FU­EL­ING AROUND

CUM­MINS 12-VALVE FUEL SYS­TEM & PUMP MODS

Ultimate Diesel Builder's Guide - - Contents - Text / Pho­tog­ra­phy: Chris Tobin

Fuel Sys­tem and Pump Mod­i­fi­ca­tions

Af­ter some sim­ple pre­ven­ta­tive main­te­nance and in­stalling a per­for­mance-built Fire­punk Diesel Per­for­mance trans­mis­sion in this oth­er­wise stock 1997 Dodge Ram 2500 to han­dle more ag­gres­sive per­for­mance up­grades it was time to re­ally turn up the wick on the sleeper and make the "P-paw" truck be­gin to live up to its 12-valve Cum­mins po­ten­tial. Owner Ryan Bean of Beans Diesel Per­for­mance in Wood­bury, Ten­nessee, started the process by in­stalling a set of ARP head studs, and then per­formed some rel­a­tively easy in­jec­tion pump mod­i­fi­ca­tions to squeeze more power out of the me­chan­i­cally fuel-in­jected Cum­mins.

Get­ting more fuel into a diesel en­gine is the key to mak­ing more power and the 12-valve Cum­mins en­gine is no dif­fer­ent. Within rea­son, if we give it more fuel, it will make more power with more air down the road for im­proved throt­tle re­sponse and lower EGTS. To pro­vide the me­chan­i­cal P-pump on the Cum­mins en­gine plenty of clean diesel fuel, Bean in­stalled one of their orig­i­nal sin­gle-bolt fuel tank sumps along with an Air­dog II fuel pump and fil­ter sys­tem.

Bean brought the truck down to Chat­tanooga, Ten­nessee, to run it on the Dyno Proven chas­sis dyno be­fore and af­ter the pump mod­i­fi­ca­tions. Be­fore he tweaked the in­jec­tion pump, he in­stalled a set of ARP head studs to keep the head sealed to the block, a pro­ce­dure he rec­om­mends be­fore try­ing to squeeze more power out of the en­gine.

In­stalling head studs on the 12-valve Cum­mins en­gine re­quires ma­chin­ing the rocker arm pedestals to pro­vide proper clear­ance be­tween the stud’s 12-point nut and washer and the valve cover. For­tu­nately, Dyno Proven has a full ma­chine shop on the premises so Bean was able to pull and dis­as­sem­ble the rocker arm pedestals and handed them off to be milled in the ma­chine shop rather than hav­ing to ship them off or take them to an­other fa­cil­ity.

Typ­i­cally, when in­stalling head studs on an en­gine that’s run­ning and still in the truck, Bean re­places one head bolt with a stud one at a time. How­ever, with the 12-valve Cum­mins and the need to ma­chine the rocker pedestals, he re­moved all of the pedestals to have them ma­chined and then re­in­stalled them be­fore mov­ing on to the rest of the bolts and studs one at a time. Be sure to fol­low the rec­om­mended torque pro­ce­dure and use the supplied ARP Ul­tra-torque fas­tener assem­bly lu­bri­cant to get ac­cu­rate torque mea­sure­ments. And, since the rocker arms and pedestals are re­moved and re­in­stalled, do not for­get to read­just the valve lash. Bean uses .010-inch for the in­take valves and .020-inch for the ex­haust valves.

To im­prove air­flow into the cylin­der head, Bean in­stalled a ma­chined alu­minum plate and spacer to re­place the fac­tory

cast alu­minum in­take plate and in­te­grated grid heater. He also drilled and tapped the ex­haust man­i­fold for an EGT probe and in­stalled an Edge CTS to mon­i­tor the en­gine vi­tals, in­clud­ing trans­mis­sion tem­per­a­ture and boost with the add-on Edge har­ness mod­ules.

Af­ter Bean com­pleted the head stud in­stal­la­tion and ad­justed the valve lash, they strapped the truck to the Dyno Dy­nam­ics chas­sis dyno and he turned his at­ten­tion to the in­jec­tion pump. The first pro­ce­dure was to in­stall a Dynomite Diesel Per­for­mance fuel plate kit to in­crease fuel out­put. With the fuel plate in­stalled in the truck, he picked up about 100 horse­power and about 125 lb/ft of torque at the wheels, nearly dou­bling the available power and torque orig­i­nally mea­sured on the truck.

Then he ad­vanced the in­jec­tion pump tim­ing to 21 de­grees, which is a lot of tim­ing. Bean does not rec­om­mend go­ing past 19 de­grees ad­vanced un­less you in­stall head studs. The tim­ing ad­vance only pro­vided a few ad­di­tional horses so un­less the tim­ing is sus­pected to be off on your truck or you’re re­ally scram­bling to squeeze that ex­tra lit­tle bit of power out of the en­gine, it’s some­thing prob­a­bly best left to the pros rather than Diy­ers in the garage.

New gover­nor springs from Dynomite Diesel Per­for­mance were the next pump up­grade Bean in­stalled. The spring in­stal­la­tion re­quires ro­tat­ing the en­gine over by hand un­til the springs are aligned with a small open­ing in the side of the pump and re­plac­ing the springs, then ro­tat­ing it over again to re­place the springs on the other side of the in­ter­nal assem­bly.

The gover­nor springs con­trol how high the truck will be able to rev, as can be seen by the dyno graphs. Even with the previous mod­i­fi­ca­tions, power and torque fall off steeply af­ter 2,300 rpm, which doesn't give a lot of op­er­at­ing rpm range to work with. With the new springs in­stalled, the en­gine revved freely to nearly 3,800 rpm, ex­tend­ing the power band and giv­ing the en­gine a much larger op­er­at­ing range while also in­creas­ing the peak

horse­power slightly. At 2,800 rpm, be­fore the new DDP gover­nor springs, the en­gine made about 75 horse­power and about 150 lb-ft of torque, but af­ter the spring in­stall the en­gine is still mak­ing nearly 275 horse­power and over 500 lb-ft of torque at 2,800 rpm!

To fin­ish things up, Bean in­stalled the DDP boost-fit­ting el­bow on the turbo out­let. The new fit­ting has a smaller ori­fice to al­low more boost be­fore the waste­gate opens and help pre­vent it from open­ing pre­ma­turely. Peak power only in­creased by about nine horse­power but peak torque grew by close to 75 lb-ft with a peak of nearly 675 lb-ft of torque.

In­stalling the fit­ting took only a few min­utes and pro­vided ex­cel­lent in­creases in power and torque, es­pe­cially down low in the rpm range.

In­clud­ing the head studs and ma­chine work, the in­stal­la­tion took a full day. Add in some time for the Edge CTS sen­sors, and Air­dog fuel pump/fil­ter sys­tem and sump, and you can fill a solid week­end with wrench­ing on your truck, maybe even longer if you have to wait for a ma­chine shop. As usual, prac­tice safe shop tech­niques, and if you doubt your skills or the tech­niques used, have your lo­cal diesel per­for­mance shop in­stall your up­grades for you. UDBG

2 BDP even sup­plies their sump with a hole saw so you don't have to fid­dle around look­ing for the cor­rect size. Af­ter drain­ing the tank, Ryan Bean drills the hole for the sump. 4 As typ­i­cal with an Air­dog fuel pump/fil­ter sys­tem, Bean chose to mount it on

1 The sin­gle-bolt fuel sump from Beans Diesel Per­for­mance mounts with a sin­gle bolt and seals to the bot­tom of the fuel tank with a high-qual­ity O-ring. 3 Then it’s sim­ply a mat­ter of putting the cross brace in the tank and mount­ing the sump. Clean­ing the

5 To pre­vent the in­creased per­for­mance and fuel from lift­ing the 12-valve head and blow­ing the head gas­ket, Bean opted to in­stall a set of ARP head studs. The complete kit in­cludes the various lengths needed for the en­gine and even in­cludes the smaller se

6 Of course, each of the valve covers needs to be re­moved to in­stall the studs, but with the 12-valve Cum­mins, the rocker arm pedestals must also be re­moved and ma­chined for the studs and nuts to prop­erly clear the valve covers. 7 Bean uses a set of snap-

11 While the in­take man­i­fold was off the truck and the rocker pedestals were be­ing ma­chined, Bean drilled and tapped it for the EAS boost sen­sor. 12 He also in­stalled the tem­per­a­ture sender in the B&M trans­mis­sion pan. By act­ing quickly, you can re­move th

8 Brian Ple­mons is one of the ma­chin­ists at Dyno Proven; he was able to quickly mill the re­quired step into each of the six rocker pedestals.

10 The In­sight CTS (or new CTS2 from Edge Prod­ucts can be used for gauges even on a non-com­puter con­trolled truck like this 12-valve Cum­mins thanks to the EAS har­nesses and con­nec­tors. We in­stalled senders for trans­mis­sion tem­per­a­ture, boost and EGT.

9 As shown here, the re­quired 1.100-inch wide cut is 0.200 inch deep to pro­vide proper stud and nut clear­ance in­side the stock valve covers. Be sure that your ma­chin­ist cuts the top of the rocker on the side for the 12mm stud, not the 8mm bolt.

13 The Edge EAS har­nesses are truly plug and play with con­nec­tions for various senders and ex­pand­abil­ity built into the pro­pri­etary har­ness plugs. 14 Af­ter the pedestals were ma­chined, Bean re­assem­bled the rocker arms and in­stalled the rocker as­sem­blies o

17 But­ton­ing up the top end of the en­gine af­ter the valve lash is set is sim­ply the re­verse of dis­as­sem­bly, in­stalling the fuel lines, valve covers and such in the re­verse or­der they were re­moved. 18 To in­stall the EGT probe for the Edge EAS sen­sors, Bean

19/20 The har­nesses for the Edge In­sight CTS were routed up the A-pil­lar then bean mounted it to the top of the dash us­ing an alu­minum bracket rather than us­ing the supplied suc­tion-cup wind­shield mount. In ad­di­tion to the cus­tom back­ground graph­ics the I

16 To help with air­flow, Bean re­placed the cast alu­minum in­take plate and its in­te­grated grid heater with a ma­chined alu­minum plate and spacer from Dyno Proven.

25 Bean uses a cal­i­brated Snap-on Blue-point tool to mea­sure the de­liv­ery valve po­si­tion to ad­vance the pump tim­ing to 21 de­grees ad­vanced be­fore lock­ing the pump gear back into place and torquing the mount­ing bolt. If you don’t have the spe­cialty tools n

23 The plate sim­ply drops into the top of the pump hous­ing and can be ad­justed front to rear for fuel de­liv­ery. The fur­ther forward the plate, the more fuel the pump will de­liver. Of course, Bean in­stalled his plate in the full forward po­si­tion as noted i

27/28 The DDP boost fit­ting (on right) re­places the fac­tory fit­ting and uses a smaller ori­fice to con­trol the boost read by the waste­gate and pre­vent pre­ma­ture open­ing al­low­ing the en­gine to build more boost and power. It is lo­cated on the front of the tu

21 Bean re­moves the AFC hous­ing from the rear of the pump to start the in­jec­tion pump mod­i­fi­ca­tions. If your truck is stock and un­mod­i­fied, you will prob­a­bly have to use a punch to re­move the anti-tam­per bolt. 22 With the AFC hous­ing re­moved, the fuel pla

24 While the AFC hous­ing is out of the truck, you can also re­place the AFC spring, which con­trols off-boost fu­el­ing and helps to give good throt­tle re­sponse with­out smok­ing out in­ter­sec­tions each time you take off.

31 The DDP gover­nor spring kit re­ally woke up the en­gine, pro­vid­ing a lit­tle bump in peak power along with an ad­di­tional 1,000 rpm of us­able power to broaden the power band of the 12-valve Cum­mins and make the truck much more en­joy­able to drive.

32 The sim­ple boost fit­ting from DDP pro­vided a good bump in power and torque es­pe­cially in the lower por­tion of the power band.

30 In­stalling the DDP fuel plate gave a good boost in both horse­power and torque, but the power band is still pretty nar­row.

29 The base­line dyno mea­sure­ments are noth­ing to write home about, with pretty weak horse­power and torque.

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