HOT ROD to the Res­cue

The Mag­num Heads on Brian Fer­gu­son’s 1997 5.9L Dodge Ram Truck Over­heated.

Hot Rod - - Contents - Mar­lan Davis Norm Bran­des, Brian Fer­gu­son, and Dave Hughes

THE COMBO

When the 5.9L (360ci) Mag­num EFI en­gine in Brian Fer­gu­son’s 1997 Dodge Ram 1500 Sport 4x4 truck reached the end of its tether at 130,000 miles, it was com­pletely re­built. The up­per end was en­hanced with Hughes En­gine parts, in­clud­ing its EQ iron Ram HD Mag­num heads with bronze guides, a hy­drauli­croller RV cam (0.523/0.533-inch valve lift with 1.6:1 rock­ers, 208/214 de­grees du­ra­tion at 0.050, 114 lobe-sep­a­ra­tion an­gle), and a sin­gle-plane EFI in­take man­i­fold. “I wanted more power with­out sac­ri­fic­ing 100,000-mile re­li­a­bil­ity,” Fer­gu­son says. “It’s a toy, used to play off-road and tow my dirt bikes.”

THE PROB­LEM

“I had about 2,000 miles on the new en­gine,” Fer­gu­son con­tin­ues. “When I lost com­pres­sion on cylin­der No. 1, I took the heads over to Hughes for in­spec­tion. The valveg­uides were blown out. I hadn’t even towed any­thing yet. The en­gine had never run hot on the gauge or boiled over.”

THE DI­AG­NO­SIS

Long­time Mopar spe­cial­ist Dave Hughes had never seen such a fail­ure in such a short time on an en­gine with such low miles. No one wanted a re­peat, so HOT ROD and Westech Au­to­mo­tive—our go-to Chicago-area res­cue shop—got in­volved to sci­ence-out the root causes of the per­plex­ing prob­lem.

As Bran­des tells it, “Hughes told me the valveg­uides had lit­er­ally melted, ob­longed, and lost valve con­trol. Hughes re­paired the heads, but mak­ing sure it wouldn’t hap­pen again was my baili­wick. We’d never seen so much heat in the head. We looked at the ex­haust (the header flanges were blued), the cool­ing, fuel and ig­ni­tion curves, and so on.

“We found the two air temp sen­sors were flaky and re­placed them with new ones. The speedome­ter was read­ing high, which we traced to a wrong speedome­ter gear. At 40 mph, the ECU [elec­tronic con­trol unit] thought we were re­ally do­ing 50. This caused the ECU to pre­ma­turely lock up the A518 over­drive au­to­matic’s torque con­verter at only 1,400 rpm. Fer­gu­son had swapped out the orig­i­nal long-run­ner Dodge fac­tory ‘keg’ EFI in­take for a short-run­ner sin­gle-plane. He was driv­ing the truck in town at 35 to 40 mph. Com­bined with the early con­verter lockup, around town Fer­gu­son was con­stantly lug­ging the en­gine. He was still run­ning the orig­i­nal fac­tory com­puter pro­gram­ming, so the con­fused ECU also leaned out the fuel mix­ture.

“It gets worse. The fac­to­rystyle oval-dish pis­tons were about 0.060-inch down in the hole at TDC. The high-swirl fac­tory Mag­num heads couldn’t gen­er­ate good mix­ture mo­tion with such a low pis­ton deck height. At only about 8.7:1, the static com­pres­sion ra­tio was way too low any­way.

“Put all this to­gether and we had a lazy, slow-burn­ing air/fuel charge that caused the cham­ber to re­tain too much heat. We might have been able to bandage the combo with some care­ful tun­ing and just chang­ing the speedo gear, but we de­cided to re­ally make this combo all it should be with a pis­ton swap to raise the com­pres­sion ra­tio as well as gen­er­ate some mix­ture mo­tion.”

THE FIX: SHORT-BLOCK

A pis­ton change meant bor­ing the al­ready 0.030-inch over block an­other 0.010-inch (0.040over an orig­i­nal 360’s 4.0-inch bore size). On his own, Fer­gu­son de­cided since the en­gine needed pis­tons any­way, why not step up to a 4-inch Scat cast stro­ker crank for 410.2 cubes? With less than 2,000 miles on the pre­vi­ous build, Bran­des could re­use the ex­ist­ing, un­dam­aged main and rod bear­ings.

Stro­ker crank in hand, Bran­des se­lected a match­ing pis­ton. He went with a UEM KB Pis­tons hy­per­eu­tec­tic step-dish KB416 pro­file. “The step-dish gives you es­sen­tially a quench area on the open-cham­ber cylin­der head,” he ex­plains. “It forces the air/ fuel charge to­ward the valve and spark plug. This gen­er­ates mix­ture mo­tion and speeds up the burn. It made up for the fact the pis­ton was still 0.050-inch down in the hole. The static com­pres­sion ra­tio went up to 9.4:1.”

The pis­tons were or­dered as a pis­ton-and-ring kit that in­cludes iron moly com­pres­sion rings. Also or­dered was an op­tional add-on to the ba­sic pis­ton:

KB’s newly avail­able Line 2 Line abrad­able skirt coat­ing. It’s sprayed onto the pis­ton skirt, adding thick­ness to de­velop zero pis­ton-to-wall clear­ance for re­duced pis­ton rock and qui­eter op­er­a­tion. While it ben­e­fits even tight clear­ance hy­per­eu­tec­tic pis­tons, the coat­ing re­ally comes into its own with forged pis­tons (like UEM’s Icon pis­ton line) that re­quire higher ini­tial skirt clear­ances. Dur­ing ini­tial en­gine run-in, the coat­ing wear-mates to the cylin­der, de­vel­op­ing mi­cro­scopic high/low spots that ac­tu­ally re­tain ad­di­tional oil for re­duced fric­tion.

THE FIX: VSS ER­ROR

The speedome­ter and the ECU in late-model ve­hi­cles rely on elec­tri­cal pulses from a ve­hi­cle speed sen­sor (VSS). In the 1997 Dakota, the VSS is a hy­brid de­vice that mounts into the side of the trans like an old-school speedo ca­ble, but in­stead of con­nect­ing to a ca­ble, the gear out­puts to the VSS. Fer­gu­son’s non­stock, 35-inch-tall, off-road tires and 4.56:1 rear gears had to­tally con­fused the speedo and ECU—eas­ily cor­rected by in­stalling a driven gear with ad­di­tional teeth. (For more on speedo cal­i­bra­tion, see this month’s Pit Stop col­umn.)

THE FIX: ECU

With me­chan­i­cal is­sues cured, the ECU was re­pro­grammed to work with the sin­gle-plane in­take, higher com­pres­sion, and added dis­place­ment. Chrysler “Jetronic” com­put­ers re­quire a sep­a­rate flash pro­gram­mer for se­ri­ous re­cal­i­bra­tion. SCT’s X3 DCX Power Flash unit (PN 3200) is the pre­ferred so­lu­tion. It plugs into the ve­hi­cle’s di­ag­nos­tic port to trans­fer cus­tom tunes. The de­vice can store up to three sep­a­rate cus­tom tunes, re­tain the orig­i­nal fac­tory tune in case it’s ever needed, read and clear trou­ble codes, and even data-log dur­ing a test drive. Al­though the X3 DCX isn’t promi­nently fea­tured on SCT’s web­site, it’s still avail­able new, tar­geted to hard-core cus­tom tuner shops. As of early 2018, Sum­mit Rac­ing has them in stock.

Chrysler tuner Dale Matthews was brought in to work his magic on the X3. Ac­cord­ing to Matthews, “I raised the idle speed from 600 to 720 rpm, then ad­vanced the base tim­ing to 16 de­grees BTDC to hold a smoother and bet­ter burn­ing cylin­der at idle. To ad­just for the added cu­bic inches, in the main spark ta­ble, I added from 3 to 7 de­grees of tim­ing to cer­tain ar­eas of the map, mostly in the higher rpm/load range. I set the max ad­vance at WOT [wideopen throt­tle] to 36 de­grees. The

added cu­bic inches re­quire more fuel. The oxy­gen sen­sor con­trols the air/fuel ra­tio in closed loop be­low 3,000 rpm; once that thresh­old has been crossed, the Speed Den­sity–based sys­tem de­fines the air/fuel ra­tio from the ta­ble. Tar­get­ing the WOT A/F ra­tio to 12.5–12.8:1, I ended up adding an ad­di­tional 15-per­cent fuel over the stock ta­ble.” Flow­ing 21.1 lb/hr at

43.5 psi, the Ram’s ex­ist­ing fuel in­jec­tors proved up to the task.

THE RE­SULTS

Last Thanks­giv­ing, liter- ally sec­onds af­ter some fi­nal tweaks on Westech’s chas­sis dyno, Fer­gu­son hopped in the truck, left south­ern Wis­con­sin, and drove crosscoun­try to his new home in San Bruno, Cal­i­for­nia—about a 2,300-mile drive. He went through Den­ver and the Rock­ies on I-70, climb­ing as high as 11,158 feet. Did we men­tion he was tow­ing a 500pound trailer—and run­ning 87-oc­tane gas? “I’m su­per happy!” Fer­gu­son says. “It’s just got so much more ef­fec­tive power ev­ery­where. I’ve had no ma­jor prob­lems since.”

LESSONS LEARNED

You could say the wrong speedo/VSS driven gear was the straw that broke the camel’s back, but with­out higher com­pres­sion and good mix­ture mo­tion, the ex­ist­ing truck would still have re­mained lazy on the bot­tom end. This points out the need for to­tally match­ing your de­sired end goals and us­age when plan­ning your re­built en­gine com­bi­na­tion.

12–13] Next, it’s over to the grind­ing wheel to care­fully clear­ance the rods’ pin ends ( 12). Most ma­te­rial was re­moved from the for­merly square pin-end cor­ners ( 13).

14–15]

“They didn’t hear any det­o­na­tion, so they fig­ured ev­ery­thing was OK!” — Norm Bran­des

16–18] Chrysler speedo-driven gears come in both long- or short-stem ver­sions ( 16). The long stem has a 3-inch shaft length and fits ca­ble-driven speedos; the short stem’s 1.5-inch shaft is for late-mod­els like the Ram truck and work with a slip-in...

Hughes’ $5 ad­justable slip col­lar keeps the dis­trib­u­tor from walk­ing up and down in the block as it meshes with the he­li­cal cam drive gear. Gear-walk causes tim­ing vari­a­tions and can de­grade se­quen­tial in­jec­tor tim­ing. Ad­just col­lar-to-gear clear­ance...

08–11] The stock Mag­num rod’s small end must be ground to clear the bot­tom of KB’s stro­ker pis­ton. To find out how much to shave off the rod, insert two pins (one through each pis­ton pin-hole) un­til they nearly touch, leav­ing just enough gap for a...

Ama­zon.com 04] Scat’s af­ford­able ($382 at Ama­zon) cast 4-inch stroke crank plus a 4.040-inch bore yields 410.2 ci—plus mas­sive torque po­ten­tial. The crank can be neu­tral­bal­anced (it may take some Mal­lory), but Bran­des elected to bal­ance it for a...

Mar­lan Davis 05] The stock flat-top pis­tons ( left) make for a lazy, slow burn that kept too much heat in the open-cham­ber Mag­num heads. The KB416 pis­ton for 4-inch stro­ker cranks and Mag­num heads ( right) has a step dish that cre­ates quench by...

06–07] Bran­des spe­cial-or­dered the hy­per­eu­tec­tic pis­tons with KB’s new Line2Line abrad­able skirt coat­ing that re­duces pis­ton rock as well as fric­tion. It wear-mates to the cylin­der, safely achiev­ing zero pis­ton-towall clear­ance. But with a...

02–03] The stock long-run­ner “keg”-style in­take ( 02) works best in the 1,800–2,000-rpm range, but then runs out of breath. Fer­gu­son had re­placed it with a Hughes F1 sin­gle-plane ( 03), whose un­der-plenum air gap is said to cool the charge as much as...

01] The wrong speedo gear messed up the ECU: It thought the truck was trav­el­ing much faster than it was. It re­sponded by lean­ing out the fuel curve and ad­vanc­ing the spark. This caused heat buildup in the com­bus­tion cham­ber, melt­ing the valveg­uides....

[ ECU tun­ing plus a speedo gear swap were only a par­tial an­swer. The full big-torque fix ul­ti­mately in­volved build­ing a 4-inch stro­ker mo­tor.

[ The ECU went “lean,” melt­ing down the valveg­uides. Norm Bran­des ( shown), Dave Hughes, and Dale Matthews sleuthed out the prob­lems.

[ Af­ter fi­nal tweaks on Westech’s chas­sis dyno, Fer­gu­son drove the truck from Illi­nois to Cal­i­for­nia across the Rocky Moun­tains.

[ A good ECU pro­gram and the right speedo gear weren’t enough! Fer­gu­son’s orig­i­nal goal was more down­stairs torque. But the en­gine’s top-end mods helped mainly midrange and higher rpm per­for­mance, so Bran­des turned the 360 into a 410. Fel-Pro stan­dard...

[ Fer­gu­son says, “I use my truck as an off-road toy and to tow a trailer with my dirt bikes. I wanted more low-end power—and re­li­a­bil­ity.”

[ Source of the chain of fail­ure: The 30-tooth speedo driven gear wasn’t right for the 4.56:1 axle ra­tio and 35-inch tires, con­fus­ing the ECU.

[ Owner Brian Fer­gu­son wanted enough power and re­li­a­bil­ity for off-road fun and games, but the ini­tial re­built en­gine and tune had is­sues.

19] SCT’s X3 DCX Power Flash pro­gram­mer was used to dial-in the Ram’s 410ci en­gine. Geared to­ward hard-core tuners, it comes with no pre­loaded tunes, but there are lots of pre­de­fined tunes you can down­load—or con­struct or mod­ify any tune on a PC, then...

20] There’s a mo­tor in there some­where. Back in the truck and fully tuned, the fresh 410 is nearly ready to head west.

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