MDE Unit 6 Q3

A higher than normal crankcase pressure reading can indicate several potential issues with the engine:

Internal Engine Issues:

• Blow-by gases: Excessive combustion gases escaping past the piston rings into the crankcase. This can be caused by worn piston rings, cylinder bore wear, or incorrect valve timing.   1. Influence of Compression Rings on the Dynamic Characteristics and Sealing Capacity of the Combustion Chamber in Diesel Engines – MDPI www.mdpi.com
• Piston ring sticking: If piston rings stick in their grooves, they cannot effectively seal the combustion chamber, leading to increased blow-by gases.   1. The Effects of Stuck Rings & Blowby on Engines – YouTube www.youtube.com
• Crankshaft oil seal failure: Leakage of oil into the crankcase from the crankshaft seal can increase the volume of fluid in the crankcase, leading to higher pressure.
• Valve guide wear: Excessive wear of valve guides can allow oil to seep into the combustion chamber and then back into the crankcase.

Ventilation System Issues:

• Clogged PCV (Positive Crankcase Ventilation) valve: The PCV valve is responsible for venting crankcase gases. If it’s clogged, pressure can build up.   1. Crankcase ventilation system – Wikipedia en.wikipedia.org2. When Should You Replace the PCV Valve? – Cars.com www.cars.com
• Blocked crankcase breather: Similar to the PCV valve, a blocked breather can prevent the escape of crankcase gases.
• Breather hose collapse or blockage: If the hose connecting the crankcase breather to the atmosphere is collapsed or blocked, it can restrict airflow and increase pressure.

Other Factors:

• Overfilling the crankcase: Excessive oil in the crankcase can lead to foaming and increased pressure.   1. What does Too Much Oil do to an Engine? – Crossroads Helpline www.crossroadshelpline.com
• Engine overheating: High engine temperatures can increase the volume of gases in the crankcase.

It’s important to investigate the root cause of the high crankcase pressure to prevent further engine damage.

A high crankcase pressure reading indicates underlying issues that can lead to significant problems if not addressed promptly.

Engine Damage:

• Increased wear: Elevated pressure can accelerate wear on engine components, such as piston rings, cylinder walls, and bearings.
• Seizure: In severe cases, excessive pressure can lead to engine seizure due to oil starvation or mechanical failure.
• Oil foaming: High pressure can cause oil to foam, reducing its lubricating properties and increasing engine wear.

Performance Issues:

• Reduced power output: Blow-by gases can reduce engine efficiency and power.   1. Blow-By 101: How To Prevent It From Ruining Your Engine – Pit+Paddock pitpad.com
• Increased fuel consumption: Incomplete combustion due to blow-by can lead to higher fuel consumption.   1. What Is Engine Blow-by? What Does it Mean? – Woodstock Power woodstockpower.com
• Increased emissions: Higher levels of harmful emissions, such as hydrocarbons and carbon monoxide, can result.

Safety Risks:

• Fire hazard: If the crankcase pressure becomes excessive, it can lead to an explosion or fire.
• Personnel safety: An engine failure due to high crankcase pressure can pose risks to personnel on board.

It’s crucial to identify and address the root cause of high crankcase pressure to prevent further damage and ensure the safe operation of the engine.

If the engine crankcase pressure gauge indicates an abnormally high reading, the following immediate actions should be taken:

1. Reduce Engine Load: Gradually reduce the engine load to minimize stress on the engine components.
2. Monitor Engine Parameters: Closely observe engine parameters such as oil pressure, temperature, and vibration for any abnormal indications.
3. Inspect for Oil Leaks: Check for visible oil leaks around the engine and turbocharger.
4. Prepare for Emergency Shutdown: Be ready to shut down the engine if the situation deteriorates rapidly.
5. Notify Engineering or Maintenance: Inform the relevant personnel about the issue for further assessment and action.

Remember: These are general guidelines and specific procedures may vary based on the vessel type, engine model, and emergency procedures in place. Always prioritize safety and follow established protocols.

To accurately determine the root cause of high crankcase pressure, a systematic approach is required. Here are some essential checks and investigations:

Visual Inspections:

• Engine oil: Check for excessive foaming, water contamination, or metal particles.
• Crankcase breather: Inspect for blockages or restrictions.
• Turbocharger oil lines and seals: Look for signs of leakage or damage.
• Engine external components: Check for any visible signs of oil leaks or damage.

Diagnostic Tests:

• Compression test: Assess the compression pressure in each cylinder to identify potential issues with piston rings, valves, or head gasket.
• Leakdown test: Determine the condition of the cylinders and piston rings by checking for air leakage into the cooling system or crankcase.
• Cylinder balance test: Evaluate the power output of each cylinder to identify potential imbalances.
• Oil analysis: Send an oil sample for laboratory analysis to detect contaminants or wear metals.
• Engine vibration analysis: Check for abnormal vibration patterns that might indicate mechanical issues.

Additional Considerations:

• Engine operating history: Review the engine’s operating history for any recent changes or unusual events.
• Maintenance records: Check for any previous engine repairs or overhauls.
• Fuel quality: Verify the quality of the fuel used.
• Cooling system performance: Ensure the engine is not overheating, as this can contribute to increased crankcase pressure.

By conducting a thorough investigation and considering multiple factors, the root cause of the high crankcase pressure can be identified and addressed effectively.