View Full Version : 12v vs 24v

09-13-2012, 09:39 AM
So whats the diff between 12v Ccummins and 24v Cummins?

I know nothing about them , why did they change and in what years?

09-13-2012, 10:31 AM
the 12 valve is a mechanical injection engine, very reliable and easy to work on. this engine has the P-7100 or P Pump that can be made to put out huge H.P.
the 24 valve has the vp44 pump which is electric and controls fuel delivery. on this engine it is plug and play for more H.P.
the commonrail is an engine where the rail is at very high pressure all of the time
and the injectors are told to open and close by the Engine Control Computer.
this engine is 6.7 L but bogged down with smog control.

12v is the engine to have. 94-98.5
24v has some blocks that crack i think it is #53 or #54 castings. 98.5-2002
Common Rail 6.7 you get sorry MPG because of DPF and added fuel events.
Read more: http://forums.dieselpowermag.com/70/7713099/cummins/12valve-vs-24-valve/#ixzz26Msv0XTV

First off, the 12 vavle is not louder. It is a little quieter in terms of engine noise due to the simple 12v design, with half the valves of the 24v. If you were to straight pipe either truck, the exhaust note difference would be pretty negligible.
The 12v gets high praise for it's ability to take gobs of horsepower, as well as the fact that it's a mechanical engine. There are no electronics to suddenly go haywire and dampen your day. In terms of stock power, the 24v is more powerful than the 12v, but it doesn't take much money (if any) at all to make the 12v outpower a stock 24v. You can gain quite a bit of extra horsepower/torque just by getting a fuel plate or modifying your own. However, there are plenty of aftermarket chips/programmers/fueling boxes that can bring the 24v right back. I would choose the 12v over the 24 due to the fact that the 12v has the most respected injection pump in light duty diesel performance - the Bosch P7100. Many of the high horsepower 24v guys opt to remove the vp44 injection pump and swap it for a "P" pump. Most if not all of the highest horsepower Cummins engines are 12 vavles. The "modified" pulling trucks are putting out in excess of 1800 horsepower. One of the quickest Cummins trucks (installed in a Ford Super Duty) is that of Richard "maddog" Madsen, putting out more than 1100, if not 1200+ recently. Jimmy and Dale Smith have a 12v that ran a record 9.97 4x4 pass this year at Indianapolis Raceway Park. Bottom line the 12v is still the king according to most Cummins enthusiasts. They like the simplicity of it being mechanical. Throwing on big injectors and a big turbo or two - along with other supporting mods can yield huge power numbers without the worry of the electronics. Also when looking for 24v engines make sure it is not a "53" block, as some blocks have been prone to cracking in a certain area.
If you find a clean, lightly used 12v, jump all over it. If you find a clean lightly used 24v, go for it too. But the first thing I would do the 24v is put an aftermarket lift/fuel pump on. The biggest killer of the 24v's vp44 injection pump is when the lift pump goes out and takes the IP with it.

as for the "why," its just like why all things went from mechanical to electronic. the computer can compensate for some variables making it less work to an end user, and electronic can achieve better emissions.

09-13-2012, 06:49 PM
Thanks Crimsen

09-15-2012, 12:25 AM
but the 12 valves get better mpg!!
my 95 3500 gets 30 mpg loaded