Twin Cummins 6BTA5.9 M3 Diamond Series Diesel Engines • ZF 220A Marine Transmissions
Marine Engine Survey
Conducted by: Jeff Lendall & Sons — 805 Marine Diesel Mechanic
This survey documents the visual inspection, operational testing, sea-trial performance, cooling-system condition, turbocharger findings, ZF 220A transmission operation, fuel-system condition, oil-analysis sampling, repair recommendations, and final machinery assessment for the propulsion systems aboard this 2003 Luhrs 34 Convertible.
Cummins 6BTA5.9 M3
ZF 220A
Sea Trial
Cooling System Review
Executive Survey Summary
As a result of my investigation, marine engine survey, visual inspection, operational testing, oil-analysis sampling, and sea trial, my opinion is that the overall machinery rating is VERY GOOD, with several important maintenance items requiring attention.
The twin Cummins 6BTA5.9 M3 Diamond Series engines have low operating hours for machinery of this age and demonstrated smooth starting, strong oil pressure, very minimal smoke, smooth ZF transmission engagement, and acceptable high-load performance.
VERY GOOD
1235 Port / 1228 Starboard
Port turbocharger and cooling-system service
Important Finding:
The port-side turbocharger is leaking oil from the seals and requires replacement. The port-side cooling system also requires service, including the heat exchanger, lube oil cooler, transmission oil cooler, hoses, and hose clamps.
System Condition Matrix
| System | Condition |
|---|---|
| Fuel Filtration System | Very Good |
| Lubrication System | Very Good |
| Cooling System | Port side requires complete scheduled service |
| Seawater Pumps | Very Good |
| Turbochargers | Port side leaking oil — replacement required |
| Engine Alignment | Very Good |
| ZF 220A Marine Transmissions | Very Good |
| Throttle & Shifter Controls | Operational — cable replacement recommended due to age |
| Cooling-System Hoses & Clamps | Port side replacement required |
Vessel & Engine Identification
| Specification | Port Engine | Starboard Engine |
|---|---|---|
| Engine Make | Cummins | Cummins |
| Engine Model | 6BTA 5.9-M3 Diamond Series | 6BTA 5.9-M3 Diamond Series |
| Engine Type | Inboard | Inboard |
| Power | 370 HP | 370 HP |
| Fuel Type | Diesel | Diesel |
| Hours | 1235 | 1228 |
| Serial Number | 46260015 | 46260014 |
| Engine Location | Port | Starboard |
| Transmission | ZF Marine Transmission 220A | ZF Marine Transmission 220A |
Operational & Visual Inspection Findings — Cummins 6BTA5.9 M3
Fuel Filtration System:
Racor Twin Fuel Filter/Water Separator 10-micron port and starboard assemblies appeared serviceable with no water present.
Throttle & Shifter Controls:
Morse cable shifters worked properly at flybridge and main cabin locations. The older red-jacket control cables should be replaced to improve smoothness and long-term reliability.
Seawater Pumps:
Seals were not leaking, no water was present, and adequate seawater pressure was observed.
Tube-Type Heat Exchanger:
Port-side cooling system requires service. Inlet and outlet temperatures remained within operating parameters during testing.
Engine Oil Cooler:
Port-side cooling system requires service. Inlet and outlet temperatures remained within acceptable operating range.
Coolant Level Sensors:
Working properly with no leaks observed.
Engine Mounts and Beds:
Main engine beds consist of heavy longitudinal stringers inboard and outboard. Engine mounts appeared satisfactory.
Lube Oil Pressure:
At 100% engine load, oil pressure measured approximately 42 PSI port and 43 PSI starboard.
Cooling System Type:
Freshwater reservoir cooling with seawater-cooled wet exhaust operated satisfactorily.
Seawater Strainers:
2-inch Groco bronze-alloy strainers with sight glass appeared serviceable and maintained.
Hoses and Clamps:
Most port-side cooling-system hoses and hose clamps require replacement.
Belts and Pulleys:
Belt and pulley condition appeared serviceable.
Engine Alignment:
Appeared smooth and without vibration.
Turbochargers:
Port-side turbocharger is leaking oil and requires replacement. Turbochargers appeared to spool around 1200 RPM and operated satisfactorily during testing.
ZF Marine Transmissions:
Both ZF 220A marine transmissions shifted adequately with no excessive vibration or abnormal noise underway.
Sea Trial Report
| Sea Trial Item | Observation |
|---|---|
| Engine Start | Both Cummins engines started without excessive cranking. |
| Exhaust Appearance | Very minimal smoke observed for engines of this age. |
| Cooling Water Discharge | Cooling-water discharge appeared adequate and normal. |
| Instrumentation | All gauges operated within normal operating limits at idle, cruise, and WOT. |
| Oil Pressure | Approximately 42 PSI port and 43 PSI starboard under full load. |
| Steering System | Steering system was very responsive underway. |
| Transmission Operation | Both ZF 220A transmissions shifted smoothly with no excessive noise. |
| Backdown Test | Backdown test was satisfactory. |
| Rudder Linkage | Rudder linkage operated smoothly underway with no leaks observed. |
| WOT Test | Port engine reached approximately 2800 RPM and starboard approximately 2900 RPM with no visible smoke. |
Wide Open Throttle Test:
Port Cummins 6BTA5.9 M3 reached approximately 2800 RPM and starboard approximately 2900 RPM, both within acceptable operating parameters. Port oil pressure remained approximately 42 PSI and starboard approximately 43 PSI. No visible smoke was observed and the propulsion systems operated smoothly under high load.
Recommendations & Observations
Both Cummins 6BTA5.9 M3 marine engines have very low hours considering the machinery is more than 20 years old. Both engines ran well and appear relatively fresh for their age and operating hours.
Primary Recommendations:
-
The Morse throttle and shifter control cables are older red-jacket style cables. Although they operated during the survey, replacement is recommended for smoother operation and improved long-term reliability.
-
The port-side turbocharger is leaking oil from the seals and requires replacement.
-
The port-side heat exchanger, lube oil cooler, transmission lube oil cooler, and associated cooling-system components require scheduled servicing and descaling.
- The aftercooler appears to be fairly new.
-
Most port-side cooling-system hoses and hose clamps require replacement.
Master Marine Diesel Troubleshooting Guide – 805 Marine Diesel Mechanic
Cooling-system pressure testing was performed satisfactorily.
Starboard Engine Injector Line Leak
Starboard Cummins 6BTA5.9 M3 observed under load. A leaking injector line was identified and requires repair.
Port Engine — 2800 RPM @ WOT
Port Cummins 6BTA5.9 M3 observed at approximately 2800 RPM during wide-open-throttle testing.
PORT TURBOCHARGER LEAKING OIL — REPLACEMENT REQUIRED
Port Cooling-System Service Findings
Port Cooling System Requires Service:
Heat exchanger, lube oil cooler, transmission lube oil cooler, associated hoses, hose clamps, gaskets, seals, and cooling-system components require scheduled service.
Oil Analysis Samples
The following laboratory oil-analysis samples are included as part of the machinery survey record:
| Component | Oil Analysis Link |
|---|---|
| Port Cummins 6BTA5.9 Engine | Oil analysis link not provided in source survey. |
| Starboard Cummins 6BTA5.9 Engine | Oil analysis link not provided in source survey. |
| Port ZF 220A Marine Transmission | Oil analysis link not provided in source survey. |
| Starboard ZF 220A Marine Transmission |
Priority Recommendations & Estimated Repair Cost
| Recommended Repair / Service | Estimated Labor |
|---|---|
|
Port Engine Cooling System: Remove, descale, and clean cooling-system components. Replace gaskets and seals. Service heat exchanger, lube oil cooler, transmission lube oil cooler, aftercooler, and exhaust mixing elbow. |
9 hours |
|
Port Engine Turbocharger: Replace leaking turbocharger. |
4 hours |
|
Port Cooling-System Hoses & Clamps: Replace cooling-system hoses and hose clamps. |
7 hours |
|
Port Engine Oil Filter: Replace leaking oil filter. |
0.5 hour |
|
Starboard Engine: Repair leaking fuel injector line. |
1 hour |
| Materials | Estimated Cost |
|---|---|
| Cooling-system hoses and hose clamps | $1,200 |
| Turbocharger | $3,850 |
| Turbocharger gasket, bolts, V-clamp & hoses | $220 |
| Cooling-system gaskets and seals | $120 |
| Oil filter | $26 |
| Zinc anodes | $86 |
Labor:
21.5 hours × $175/hr = $3,675
Parts:
$5,502
Estimated Total:
$9,177
Final Surveyor Conclusion
Based on visual inspection findings, operational testing, oil-analysis sampling, and sea-trial observations, the propulsion systems aboard this 2003 Luhrs 34 Convertible appear mechanically sound and generally well maintained for engine age and operating hours.
The twin Cummins 6BTA5.9 M3 Diamond Series engines demonstrated favorable operational characteristics including smooth starting, strong oil pressure, minimal exhaust smoke, satisfactory ZF transmission engagement, and strong high-load performance.
The primary concerns identified during this survey are the port-side turbocharger oil leakage, deferred port-side cooling-system service, aging cooling-system hoses and hose clamps, older Morse control cables, and the starboard fuel injector line leak.
Pending correction of these maintenance items, the machinery package demonstrated generally favorable operational performance.
Overall Machinery Condition: VERY GOOD
Professional Survey Notes
NOTICE:
The following statements limit the liability of the undersigned and set ethical standards associated with this report. Use of this report for any purpose constitutes acceptance of the following:
NOTE A:
This report is issued without prejudice and is the property of the Requestor as listed above. Any use or distribution by another party is prohibited and shall render this report invalid.
NOTE B:
This report is issued subject to the understanding that the undersigned surveyor is not responsible for error, omission, negligence, or misstatement. This report is a statement of my opinion based on the conditions as I found them. It is not a warranty, express or implied.
Professional Marine Engine Surveys
805 Marine Diesel Mechanic provides professional marine engine surveys, pre-purchase diesel inspections, sea trials, cooling-system evaluations, oil analysis, transmission inspections, fuel-system diagnostics, and marine diesel troubleshooting throughout Ventura, Oxnard, Channel Islands Harbor, Santa Barbara, Marina del Rey, and surrounding Southern California harbors.
Survey Conducted By
Owner / Surveyor: Jeff Lendall
Jeff Lendall & Sons
805 Marine Diesel Mechanic