Piston Ring Gap Alignment Influence on High Blowby and Oil Consumption on All Engines {1000, 1215} Caterpillar

Piston Ring Gap Alignment Influence on High Blowby and Oil Consumption on All Engines {1000, 1215}

Usage:

Engine: 3126; 3126B Truck Engine; 3126E Truck Engines; 3400 All, 3300 All, 3200 All, 3100 All, 3000 All, and D-series All; 3406E; 3456; 3500 and G3500 Engines; All 3600; All 3600 Engines; All C27 Engines; All C280; All C280 Engines; All C280 and 3600 Commercial Engines; All G3600; All Tier 4 Interim and Final Engines; C-10 All; C-9 and C9 All; C11 All; C12 and C-12 All; C13 and C-13 All; C15 and C-15 All; C175 Commercial Engines; C175 Engines; C18 and C-18 Engines; C27 Engines; C32 Engines; C7 All; C7 On-Highway; C9 On-Highway; Tier 4 Engines; With ACERT Technology
Engine Commercial: 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Commercial: 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Commercial: 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Commercial: 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Commercial Electronic: 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Commercial with Mechanical Unit Injection (MUI): 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Industrial, Marine, and Generator Set that Use Flash Programming: 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Machine: 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Machine with Mechanical Unit Injection: 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Truck: 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Trucks that Use Flash Programming: 3500 and 3500B; 3500 and 3500B Engines with Standard Displacement; All Diesel; G3500 Family
Engine Commercial: 3500B and 3500C
Engine Commercial: 3500B and 3500C
Engine Commercial: 3500B and 3500C
Engine Commercial: 3500B and 3500C
Engine Commercial Electronic: 3500B and 3500C
Engine Commercial with Mechanical Unit Injection (MUI): 3500B and 3500C
Engine Industrial, Marine, and Generator Set that Use Flash Programming: 3500B and 3500C
Engine Machine: 3500B and 3500C
Engine Machine with Mechanical Unit Injection: 3500B and 3500C
Engine Truck: 3500B and 3500C
Engine Trucks that Use Flash Programming: 3500B and 3500C
Engine Commercial: 3500
Engine Commercial: 3500
Engine Commercial: 3500
Engine Commercial: 3500
Engine Commercial Electronic: 3500
Engine Commercial with Mechanical Unit Injection (MUI): 3500
Engine Industrial, Marine, and Generator Set that Use Flash Programming: 3500
Engine Machine: 3500
Engine Machine with Mechanical Unit Injection: 3500
Engine Truck: 3500
Engine Trucks that Use Flash Programming: 3500
Engine Commercial: All
Engine Commercial: All
Engine Commercial: All
Engine Commercial: All
Engine Commercial Electronic: All
Engine Commercial with Mechanical Unit Injection (MUI): All
Engine Industrial, Marine, and Generator Set that Use Flash Programming: All
Engine Machine: All
Engine Machine with Mechanical Unit Injection: All
Engine Truck: All
Engine Trucks that Use Flash Programming: All
Engine Commercial: All 3412
Engine Commercial: All 3412
Engine Commercial: All 3412
Engine Commercial: All 3412
Engine Commercial Electronic: All 3412
Engine Commercial with Mechanical Unit Injection (MUI): All 3412
Engine Industrial, Marine, and Generator Set that Use Flash Programming: All 3412
Engine Machine: All 3412
Engine Machine with Mechanical Unit Injection: All 3412
Engine Truck: All 3412
Engine Trucks that Use Flash Programming: All 3412
Engine Commercial: 3500 Series
Engine Commercial: 3500 Series
Engine Commercial: 3500 Series
Engine Commercial: 3500 Series
Engine Commercial Electronic: 3500 Series
Engine Commercial with Mechanical Unit Injection (MUI): 3500 Series
Engine Industrial, Marine, and Generator Set that Use Flash Programming: 3500 Series
Engine Machine: 3500 Series
Engine Machine with Mechanical Unit Injection: 3500 Series
Engine Truck: 3500 Series
Engine Trucks that Use Flash Programming: 3500 Series
Engine Commercial: Electronically Controlled
Engine Commercial: Electronically Controlled
Engine Commercial: Electronically Controlled
Engine Commercial: Electronically Controlled
Engine Commercial Electronic: Electronically Controlled
Engine Commercial with Mechanical Unit Injection (MUI): Electronically Controlled
Engine Industrial, Marine, and Generator Set that Use Flash Programming: Electronically Controlled
Engine Machine: Electronically Controlled
Engine Machine with Mechanical Unit Injection: Electronically Controlled
Engine Truck: Electronically Controlled
Engine Trucks that Use Flash Programming: Electronically Controlled
Engine Commercial: All
Engine Commercial: All
Engine Commercial: All
Engine Commercial: All
Engine Commercial Electronic: All
Engine Commercial with Mechanical Unit Injection (MUI): All
Engine Industrial, Marine, and Generator Set that Use Flash Programming: All
Engine Machine: All
Engine Machine with Mechanical Unit Injection: All
Engine Truck: All
Engine Trucks that Use Flash Programming: All
Machine Engines: 3003; 3013; 3014; 3024; 3046; 3054; 3054B; 3054C; 3054E; 3056; 3056 and 3064; 3056E; 3066; 3114; 3116; 3126; 3126B; 3176; 3176C; 3196; 3204; 3208; 3304; 3306; 3406; 3406B; 3406C; 3406E; 3408; 3408E; 3412; 3412E; 3456; 3500B and 3500C High Displacement; 3508; 3512; 3516; All; C-12; C-15; C-16; C-9
Machine Engines with Mechanical Unit Injection: 3500 Series

Introduction

This Special Instruction describes the misconceptions of high blowby and oil consumption issues caused by the alignment of piston ring gaps.

Do not perform any procedure in this publication or order any parts until you understand the information that is contained in this publication.

Understanding High Blowby and Oil Consumption

There are occasional reports of engines with high blowby and high oil consumption that claim to be caused by alignment of piston ring gaps. The aligned piston ring gaps are not necessarily the cause of these engine issues. Caterpillar provides documentation related to high blowby and oil consumption.

Refer to your applications System Operation/Testing and Adjusting, Troubleshooting, and Operation and Maintenance Manual as well as the articles listed below:

Special Instruction, REHS7857-00, "Testing for Excessive Cylinder Blowby in 3500 Engines"
Engine News, SEBD9514, "Piston and Ring Wear"
Engine News, SEBD9263, "The Causes Of Worn And Broken Piston Rings"

Caterpillar recommends piston rings to be oriented at 120 degrees apart when installing new rings Piston rings are designed to rotate freely during engine operation. The rate of ring rotation is unique for each ring and the rotation will provide a uniform ring and piston groove wear. The ring end gaps will align with one another at random intervals during engine operation. Normal ring gap alignment is brief because the rings continue to rotate at different speeds and directions.

The ring end gap dimension will increase over the service life of the engine. Rings exert pressure onto the cylinder wall, and the pressure is a direct function of the rings radial thickness. As the ring face wears, the pressure keeps the ring face in contact with the cylinder bore. This wear results in the ring gap dimension increasing with continued operation.

Rate of oil consumption is called Brake Specific Oil Consumption (BSOC). The unit of measure is grams per kw/h or lbs/bhp·h. The BSOC depends on the engine model, aspiration, and the operating load and oil that is used. Consult your Cat dealer for assistance in determining the correct oil consumption rate for your engine.

Reference: For information on calculating the BSOC, refer to the Electronic Media Center for Engine Data Sheet 96.2, LEKQ4028, "Oil Consumption Data". This Engine Data Sheet can be found at the address below.

https://catpublications.com/

Excessive low engine speed or running the engine with a low load for extended periods can lead to excessive oil consumption and carbon buildup on the top of the piston, piston rings and the piston ring grooves. These issues can lead to excessive wear and damage to components.

If necessary, gather data using the Service Form, 01-081227-02, "Oil Consumption Test Report", to verify that oil consumption exceeds specifications per amount of fuel burned.

Recommendations

In order to minimize risks of blowby and/or excessive oil consumption, follow the maintenance interval schedule for inspection of the cylinders, along with required engine overhauls. During scheduled maintenance inspections of cylinders, insure that rings are free to rotate. Examine the rings for wear and increase in ring gap.

Follow Systems Operation/Testing and Adjusting and Troubleshooting for diagnosing engine performance issues. If the piston rings are free to rotate, the location of the ring gap is not likely the cause of high blowby or oil consumption. Investigate other possible root causes, and ask your Technical Communicator to use the Dealer Solution Network (DSN) to seek expert assistance.