Why Is 12v So Popular?

[cgoder]

WHAT IS THE ADVANTAGE OF THE 12V OVER THE 24V? : LOOKING TO BUY USED TRUCK DO TO PRICE ISSUE. ANY INFO WOULD HELP. THANKS

 

[HerbW]

Cause it's got the "BIG P Pump in it!

The 12V's have a super mechanical injection pump with mechanical injectors in it. Where as the 24v engines use alot of electronics to run the pump and injectors. The 24Vs are great engines, but I don't like to depend on electronics when I'm out elk hunting. If your alternator goes out the 12Vs should go farther before dying. My choice would be an early 1998 that has a 12V in it. It was the first year of quad cab and mid year switched to 24V engines. This way you get the best of both worlds! I've lived thru electronic injectors dying when I owned a Chevy 6. 5 diesel and then you walk! Just my 2 cents! Their both Great engines!

 

[Don M]

12 valves are cheaper to get the extra pop from.

12 valves still use the mechanical fuel delivery system.

24 valves use a ECM controlled injector pump but, still use mechanical injectors.





Don~

 

[Teacher]

12 Valve Popular

I sat in on a presentation by a Cummins Engineer at the Timberline B-B-Q shindig last month. He said something very interesting:

"The only reason Dodge/Cummins made the 24 valve was to meet EPA Emissions requirements. Otherwise the engines are the same!. "

What conclusions do you make???

 

[illflem]

Don't forget that the 12 valve gets much better fuel economy.

 

[dan_gilson]

A couple of more things...

I got 22MPG unloaded from my 12V and only

get 17. 5 from my 24V. Both have 5 speed trans

but the 24V is much nicer to drive. That is

because the 12V shift points don't have

much room for error. The 24v gives a much

wider sweat range which make the 5 speed

easier to deal with.



The 12V starts to smoke after peak HP ~2250 RPM.

The 24V just does not seem to smoke ever.



Sometimes the smoke can be nice like when

some a$$hole climbs up the tail pipe on an

on ramp and you decide to let it run an extra

couple of hundred RPM just to give him the

taste of diesel.



The 12V because of the smoke, blackens the oil

much quicker than the 24V.



The heads are different not just because of

the # of valves but the placement of the

injector is from the side on the 12V and like

a hemi on the 24V. I have been told that the

piston faces are also different.



The 24V breaths much better for obvious

reasons. I think it has better pickup but

don't have any times to prove it.



The 12V uses mechanical push rods. The 24V

uses hydralic (?sp) lifters which gives the

24V a 500 RPM improvement on the red line.

 

[Evan A. Beck]

The 12V is a good engine, but the P7100 pump is not as idestructable as a lot of people think it is. I have a seen a lot them with problems, such as uneven fuel delivery between cylinders, plunger seizing, and various other things. IMO, the VP44 is just as good as the P7100, and is MUCH cheaper to replace, if need be.

 

[HEMI®Dart]

Evan,



I read in a thread somewhere that the Dodge dealer quoted a guy $4,000+ for a new VP44.



Is it true?

 

[danandamy]

Whoa there pardner...

Originally posted by Evan A. Beck

[B... . IMO, the VP44 is just as good as the P7100, and is MUCH cheaper to replace, if need be. [/B]

The VP44 as good as the P7100? Cummins won't even try and make that claim. The P7100 may not be indestructable but the VP44 is a LONG WAY from being in the same class.

 

[DieselDoghouse]

I had heard a rumor that much of the lubrication for the VP44 comes from delivered fuel (that the VP44 depends more on fuel lube and cooling than the P7100). Due to this if the pump is wound up to higher speeds and then the ECM lowers the 'fuel call'the pump can be momentarily left spinning relatively dry - with increased wear or even impending failure a result. Can Evan or anyone else comment on this - 'legend or fact??'

 

[maint.man]

It is my understanding that the P 7100 is cooled/lubricated by engine oil , whereas the VP44 is lubed by fuel only.

 

[KatDiesel]

Originally posted by HEMI®Dart

Evan,



I read in a thread somewhere that the Dodge dealer quoted a guy $4,000+ for a new VP44.



Is it true?

Thats "installed" by a Dodge dealer. A VP44 is roughly $1300 if ya just buy it from a few different people, Piers being one of them. A P7100 runs about $2200 now I think. There was a price increase a few months ago.



Yes the 12v is a good engine, but the more I think bout it, I really do love the ability to push a button, and turn on and turn off 0 to 120hp (PE COMP). That is a nice feature.

 

[R.ebel]

12 valve

I'm starting to think the 24 valve guys have pump envy



The mighty P7100 is also used on the 8. 3L Cummins, if it can fuel 8. 3L then there is plenty of overkill built into the fuel delivery of a 5. 9L Cummins.

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[MikeR]

12v's are popular because the fuel system in it is all mechanical pumps,whereas the 24v fuel system is all electric pumps controlled by the ECM. Both engines have solid lifters and mechanical injectors. You can tweak and fine tune the 12v... that's something you can't do to a 24v. The P7100 is lubed by engine oil,and the VP44 is lubed by diesel fuel(you run it out of fuel,you shorten it's life).



I sure don't have any problems with my VP44,but that's because I monitor the fuel system periodically for piece of mind. However,I will not say it's as good as a P7100. If a P7100 takes a dump,the truck runs like crap. If a VP44 takes a dump,usually you are stranded 'til help arrives.



Looking at the latest prices from pretty much everyone: the P7100 is $2200 and the VP44 is $1350.



Transmissions are a whole other story. The most reliable Dodge/Cummins will be a 12v with a 5spd.



-Mike

 

[JWEST]

12valve!

All of the electromechanical, reliability and maintenance reasons aside, I like the driveability of my 12 valve. After having mine

set to the "high end of the spec" by Jim Jessup, I believe the 12V

has better response at just about any rpm, up to 3400. That's where a properly tuned 12V runs out of fuel and air. The off-idle torque and the mid-range strength of the 12V are what keep me

driving mine until the Ram falls apart.

 

['956Wheel]

1. ) Simplicity



2. ) Less to go wrong (mechanical vs electronics) (flame) if you must.



3. ) Time proven



4. ) Easy mods



5. ) Fuel economy



And yes th 24s creation was to please the EPA, as previously posted.





I would like to ask how many members had a P7100 failure... . stock!

 

[QRTRHRS]

Not all 12V are created equally. Check out this site for specific specs.



http://dodgeram.org/support_pgs/diesel_ix.htm

 

[Evan A. Beck]

Danandme,



I would not go as far to say the VP44 is a long way from the P7100... Take a look at failure rates in motorhomes and trucks, and you will find very few VP44 failures.



The bad thing about the VP44 is that it is not rebuildable--yet. That's one of the benefits of the P7100 pump, is that it is rebuildable at most fuel injection shops.



Also, cold weather performance is better with the VP44. Go start up a 12V truck in 20 degrees and see how it runs compared to a 24V.



Yes, the VP relies on fuel supply for lubrication and cooling... Is that bad? Well, yes and no. Yes because diesel fuel these days lacks the needed amount of sulphur, which is critical for lubrication. That's why a lot of people use a fuel conditioner of some kind or another. It is a good thing because there is little risk of oil intrusion into the fuel, and vice versa. Same thing can happen with the mechanical lift pump on the 12V trucks.



Personally, I like the way the 24V performs as compared to the 12V trucks. However, if I was building a drag truck, it would have a P7100.