Breaking down the difference

cummins part shown over poor performing oem part

We tested 237 non-genuine components for 19L and above engines including pistons, rings, valves, cylinder liners, connecting rods and pins. In virtually every case, issues were identified which would have a negative impact on fuel economy, performance, blow-by, reliability and durability.

Below is a summary of findings for each part, and the danger of using anything but genuine Cummins parts.

View K Series brochure

POTENTIAL IMPACTS


Pistons

Issue Damage/Performance
Shallow ring grooves Ring breakage, high oil consumption, blowby, scuffing
Out-of-spec bowl dimensions Excess heat, cracking, high fuel consumption, visible smoke
Debonding of ring carriers Catastrophic engine failure

 


 

Piston rings

Issue Damage/Performance
Out-of-spec ring angles
 
Insufficient sealing, excess fuel usage, decreased performance
Incorrect size of oil ring (too thick) Poor oil scraping, excessive oil consumption
 
Incorrect size of top ring (too thin) Excess rotation, poor sealing, increased blowby

 



Piston pins

Issue Damage/Performance
Missing from some kits
 
Repaid delays, downtime, extra cost
 
Out-of-spec outer diameters
 
Incorrect fit issue, repair delays
 
Intergranular oxidation Manufacturing defect, increased potential for premature fatigue and cracking

 



Cylinder liners

Issue Damage/Performance
Oversize outer diameters
 
Radial stress leading to metal fatigue
 
Insufficient lower outer diameters
 
Liner rocking and fretting
 
Oversize inner diameters
 
Cavitation leading to pitting, coolant leaks and mission-disabling failure
 
Improper cross-hatching
 
Compromised lubrication, increased wear, higher blowby and oil consumption, decreased service life
 
Excess crystals in liner coating
 
Poor coating adhesion
 
Insufficient metal strength Premature wear, potential failure

 



Valve springs

Issue Damage/Performance
Below spec for hardness
 
Degraded performance over time
 
Insufficient height load Improper seating resulting in combustion leaks and premature wear-out of valve seat inserts

 



Valve seat inserts

Issue Damage/Performance
Runout does not meet specifications, can't square to seat Increased wear, combustion leakage, potential valve failure

 



Connecting rod bearings

Issue Damage/Performance
Tangs too narrow
 
Interference issues, misalignment of oil holes hindering oil flow
 
Metals sintered, not cast
 
Lower corrosion resistances
 
Excess lead pooling Fatigue cracking

 



Connecting rod bushings

Issue Damage/Performance
Excess lead in lining layer Delamination and crackin

 


Saving a little upfront could ultimately cost you

Using non-genuine parts does more than compromise the performance of your high-horsepower engine.

It jeopardizes your business and makes it hard to meet customer expectations. The miniscule amount you save upfront using non‑genuine parts is likely to cost you big time down the road. When your profitability and reputation count on it, use Genuine Cummins Parts to assure continuous performance.
 

engine icon

Early life
failure

stopwatch icon

Downtime

dollar sign icon

Non-warranty
repair cost

 

 

fuel pump icon

Additional
fuel cost

engine with alert symbol icon

Catastrophic
failure

 

 

Only buy Genuine Cummins parts and accessories from
Cummins distributors or Cummins authorized dealer locations

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