Talk:Firing order

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There are atleast 3 cylinder numbering conventions for 90 degree V8s used in vehicles.

First some basics on orientation. The back of the engine is nearest the flywheel. The right bank is on your right if you're at the back of the engine looking toward the front of the engine. Put another way, for rear wheel drive vehicle in right hand side of road countries, eg. US and Canada, left bank is on the driver's side and the right bank is on the passenger's side.

Ford: Counting from front to back on the engine:

1 2 3 4 on right bank,

5 6 7 8 on left bank.


Chrysler and GM-Except NorthStar(tm): Counting front to back on the engine:

2 4 6 8 on right bank,

1 3 5 7 on left bank.


Northstar (GM): Counting front to back on the engine on the engine:

1 3 5 7 on right bank,

2 4 6 8 on left bank.


In V8 engines there is usually an offset between the front of the right bank compared to the front of the left bank about equal to the width of the lower part of the connecting rod. This is because piston/connecting rods assemblies are identical and share a common journal on the crankshaft between the banks. Hence there are only 4 journals on the crankshaft for connecting rods. In the Chrysler case: "1" and "2" share one journal, "3" and "4" share a journal, etc. Typically the cylinder nearest the front of the engine is numbered cylinder "1".

In the Chrysler case the left bank is nearest the front of the engine. Hence cylinder "1" is on the left side of the engine. When the Northstar engine was designed it was determine that some space would be saved if the right bank was moved ahead of the left bank. Consequently the apparent flip, left to right, of the cylinder numbering.

These differences in numbering conventions gives rise to differences in the "firing order". As expected, the actual design of the crank shaft also affects the firing order.

  • These numberings are IRRELEVANT without a list of the numbering pattern of the cylinders For example, the GM LS1 example has the exact same firing pattern as all Ford V8s (post 1988), the only thing that differs, is the cylinder numbering. 192.197.71.189 14:05, 22 December 2006 (UTC)
  • Your Ford/GM/Chrysler numbering is backward. The left back is the left side, when you are standing in FRONT of the car 192.197.71.189 14:24, 22 December 2006 (UTC)


Great! Now incorporate this into the article... MH 21:25, August 21, 2005 (UTC)

[edit] V-12

If you had a 12 cylinder 4 stroke engine how can you determine how many degrees apart the firing intervals are,

A complete cycle for a 4 stroke engine is two revolutions of the crank, or 720 degrees. Simply divide 720 by the number of cylinders to find the spacing. A 12 cylinder engine would have 720/12=60 degrees of crank rotation between each cylinder firing. There are some (mainly two-cylinder motorcycle) engines and V8-derived V6 car engines that use an irregular spacing but for an automobile engine this formula is usually accurate. Rpvdk (talk) 10:18, 22 May 2008 (UTC)

[edit] Clarity on Directions

The section on cylinder numbering isn't very clear about its directional relativity. For example, when it says "left", is it left as viewed from standing in front of the car, looking at it, or left from sitting inside the car, looking out straight ahead?

For example, when standing in front of a car, looking at it, the steering wheel is on the left in Australia, but right in America, while, sitting inside the car, the steering wheel is on the right in Australia, but left in America.

This is where the confusion arises, and I think it should be clarified.

203.122.107.112 (talk) 14:07, 21 May 2008 (UTC)

Agreed. I've added a section explaining left/right as they are generally used in the automobile industry, and removed the superfluous left/right references elsewhere. I think this will make the article more readable. Rpvdk (talk) 10:18, 22 May 2008 (UTC)
The article makes more sense now with the explanation. I personally find directions like that a bit confusing, though, because we look into engine bays by standing in front of the car, not by being inside the car. The directions are opposite in the two cases, of course. For example, if a mechanic was working on a transverse-engined car, the pulleys would be on their left, but to a driver they're on the right. Since the article is about cars technically, I tend to have the mechanic's perspective. Just my opinion, though. 203.122.107.112 (talk) 10:50, 24 May 2008 (UTC)
That's the problem with left and right, it's all relative :) . I think this is one reason ships use "port" and "starboard" but that terminology never caught on for cars (it is used for aircraft sometimes). Anyway, most automotive technical manuals and parts books I've seen use left/right always as seen from the driver's seat; that way, the right front wheel is always the same one no matter where you stand :D Rpvdk (talk) 19:42, 24 May 2008 (UTC)