Is it possiable to put 24v heads on a originaly 12v motor?, then possiably twins? What would be the most powerful combonation? Or just doing the pump conversion to a 24v?

 

The 12 valve and 24 valve engines use different pistons with combustion chamber differences, so the heads will not interchange without a piston swap.

I am not sure what you are trying to accomplish, but if it is more power for your 12 valve there are a number of modifications that will take it way beyond where any 24 valve would dare tread. Even Cummins had to derate the 370 marine engine when it went to the 24 valve design, and now all you can get is 330 horses.

If you want power in a 12 valve, you need to sit down with a vendor and make a plan, then approach that plan in affordable increments.

If you have an automatic, you need a different plan than with a 5 speed, and if you tow a heavy RV then you have to consider options that are different than running an empty truck.

Go to one of the sites like Piers diesel research (www.piersdiesel.com) and look through the price list for your truck to get an idea of what is available. If you have an automatic, read the article (click on the top bar section for articles) on the automatic transmission, and then spend some time on DTT's website reading their transmission technical articles. www.dieseltrans.com

With all that background stuff out of the way, if you want a lot more horses, you will need to consider the following:
-A first generation 12 valve head that is ported, polished, O-ringed, and the obstructions cut from @1 intake and exhaust. A first gen head is thicker and will handle the pressures better than the second gen head.
-A zero or custom fuel plate from TST.
-A set of 370 delivery valves and 370 injectors (make sure the head is machined for the size injectors you order). There are other aftermarket delivery valves and injectors, it is only a matter of money.
-A top of the line aftermarket copper headgasket and quality O-rings, and a full set of head studs to replace the weak OEM headbolts.
-An aftermarket camshaft.
-An HX40 that has the exhaust side modified to spin up on this engine, and a full 4" downpipe to connect to your 4" exhaust. Or, use one of the other aftermarket high flow turbos, again dollar to performance is the key.
-An ATS exhaust manifold - this should be required on all Cummins engines, period.
-Set your timing anywher from 17 to 21 degrees on an empty truck. 13.5-15.5 on a truck that pulls a reasonably heavy trailer.
-Install the light spring from the TST AFC kit.
-Install the 3,000 rpm GSK, and torque the counterweights up 3 clicks beyond the OEM setting (count them when you take off the old ones). That will give you about 3250 before it defuels. You can go higher, or even install the 4000 GSK, but after 3750 the stock engine starts to unglue and can be dangerous!
-For 5 speeds. Make a phone call to Southbend Clutch and obtain the best you can afford, then figure it will only last a few weeks. Then, call Southbend again and get the dual plate version with a balanced flywheel and the heavy input shaft for the transmission.
-For automatics. A phone call to DTT or Goerend Brothers for a custom built transmission and torque converter. There are others, but I know these work. If you have an automatic, be careful about changes to the AFC spring until you work with the transmission vendor to know what it will handle.

The above will take you to right around 550-600 real horses that will last, give or take a few.

If you want even more power, go to Piers or one of the other guys and pick up a dual turbo setup. Each is custom designed for the application, and there is no one size fits all here, so work with the provider of the above parts to get a system designed for you.

At this juncture you will be ready for a custom built injection pump to bring your power up any higher. Again, the vendor you choose will be able to help you find what fits, do not try a mix and match program or you will be throwing your money away and starting over on various parts.

There are a few other things to consider. You want a dense fuel charge without air, so consider installation of a FASS to replace the OEM lift pump. Air intake is an issue, so think about installing the turbo outlet from a commercial truck to get a matched size hose from the turbo to the intercooler. Then use the intercooler from the late model HO. Pick up the inlet elbow for a 190 horse truck engine, and then use the larger hose that matches the intercooler on that side too. You will then be shopping for hoses at Cummins or Detroit, not Dodge. Get the largest freeflowing air filter and inlet pipe you can find. Install 1/2 inch fuel feed lines and 3/8 fuel return lines.

Getting the power is pretty easy, keeping it stuck to the road or from ungluing parts of the powertrain is the difficult part. Also, keep in mind that you can get the power, but it will be for short periods of time, as the radiator on these rigs is way too small to shed the heat that all the burning fuel will generate. But, the good thing is that the power is only there when you need it, the rest of the time the engine is really timid and quite streetworthy.

Have fun.

 

I just bought a new SB clutch, I just a new fully spinned mainshaft 5 speed. I proably won't ever haul with my truck. I will end up spending so much money on mods, that I wont be able to afford anything else. I am working on trading in my TST plate for a #10 right now, and building a BAHF to help out airflow. Right now, I am pull about 31psi with the stock turbo. I thinking I want to jump to twins, I want to miminize lag with boost. One question? If I push enough fuel, will that lag be less then stock? and alot more boost?

 

Add bigger valve to the 12v head. the convert 24v to 12v but i have not heard of doing what you are talking about.

 

The first thing to do is to time your truck. I suspect you have slipped timing, all of the P pumped Cummins engines that have not been retimed since they left the factory will be running low timing somewhere around 9 degrees of even less. That is because Cummins did not use enough torque on the nut on the pump shaft, and it slips.

Good timing will result in a huge increase in engine response and a significant decrease in turbo lag.

Dual turbos will lag more than a single turbo that is properly sized and set up for the engine. So, unless you have enough engine modifications to justify the increased air pressure and flow, I would not even consider this option.

The automatic transmissioned truck has smaller delivery valves and a tighter spring in the AFC to keep it from developing too much torque too early for the transmission pump to have built up enough line pressure to hold the starting torque. I would avoid doing anything, outside of proper timing and a GSK kit, to increase your low end snap until you sort out a transmission package that will not break. Also, do not wait for your transmission to break to fix it. If the torque converter clutch fails, you have to also replace your radiator and all the cooling lines (they are nearly impossible to clean of the particles), or you will blow the new transmission right after it is installed.

If you want a lot more felt power, do the timing, then pick up the 3,000 GSK and install it with the new fuel plate.

I would not go with the #10 but would stick with TST's recommendation for the #8 or the #6 on a diesel with a stock automatic from 96. The #10 can have difficulties with the governor properly functioning, unless you swap your delivery valves to the same as those used on the 215 horse engine, you also need to have a pump shop crank in 6 degrees fuel lead in the pump itself, to make the 10 work well.

 

I does seem to have some lag until I get up in RPMs, it will drag to some what between 10 and 30 psi, I will go to 32 psi, but my EGTs never really get hot. I think I am a good candidate for injectors. I just found a shop about 80 miles away who can work on my pump. 4 gear is my highest gear, I can't get EGT's to go over 900 right now. I stomped on it for a good mile, It was floored the whole time, and it just stayed at 3000rpm and didn't 900degrees, It didn't take much to get there, but I was having trouble with a chevy truck because of lag until I hit 2100rpm, it any of this normal?

 

The lag you describe is not normal, you should start pulling really hard at 1500 rpms. Get some kid's bubble blowing soap and dope up all your air tubes and the intercooler, start the engine and look for bubbles.

Also, there is a fitting at the back of the AFC housing that routes the air pressure line from the plenum to the AFC and on to the wastegate on the turbo. Inside the back connector is a little rubber gasket, I suspect it is gone and letting your air pressure bleed off and keeping the AFC from pulling back like it should.

I would also dump the #12 plate and go back to a stock plate and slide it forward to within about 1/16th of an inch of the full travel, it will give you about 40 more horses than the #12. When you reinstall the AFC housing, push it all the way forward on its adjustments, too. Also, check your fuel shutoff solenoid travel and adjustment to be sure it is opening all the way. Sometimes the rod will get a bit bent and bind a bit and keep it from opening all the way.

The ability to get to 3000 rpm tells me someone has cranked the flyweight screws on the governor down about 3 clicks. Otherwise you would be defueling at around 2650 or so.

 

Has any one ever done a 24 valve to 12 conversion.
I am going to buy a 2001 or 2 with a 6 speed and 4 wheel brakes. I have heard of lift pump problems and injection pump problems. I have thought that I could buy a good 215 engine and install it in the 24 vavle truck if I have very many problems. That would be cheaper than a p pump conversion . I dont wont a hot rod or a fuel hog... Just a good truck. I would like to know if that change is possible( 24 to 12 ) I would think that I could sell the 24 valve engine. Does any one know what would be involved? thanks Jim

 

Thats quite an involved project and will be more work than you suspect. Im not sure how you would make the cruise control work.....does anyone have any ideas on that?

 

I have cruise control in my 1996, so that shouldn't be a problem. You could just get the parts you need that is compatiable wiht that 12 that you are going to us. Like if you get a 12v from a 96, use those the CC parts from a 1996 or 1997, 1995 etc. I dont see why you couldn't put a 12v in a 2001. The ECU is no longer any good. Won't work with the 12v, you woun't need it. The computer in the 12v does control alot of other things though, so you mite just want to just a swap with that too. It seems like alot of work and money to me. I think it would just be easier to get a early 98 truck, that seems to be the best year as far as nice interiors go, the rear doors and such. If its the better brakes you are after, you could just upgrade the rear drums to disc. That would make a big differnce there, and it would be alot cheaper still then trying to put a 12v into a 2001.

 

Obviously, you dont know how rare a 98 12V quad cab is......

In a 12V cc is controlled by the vacume pump and on a 24V its controlled by the pcm/ecm

 

I will have to ask around on how to make that work. I had heard that it had been done up in Canada. I am just not interisted in having fuel pump problems. I have seen 24 valve engine that had a p pump conversion for sale. The whole idea is to have a trouble free as possible engine. thanks for any ideas Jim

 

I think it would be easy to do the swap. Proably alot easier then trying to go back the other way, 24v into a 12v truck (which would be stupid) I mean, tear out all the 24v stuff, get a good 12v. Hardly anything to hook up. Just drop it in. You could go with aftermarker cruise control. I saw and artical in a magazine that some one did it on an old chevy tri-five, and it worked great. but then again, it wouldn't be with your steering wheel. I think the cruise control would be very hard to work out. But you could just wire in the 12v cuise control with the switches. I am sure there is a vacume souce for the system to work. You would just have to splice in a 12v system, and use the 24v switches in the truck. The buttons are standard. Tell me if this makes sense.

 

I thing that you are right. I have installed aftermarket cruse control before when I was a line mechanic to GM a long time ago.
thanks for your help Jim

 

I think they would both work well. Wiring in the older truck cruise control would be pertty tough, but I was reading instructions on an Audiovox system, it still included vacume control throttle. So I dont think that wouldn't be much different then using the older truck system. And you wouldn't have the steering mounted controls with the aftermarket system. The Audiovox system is has a switch box with the standard cruise control buttons.