Diesel valves

01-06-2007, 01:28 AM
Can someone explain to me why the 12v cummins is more sought after than the 24v even though the 24v has a greater power advantage?

Chris Stewart
01-06-2007, 02:06 PM
Nope, I prefered the '98.5-'02 24valve motor with it's inherent problems over the '94-'98 12valve motor with it's problems.

The 12 valve motors have the Killer Dowel Pin, an alignment pin that when it gets loose in the timing case-busts gears...taking the front off the motor and tabbing said dowel pin is the fix..
The 12 valve motors get the 5 spd man. trans. with the 5th gear nut falling off the shaft.
The 12 valve motors after being turned up, require turning back down to pass emissions...a consideration of mine.
The 12 valve motor gets one tough, reliable injector pump.

The 24 valve motors have a fragile injector pump...I chose to address mine with a really good delivery (lift) pump system with better plumbing, a fuel cooler and a pressure gauge to keep an eye on things.
The 24 valve HO motors get a 6spd. man. trans that's a good piece.
The 24 valve motors can be turned up or down electronically inside the cab.

01-09-2007, 08:12 AM
why are they more sought after? because their are many examples out there with over a million miles on them with out anything major being done. the nv4500 manual trans is a stout unit with the nut fallin off on fifth gear usually at insane high mileage. although i will admit i would rather have the 6 speed (nv-5600). that is on most 24 valvers with a manual. the kdp on the 12 valvers is not as serious as it sounds. most that do fall out just fall to the oil pan and stay. some do cause catastophic failure. and keep in mind alot do not fall out. if you do buy a 12 valve have the kdp fixed with either the jig or the tab method so you don't have to worry in the future. it is a diy job.
also the reason the the 24 valve gets such a bad rap is because of the vp44 injection pump and lift pump set up. they seem to fail early in some cases. as long as you dont get a 24 valve 53 block (1999-2001) the 24 valve can last as long as the 12 valve as long as you feed it i.p.'s and lift pumps.

one last thing the 12 valvers have alot less electronics. which we all know means easier for us to work on! mike

01-09-2007, 04:47 PM
The truck to have is a '98 quad cab, with the 12 valve.

01-10-2007, 11:35 PM
Long live the 12 valvers. Cheap and easy to get big power with, lots of room to work in there, no fuel problems. The 7100 pump and lift pump are rock solid. I guess it shows Im a fan of the 12valves. Oh, by the way..do check and I think you will find the KDP problem continues right into the 2001s [or some of them] They still had lots of timing covers to use up and didnt just change them when the 24 valves came out....The auto trannys were good if you change the torque convertor and valve body. Then you could get the power to the road without that slushy oem tc. I have a tranny built by DTT company and it shifts like a standard and will hold up to 600 hp and 800 lbs of torque. I havent got that much so it should last for a long while..Just got a few mods to the engine to pull a horse trailer.....

01-11-2007, 12:52 AM
Yeah I hear that, funcruise. Ain't nothing like having 600 horse to pull two or three.

01-27-2007, 09:19 PM
ok 81 here is the simple truth both have good and bad points KDP on the 12v and lift pump/injection pump on the 24v

the 12valve is more sought after because it is very easy to turn these motors up and get more hp and Trq from them. and at a very low cost.

but if you get emmision tested then you have to go back in and turn it back down ! the 12v is not computer controled the 24 valve is .

so it boils down to cheap affodable hot rodding

hope this helps. :)

Add your comment to this topic!