timjet
Guru
- Joined
- Apr 9, 2009
- Messages
- 1,920
My twin Cummins 6B 330 series have performed flawlessly for the last 2 years. A little history. The port engine was replaced with a Cummins certified reman in November 2013. Part of the reason was both engines were over-propped for the first 1300 hrs of their lives. So the port engine reman has 500 hrs properly propped its entire life and the starboard engine has 1850 hrs with the first 1300 hrs over-propped.
I run the boat 75% of the time at 1400 rpm at displacement speed, the rest is at 2400 rpm on plane. Coolant temps on the port reman engine is 180 at 1400 rpm and 190 at 2400 rpm. Coolant temps on the starboard engine is 180 at 1400 rpm and slightly above – 182 at 2400 rpm. Boost pressures at 2400 rpm are 8.5psi for the reman and 10 psi for the starboard engine. When Cummins certified the reman their test data showed a boost of 11.8 psi on the reman. I recorded the boost shown on the gauge at certification and it was 8.5, so my gauge is probably off or I’m getting leakage somewhere in the tube or connection. The important thing here is that the boost has not deteriorated since the install.
This data shows an interesting point. The original starboard engine seems to perform better than the port reman. Coolant temps are lower and boost is higher.
I installed SBMar’s envirovent crankcase ventilation system when I purchased the boat at 1000 hrs on the original engines. This system collects blow-by in a “puke bottle” rather than re-introduce it back into the crank case like the Walker air sep system, which I removed when I bought the boat. The reman engine has no blow-by but the original starboard engine produces about ½ qt of blow-by when run at 2400 rpm after about 15-20 hrs. It produces an insignificant about of blow-by at 1400 rpm.
If you’ve read this far I have a couple of questions. It’s been 500 hrs and 2 years since the aftercoolers have been serviced. Being back in Tampa after our 2 year cruise to the Chesapeake, I removed both aftercoolers and have disassembled the port reman. It looks very clean for 500 hrs of use with a little gunk that’s easy to remove. All the zincs were in good shape.
I will disassemble the starboard original aftercooler this morning. The air cleaner on this engine has a lot of blow-by gunking up the bottom of the air filter. This would be normal since the suction to remove the blow-by is created by the turbo.
1. The reman runs 10 deg hotter at planning speeds, should I also remove the heat exchanger and inspect? There was nothing blocking raw water flow in the aftercooler or tranny cooler. New impellers were installed 200 hrs ago and when they were replaced the old ones looked new. I don’t think the heat exchanger in terms of time needs to be cleaned. Does the fact that is runs 190 deg at planning speed something to be concerned about?
2. The original starboard engine has blow-by. Is ½ qt in 15-20 hrs at 2400 rpm excessive? Almost none at 1400 rpm. And if so is there anything I can do about it?
3. The original engine has 900 hrs since the heat-exchanger was serviced. Should I remove and clean? Coolant temps on this engine are good.
Lastly WOT at time of reman certification was 2950 on both engines 2 years ago. Last time I checked, 10 engine hours ago I got port reman – 2900 rpm, starboard original engine – 2800 rpm. The boat was heavy with 8 months of accumulated junk from living on it.
I run the boat 75% of the time at 1400 rpm at displacement speed, the rest is at 2400 rpm on plane. Coolant temps on the port reman engine is 180 at 1400 rpm and 190 at 2400 rpm. Coolant temps on the starboard engine is 180 at 1400 rpm and slightly above – 182 at 2400 rpm. Boost pressures at 2400 rpm are 8.5psi for the reman and 10 psi for the starboard engine. When Cummins certified the reman their test data showed a boost of 11.8 psi on the reman. I recorded the boost shown on the gauge at certification and it was 8.5, so my gauge is probably off or I’m getting leakage somewhere in the tube or connection. The important thing here is that the boost has not deteriorated since the install.
This data shows an interesting point. The original starboard engine seems to perform better than the port reman. Coolant temps are lower and boost is higher.
I installed SBMar’s envirovent crankcase ventilation system when I purchased the boat at 1000 hrs on the original engines. This system collects blow-by in a “puke bottle” rather than re-introduce it back into the crank case like the Walker air sep system, which I removed when I bought the boat. The reman engine has no blow-by but the original starboard engine produces about ½ qt of blow-by when run at 2400 rpm after about 15-20 hrs. It produces an insignificant about of blow-by at 1400 rpm.
If you’ve read this far I have a couple of questions. It’s been 500 hrs and 2 years since the aftercoolers have been serviced. Being back in Tampa after our 2 year cruise to the Chesapeake, I removed both aftercoolers and have disassembled the port reman. It looks very clean for 500 hrs of use with a little gunk that’s easy to remove. All the zincs were in good shape.
I will disassemble the starboard original aftercooler this morning. The air cleaner on this engine has a lot of blow-by gunking up the bottom of the air filter. This would be normal since the suction to remove the blow-by is created by the turbo.
1. The reman runs 10 deg hotter at planning speeds, should I also remove the heat exchanger and inspect? There was nothing blocking raw water flow in the aftercooler or tranny cooler. New impellers were installed 200 hrs ago and when they were replaced the old ones looked new. I don’t think the heat exchanger in terms of time needs to be cleaned. Does the fact that is runs 190 deg at planning speed something to be concerned about?
2. The original starboard engine has blow-by. Is ½ qt in 15-20 hrs at 2400 rpm excessive? Almost none at 1400 rpm. And if so is there anything I can do about it?
3. The original engine has 900 hrs since the heat-exchanger was serviced. Should I remove and clean? Coolant temps on this engine are good.
Lastly WOT at time of reman certification was 2950 on both engines 2 years ago. Last time I checked, 10 engine hours ago I got port reman – 2900 rpm, starboard original engine – 2800 rpm. The boat was heavy with 8 months of accumulated junk from living on it.