Diesel World – October 2019

Inadditiontotheoversizedvalveseatsbeingresistanttocrackingthankstoheat-

treating,theyarealsopressedindeeperthanthefactoryseatsare.Likethescrew-instyle

internalfreezeplugsolution,hardenedvalveseatsarea goodideaanytimeyouhavetopull

theheadoffyourCummins.

Nowthatthenewvalveseatsareinplace,theheadis transferredovertoFleece’sNewen

CNCvalvecuttingmachinefora 5-anglevalvejobwithblending.A singlepointcutting

toolisusedtoperformthework,andeachcounterboreisperfectlymachinedinlessthan

a minute.

Forutmostqualitycontrol,FreedomRacingEngine’sshopmanager(andformerDonSchumacherRacing

mechanic),JohnBenshoof,checksthevalvedepthofeachcounterborebetweencuts.Withoptimumvalve

sealingbeingoneofthemostcriticalaspectsofanycylinderhead—letalonea highboostdiesel—it’sworth

takinga fewextrasecondstodouble-checktheprecisionNewenCNCmachine’swork.

Afterallmachineworkis complete,Fleeceinstallsthe 11 screw-instylefreezeplugstheheadwasmachinedto

acceptatthebeginningoftheremanufacturingprocess.Eachsteelpipeplug’souterdiametermeasures 24

mmandthethreadsarehitwitha coatofsealantpriortogoingin.Onceeachplughasbeensnuggedup,they

arealltorquedto 100 ft-lbs.

Fromthere,theremaining 15 traditionalfreezeplugsarepressedinto

place,whichincludesthetwo1.5-inchdiameterfreezeplugslocatedin the

intakeshelf,alongwithalltheother1-inchplugs.Thesefreezeplugsare

treatedto a coatof Loctiteretainingcompoundbeforebeinginstalled.

Attachedto thefreezeplugat eitherendof thehead,Fleeceaddsa one-time

use,singlepoint,240-degreecoolanttemperatureindicator.Should

theheadevermakeitswaytoa secondorthirdowner(orevenback

toFleeceforthatmatter),thiscanrevealwhetherornottheheadhas

seenanexorbitantamountofheat.Locatinga temperatureindicator

neartheNo.6 cylinderwillbethemosttelling,asthiscylinderrunsthe

warmestintheCumminsapplication.

Eventhoughit’sextremelyraretofinda coolantleakina cylinder

head,thatdoesn’tstopFleecefromperforminga coolantleaktestprior

tofittingit withvalvesprings,retainers,andlocks.Duringtheprocedure,

a specialtestplatewitha rubbercompoundsandwichedbetweenthe

combustionsideoftheheadandthesteelplateis installed.Thehead

boltholesareusedtofastenit inplace.

SOURCE

FLEECEPERFORMANCE

ENGINEERING

317.286.3573

FLEECEPERFORMANCE.COM

TECH COMPETITION-READY, OFF-THE-SHELF AVAILABILITY

80 OCTOBER I 2019 • DIESEL WORLD http://www.dieselworldmag.com