Engine/Transmission (1994 - 1998) 24 valve head

[WAYNE]

Has anyone ever put a 24 valve head on a 12 valve truck? Is this possible , if so would the computer or anything else have to be swapped. Thanks for any info.

 

[Reb.B]

oaky, this is how it goes, . . if u want a 24v head on a 12v block, u need to, : change the pistons to a 24v piston, grind on the head so there is clearance between the head and the studs for mounting the p-pump, the cam should be changed for the 24v grind on the 12 cam. Usually this is done on a 1st gen cam because it has more meat on it. need to put a 90 degree fitting on the oil feed to the inj. pump, need injection lines from Schied diesel, need another spacer block (hog out grid heater) between the manifold cross over and the original grid heater, i think thats it, may be more, can't remember right now.

 

[Cooker]

You might try a search as this has been brought up before. If I remember correctly, you are better off porting a 12v head head than messing around with putting on a 24v head.

 

[Reb.B]

depends how u look at it. U can flow more out of the 24v head, . . but it is much cheaper to port and run bigger valves in the 12v head. If u are serious about this give Piers a call and get a head from him. Piers has flowed so much out of the 24v heads, that the ported ATS manifolds are too restricted.

 

[WAYNE]

Thanks for all the reply's , you guys posess a wealth of knowledge.

 

[F8LDOSE]

Reb B, I've talked to Al at PDR and was told that a stage 3 12 valve head will flow 3% better than a stage 3 24 valve head. Stock for stock the 24 valve is better , but port a 12 valve head and use bigger exhaust valves and you have something.

 

[Reb.B]

hey hufnpuf, call back and next time talk to PIERS he will tell u that the 24v flows more. who is right, i don't know, but i'm not going to worry about it. Depends who u ask, but Piers has never led me wrong before. Take it for whats its worth, i have not ported either one and i have not flow tested either one. What Al may have left out was a port 12v head with large valves vs. a ported 24v head with stock valves. Not sure through, Al know a guy in the bay area that does 24v race heads.

 

[F8LDOSE]

he said not much room to put bigger valves in a 24 valve head? I'm not sure I'm never even looked at one first hand. Also very pricey to do 24 valve head, 700 bucks for just springs? ouch! Titanium valves , retainers and good springs don't even cost that much. For the poor man like me, i'd stick with the 12 valve head.

 

[Reb.B]

the 12v is cheaper, like i said, but there IS room for bigger valves on the 24V. The valves aren't too expensive, but there are twice as many valves so this raises the price. It all what u are doing. If ya just want to go fast, then ya, go with the 12V, but if your eyes are out to conquer the world, then u go with the 24v. U can get the spring pressures pretty good on the 24v head by setting the hardened saets where u want them and shimming the springs, but Piers says the problem is with spring bind. Don't worry, the 12v were the same way, . . in a short while 24v will be cheapper to buld than they are now. Like i have always said, . . its all it what u want to do. I'm gonna run both, put them on a dyno, and go from there.

 

[drees1]

While we are on this subject, what about the added mass of the 24 valve over head? Is the same top rpm (to valve float) available from 24 valve as 12 valve? What is required on the valve train to run at max rpm? What is max rpm sustained in racing so far, 12 valve, 24 valve?? Just curious.



Doug Rees

 

[Reb.B]

well more air flow gives us more potential for rpm HP, but the problem is valve spring bind and strength. The 12v valves will rev higher because this problem hasn't be taken care of in the 24v's yet, and i say again, YET, lol. this information came from PIERS. i would like to spin the rpm's in my drag race truck. I'm going with a 12v first in that truck. supposily the 24'v will float at 3600. i'm gonna shim my 24v sled pull truck, but i won't address the coil bind problem yet, ... next motor i guess.