Hi all, is a 456M engine even or odd fire?
The search function is your friend. Even Google pulled this link in. https://www.ferrarichat.com/forum/posts/145189420/
Hi, the thread does not say odd or even ? How am I to determine it ? is it the last number in the firing order?
It actually did. Here you go though. The cylinder numbering is irrelevant to your question. My first response had the answer. Even/odd is all about phase. EVEN An even fire V12 has 60 degrees (or 120 or 180 degrees) spacing between the cylinder banks and a firing impulse every 60 degrees (720/12). Following Formula 1 practice where they opened up the spacing on the V6s and V12s to 65 degrees to improve room for induction, Ferrari introduced the same 65-degree spacing in the Dino 206/246 GT and the 456. These engines are odd firing. The Daytonas and Boxers/Testarossas were even firing with 60 degree and 180-degree cylinder bank angles respectively.
No, I am saying that the 456M 65Degree V-12 has an 'odd" firing order. Sorry if my posts aren't answering your question, but I think you need to brush up on the terminology. The Wiki link filled in a lot of blanks. Cylinder count, the block angle, and the crank determine phase. What are you really asking about 456Ms??? I am a former owner of a 2000 456M.
Alex-What is your definition of odd fire and even fire? Give us a clue what you are talking about and somebody can answer your question. I have never heard that term mentioned about Ferraris in 40+ years of ownership. The 456M has a different firing order from the 456 GT and the other 65 degree V12s, so it is weird, but not necessarily odd.
I was going off this definition, which is what I was taught. The odd/even thing is all about phase. This is in the Wiki link I posted. Evenly spaced firing order (also called even firing order or even firing interval) means that the angle between each firing is equal. In four-stroke engines this requires a firing interval of 720° divided by the number of cylinders. On the other hand, engines with unevenly spaced firing order (sometimes called odd firing order) not all angles between firings are equal, for example a six-cylinder engine with unevenly spaced firing order can have a combination of 90° and 150° firing intervals compared to a six-cylinder engine with even firing order which must have 720° / 6 = 120° firing interval. Engines that are even-firing will sound more smooth and steady, while engines that are odd, or uneven firing will have a burble or a throaty, growling sound in the engine note, and, depending on the crankshaft design, will often have more vibrations due to the unevenness of power delivery. Most racing engines such as those in Formula One often have even firing intervals in all or the most part (e.g. within each bank of a V-engine) of their firing order, mostly for easier packaging of performance exhaust systems.[4] Engines that employ some variation on the Big-bang firing order theme will often have an uneven firing order, because the torque pulses arising from the second order kinetic imbalance of a traditional inline four have a worse effect on rear wheel traction than uneven power delivery as RPM increases.[5]
+1 - For even vs uneven, virtually every modern car engine is even - unless you put a Harley Davidson engine in it The "smoothness" (and max power) subset for the V-engine configuration is alternate bank firing vs not alternate bank firing -- even though the 456 firing order is different than the other Ferrari V-12s, it still has an alternate bank firing order (so is super-smooth and sounds very sweet). Typical US V-8 engines are not alternate bank firing so sound a little bit lumpier (because the timing between the exhaust pulses entering each exhaust manifold are not all the same) and have a broader torque curve while sacrificing a small amount of max power - but they are still "even".
Steve- Affirmative, our 65 degree V12s are still two sixes on the same crankshaft and fire evenly on alternate banks throughout the order. V angles other than multiples of 60 degrees may introduce some secondary imbalances, just like the flat plane V8s have secondary imbalances, but not enough for issues. Ferrari has used V angles of 60, 65, 75, and 180 degrees in their V12 F1 engines with no problems. Should have no effect on ECU design, either.
Thanks for the confirmation - I didn't believe the "expert" and called Ferrari of Beverly Hills - the 456M is a EVEN fire 65 degree engine.
As a former aircraft technician, I was told to always consult the manuals (rather than relying on memory). I'm not saying the person who answered your question was wrong, but calling someone out of the blue, especially a busy person, and not knowing his/her depth of knowledge, can get you into all kinds of problems. Having said that, I've found so many mistakes in Ferrari manuals, it's laughable.
Hey Ian, I view you as one of the top posters in the car threads. You have helped out a lot of guys with answers. Not to stir the pot, but to satiate my curiosity, in piston aviation engines including radials, how is the odd/even issue addressed??? Is there a different nomenclature??? The aviation stuff always interested me and the evolution of early stuff is close to the antique motorcycles that I collected in the past. Cheers, Marc
I thought I was going crazy, until I realized this thread is almost verbative duplicate of another thread in the 456 forum. Okay re-reading this thread the root I believe is @BOKE use of he word odd (in quotes or none) - I believe at times he implied a non-standard firing order, and other times literally odd (as in strange). I think this double entendre is what caused the OP to think @BOKE was 'trolling.' It's all silly in the end. Let's all reset and wipe the slate clean. @63250meade & @BOKE let us move forward as gentlemen and consider this a awkward misalignment of intentions. No harm no foul. In an effort to get this back on track, let's keep the discussion on point and see if we can get a definitive answer for @63250meade Thank you.
After I posted the above in the other thread as well @63250meade decided that taking another shot @BOKE was the pertinent thing to do. (sigh) Thread locked.
