44 ft Endurance Diesel
12-31-2013, 12:41 PM
#141
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The fuel coolers your probably right you have 80+ deg water! Again if you had an old Post, Ocean, even Hatteras sport fih the fuel tanks were coomon to the engine room so after a full day or running the engine heat allow heats up the fuel, forget that the DDA's push all the return fuel through the cylinder heads so that adds lots of heat. Maintaining at 100 is probably the best you can do.
(And I have on 2) of those mentioned) (One caveat here, adding to the problem of high temps vs performance, was some engine mfr's look at Delta-T, some max temp, some depression).
I see the Cummins spec back a few pages listed 294sqin per as required air. That is for consumption AND ventilation. As Joe mentions, in the distant past, OEM's disregarded ventilation air, and only calculated for consumption. (Often this was borderline at best, and miscalculated simply by forgetting the generator) If the consumption air was routed across hot or obstructed components...performance suffers.
(If I had a dollar for every E.R. door or hatch I couldnt open underway....but I digress).
I have seen many times (especially on Tier 3 engines w/high radiant heat) that ventilation sizing (& just as important) their location, will drop E.R.temps (incl fuel) in particular hulls.
I'm just speculating here based on my experience, but those Yanmars seem to be pretty close together. Without knowing where the air is coming & going in that engine room as I write, you may get some benefit(s) just from forcing ambient air between the engines. If you were to drop the E.R..temp, the tank temp should follow. A well-engineered ventilation sytem will see temps drop everywhere in the engine room, as speed increases.
12-31-2013, 02:44 PM
#142
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Think you can go without the twospeed for pleasureboating. Need the first gear with full tanks (1400 liters) and for really heavy seas. Makes almost 70 mph in first.
12-31-2013, 03:44 PM
#143
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stirling - the fuel injections pumps do not pull any fuel at all, they are a pressurized storage area where fuel is collected before it is forced into the high pressure plunger. All inline plunger and barrel or rotary pumps have lift pumps when you look at a DB-2 (on old 6.9, 7.3 & 5.7) there are actually 3 fuel pumps, supply or lift (externally mounted) suppling a medium pressure vane pump in the DB-2 to supply presure to the rotary plungers for high pressure.
12-31-2013, 03:49 PM
#144
Registered
Actually, you might be able to lessen.
(And I have on 2) of those mentioned) (One caveat here, adding to the problem of high temps vs performance, was some engine mfr's look at Delta-T, some max temp, some depression).
I see the Cummins spec back a few pages listed 294sqin per as required air. That is for consumption AND ventilation. As Joe mentions, in the distant past, OEM's disregarded ventilation air, and only calculated for consumption. (Often this was borderline at best, and miscalculated simply by forgetting the generator) If the consumption air was routed across hot or obstructed components...performance suffers.
(If I had a dollar for every E.R. door or hatch I couldnt open underway....but I digress).
I have seen many times (especially on Tier 3 engines w/high radiant heat) that ventilation sizing (& just as important) their location, will drop E.R.temps (incl fuel) in particular hulls.
I'm just speculating here based on my experience, but those Yanmars seem to be pretty close together. Without knowing where the air is coming & going in that engine room as I write, you may get some benefit(s) just from forcing ambient air between the engines. If you were to drop the E.R..temp, the tank temp should follow. A well-engineered ventilation sytem will see temps drop everywhere in the engine room, as speed increases.
(And I have on 2) of those mentioned) (One caveat here, adding to the problem of high temps vs performance, was some engine mfr's look at Delta-T, some max temp, some depression).
I see the Cummins spec back a few pages listed 294sqin per as required air. That is for consumption AND ventilation. As Joe mentions, in the distant past, OEM's disregarded ventilation air, and only calculated for consumption. (Often this was borderline at best, and miscalculated simply by forgetting the generator) If the consumption air was routed across hot or obstructed components...performance suffers.
(If I had a dollar for every E.R. door or hatch I couldnt open underway....but I digress).
I have seen many times (especially on Tier 3 engines w/high radiant heat) that ventilation sizing (& just as important) their location, will drop E.R.temps (incl fuel) in particular hulls.
I'm just speculating here based on my experience, but those Yanmars seem to be pretty close together. Without knowing where the air is coming & going in that engine room as I write, you may get some benefit(s) just from forcing ambient air between the engines. If you were to drop the E.R..temp, the tank temp should follow. A well-engineered ventilation sytem will see temps drop everywhere in the engine room, as speed increases.
Aside from that you're running little Yanmar's that the Hp/cui already has them as "hi-performance" engine. You want to put more furl into them and get more power. This entire site is full of people telling others they are "stupid"(harsh for effect only) if when they add a bigger carb they have to change the stock exhaust, they change the intake, change the cam and you can't use those heads and on and on....
The more HP you try for the higher the EGT and you will get to the point that engine life is shorten so much their is no point to a diesel. The things I talked about on here earlier about flow, etc is just so you realize "hey to take it to the next level is not easy".
This was my beef with Fabio - great you have a engine that runs two races and then it needs "maintanance", how is that different than a gas engine and who in their right mind will buy them for commerical or pleasure applications? Looking back now 20+ years and I was right Seatek is irrelevant and Fabio went to FPT.
Don't build headaches build memories and on this ngiht of the year when we look ahead and back at highs and lows I regret the time I spent playing with the engine room when I should have just spent time on the water. For me the later years of doing all kinds of work was a job, we got paid to develope and test, the early years were to get to that point - you guys don't plan on making a business out of it so be careful and don't take the pleasure out of your hobby.
I'm going out now have a Happy New Year's and chat next year!!!
12-31-2013, 03:54 PM
#145
Registered
Joe ,I haven,t got the boat in the water yet ,I let both engines run on the hose for 15 min , just to see if everything was working properly ,the engines kept running (although idling only ) so my guess was the injection pump pulls fuel by using that manual operated pump that is used to prime the engine at its first start ,or when running out of fuel ... I thought those pumps were pushed by a cam ...
I might not have understood what you were asking when I answered, apologies!
Now I'm signing off before my wife kills me!
01-01-2014, 01:22 PM
#146
Registered
On lift pumps and bypass setups, I run a simple vane stlye from SX performance. Actually it's tagged as an elderbrock, it's the cheapest 190gph unit that summit sells. Contains a built in bypass valve / pressure regulator and no return line. This just provides added lift to the factory mechanical lift built on the cp3 high pressure pump. Since the regulator on the cp3 returns to tank, I prefer to let it manage that task.
If the SX pump fails, the mechanical lift still pulls enough fuel thru it for normal operation and will get ya home. Wide open running is no longer an option because she starves and will go into limp mode without the added fuel flow. I've considered ditching the mechanical lift, but it's not hurting anything. I also like that fass setup, but IMO its overkill and over priced for anything under 800hp. Most modern diesels are designed to deal with some air in the system from factory.
On fuel temps and return cooler, here is where it also gets specific to engine manufacturer. Since I have little experience with common marine diesels, I'll defer to each manufacturer requirements. What I can say is on anything running Bosch common rail, ya need it. I considered ditching that part on the Dmax till I saw the log data from normal cruising below. On the last rebuild I actually ditched the power steering cooler, and moved fuel return to an extra passage in the engine oil cooler unit. The Bosch design contains a temp sensor in the return line after all injector discharge converge. I normally see average fuel temps heading to the tank around 140-160F. So even 100 gallons is gonna warm pretty quick.
If the SX pump fails, the mechanical lift still pulls enough fuel thru it for normal operation and will get ya home. Wide open running is no longer an option because she starves and will go into limp mode without the added fuel flow. I've considered ditching the mechanical lift, but it's not hurting anything. I also like that fass setup, but IMO its overkill and over priced for anything under 800hp. Most modern diesels are designed to deal with some air in the system from factory.
On fuel temps and return cooler, here is where it also gets specific to engine manufacturer. Since I have little experience with common marine diesels, I'll defer to each manufacturer requirements. What I can say is on anything running Bosch common rail, ya need it. I considered ditching that part on the Dmax till I saw the log data from normal cruising below. On the last rebuild I actually ditched the power steering cooler, and moved fuel return to an extra passage in the engine oil cooler unit. The Bosch design contains a temp sensor in the return line after all injector discharge converge. I normally see average fuel temps heading to the tank around 140-160F. So even 100 gallons is gonna warm pretty quick.
Last edited by kidturbo; 01-01-2014 at 02:07 PM.
01-01-2014, 02:54 PM
#147
Registered
I would think you want your water temps to be closer to 200deg? You said lowered the seawater bypass pressure, you mean water is going through the engine faster or slower now? If you are running an open loop meaning seawater in and back out how are you controling air in the engine?
My guess is and I could be dead wrong that water is going through the egine too fast, you are not taking out enough heat and the high temps you see might be steam pockets, again i don't know what you're cooling looks like.
We had similar problems years ago and had to add various vent lines at all the high spots to get air out of the block, remember your cylinder temps are very high, cyl head temps are boiling hot because of your EGT's (that heat is cooking those heads and goes into the water) and the high compression with the turbo makes for cavitation around your cylinders whether there and liners or not the water will still boil around the cylinders from the oscillation that is just a by-product you can't get away from.
Just think about these things sometimes what you're seeing is the result of other forces and that what it appears to be on the surface?
My guess is and I could be dead wrong that water is going through the egine too fast, you are not taking out enough heat and the high temps you see might be steam pockets, again i don't know what you're cooling looks like.
We had similar problems years ago and had to add various vent lines at all the high spots to get air out of the block, remember your cylinder temps are very high, cyl head temps are boiling hot because of your EGT's (that heat is cooking those heads and goes into the water) and the high compression with the turbo makes for cavitation around your cylinders whether there and liners or not the water will still boil around the cylinders from the oscillation that is just a by-product you can't get away from.
Just think about these things sometimes what you're seeing is the result of other forces and that what it appears to be on the surface?
When they laid out my boat with an open loop setup, they opted for a 3/4" bypass line into the exhaust from where it enters the engine water pump. There is also a small factory cooling line off that GM pump feeding the turbo, then exiting into exhaust. So 95% of the water entering the engine must flow past the thermostats. Before that GM pump, on the charge cooler is a small pressure bypass valve and 5/8" line exiting out the side of the boat. With a fresh impeller in the seawater pump, it's pretty hard to maintain any decent engine temps when operating with standard water pressures.
That little bypass valve was meant to control cooling system pressure, but I cheat and let it bypass at around 3-4lbs vs 15-20lbs to raise engine temp. Works fine until ya open her up, then ya need to close it off again, which isn't possible on the fly. What's needed is another electronic bypass valve controlled by the ECU, and based off engine temp. But on my next design I'm going closed loop an won't have to mess with it..
01-02-2014, 01:25 PM
#148
Registered
Kid - I think so just close cool the engine itself and it will save you allot of troube, the cooler won't add that much weight, it's cooling the manifolds and turbos that use allot of the exchangers cpacity.
01-02-2014, 04:52 PM
#149
Registered
Actually, you might be able to lessen.
(And I have on 2) of those mentioned) (One caveat here, adding to the problem of high temps vs performance, was some engine mfr's look at Delta-T, some max temp, some depression).
I see the Cummins spec back a few pages listed 294sqin per as required air. That is for consumption AND ventilation. As Joe mentions, in the distant past, OEM's disregarded ventilation air, and only calculated for consumption. (Often this was borderline at best, and miscalculated simply by forgetting the generator) If the consumption air was routed across hot or obstructed components...performance suffers.
(If I had a dollar for every E.R. door or hatch I couldnt open underway....but I digress).
I have seen many times (especially on Tier 3 engines w/high radiant heat) that ventilation sizing (& just as important) their location, will drop E.R.temps (incl fuel) in particular hulls.
I'm just speculating here based on my experience, but those Yanmars seem to be pretty close together. Without knowing where the air is coming & going in that engine room as I write, you may get some benefit(s) just from forcing ambient air between the engines. If you were to drop the E.R..temp, the tank temp should follow. A well-engineered ventilation sytem will see temps drop everywhere in the engine room, as speed increases.
(And I have on 2) of those mentioned) (One caveat here, adding to the problem of high temps vs performance, was some engine mfr's look at Delta-T, some max temp, some depression).
I see the Cummins spec back a few pages listed 294sqin per as required air. That is for consumption AND ventilation. As Joe mentions, in the distant past, OEM's disregarded ventilation air, and only calculated for consumption. (Often this was borderline at best, and miscalculated simply by forgetting the generator) If the consumption air was routed across hot or obstructed components...performance suffers.
(If I had a dollar for every E.R. door or hatch I couldnt open underway....but I digress).
I have seen many times (especially on Tier 3 engines w/high radiant heat) that ventilation sizing (& just as important) their location, will drop E.R.temps (incl fuel) in particular hulls.
I'm just speculating here based on my experience, but those Yanmars seem to be pretty close together. Without knowing where the air is coming & going in that engine room as I write, you may get some benefit(s) just from forcing ambient air between the engines. If you were to drop the E.R..temp, the tank temp should follow. A well-engineered ventilation sytem will see temps drop everywhere in the engine room, as speed increases.
01-02-2014, 05:00 PM
#150
Registered
On lift pumps and bypass setups, I run a simple vane stlye from SX performance. Actually it's tagged as an elderbrock, it's the cheapest 190gph unit that summit sells. Contains a built in bypass valve / pressure regulator and no return line. This just provides added lift to the factory mechanical lift built on the cp3 high pressure pump. Since the regulator on the cp3 returns to tank, I prefer to let it manage that task.
If the SX pump fails, the mechanical lift still pulls enough fuel thru it for normal operation and will get ya home. Wide open running is no longer an option because she starves and will go into limp mode without the added fuel flow. I've considered ditching the mechanical lift, but it's not hurting anything. I also like that fass setup, but IMO its overkill and over priced for anything under 800hp. Most modern diesels are designed to deal with some air in the system from factory.
On fuel temps and return cooler, here is where it also gets specific to engine manufacturer. Since I have little experience with common marine diesels, I'll defer to each manufacturer requirements. What I can say is on anything running Bosch common rail, ya need it. I considered ditching that part on the Dmax till I saw the log data from normal cruising below. On the last rebuild I actually ditched the power steering cooler, and moved fuel return to an extra passage in the engine oil cooler unit. The Bosch design contains a temp sensor in the return line after all injector discharge converge. I normally see average fuel temps heading to the tank around 140-160F. So even 100 gallons is gonna warm pretty quick.
If the SX pump fails, the mechanical lift still pulls enough fuel thru it for normal operation and will get ya home. Wide open running is no longer an option because she starves and will go into limp mode without the added fuel flow. I've considered ditching the mechanical lift, but it's not hurting anything. I also like that fass setup, but IMO its overkill and over priced for anything under 800hp. Most modern diesels are designed to deal with some air in the system from factory.
On fuel temps and return cooler, here is where it also gets specific to engine manufacturer. Since I have little experience with common marine diesels, I'll defer to each manufacturer requirements. What I can say is on anything running Bosch common rail, ya need it. I considered ditching that part on the Dmax till I saw the log data from normal cruising below. On the last rebuild I actually ditched the power steering cooler, and moved fuel return to an extra passage in the engine oil cooler unit. The Bosch design contains a temp sensor in the return line after all injector discharge converge. I normally see average fuel temps heading to the tank around 140-160F. So even 100 gallons is gonna warm pretty quick.
Also I disagree completely about diesels, especially modern common rail, being designed to deal with some air in the system. The least bit of air can quickly cause permanent damage to injectors and pumps.
