Thedieselkid

Hello,

My name is Paul and I am looking at buying a Cummins truck. I am just wondering what you all think I should be looking for as far as engine 24v or 12V? I am wondering how do they compare when it comes to longevity and cost to maintain, how does the fuel economy and power compare, and lastly which would you rather mod?
I am looking for a truck that will last and have plenty of power when I am hauling. I am def a newb so even the most basic of reason why you would choose one over the other is probably something new to me. I already know about the 53 block and don't want to go down that road, but other then that what should I look for as a potential problem down the road?
I appreciate the help, and look forward to learning as much as I can

Thanks,

Paul

PS the truck will be an automatic quad cab

CTD NUT

If you are set on a quad cab and you want a 12v, you just narrowed your search down to a 98.0 model only - 98.5's were 24v and there were no QC's prior to 98. IMO, I would go with the 12v, I have owned both and it certainly has the better fuel system of the two engines (read potentially MUCH lower maintenance costs). When I was searching for a 3500 I was looking for the elusive 12v QC 5 spd and never did find one in a 3500 4x4....I settled on a 24v which has turned out to be a great truck but still wish I could have found it in a 12v.

Either engine will be capable of producing WAY more power over stock with little effort.

Thedieselkid

Wow thanks for the fast responce. I will even take an extended cab, I just want the extra seating room.

Thanks,

Paul

storx

you can get a 24valve but you will have the dreaded vp-44 pump setup.. which is becoming easier and easier to replace or fix since prices keep coming down on it all..

megajoltman

If you want automatic quad cab you will find a 24V way easier and cheaper

Took me over 2 years to find my 12V auto quad Cab 4x4, well one I could afford anyways

DL1221

As someone else pointed out, both of these engines are capable of producing an amazing amount of power, and both of these engines will last hundreds of thousands of miles, if you take care of them. I have one of each, and here is my two-cents worth of opinion:

The 12-valve motor is a fully mechanical engine, once you start it, it only needs fuel to run. 12-valved trucks do have a computer, but it only controls the transmission shift points, cruise control, alternator, heater grids, etc., not the fuel management system. You can modify a 12-valve, to produce more power, at a cost of zero to a few hundred dollars, depending on how mechanically inclined you are -- no software or computers to mess with. The biggest problem for a 12-valve is what is commonly referred to as the Killer Dowel Pin (KDP) – this is a design defect which allows a locating dowel pin to fall into the front gear train causing significant and expensive engine damage. However, if caught in time, the KDP problem can be easily fixed for under $50. The Bosch P7100 fuel pump on these engines is very reliable, very adjustable, easy to modify. Overall the 12-valve is a great motor. One down side is that these 12-valved trucks are getting harder and harder to find in decent shape, especially if you want the hard to find standard 5-speed transmission.

In contrast to the fully mechanical 12-valve, the 24-valve engine is a fully electronically controlled engine with multiple computers. These engines can also put out a mind-blowing amount or horsepower and torque, but since these are electronic engines you will need to add software programmers and piggyback fuel control boxes, which run from $500 to $1000, each. However, unlike a 12-valve in which you get full power all the time, with a 24-valve you can install a fuel control box that will allow you to adjust the power on the fly – from stock to +200 horsepower with a touch of a button – a very nice feature. The 24-valve engines had three major issues, 1) the manufacturing defects of the 53-block, which you already know about, 2) bad lift pumps from the factory, and 3) bad injector pumps (VP44). You can solve the bad lift pump problem by replacing them as they go bad, about $64-180 for a new pump, or you can install a high performance lift pump for $400-600, and never worry about it again. The Bosch VP44 injector pump on these 24-valve engines also suffers from poor engineering design, and is no where as reliable as the P7100 pump on the 12-valve motors. Most people that own a 24-valve with have to replace the VP44 at least once in the truck’s life; the cost is $1000-1500 for a rebuilt pump.

The last thing I want to point out is the platform that these engines are mounted too. The 24-valvers are newer trucks which are much more refined that the older 12-valvers. My 01 24-valve rides, drives, handles, brakes much, much better than my 96 12-valver. One particular example is the brakes, on my 96 the brakes suck! In contrast, the brakes on my 01 work flawlessly and stop the truck on a dime. Both trucks are great, that’s why I wanted one of each, but the 24-valved trucks are more modern and refined, while the older 12-valve trucks are simpler to work on and can be more reliable.

Just my opinion, I like them both.

Krob

S*** ive been looking for your coparison for a long time since im in the same boat thanks that is very helpful.

dsl kicks gas

i have a 98 24 with 207,000mi on it(which has been nothin put a pain in the but for the past year and is for sale) but i love it and drives great and has a boat load of power, but the problem is the dang fuel system it's had 3 injector pumps in it's life, one being 2 months ago, 3 lp's that i've put on, the whole front axle basicly rebuilt(everything but the gears), 5th gear has went out twice(the 2ed time being 20 mi after having it rebilt, the set screw and nut fell off in the case and chewed everything up but it had a warenty) transfer case rebuilt, fuel gauge sending unit, and only god knows what now with the pick up in the tank oh and ya cant forget the clutch.....but that was my fault

and my 1st gen 12 valve with 185,000mi on it and it hasnt had nothin done to it since 93 except just the normal PM stuff(oil change fuel filter change gear oil and so forth) it was already straight piped when i got it and i turned the fuel up on it and it'll out pull my buddys 01 with 275's and a hot comp.


between the 2 trucks id take the 93 any day of the week but thats just my 2 cents and when i sell the 98 im gonna try to find a 96 or 97 4x4 5spd std cab.

so i think the 12v is a lot better motor, but a 24v with a p-pump converson may be a whole diffrent story

jakerudy

I have towed with my 24 valve and my Dad's '91 12 valve. The 12 valve is simpler but the engine power comes on in a more narrow rpm range. My truck is much nicer to drive and live with but the electronics make it more complicated. I needed the Quadcab and found a babied truck so decided to live with the potential fuel problems. Both trucks are stock and mine tows better but will probably cost more over the life of the truck. There are several improvements available for the lift pump.

dsl kicks gas

oh yea i forgot to mention they have there tq in diffrent places.....the 93 will lugg and chugg and pull what ever ya want, but on the 24v it likes runin up in the rpm's and dont seam to have the power in the lower range. dads 97 is just like the 93 so i guess it's just a mechanical pump thing(all 3 trucks hae 3:55's)

ellerman

I would buy the newest truck your budget will allow. I do believe the 12 valve is a better engine but you will be buying a truck that is falling apart around the engine. If you can afford it get an 01.5 or newer and buy a FASS fuel system and you should be good for many years. My 2 cents, Eric

RowJ

Paul,
'DL1221' gave nice run down on differences, and Eric, above, added another dimension worth considering.
For me, I love my 02 24v. Last of the non common rail fuel delivery systems and has many subtle improvements over earlier models. Costs are a little higher (than a 12v) to fix what Dodge should/could have handled for us, but I don't care. I love it.
IMHO, the long bed, extended cab, 4x4, 2nd gen is the best looking CTD on the road!
Getting hard to find one under 100,000 miles, but I'm looking for a second one....and only an 02 4x4!

JMO - RJ

PaulDaisy

I totally agree! I chose a shortbed though on the advice of a friend with a LB who said getting in and out of tight places is not fun on his LB. But I do agree the 2nd gens are best looking, to me!
On the mileage vs year, I saw a 98 LB in the paper with 68k on it, for $16k with a slide-in camper! I am almost tempted to go look at it.
-P

dsl kicks gas

the OQ long box isn't bad at all.....the way i see it after ya put a toolbox in it ya got a short bed, but if ya put a toolbox in a short bed ya dont have no bed.

Forrest Nearing

how 'bout buying lower miles versus newer? I'd much rather have a 10yr old truck with 75k miles than a 5yr old truck with 200k miles...

P7100 for life!