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Servic Service e Bullet Bulletin in
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Subject
Camshaft Camshaft and Tappet Tappet Reuse Guidelines Guidelines BulletinNo.
Date:
November 1999
3666475 Camsha Camshafts fts (Cast (Cast Iron) Iron)
General Information: This
bulletin bulletin applies applies
with
the flat-sliding tappets.
cam
lobes lobes
and
tappet tappets. s.
This
and
speciflc speciflc
for rankin ranking g
bulletin addresses
Dist Distri ribu buto tors rs
and and
high high-q -qua uali lity ty
visual inspection inspection The
the testad testad
cam
the deterioration
Deal Dealer ersa sare re
criteria criteria for B & C chillad ductile ductile
photographs lobes lobes
and
of cam
enco encour urag aged ed
repa repair ir of Cumm Cummin ins s
will help, as reference for determ determini iningt ngthe he
loba
to use use
surfaces
at the
thei their r tech techni nica cal l
iron or chillad chillad casI iron camshaft camshaft
tools for inspection percen percentag tage e
ramps,
expe expert rtis ise e
and
comparison
of the useful usefullif life e
edges,
and
to impl implem emen ent t
cantar the the
material material
of the sample
lefton the camsha camshaft ft
of the
lobes.
gui guide deli line nes s
Cummins
for for lowlow-co cost st
and and
prod produc ucís ís. .
Definitions: .
Pitting: haya
.
Loss Loss
of a
rough,
piec piece e
dark
of mate materi rial al
bottoms
near the edges ofthe cam cam
Chatter:
The The
.
'\.-
.
Goul Gould d cam cam
Dist Distre ress ss: :
roug roughe heni ning ng
loca locali liza zad d
loba loba, , and
resu result ltin ing g usually
in a
hola hola
occur
that that
in the
is visi visibl ble e
h ea eavily
to the the
lo.aded
nake naked d
aya. aya.
areas
of the
Pits Pits
typ typic ical ally ly
ca cam
nose
or
.
para parall llel el with with the the axial axial of the the cam
caus cause e
whic whichi hinc ncr rease easest sthe he A
the the
edges
lobes.
axia axiall llil ilJe Jes s that run run
the the oil oil fi,l fi,lmt mthi hick ckh~ h~$s $s.l .lt t
from from
andsharp
the the meta metal l
loba loba wear wear
rata ratas s
of the the
to meta metal l
cont contac act t
andp andpo otent tentia ial l
surf surfac ace e
betw betwee een n
for for cam cam
that that does does
not not
lobe lobes. s. The cam cam
loba loba
exte extend nd
and and
chat chatte ters rs lobe lobean and d
tapp tappet et
to any any
brea break k tapp tappet et
down down
and and
runn runnin ing g
surf surfac aces es, ,
pitt pitti ing fail failur ure. e.
sign signif ific ican ant t
dist distan ance ce
dist distur urb b
,,' ,,'
belo below w
the the
loba loba
surface.
}
.
Maco-Spalling:
Very Very
larga larga
pittin pitting. g. A
larga larga
local area area
loss loss of materi material al
from from
the cam
loba loba
surface surface. .
Guidelines: RankilJg Scale
¡.
Estimate..%of camshaft
, Reuse
Lobe
liferemaining
O
New
1
Normal polish ,likenew
Unconditional Unconditional
reuse
100% 90%
Heavy
Unconditional Unconditional
reuse
70%
2
3 4 5
~
Conditionof . cam cam
polish wear, few pittingless
than than 2 mm Heav Heavy y
wear wear
indiamete indiameter r and and
cam nose nose area Heavy Heavy
No
loba, loba, neverr neverrun un
wear
and
areas areas at cam
larga larga
at
multiple multiple largar largar pitting pitting
nose nose
Veryh Veryheav eavy y
cam
loba loba
pittin pitting g and
heavy heavy
pitt pittin ing g area areas s
loba loba wear wear
and cam cam
gallin galling g
camshaft ft * Do not reuse the camsha
ifthe angin angina a
This bulletinis a supplement supplement
to the applicable angina
restriction
Cond Condit itio iona nal l
reus reuse e
50%
*
¡;
Less than 30% ,
Replace
10% or
Replace
less less
I
is being being overhaul overhauled ed
or ifthe ifthe camsh camshaft aft
family troubleshooting troubleshooting
and
is out of the angina angina
for any reason~. reason~.
repair manual.
Cummin Cumminss Engine Engine Compan Company, y, Inc., Inc., Colum Columbus bus,, Indian Indianaa 4720247202-300 3005 5 Cummln Cummlnss Englne Englne Compan Company y LId., LId., Dave Daventr ntry, y, Northa Northants nts,, Englan England d NN11 NN11 5NU RegisteredOffiee:46-50CoombeRoad, NewMalden,SurreyKT34QL RegisteredNo.573951England
Copyright Copyright @ 2000
CumminsEngineCompany,Ine. AIIrightsreservad
Paga 1 of of 4
Camshaft and Tappet Reuse Guidelines Paga 2 Tappets General Information:
\
This bulletin applies specific visual inspection criteria for B & C sliding tappets when running with chilled ductile iron, chilled cast iron, and steel éamshaft materials. The photographs will help as reference tools for inspection and comparison of the sample tappets and for ranking the tested tappets and for determining the percentage of the useful life left on the tappets. This bulletin addresses the deterioration of sliding tappets at the running surface. Cummins Distributors and Dealers are encouraged to use their technical expertise to implement the guidelines for low-cost and high-quality repair of Cummins products. Definitions:
. Pitting: Same
.
as cam jebe pitting, the running face of the sliding tappet loses one or many small pieces of material from the running face of the tappet, resulting in a hole that is visible to the naked eye. Pits typically have rough, dark bottoms and sharp edges and usually occur in the heavily loaded areas of the tappet. Scuffing: The running face of the tappet is galling and the material is removing
~stress: " surface.
.
at a high rateo The running surface
will lose the material. A localized roughening of the surface that does not extend to any significant distance below the tappet
Maco-Spalling: Very large pitting. A large local area 1055of material from the running surface of the sliding tappet.
Guidelines:
Ranking Scale O 1
2 3 4 5
Condition of Tappet
Reuse
No restriction New taooet, nevar run Unconditional reuse Wear oolish, like new Normal polish wear, few pitting less Unconditional reuse than 2 mm in diameter Heavy wear, multiple pitting, wave Conditional reuse * wear pattern, rouah surface distress Excessive wear, multiple larger pitting, scuffing, edge chip out, surface Replace porositv. Very heavy wear, scuffed, heavy gallReplace ing, tappet breaking
Estimate % of tappet life remaining 100% 90%
70% 50% Less than 30% 10% or less
* Do not reuse the tappets if the engine is being overhauled or if the tappets are out of the engine for any reason. This bulletin is a supplement to the applicable engine family troubleshooting and repair manual.
Camshaft and Tappet Reuse Guidelines Paga 3
Camshaft and Tappet Reuse Guidelines Paga 3
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