crankshaft "handedness", the direction of rotation and which of the 360° pairs is ignited first in the order.
caption: This is a modern, less serpentine street version of the crossover exhaust on a Ford GT40.
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