HOT ROD to the Res­cue

Hot Rod - - Contents - Mar­lan Davis Brett Tur­nage


Af­ter Tevete “T” Usumalii gained ti­tle to a 1988 Ford Bronco 4x4 that had been sit­ting derelict in an old buddy’s drive­way since 2008, he soon re­al­ized its tired 302 mo­tor needed some ma­jor help. As T puts it, “I wanted a week­end fun truck, off-road-ca­pa­ble that I could take to the moun­tains, desert, or beach. It had to have good per­for­mance un­der load. When I put my foot to the floor, does it do what I want?”

What he wanted was a

347ci stro­ker (4.040-inch bore by 3.40-inch stroke), with a high-per­for­mance RV cam and free-flow­ing Air Flow Re­search (AFR) alu­minum cylin­der heads. “Two dif­fer­ent guys had their hands in this project and they turned out to be real shady,” T says. When the engine was fi­nally fin­ished and in­stalled, it was trans­ported to Westech Per­for­mance in Mira Loma, Cal­i­for­nia, to tune-in its after­mar­ket Me­gaSquirt EFI sys­tem.


Run­ning on Westech’s Su­perFlow chas­sis dyno, right from the start ( err— no start?) the Bronco had a crank/no-fire con­di­tion. It wasn’t get­ting any spark. The truck’s new after­mar­ket coil had burned up. It was tem­po­rar­ily re­placed with an OE coil, and the truck started right up, but then it wouldn’t shut off. It turned out the ig­ni­tion cir­cuit was in­cor­rectly wired. There was a feed-back to the ig­ni­tion switch key, so the sys­tem never de-en­er­gized. The elec­tronic

con­trol unit (ECU), re­lays, and coil re­ceived con­stant power all the time (at least un­til the bat­tery died). This over­heated the coil, caus­ing the fail­ure.


Nearby ace Ford tuner Mark Sanchez (Ad­vanced En­gi­neer­ing West) was called in for a con­sul­ta­tion. “I went to check the engine at Westech,” Sanchez says. “The lifters were mak­ing noise, so be­fore look­ing at the wiring, I checked the oil. There was no dip­stick tube in the mo­tor. The dip­stick tube hole had been slop­pily filled with sil­i­cone. We drained the pan to find if there was any oil in the engine. There were 5 quarts in the pan. It was al­ready dirty, so we threw it out and put in an­other 5 quarts of clean oil.

“I got the engine to shut down on its own with­out dis­con­nect­ing the main bat­tery ground. First I hooked up a late-1980s fac­tory Mus­tang ECU us­ing my Ford ser­vice 60-pin break­out box—think of an old-school switch­board deal—and by­passed all the crappy wiring. The engine now started and shut down on its own. Once we knew the nos­tart had noth­ing to do with the mo­tor, I par­tially re­worked the butchered har­ness so it would start with the Me­gaSquirt. Westech then at­tempted to tune the ECU, but the engine had a con­stant miss. Ev­ery lifter on the driver side was noisy. Westech aborted the tune; they were wor­ried about the noisy lifters.”

Westech is a tuner shop and doesn’t usu­ally get in­volved in long-term engine builds, so Sanchez and HOT ROD de­cided to ride to the “res­cue.” The Bronco was trans­ported to nearby AEW for hard-core di­ag­nos­tics.


AFR heads have a fully ad­justable, stud-mounted valvetrain. When Sanchez re­ceived the car, he hooked up an ex­ter­nal oil pres­sure gauge to the stan­dard pres­sure-gauge port above the oil fil­ter and re­moved the spark plugs, dis­con­nected the ECU (which turns off the elec­tric fuel pump), and cranked the engine over to fully pump up the lifters. “Dur­ing crank­ing, the oil pres­sure gauge read 65 pounds,” Sanchez ex­plains. “I tried to ad­just the heads’ Scor­pion roller rock­ers, start­ing at the No. 1 cylin­der and work­ing my way through the fir­ing or­der. When I got over to the driver side, I no­ticed the rock­ers on cylin­der Nos. 5 and 6 (the first two driver-side cylin­ders on a Ford) weren’t get­ting any oil out from the pushrods. At that point, I thought there must be some­thing wrong in the lifter area.

“The Bronco had a two-piece Edel­brock EFI in­take. To check the lifters, you must re­move the up­per plenum half, pull out the dis­trib­u­tor, and then re­move the lower half. Af­ter I re­moved the dis­trib­u­tor, I saw it had a ca­st­iron dis­trib­u­tor gear, typ­i­cal for an ’88 that would have orig­i­nally come with a non-roller cam. Look­ing more care­fully down the dis­trib­u­tor hole in the block with a flash­light, I ob­served the mo­tor had a hy­draulic-roller

cam, which re­quires a dif­fer­ent dis­trib­u­tor gear. Sud­denly, I saw there was no plug for the pas­sen­ger-side oil gal­ley (which is the only one you can see through the hole—I got lucky). Un­for­tu­nately, the mo­tor had al­ready run for about 15 min­utes.”


D’oh! The engine now re­quired a com­plete stem-to-stern dam­age in­spec­tion. Although the top half could be checked in the ve­hi­cle, the eas­i­est way to check the con­di­tion of the cam and bot­tom-end bear­ings was, ac­cord­ing to Sanchez, “To just go ahead and pull the mo­tor. Only a lazy man works twice.”

With the mo­tor on an engine stand, Sanchez no­ticed the oil pan’s rear lip seal had slipped into the oil pan when it was be­ing as­sem­bled: “It was leak­ing big time. Some id­iot had put sil­i­cone sealant through the top, bot­tom, and edges of every­thing.”

Sanchez re­moved the pan, then the No. 3 main cap. “That’s the thrust bear­ing on a Ford, so it usu­ally re­ceives the most abuse. The thrust end turned out to be OK, but the bear­ing’s crank-jour­nal sur­face had se­ri­ous scratches and wear for an engine that had al­most no run­ning time on it.” Fur­ther tear­down re­vealed ad­di­tional cam, rod, and main-bear­ing dam­age; scuffed pis­ton skirts; and deep ver­ti­cal cylin­der-wall scratches. Nev­er­the­less, the pis­tons and crank jour­nals ap­peared

“25 cents cost him a whole engine!” — Mark Sanchez,AEW

sal­vage­able, while the cam was un­dam­aged.


Al­ready 0.040-over, the bores were as big as one dares go on a small-block Ford. “If you go 0.060-over, it’ll run hot on the street,” Sanchez ex­plains. “Luck­ily, I had plenty of blocks ly­ing around, in­clud­ing some 1985-and-later roller-cam ver­sions. A good used block is cheaper than buy­ing a new set of forged pis­tons.” A&A Mid­west is one ma­jor na­tion­wide source of pris­tine re­build­able cylin­derblock cores for most engine makes.

Ma­chin­ing and short-block as­sem­bly us­ing Mahle, Cle­vite, and ARP parts was han­dled by L&R Engine—a Santa Fe Springs, Cal­i­for­nia–based, third-gen­er­a­tion, fam­ily-owned busi­ness that builds every­thing from Mom’s gro­cery-get­ter to full-race mills. The re­place­ment block was first cleaned, mag­netic-par­ti­cle-in­spected, and sonic-checked. The lat­ter is a crit­i­cal qual­i­fier be­fore bor­ing a thin-wall cast­ing like the small­block Ford more than 0.030-inch over­size. The sonic checker uses sound waves to mea­sure cylin­der-wall thick­ness. For rea­son­able strength and ad­e­quate heat trans­fer on street-driven

en­gines, L&R says 0.187 inch is the min­i­mum safe wall thick­ness post-over­bore. In this case, there was plenty of ma­te­rial left af­ter sub­tract­ing half the pro­jected 0.040-inch over­bore:

0.740 − (0.040 ÷ 2) = 0.720.

Go­ing 0.040-over per­mit­ted reusing the ex­ist­ing pis­tons.

L&R was able to sal­vage both the pis­tons (sav­ing at least $600), as well as the crank with only min­i­mal polishing on their scratched sur­faces. L&R also align-honed the main jour­nals, squared and zero-decked the head mount­ing sur­faces, and tapped the oil­gal­ley holes for screw-in plugs.

Short-block as­sem­bly com­plete, L&R turned it back over to Sanchez for up­per-half as­sem­bly and re­in­stal­la­tion into the Bronco. Un­for­tu­nately, ad­di­tional prob­lems would pop up dur­ing that phase, to in­clude both engine top-end as­sem­bly com­po­nent mis­cues and slip­shod chas­sis in­te­gra­tion. Next month we’ll deal with th­ese pesky is­sues and hope­fully put the Bronco back on the Westech chas­sis dyno for a fi­nal test-and­tune ses­sion.


L&R did what the orig­i­nal two engine builders failed to do: metic­u­lous ma­chin­ing, in­spec­tion, and at­ten­tion to de­tail dur­ing as­sem­bly. It was able to save every­thing but the orig­i­nal block, bear­ings, and pis­ton rings, which keeps costs un­der con­trol.


Just be­cause there’s good oil pres­sure at the stan­dard pres­sure check­ing point doesn’t nec­es­sar­ily mean all ar­eas of the engine are get­ting oil. Pre-prime a new mo­tor be­fore in­stalling the in­take. That way you can see that oil is go­ing where it should go, not where it shouldn’t. Over­look­ing one small thing could cost you an en­tire mo­tor, so don’t rush through an engine build— check every­thing! If farm­ing out the build, choose a rep­utable, le­git­i­mate shop with a qual­ity rep­u­ta­tion. You may pay a lit­tle more up front, but end up sav­ing a bun­dle in the long run.

16) 18] ARP supplied its High-Per­for­mance Se­ries main cap bolts and just about ev­ery other fas­tener. Go­ing from OE to high-strength main cap bolts changes the clamp­ing force and tol­er­ances. En­sure the bear­ing bores are round and prop­erly sized af­ter...


16–17] The new bear­ings are Cle­vite NASCAR-level trimetal H-se­ries main ( 16) and rod bear­ings ( 17, right, com­pared to stan­dard re­place­ment, left). H-se­ries shells fea­ture medium ec­cen­tric­ity, a high crush fac­tor, and hard­ened steel backs with thin...

13–15] No two mi­crom­e­ters are ex­actly the same, so to min­i­mize tol­er­ance drift, ex­pe­ri­enced engine ma­chin­ists use a com­mon base­line. Af­ter mea­sur­ing the crank jour­nal with an out­side mike, that di­men­sion is trans­ferred to an in­side dial-bore gauge ( so...

Mark Sanchez 07–08] A 1985-and-later roller-cam block was needed to sup­port the Bronco’s OE-style hy­draulic roller lifters re­tained by a spi­der and dog­bones. Roller-cam blocks have taller lifter bores and spi­der re­ten­tion-bolt bosses in the lifter...

Jim Smart 09] To clear the 3.40-inch stro­ker crank, the block must be clear­ance­ground at the bot­tom of each cylin­der ( ar­rows).

Mark Sanchez

11–12] Block deck-sur­fac­ing ( 11) achieves sev­eral goals: restor­ing a smooth sur­face, squar­ing the block so all four cor­ners are par­al­lel and at the same height rel­a­tive to the main bear­ing jour­nals’ cen­ter­line, and de­vel­op­ing the de­sired pis­ton deck...

10] L&R mi­crop­ol­ished the after­mar­ket crank’s min­i­mally hurt, stan­dard-size jour­nals and avoided the need to turn them un­der­size. The rods didn’t need re­build­ing, but L&R did dis­cover and cor­rect a slight un­bal­ance in the ro­tat­ing as­sem­bly.

04–06] Not even 15 min­utes of run­ning time: Lack of oil and per­haps fail­ure to thor­oughly clean the block be­fore fi­nal as­sem­bly deeply gouged the cylin­der walls ( 04) beyond the point the block could be saved. Cor­re­spond­ing scratches marred the pis­ton...

[ The short-block went back to AEW for top-end as­sem­bly and in­stal­la­tion. Stay with us next month as we ex­pose more sloppy work­man­ship.

[ L&R En­gines, owned by three gen­er­a­tions of Ran­neys, built a re­place­ment short-block. From left, Derek Jr., Grandpa Larkin, and Derek Sr.

[ The team at L&R fully ma­chined a used block, bor­ing it 0.040-over so they could sal­vage and re­use the old ro­tat­ing as­sem­bly com­po­nents.

01–03] 02 03). 01).

Get­ting un­plugged: The driver-side valvetrain was noisy. When ad­just­ing the valves had no af­fect, Sanchez sus­pected a lifter prob­lem and be­gan tear­ing apart the top-end. Look­ing down the dis­trib­u­tor hole in the block, he no­ticed a miss­ing oil-gal­ley...

[“For want of a nail”: Left out dur­ing as­sem­bly, this lit­tle 25¢ part—the driver-side front oil gal­ley plug—cost Usumalii his cylin­der block.

[ Usumalii had a 349ci stro­ker Ford built by what he thought was a rep­utable shop, then had an­other shop in­stall the mo­tor in the Bronco.

[“T” Usumalii wanted a fun yet pow­er­ful off-road truck, but the 6,000-pound 1988 Ford Bronco’s tired 302 was a snoozer.

19] A pre­mium Mahle Orig­i­nal (for­merly Per­fect Cir­cle) plasma-moly cast-iron re­place­ment pis­ton ring set (PN 40564CP.040) was used. Its 5⁄64-5⁄64-3⁄16- inch-od ring grooves match the ex­ist­ing Probe forged pis­tons’ grooves. The com­pres­sion rings are...

20] Af­ter lightly polishing out the skirt scratches, L&R re­in­stalled the pis­ton/rod as­sem­blies in the mo­tor us­ing the new Mahle pis­ton rings com­pressed by ARP’s trick bil­let ring com­pres­sor.

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