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Detroit Diesel 8V71TA Marine Engine Survey

46ft Bertram Marine Engine Survey

Conducted by : Jeff Lendall & Sons. 805 Marine Diesel Mechanic

 

Detroit Diesel 8V71TA Marine Engine Survey

     M/V Bad Habit:

                    HIN/IMO: 116E595 OFFICIAL#:949819 LOA:46.5FT YEAR: 1978

ENGINE 1:

 

ENGINE 2:

 



GENERATOR 1:



 




FUEL FILTRATION SYSTEM: Racor Twin Turbine Series Fuel Filter/Water Seperator 10 Micron Port & Starboard side filter assembly: Appeared serviceable, No water present. Electric priming pump & vacuum gauges installed


THROTTLE & SHIFTER CONTROLS: Morse cable shifters worked properly at flybridge and Main cabin locations.


SEAWATER PUMP: Seals not leaking/no water present. adequate pressure.


PLATE-TYPE HEAT EXCHANGER: checked inlet and outlet flow temperature, within parameters


ENGINE OIL COOLER: checked inlet and outlet temperatures, all within parameters


ENGINE MOUNTED FUEL COOLER: checked inlet and outlet temperatures, all within parameters


SEAWATER PUMP OUTLET PRESSURE: adequate pressure


COOLANT LEVEL SENSOR: working properly no leaks observed.


ENGINE MOUNTS AND BED:  Main engine beds are heavy longitudinal stringers inboard and outboard. Engine Mounts Satisfactory


LUBRICATION: Oil Level indication is normal both port and starboard.


LUBE OIL PRESSURE: (WOT) engine 100% load 51 psi. port engine 50 psi starboard engine


COOLING SYSTEM TYPE: Freshwater reservoir type cooling with Seawater cooled wet exhaust, Operated satisfactory.


SEAWATER STRAINERS: 3 inch Groco bronze alloy with sight glass. Appeared serviceable. well maintained


COOLANT LEVEL: Normal levels observed. Pressurized expansion tanks on both engines to 25psi no noticeable drop in pressure. used heat sensing gun on all cooling system surfaces. operated normal.


HOSES AND CLAMPS: Double clamped where sighted. All quality 304 SS style hose clamps. 


BELTS AND PULLEYS: Belts & Pulleys condition appeared serviceable


SEACOCKS AND STRAINERS: Seawater seacocks were ball valve type. Operated smooth & satisfactory. 


EXHAUST SYSTEM: Seawater cooled with risers and flexible coupling sections double clamped where sighted. 


ENGINE ALARMS: Test of port and starboard low oil pressure alarm, and coolant overheat warning audible at helm station. Operated satisfactory.


ENGINE SHUT DOWN: electronic style shut off solenoid switches operated satisfactory 


STUFFING BOXES: Packing gland style, both leaking at correct rate.


EMERGENCY SHUT-DOWNS. Port and starboard emergency shut down morse cable, both engines cables and actuators need to be replaced/serviced


ENGINE ALIGNMENT: Appeared Smooth & without vibration.


RUDDERS: Packing gland style, not leaking excessively appeared serviceable. no vibration.


TURBOCHARGERS: no tests performed on turbos, sounded like they spooled up around 1200 RPM and operated satisfactory


ALLISON TRANSMISSIONS: Both performed adequately while shifting no excessive noise or vibration while under way. port side leaking excessively at engine pump


——————————————————————————————-


SEATRIAL REPORT:


1. The engines started without excessive cranking.


2. The engine exhaust appeared normal. very minimal smoke for engines of this age.


3. The cooling water exhaust appeared adequate and normal.


4. The engine instruments operate within normal operating limits at idle, cruising speed and at wide open throttle.


5. The steering system operated normally. very responsive.


6. The throttles operated normally. need adjustment for WOT synchronization.


7. The transmissions, both went in & out of gear smooth with no excessive noise


8. The backdown test was satisfactory.


9. both rudder linkage operated smooth while underway, no leaks detected


10. OIL LEAKS detected at port transmission, starboard governor, port and starboard valve covers.


WOT TEST: (wide open throttle) Starboard engine smoking a little. 
but it seems to go away as soon as you throttle down. 
Master Marine Diesel Troubleshooting Guide - 805 Marine Diesel Mechanic
   
OIL ANALYSIS PORT ENGINE:
Port Engine

OIL ANALYSIS STARBOARD ENGINE:  
Starboard engine

OIL ANALYSIS PORT TRANSMISSION:
Port Allison Transmission

OIL ANALYSIS STARBOARD TRANSMISSION:
Starboard Allison Transmission


OIL ANALYSIS GENSET:
Generator



 


MARINE ENGINE SURVEY SUMMARY:


As a result of my investigation, MARINE ENGINE SURVEY, and by virtue of my experience, my opinion is OVERALL ENGINE RATING:  GOOD: the engine room and engines appear to be well maintained.


marine engine survey rating


 


emergency shutdown cables detroit diesel engine


Port and starboard emergency shut down morse cables, both engines cables and actuators need to be replaced/serviced


oil leaking at marine engine governor


Oil Leaking at starboard side governor


 


oil leak at transmission pump


Excessive oil leaking from transmission pump port side, needs to be repaired (seals) or replaced 


 


 




Detroit Diesel 8V71TA Marine Engine Survey: Comprehensive Inspection, Diagnostics, and Pre-Purchase Evaluation




















A Detroit Diesel 8V71TA marine engine survey delivers an in-depth assessment of a two-stroke, V-8 turbocharged and aftercooled powerplant to verify performance, safety, and condition before purchase or major voyage. By combining visual inspection, sea trial data, diagnostic testing, and fluid analysis, this specialized service uncovers hidden wear, failure risks, and efficiency opportunities. In this guide, you’ll explore:






    

  1. 

    Key specifications and performance features of the 8V71TA
    

    2. 

  2. 

    The critical importance of a professional survey
    

    3. 

  3. 

    Common failure points and symptoms to watch
    

    4. 

  4. 

    A step-by-step survey checklist
    

    5. 

  5. 

    Cost factors and price ranges
    

    6. 

  6. 

    Maintenance best practices
    

    7. 

  7. 

    Criteria for choosing a qualified surveyor
    

    8. 

  8. 

    Overhaul and rebuild considerations
    

    9. 

  9. 

    Fuel efficiency and performance optimization strategies
    

    10. 

















Whether you’re buying a vessel, scheduling routine upkeep, or planning an overhaul, understanding the Detroit Diesel 8V71TA survey process ensures informed decisions and prolonged engine life.


















What Are the Key Specifications and Performance Features of the Detroit Diesel 8V71TA Engine?


















Detroit Diesel’s 8V71TA combines a two-stroke cycle with turbocharging and aftercooling to deliver exceptional power density in a compact marine package. This design promotes efficient scavenging, improved combustion, and reliable output under continuous load. The engine’s V-8 layout, 71 ci displacement per cylinder, and forced induction yield robust torque curves and fuel-efficient operation.


















What are the horsepower and torque ratings of the 8V71TA?


















At rated speed, the 8V71TA produces between 305 and 370 hp, with peak torque ranging from 863 to 1,112 lb-ft. These figures enable strong acceleration and cruising ability on vessels up to 40 feet.








 
















Detroit Diesel 8V71TA Engine Specifications






The Detroit Diesel 8V71TA is a two-stroke diesel engine with a displacement of 568 cubic inches. It produces between 350 and 500 horsepower, depending on the configuration. The engine is known for its robust design and high power-to-weight ratio, making it suitable for various marine applications.


















This source provides key specifications for the Detroit Diesel 8V71TA engine, which is essential for understanding its performance features.




















Typical brake specific fuel consumption (BSFC) for the 8V71TA falls between 0.38 and 0.45 lb/hp-hr, equating to about 20–22 gallons per hour at 80% load. Efficient marine gearing and propeller calibration can further lower fuel burn during extended cruising.


















What are the physical dimensions and weight of the 8V71TA marine engine?


















Below is an EAV table detailing the 8V71TA’s size and installation considerations:














Configuration




Measurement




Relevance








Length




46 in (1,168 mm)




Fits standard V-8 engine beds








Width




28 in (711 mm)




Clearance for service access








Height




35 in (889 mm)




Hood and exhaust space requirements








Dry Weight




2,215 lb (1,005 kg)




Hull trimming and balance considerations








Rotation Options




Left- or right-hand




Matching propeller shaft orientation


























Why Is a Marine Engine Survey Crucial for the Detroit Diesel 8V71TA?


















A marine engine survey is a systematic evaluation that uncovers hidden wear, misalignments, and performance degradations before they escalate into costly failures. By assessing mechanical, thermal, and fluid-related parameters, a certified surveyor verifies the engine’s suitability and safety for intended use.


















What benefits does a pre-purchase 8V71TA engine survey provide to buyers?




    

  1. 

    Risk Reduction – Identifies wear, corrosion, or damage that could lead to failure.
    

    2. 

  2. 

    Negotiation Leverage – Empowers buyers to adjust offer price for discovered defects.
    

    3. 

  3. 

    Usage Forecasting – Predicts maintenance needs and remaining service life.
    

    4. 

















Survey findings foster confidence and informed decision-making during vessel acquisition.


















How does a survey ensure vessel safety and engine longevity?


















By examining heat exchanger condition, cooling circuit flow, and exhaust parameters, a survey uncovers overheating risks early. Inspecting mounts, alignment, and vibration levels prevents hull stresses and bearing damage. Verifying oil and coolant cleanliness forestalls corrosion and component wear, directly extending engine lifespan and minimizing downtime.


















What role does the marine surveyor play in the 8V71TA inspection process?



















Their professional judgment transforms raw data into actionable recommendations.


















What Are the Common Issues and Failure Points Specific to the Detroit Diesel 8V71TA Marine Engine?


















Despite renowned durability, the 8V71TA exhibits known trouble spots tied to its two-stroke design, forced induction, and continuous marine operation. Early detection of these issues prevents major repairs.


















What causes overheating in the 8V71TA and how can it be detected?


















Overheating often stems from fouled heat exchangers, impeller wear, or blocked raw water intakes. Monitoring engine coolant temperature above 190 °F or observing warped exhaust manifolds signals inadequate cooling. A thermal scan of hoses and connections during a sea trial confirms hotspots.


















How to identify and address smoking exhaust problems?


















Black exhaust indicates rich fuel mixture or clogged air filters; remedy by cleaning the turbo inlet and adjusting fuel rack. Blue smoke suggests excessive oil consumption from worn piston rings or cylinder liners; address via compression testing and ring replacement. White smoke often results from coolant leaks into combustion chambers, requiring head gasket inspection.


















What are typical oil leaks and fluid contamination signs?


















External oil leaks appear at pump seals, valve covers, or drain plugs. Internally, emulsified oil with a milky appearance reveals coolant intrusion. High particulate counts in oil analysis point to bearing wear or metal scoring, necessitating component teardown.


















How do turbocharger and blower malfunctions affect engine performance?


















A failing turbocharger reduces boost pressure, causing sluggish acceleration and soot-laden exhaust. Bearing noise, shaft play, or oil bypass into the intake indicate imminent failure. Similarly, a worn Roots blower on non-turbo variants results in low low-end torque and rough idling.


















What are crankcase pressure issues and their symptoms?


















Excessive blow-by gases elevate crankcase pressure, leading to oil seal leaks and stiff reverse gear engagement. Symptoms include a whistling hiss and oil mist around seal edges. A blow-by test quantifies gas escape to determine needs for ring or liner overhaul.


















What Does a Comprehensive Detroit Diesel 8V71TA Marine Engine Survey Checklist Include?




















A structured checklist guides surveyors through every critical inspection point, ensuring no detail is overlooked and engine condition is accurately recorded for decision-making.








 
















Marine Survey Checklist






A marine survey checklist includes visual inspections of hoses, belts, and engine mounts, as well as monitoring parameters such as RPM, temperatures, and pressures during a sea trial. Diagnostic tests like compression testing and fluid analysis are also essential for a comprehensive engine assessment.


















This source provides a detailed checklist of items to be inspected during a marine engine survey, which is crucial for a thorough evaluation of the engine’s condition.


















What visual inspection points should be checked on the 8V71TA?



















These checks reveal obvious faults that influence safety and performance.


















How is the sea trial conducted and what parameters are monitored?




    

  1. 

    RPM ranges (idle to full load) for smooth acceleration
    

    2. 

  2. 

    Coolant and oil temperatures under load
    

    3. 

  3. 

    Oil and fuel pressure readings for stability
    

    4. 

  4. 

    Exhaust smoke color and opacity trends
    

    5. 

  5. 

    Vibration levels at engine mounts
    

    6. 

















Recording these parameters under working conditions verifies real-world reliability.


















What diagnostic tests are essential for the 8V71TA engine?



















Diagnostic insights pinpoint internal wear before visual signs emerge.


















Why is fluid analysis critical during the survey?


















Sampling oil, coolant, and transmission fluid reveals microscopic contaminants and degradation markers. Oil analysis detects metal particles from wear; coolant testing identifies corrosive byproducts or freeze-point shifts; transmission checks ensure clean hydraulic drive operation. Together, fluid analysis uncovers hidden stress and guides proactive maintenance.
































What Are the Best Maintenance Practices to Extend the Life of a Detroit Diesel 8V71TA Engine?




















Regular, proactive maintenance aligned with survey findings preserves the 8V71TA’s reliability and optimizes operational efficiency. A disciplined schedule prevents most major repairs and extends engine life beyond 20,000 operating hours.










General Service Guidelines for Detroit Diesel V71 Series Engines






Preventive maintenance for Detroit Diesel V71 Series engines includes daily checks of oil and coolant levels, weekly inspections of belts and hoses, and monthly fuel pressure tests. Regular maintenance, such as oil changes and filter replacements, prevents wear and tear on key components, ensuring the engine remains in top condition.


















This source provides a recommended maintenance schedule for Detroit Diesel V71 engines, which is essential for extending engine life and optimizing performance.


















How often should oil and filter changes be performed?


















Oil and filter replacements at 100-hour intervals or every six months (whichever comes first) keep lubrication clean, remove contaminants, and protect bearings and seals from accelerated wear.


















What cooling system maintenance is essential for the 8V71TA?



















Proper cooling prevents overheated components and extends gasket and hose life.


















How can survey findings guide ongoing maintenance decisions?


















Data from a professional survey—such as elevated blow-by levels or metal traces in oil—allows owners to accelerate rebuild schedules or adjust service intervals. This targeted approach saves cost and downtime by addressing emerging wear before catastrophic failure.




























What adjustments improve 8V71TA fuel economy during operation?





























Detroit Diesel 8V71TA engines demand specialized expertise throughout purchase, operation, and overhaul. A thorough marine engine survey reveals hidden wear, confirms safe performance, and guides maintenance strategies that extend engine life. Whether negotiating a vessel acquisition or planning a mid-life rebuild, investing in professional diagnostics ensures reliable power delivery for years to come.






 


		
				

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