inquisitivej
Veteran Member
- Joined
- Oct 18, 2024
- Messages
- 49
- Location
- Seattle
- Vessel Name
- Raven
- Vessel Make
- Grand Banks 42 Classic
My port engine runs a few degrees hotter than starboard according to the gauges at both helm and fly bridge (doing 1800 rpms 175 degrees starboard and ~178 for port). Infrared thermometer says the engine blocks are pretty much the same temp. The engine heat exchanger (as opposed to the transmission oil heat exchanger) on the port read 10 to 15 degrees hotter than the starboard. I've not yet taken the temp of both transmission oil exchangers (on the todo list next time I'm underway for long enough). The flow rate out of the exhaust is unchanged from what is normal.
I've noticed no starting problems. No responsiveness or power issues of any sort. They perform almost identically. The port engine alternator charges the house battery bank so its alternator load is very often higher than starboard (only charges starting batteries).
I pulled the impeller out of the raw water pump. It was intact and in good shape as was the cam that forces the fins to flex (I've been told those can break or wear out and are often missed as a cause of cooling issues).
The coolant tank is full, the coolant looks uncontaminated and the same color as the starboard engine. The coolant pump belt is fine and same tension as starboard engine. All 4 heat exchangers (2 main and 2 transmission oil) were removed and serviced 3 years ago (not that long ago!).
The sea strainer is clean. Zincs are checked/replaced every 3 months.
I've discovered the raw water pumps are slightly different on each engine. The port engine pump is the white one in the pictures, the unpainted in the starboard. They use the same impeller, which means the GPM should be the same, yes? The raw water pumps on the 3116 are gear driven (can't imagine the gear size is different given the fixed attachment point of the pump (not like you could use a smaller or larger gear unless you could mount the pump in different spot).
These are very well maintained engines with around 3300-3400 hours on them. The prior owners did a great job, only been mine since December.
During survey haulout no issues were noticed with the thru-hull inlet for the port engine raw water intake.
I'm reluctant to take apart the heat exchangers since they were serviced so recently and I'm told they are quite hard to reassemble and have be water tight. I have not yet pulled supply side hose of the oil heat exchanger to see if i can see anything in there blocking up the whole flow of water. Seems thats the next easiest thing to check that could be playing a role. Seems low probability to me given the way water flows in this system. If something is blocking in the oil exchanger it would have had to make it past the impeller, through the engine exchanger, and to the intake side of the oil exchanger. Maybe the diameter of the tubes in the oil exchanger are much narrower?
If you have a 3116 TA 300hp I would love to hear what your infrared readings are for the main exchanger and the transmission exchanger. IIRC, on the starboard it was in the 115 degree range and the port was 125-130 ish range.
Once engines are up to temp I see no obvious exhaust from either engine while cruising at 1800rpm or when at idle after cruising.
Its not a problem, and maybe its normal? My concern is that its the beginning stages of something that *could* become a big deal, so I'm trying to listen to what the engine is telling me so it never becomes a surprise or big deal.
Hopefully thats enough detail to get some good suggestions from all of you and some good questions. I'm sure there are 3116 experts here, I am a novice still.
Thanks in advance!
I've noticed no starting problems. No responsiveness or power issues of any sort. They perform almost identically. The port engine alternator charges the house battery bank so its alternator load is very often higher than starboard (only charges starting batteries).
I pulled the impeller out of the raw water pump. It was intact and in good shape as was the cam that forces the fins to flex (I've been told those can break or wear out and are often missed as a cause of cooling issues).
The coolant tank is full, the coolant looks uncontaminated and the same color as the starboard engine. The coolant pump belt is fine and same tension as starboard engine. All 4 heat exchangers (2 main and 2 transmission oil) were removed and serviced 3 years ago (not that long ago!).
The sea strainer is clean. Zincs are checked/replaced every 3 months.
I've discovered the raw water pumps are slightly different on each engine. The port engine pump is the white one in the pictures, the unpainted in the starboard. They use the same impeller, which means the GPM should be the same, yes? The raw water pumps on the 3116 are gear driven (can't imagine the gear size is different given the fixed attachment point of the pump (not like you could use a smaller or larger gear unless you could mount the pump in different spot).
These are very well maintained engines with around 3300-3400 hours on them. The prior owners did a great job, only been mine since December.
During survey haulout no issues were noticed with the thru-hull inlet for the port engine raw water intake.
I'm reluctant to take apart the heat exchangers since they were serviced so recently and I'm told they are quite hard to reassemble and have be water tight. I have not yet pulled supply side hose of the oil heat exchanger to see if i can see anything in there blocking up the whole flow of water. Seems thats the next easiest thing to check that could be playing a role. Seems low probability to me given the way water flows in this system. If something is blocking in the oil exchanger it would have had to make it past the impeller, through the engine exchanger, and to the intake side of the oil exchanger. Maybe the diameter of the tubes in the oil exchanger are much narrower?
If you have a 3116 TA 300hp I would love to hear what your infrared readings are for the main exchanger and the transmission exchanger. IIRC, on the starboard it was in the 115 degree range and the port was 125-130 ish range.
Once engines are up to temp I see no obvious exhaust from either engine while cruising at 1800rpm or when at idle after cruising.
Its not a problem, and maybe its normal? My concern is that its the beginning stages of something that *could* become a big deal, so I'm trying to listen to what the engine is telling me so it never becomes a surprise or big deal.
Hopefully thats enough detail to get some good suggestions from all of you and some good questions. I'm sure there are 3116 experts here, I am a novice still.
Thanks in advance!