There are some who have changed the VP44 injection pump to a P-Pump and i thot i read someplace where someone even installed a pump from an early Cummins,89-1993 on to a 24 v - VP 44. Is there or could someone who has done the conversions please post the parts and procedure to do the swap,Im inclined to think that if one could put the older rotery pump from 89-93 on one would get way better milage. I knew a guy who had a new one in 1989 (rotery pump) and he got 28 MPG consistently. Im not worried about power just mileage, but the p-pump and the rotery pump both had the capability (mechanical adjustment ) to boost power. 2001-101000 miles,3 lift pumps,2 injector pumps so far,warrenty is done so time to make big change.

 

This has been discussed many times. As far as economy goes you will never get your money back out of this conversion. The set up is more for max power and it is hard to tune. You are better off getting a good reman vp44 and a lift pump upgrade.

 

The VP44s are junk,looks like life of them is anything from 0 to 60,000 miles, lift pump no better, life of the rotery or the P-pump is virtually endless, p-pump maybe $400, VP44 1200 and up,electric lift pump is $150 and up, rotery pump less than $400, lift pump on 89 to 98.5 is mecanical ,cost maybe $50 bucks at most,lasts a liftime,i kno a guy with a 1990 (rotery pump) with a little over a million miles on it with original injection and lift pump, cant beat that, VP44 is absolute junk,Chrysler should be made to either fix this pump so they last or convert everyone back to the p-pump.

 

Dc was forced to switch to the cleaner burning computerized pump by congress's strict emissions standard. The last thing an auto co. wants to do is redesign a good running system to dissatisfy their customers. If you want a p-pump or ve engine for better milage and durability go buy an older truck with low miles, they'res still alot on ebay. Maybe you'll get a million miles out of it

 

"go buy an older truck with low miles, they'res still alot on ebay. Maybe you'll get a million miles out of it "

But i dont want an older truck,i want mine with a decent pump,is that to much to ask .

 

I think there is a fellow in Dallas who did the conversion and ever though everone or it seemed that way suggested not to he did so and as far as I have read it is still going. He did a how to text. I will try to find it. That is a p7100 to a 24 valve. From what I have read the pop pressure is half the battle on the conversion. You could need 40 psi lift pump to feed the p7100 , 275 or large injectors. I think it was gunracer who did the conversion but If only I could find my notes.
I think a lot of the reason the early 12 got good mileage is a combination of camshaft timing , turbo exhaust housing size and pump timing and fuel rate, injector pop off settings. These things work together to give good mileage, I forgot to add the 24 valve has a different swirl ratio than the 12 valve
I have thought that a 24 valve truck with a set of Mach 1.6 injectors, F1 camshaft and mechanical pump, a box that gave some timing, cool air, 62 phat shaft or some things close to that, a 4 inch exhaust, 3.54 gears and a 6 speed would give good mileage. Or at least next year I plan on finding out. good luck Jim

 

Thanks jimk, good info.

 

travis is a friend of mine, he did the conversion, not me. i just pushed him to do it. i will see if i can dig up the thread

 

J.R adkins has done a few I'm sure he would tell you everything you needed to know. 317 281 3130.
DM01

 

https://www.dieseltruckresource.com/...ump+conversion

 

Mine is done, just waiting for the pump to come back from the pump shop( bad seal somewhere). Other than the bad seal that gave us trouble while trying to get it to run we would have had the thing runnin down the road within two days. It started and ran with both stock and big injectors and most of the fuel going into the oil pan through the bad seal. Once the pump comes back I will give some more results