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Discussion Starter #1
I have heard that it is possible to take a computer controlled 24V and switch the inj. pump to one from an early mech. engine and it will do away with the computer. In my mind it seems it would work, but in real life am is this just like trying to start a fire with wet matches or what?
 

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It has been done and more times than you would believe, however their is much more to it than just installing a mechanical pump and go. It is an expensive swap and requires more parts than you realize. More likely than not you can buy a 12valve and be time and money ahead. Now if you want to have something a little different and cost is not a large factor than go for it. Their is a lot of fine tunning once you have it all together.
 

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You'll want to keep the ECM on the engine as it controls the grid heaters, and if still in the original vehicle, relays info to the dash for gauges. But once you get the mech pump in there, it pretty well is ready to go.

But like was said, in the end, it would be cheaper to just get a 12v instead, as you could sell the 24v for roughly the same price and break even. Electrical is more complicated swapping engines that it would be to just swap pumps though.
 

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cheap may not be your concern.

If you want to do it.

Find a blown up 12v with inline p7100 pump because you will need
the timing cover and front gear set. we picked one a blown 12v for $400 recently for this exact conversion, they range from 400-1200 depending on who you are talking to. it was a 175 hp pump but that wasnt a big issue, we did delivery valves ect so there was some money in the pump.

We bought a custom cam from F1racing Don M it has the lobe eccentric for the piston style lift pump that 12v's use. otherwise alot of other guys like to use the FASS system and not mess with a mechanical lift pump.

lift pump and cam $140 + $700 or you can fore-go the cam and lift pump and just use the FASS if you already have it

Gasket kit $200

The injector pop off pressure level is a little to high for the p7100. it will work but at lower rpms it cackles a little. we ordered new injectors from Don M also level 3 sticks with the lower pop off pressure for $900 but this was 4 months after the conversion it ran fine without changing em but the stock injectors werent enough fuel for the twins anyways.

Custom fuel lines can be had from Schleids diesel. IIRC it was around 350-400 for those.


its a couple thousand when you are done if you add the cam ect. ive seen it done by just buying the blown 12v and using the existing FASS on a 24v truck for as little as $900. so yes it can be done. the tuning isnt much of an issue its just like a 12v once you get the pump on there. find TDC. put a dial indicator on the 1 injector port on the pump set timing by the lift of the plunger and by physical TDC and you are good to go.

:beer:

Ours didnt have grid heaters and the 2001/2002's cruise is run electronically so you will loose that feature.
 

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Discussion Starter #5
Just another random thought I had.
Lets say you can get a 6.7 for next to nothing. Would it be possible to take all the emissions BS off of it and then put a mech pump on it?
(no I didnt find one, It was just a random thought :tongue:)
 

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yes but as was said before alot involved. timing cover changes, timing gear set. potential cam swap... do able but some effort is required
 

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I've read some threads on the 6.7, blocks are different. Even the CR blocks are different, a different timing case has to be made to p-pump them, the 12v case won't bolt up to it. There is mech pumps on 6.7's in farm/industrial equipment, but they are all rear geartrain. The only front geartrain 6.7 is for the dodge, or so I've read. Theres more on this at Competition Diesel.
 

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Sooo... what would the advantage of a 24 Valve be over a 12 valve if they are both running p7100 pumps. don't start talking $$ on me, I'm talking strictly technical here. Better performance (hp, mpg?), smoother runnning, more dependable?

Also I'm a little foggy on what is needed to be 110% computer free w/ a 24valve.

The reason for all my inquiry is that ever since I heard of a 24v be able to runn computer free I have been second guessing my 4bt swap and thinking of doing a mechanical 24v instead. My 2 reasons for this are that it would be a little more unique and that I could get more power from it without pushing the perverbial envelope.

I'm also in the dark to whether or not I can use the same adapter for a 24v as a 12v.

Any and all feed back is welcome and appreciated.
 

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You will have to have the timing cover and gear set as well as the pump and a set of fuel lines....custom. The transmission adapter for either should work. With the 24V you can likely make more power at higher RPM than with a 12....more air stands to reason this way. However, I am far from an expert on that.
 

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turbos10, thanks for the reply...
Anyone else, let me know what you know!
 

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The 6.7 and same gen 4.5's are different castings. They are similiar to the older engines, but the front of the blocks are very different. Especially the rear gear engines.

From the technical standpoint, the 4V/cylinder engines have a slight advantage by flowing a bit more than an unported 2v head and having the injectors centered in the piston. The gains are negligible. Do it for the cool factor because you can't justify it by any real power or efficiency gain. A ported 12V head will flow more than you can ever need.

12V's are cheaper, more plentiful and easier to work on. The 24V valve cover isn't nearly as easy to get off in tight places as the 12 valve ones are.

There are also 16V 4BT's, even mechanical ones if you want different.
 

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Great info. Another thing I am wondering about is if the 4v/cylinder motors run smoother than the 2v/cylinder motors? I know that in stock form the 24v is smoother than a 12v, but does that have do with the computer or the 4v/cylinder?
Also, where do you find a 16v 4bt?
 

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4V 4bt

There is a QSB4.5-XT, basically a four cylinder version of the QSB6.7-XT. The basics are ratings of up to 160 hp, 460 Ftlb uprateable. You can get lots of information and a brochure at cummins.com .
 

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I've dug though all the stuff on the cummins site. What I am wondering in where to find one in it's original application (ex: 4bt in a step van). That way I could find one at a good price.
 

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In building a mechanical 24v would it be possible to use injectors from an industrial 24v? If I'm not mistaken they industrial motors came with a were all mechanical and I would they that they would have a lower pop off pressure. I also wonder if the spray pattern would be compatible with automotive pistons.
 
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