12 Valve vs 24 Valve Cummins

TheGeneral

New Member
Joined
Mar 22, 2005
Location
Wilmington
Im looking at a 97 ram 3500 with the 12 valve cummins and 158,000 miles on it. What are the differences in the 12 valve as opposed to the 24 valve when it comes to power, reliability, upgrades, and fuel mileage?? Are there any serias maintenance issues associated with either engine? Ive had a good bit of experience with a 24 valve cummins and have been very pleased with it and was wandering if the 12 valve was going to be a disapointment in the long run.
Thanks guys
Justin
 
12valve old school non-computer controlled cheap and easy power mods. 24v expensive to bump the power. Early 24v had block problems (certain casting numbers) Research more on some diesel forums , they have more info than you could want.
 
12 valves and 24 valves had problems with the injector pumps going bad prematurely and they are pretty expensive to repalce. Fuel milage is a little less from my experiance on the 12 valves. I get around 16-18 mpg on my '95 cummins w/ 36's, 4.10 gears, and a 5 speed. My buddies '01 24 valve gets around 19-20 w/ a 6 speed so they are pretty close. Upgrades are a little cheaper on the 12 valve, you can tweak the injector pump for cheap, then new injectors, exhaust, new turbo, all that.
 
12 valve

I have not heard of any problems with the 94/97 fuel pumps. I also disagree that the 24 valves get better milage than the 12 valve. The 24 V had a lot of lift pump problems that cause injector pump problems.
 
I like the adjustability you can have with a 24 valve.. want more power? crank the box up. turn it down for towing, or for when the popo is following you.. (Speaking of something like an edge comp)

However, the VP44 injection pump is not the most reliable thing, though adding a pusher pump to supply the IP with a good supply of fuel seems to really help them last.

Woody touched on the "53" block that plagued some of the early 24 valve trucks.

Mileage will be similar, depends more on your right foot. Toyota231's 36's have a lot to do with his milage. I get the same milage as he does, but am more heavily fueled, have an auto, the truck is a dually, which certainly doesn't help (nor does the bambi-slayer bumper).

I've yet to hear anything about IP's going bad on the 12v's prematurely. Hell, mine is knocking on 250k now.

If I had to do it again... Dunno. A '00 with a 6-speed would be very nice.
 
97

I'll stick with my 97 12 valve, 5 spd, 3:54, US Gear Over drive. I have a gear for every occasion.
 
upgrade

If I were going to upgrade, I would jump to the common rail with a 6spd.
 
LARRY SMITH said:
If I were going to upgrade, I would jump to the common rail with a 6spd.
Click to expand...
you may not be happy with the milage...if you can get an owner to REALLY be honest with you about it.
 
i would take the 12v anyday over the 24v the company i work for has both motors in fl70 freightliner trucks and these trucks are run wideopen from start to finish i work on these motors daily as far as reliabilty the 12v is twice as tough as the 24v i can't tell no difference in power in stock form between the two as far as the injector pumps the 24v is junk don't last sensors go bad all the time and these aren't cheap the 24v is also really bad about breaking injector lines we have 12v motors running everday with over 500000 miles on them we already have had to build the 24v with less than 300000 miles the 12v is the toughest of the two in my thoughts
 
COMMON RAIL

That is true, the milage on the 03 and up is not as good. My brother has a 03 2wd dually, at, 3:73 gear. He has been unhappy with his miliage with 25,000 miles on it. He has been able to get the miliage up to around 18 mpg with some mods, was around 15 mpg. I think most of the milage increase came with his move from Conn. to Co.
 
BIGWOODY said:
you may not be happy with the milage...if you can get an owner to REALLY be honest with you about it.
Click to expand...


I have only ran one tank of fuel through mine, and it honestly got 17 miles to the gallon. I figure by the time the truck gets a few thousand miles on it that the numbers will improve a little bit.
 
LARRY SMITH said:
I have not heard of any problems with the 94/97 fuel pumps. I also disagree that the 24 valves get better milage than the 12 valve. The 24 V had a lot of lift pump problems that cause injector pump problems.
Click to expand...

The problems with the 12 valve injector pumps aren't near as likely to happen but i have heard of some. I know the PO of my truck had problems with it and i have heard of the problem through a few more people. My fuel mileage would be a little better if i could keep my foot out of it but i just love to hear that straight piped sound. I also love that even when im pulling a trailer with my toyota on it i still get around 16 miles per gallon.
 
yota_wheeler said:
I have an '05 4x4 dually with 6 speed.

If you drive any faster than 55, the fuel mileage SUCKS.

i average 65 to 70 mph and get around 14 mpg.
Click to expand...

I have heard from a few people that the fuel mileage isn't what was expected on the new cummins. My old bossman had an '04 dually w/ an automatic and he wasnt getting but about 15 mpg running highway speeds.
 
LARRY SMITH said:
If I were going to upgrade, I would jump to the common rail with a 6spd.
Click to expand...

Oh hell yes... very nice indeedy.
 
MILAGE

I average 20 mpg to and from work. I will average 21/22 at 65/70 on a road trip, 13 to 16 towing depending on terrain and weight.

I have to comment on Purple's statement Rich. I don't think you are an ass.
 
Back
Top