Advantages/Disadvantages of V-8 vs V-12 6.0L Engines

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Discussion Overview

The discussion centers on the advantages and disadvantages of V-8 versus V-12 6.0L engines, exploring aspects such as performance, efficiency, smoothness, and design considerations. Participants examine both theoretical and practical implications of each engine type.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that V-12 engines may offer greater smoothness due to firing every 30 degrees of crankshaft rotation compared to every 45 degrees for V-8 engines.
  • Others argue that V-8 engines are generally lighter, more compact, and potentially more cost-effective, with better fuel economy.
  • There are claims that V-12 engines have a higher potential for power due to their ability to rev higher, while V-8 engines may produce more torque but with heavier reciprocating mass.
  • Some participants dispute the idea that V-12 engines have less rotating and reciprocating mass, suggesting that the crankshaft and additional components add significant weight.
  • It is noted that the advantages of each engine type may depend on specific applications and duty cycle expectations.
  • Concerns are raised about the complexity and potential maintenance challenges associated with V-12 engines, including the difficulty of finding machine shops capable of servicing them.
  • One participant mentions anecdotal evidence of a V-16 Cadillac being driven on half its cylinders, highlighting practical considerations of engine design.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the performance characteristics and practical implications of V-8 versus V-12 engines. The discussion remains unresolved, with no consensus on which engine type is superior.

Contextual Notes

Participants acknowledge that power and torque are influenced by factors beyond just the number of cylinders, indicating a need for careful consideration of various engine design parameters.

R Power
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Hi guys
What would be advantage of a V-8 6.0L over V-12 6.0L. Or any disadvantage!
Will it be more speed, smoothness or what?
 
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You may recall the old Cadillac V-16 or the Lincoln Zephyr V-12 before the War (WW II). These were developed (I think) for smoothness at low RPM. Maybe also because of the lower inertia of individual pistons and rods. However, this arrangenment was less efficient (in terms of fuel burn) than a smaller number of larger pistons, because the lower fuel-volume-to-surface ratio of the combustion chamber conducted heat away from the ignited fuel and to the walls (at ~ 180 deg F) faster, thus reducing the thermodynamic efficiency (Otto cycle).
Bob S
 
Bob S is spot on..plus the V12 fires every 30 degrees of crankshaft rotation vs. firing every 45 degrees in the V8..so the V12 is SMOOOOOOTH..but consider
V12 is heavy, compared to the V8 block, you have more parasitic drag of additional 4 pistons, rings, 4 more rod bearings, probably two more main bearings, heavier intake manifold with more intake runners, heavy longer crankshaft, cam shaft, a lot more drag to open 8 to 16 more valves.
it mat be worth it if you can up the cubic inch displacement but consider the size of the block...it really takes up a big footprint in the engine room so you got one long hood...also the damn thing will be nose heavy and hooking up the rear drive tires will be tuff..
consider a V8 with aluminum cylinder heads can put out 650 horsepower and weighs just over 300 pounds...and iaa very compact package...
 
Possible advantages of the V8: size, weight, cost, complexity, fuel economy

Possible advantages of the V12: balancing, smoothness, sound (subjective)

Basically, it depends on the application and duty cycle expectations.
 
V8 would have the potential to produce more torque, but more reciprocating mass (bigger pistons) so less revs.
V12 higher revs so potential for higher power, perfectly balanced, slightly less torque.
 
I dispute the reciprocating weight issue. No way does a v12 have less rotating and reciprocating mass.
Also RPM is relative. Yes F1 spins um to alm
ost 20000 rpm
but are we talking practical application like 2500 revs
 
I mean for each piston, the inertia loads are less for a V12 at the same rpm. As it's a set displacement he V8 pistons will be much heaftier. This is of course assiming the V12 doesn't have a silly bore to stroke ratio.

So overall static load, the V12 has more. Under operation the V12 has less dynamic load at a set rpm.
 
Right on xxchrisxx
now I understand and is good point
 
I heard of a professor at my university who a an old V-16 caddy in which the ignition points failed. So he drove home on the other 8 cylinders. (It had two distributors).
Bob S
 
  • #10
the crank should be heavier on the v12 which adds rotating mass, and finding someone to turn that thing (re-size) if it needed it may be tough. my machine shop guy had a hard time finding someone to turn a straight 8 packard crank cause it was so long, some machines couldn't jig it up correctly

dr
 
  • #11
So , which one gives more power and torque?
 
  • #12
Well it's pointless us just telling you, with no explanation. It's also very hard to be all sweeping and general about this because it's not true in all cases.

However:

V8 potential for more torque.
V12 potentially more power.

Do you know why this is?
 
  • #13
R Power said:
So , which one gives more power and torque?

Impossible to say, power and torque depend on far more than number of cylinders.
 

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