Adding Power, RPM, and Longevity to a ’98.5-’02 24-valve Cummins

While the 24-valve 5.9L Cummins found in ’98.5-’02 Dodge Rams can be a great workhorse engine, it leaves much to be desired in the way of reliability and horsepower potential. A failed lift pump tends to take out the electronic Bosch VP44 injection pump, the rotary style pump itself can’t fuel past 4,000 rpm, and as of late, ECM problems seem to be plaguing the ’98.5-’02 second-gens. After encountering the latter scenario—where the engine would spontaneously free-rev on occasion—the owner of this ’01 quad-cab ¾-ton, Thales (T.J.) Stewart, decided he’d had enough of the VP44 woes. But instead of trading the truck in on a newer common-rail, he elected to ditch the electronic rotary unit in favor of a P7100 (a.k.a. P-pump).


For both street and competition applications, P-pumping a 24-valve has long been thought of as the best of both worlds. It combines the extreme fueling capabilities of the P7100 with the higher-flowing 24-valve head. This not only brings a considerable amount of extra horsepower potential to the table, but it also brings with it the time-tested reliability of a mechanical, inline injection pump. For Stewart and countless other Cummins owners that’ve completed the swap, the P-pump is the best thing that ever happened to the 24-valve Cummins.

Thanks to Scheid Diesel, the process of hunting down all the parts needed for a P-pump swap is a thing of the past. Aside from the pump itself, the company’s P7100 conversion kit comes with everything you need to add a P-pump to your ’98.5-’02 24-valve. With one of Scheid’s bench-tested, 215hp 12mm pumps topping things off, this 16-year-old Dodge effectively went from under-powered to a force with which to be reckoned.

Scheid Diesel’s P7100 Conversion kit starts at just under $2,300 (minus a pump) and comes with virtually everything needed to perform the swap. The key items that make the swap seamless include a 12-valve gear housing, pump drive gear, stainless steel fuel lines (mild steel units are also available), throttle linkage, P-pump support bracket, injection pump oil feed line, camshaft sensor adapter, grid heater spacer, and all necessary gaskets, seals, and hardware.
P-pumping a 24-valve 5.9L Cummins requires complete access to the front cover and gear housing so that they can be removed. The catch is that the gear housing can’t be removed without first pulling the cam. This means everything in front of the engine has to be moved out of the way. Jake Bosie of Flynn’s Shop got started by unbolting the bumper, draining the coolant, removing the radiator, coolant overflow reservoir, intercooler, and vacuuming down the A/C system. After that, the upper radiator core support, fan, and fan shroud were pulled.
Next, the throttle bellcrank was unbolted and went by the wayside. Then Bosie removed the crankcase breather from the front cover, along with the factory oil catch can.
With the job requiring that the camshaft be pulled, Bosie dug into the valve train in order to gain access to the lifters. After making quick work of the rocker arms, the push tubes came out one at a time. We’ll note that Bosie arranged both the rocker arms and push tubes the same way they sat in the engine (so all wear points would remain the same when everything went back together).
After the factory injection lines were disconnected from both the head and VP44, Bosie capped off the feed tubes in the head and turned his attention toward the removal of the factory fuel filter reservoir. Although it had been retained in conjunction with the addition of an aftermarket lift pump years prior, it was finally time to say goodbye to the factory fuel filter reservoir.
Because the bolts that secure the front cover to the gear housing are of varying lengths, Bosie drew a diagram of the front cover on a piece of cardboard and placed each bolt on the diagram as it was removed from the front cover. This was done to help ease the reinstallation process later on.
With the front cover out of the way, Bosie broke the injection pump gear nut loose via an 11/16-inch socket. From there, a gear puller was employed to push the VP44’s tapered shaft out of the pump gear.
Once the injection pump gear was out, the VP44 was removed from the gear housing. Believe it or not, this was the truck’s original, 213,000-mile injection pump. Its one saving grace came in the form of being fed ample fuel supply (courtesy of an AirDog lift pump) for the majority of its life. It’s worth mentioning that injection shops (Scheid, in this case) will take VP44 pumps in as cores, which helps redeem a little bit of the money you spend on the conversion.
The next order of business saw Bosie remove the ECM from the tappet cover. While the ECM has to be retained (and relocated) in the conversion, it will no longer have anything to do with throttle position. Removal of the tappet cover followed soon after that (shown) in order to gain access to the lifters. As is common with age, the tappet cover gasket was cracked, corroded, and in the early stages of leaking oil.
In order to pull the camshaft out of the block, a set of homemade lifter holders (1/2-inch diameter wooden dowels) were installed in the push tube bores. The holders grip the lifters and suspend them above the cam, allowing the cam lobes to clear them when the cam is removed. Before the the cam was pulled, the lifter holders were zip tied in place, and then zip tied together in pairs.
As the camshaft was being pulled, Bosie was extremely careful not to damage any of the bearings. And, because having a lifter drop after the camshaft is removed means you’re pulling the oil pan, Bosie inserted a 1.5-inch diameter pipe in the cam’s bore as soon as the cam was out for added insurance.
With the cam removed, the remaining gear housing bolts (six bolts protruding into the oil pan and five T40 torx bolts) were removed and the gear housing itself was pulled off of the engine. Using a gasket scraper, followed with a grinder equipped with a Scotch-Brite pad, Bosie removed all left over material from the original gear housing gasket.
To ensure a perfect seal (and because removal of the gear housing typically damages part of the oil pan gasket), the guys at Flynn’s cut the front portion of a brand new Cummins oil pan gasket to fit under the 12-valve gear housing. We’ll note that the OEM gear housing gasket supplied in the kit was also modified in order to fit perfectly.
A combination of Indian Head Gasket Shellac (used on both sides of the new gear housing gasket) and Ultra Black silicone (used on the exposed portion of the oil pan) were applied next, followed by the new gear housing. Once in position on both alignment dowels, the gear housing was bolted in place (with the T40 torx bolts receiving Loc-Tite). Then it was time to reinstall the cam.
After carefully finagling the factory cam back into place, the crank-to-cam timing marks were lined up properly and the cam gear bolts were torqued to 18 ft-lb. While the cam was wiped clean before being reinstalled, we’ll note that no assembly lubricant was employed. Anytime you’re retaining the same cam and lifters, it’s best to not disturb their relationship. Additionally, foregoing the use of any assembly lube makes it easier to run the valves later on.
The lifter holders were then removed and the factory push tubes reinstalled, along with the valve bridges and rocker arms. After that, the stock front cover (which is reused) was cleaned up and fitted with a new crank seal, the supplied P-pump bracket was bolted to the block, and Scheid’s camshaft sensor adapter was installed in the new gear housing (shown). The factory camshaft sensor has to be retained in order for the truck’s tachometer to work.
Here you can see the modified throttle linkage Scheid includes in its P7100 conversion kit (top) vs. the factory 24-valve linkage (bottom). Essentially, Scheid makes the throttle position (APPS) linkage ball fit onto a linkage intended for a 12-valve engine.
Because the P7100 requires engine oil to lubricate the governor springs and weights (unlike the VP44, which is lubricated solely with diesel fuel), an external oil feed line has to be plumbed in. Scheid simplifies the process of adding an oil supply line by including a braided stainless steel line and the appropriate fittings in its kit. Here you can see the supplied elbow installed in the driver side of the block, along with one end of the braided line.
With the factory front cover reinstalled on the engine, Bosie installed this billet tappet cover from Scheid. The billet aluminum piece came with mounting hardware and seals via silicone, which does away with the failure-prone gasket used on the factory cover.
While the ECM obviously no longer has anything to do with the injection system, it has to be retained in order for the gauge cluster to work, along with other items such as the water temperature and oil pressure sensors. After measuring the length of the P-pump, Bosiefabbed up a bracket and relocated the ECM further toward the firewall along the driver side of the block. The one trade off in retaining the ECM yet no longer having it plugged into the VP44 means that a check engine light is permanently illuminated. Truck owners have three basic options: 1) live with the CEL always being on, 2) remove the bulb in the dash, or 3) break out the electrical tape and cover it up.
Starting with the highly desired 215hp P7100 (available on ’96-’98 model Dodge Rams with the NV4500 five-speed manual transmission), Scheid Diesel built us a pump capable of flowing 400cc worth of fuel—more than enough to clear 650-to-700-rwhp with this truck. The pump came preset with 19 degrees of timing advance (18 to 20 degrees is thought to be ideal for achieving respectable power with year-round drivability), features 4,000-rpm governor springs, and allows full fueling to 4,500 rpm. Also notice the fuel shut-off solenoid (arrow), which is what will be used to both stop and allow fuel flow to the P-pump. For the pull coil operation (used momentarily, for startup), Bosie tapped into the starter wire and utilized a heavy-duty, 70-amp relay. For the hold function, Bosie tied into a key-on source (a relay was used here as well).
As for the return fuel line leaving the P-pump, Bosie customized a portion of the VP44’s hard line, flared the end, and attached 5/16-inch fuel hose. The return line tees into the factory hard line leaving the back of the head near the firewall.


After one test fit, the return line on the P7100 was tweaked to clear the intake runner on the head and then the pump was installed in the gear housing. The pump mounts to the gear housing via four bolts, and gets reinforced thanks to a heavy-duty support bracket supplied in Scheid’s conversion kit. Prior to setting the pump in place, the pump bore of the gear housing was hit with a coating of fresh engine oil.
The pump gear nut was tightened twice when installing the P7100. The first sequence called for 11 lb-ft of torque (shown), followed by removal of the pump lock.
After one test fit, the return line on the P7100 was tweaked to clear the intake runner on the head and then the pump was installed in the gear housing. The pump mounts to the gear housing via four bolts, and gets reinforced thanks to a heavy-duty support bracket supplied in Scheid’s conversion kit. Prior to setting the pump in place, the pump bore of the gear housing was hit with a coating of fresh engine oil.
Once the pump lock was spun around, the pump gear could be torqued to spec. With a helping hand keeping the crank from turning, the pump gear nut was tightened to 144 ft-lbs.
With the P-pump mounted, the pre-clamped 0.093-inch stainless steel injection lines were installed. In order for the intake elbow to clear the new injection lines, Scheid supplies a 1-inch billet grid heater spacer. After the lines were tightened up, Bosie went ahead and ran the valves, followed by reinstalling the valve cover.
Next, Bosie connected the ½-inch fuel supply hose to the P7100. Somewhere between 45 to 50 psi of supply pressure will be fed to the P-pump, courtesy of a 220-gph Titanium series FASS fuel system.
The aforementioned FASS system was mounted up under the bed on the driver side of the truck. Capable of supporting 900-to-1,200 hp, a fuel system this serious is good insurance for the P7100 it’s feeding.
Unrestricted fuel flow begins at the tank thanks to this sump kit from Deviant Race Parts. Between this sump and the 220-gph FASS system being on board, the P7100 is guaranteed to receive plenty of fuel supply, and diesel that’s been filtered down to 3 microns.


Deviant Race Parts

FASS Diesel Fuel Systems

Flynn’s Shop

Scheid Diesel

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