Diesel engines in speed boat
01-30-2016, 08:09 AM
#401
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Location: Marco Island, FL; Waterloo, ON, CAN
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Bob
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01-30-2016, 08:15 AM
#402
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01-30-2016, 03:39 PM
#403
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Location: Sarasota FL. Priest River ID
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[QUOTE=sutphen 30;4398539]and then the crank will break.Happens in trucks,gonna happen quicker in a boat,especially a heavy boat.[/QUOTE
Guess Waglers really screwed then
Guess Waglers really screwed then
01-30-2016, 04:54 PM
#404
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01-30-2016, 06:32 PM
#406
Whats the diff between a cummins 8.3 marine engine and say an 8.3 that came out of a school bus or piece of heavy equipment?
Im interested in building a diesel powered boat about 40 ft to run from my island to cartagena daily about a 1.5 hour trip.
I will buy à boat rigged with arnesons and would like to put a pair of 500 hp ish cummins in it. Single speed gear with air tubes on the drives to help get it on plane but not looking to drop 140k on a pair of engines.
I see guys making decent power with the old 8.3 mech fi. On some of the diesel forums.
if i can run a combination of components from the iroginal engine and some marine stuff added to marinize it and throw in a few of joes mods like the on pistons to make it live, i think i could do it on a reasonable budget. I see those old 8.3 diesels in 40 year old busses down here in colombia still running daily!
Im interested in building a diesel powered boat about 40 ft to run from my island to cartagena daily about a 1.5 hour trip.
I will buy à boat rigged with arnesons and would like to put a pair of 500 hp ish cummins in it. Single speed gear with air tubes on the drives to help get it on plane but not looking to drop 140k on a pair of engines.
I see guys making decent power with the old 8.3 mech fi. On some of the diesel forums.
if i can run a combination of components from the iroginal engine and some marine stuff added to marinize it and throw in a few of joes mods like the on pistons to make it live, i think i could do it on a reasonable budget. I see those old 8.3 diesels in 40 year old busses down here in colombia still running daily!
01-30-2016, 11:23 PM
#408
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01-31-2016, 08:07 PM
#410
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I have a question for you joe, on running a diesel boat like say a 41 saber/apachce with a pair of cummins diesels in it with arnesons.
When you leave the water coming off big waves the diesels dont throttle up and down quickly , correct?, like a gas engine coming on and off of the throttles. ld think would let the turbo spool down enough for it to take a little while to be back to where it was when you chopped the throttles.
That being the case, Whats the best way to run a fast diesel powered boat in big water.
Have you ever tried a jake brake or driveline brake to unload the drive when youre air born.
i would think you do not want to over speed the engines or land with the throttles wfo
Ĺike when the posche turbo cars race, the diver stays on the gas and slows the car using the brakes but never fully coming off the gas so the turbo is always spooled up.
It would seem the instant on/off of a jake brake would have the engines at max power quicker.
Thx for sharing all your hard earned diesel knowledge with us. Rm
When you leave the water coming off big waves the diesels dont throttle up and down quickly , correct?, like a gas engine coming on and off of the throttles. ld think would let the turbo spool down enough for it to take a little while to be back to where it was when you chopped the throttles.
That being the case, Whats the best way to run a fast diesel powered boat in big water.
Have you ever tried a jake brake or driveline brake to unload the drive when youre air born.
i would think you do not want to over speed the engines or land with the throttles wfo
Ĺike when the posche turbo cars race, the diver stays on the gas and slows the car using the brakes but never fully coming off the gas so the turbo is always spooled up.
It would seem the instant on/off of a jake brake would have the engines at max power quicker.
Thx for sharing all your hard earned diesel knowledge with us. Rm
I've heard people say Buzzi would bungie cord the throttles to wide open and run the boat - that is 100% false! Watch Buzzi in Cowes Torquat Cowes maybe 88 or 89 it was rough and the boat was flying - Buzzi throttled 3 times as much as the gas boats and here's why but again mechanical fuel pumps
1) With the throttles held in a steady position (not throttled) when the props loose their bite as in leaving the water the governor would sense that the engine wants to rev way up and cuts the fuel to prevent run away without you doing anything - OK
2) When that fuel is cut to prevent run away with the loss of load on the engine, that makes less cylinder heat/pressure and the turbo boost with drop to near ZERO.
3) When the prop re-enters the water the load on the engine increase, the rpms drop the governor senses that loss and adds fuel again without moving the throttles.
4) The problem is the engine has lost boost and with the prop loaded once again the engine can not accelerate and build boost - that's the sequence of events.
Now to combat that when the props leave the water YES you pull the throttles back BUT not to prevent over-speed as much as to have the throttles back so you can pump them from idle to full throttle rapidly while the props are in the air and be ready to be push them from idle to full load as you re-enter the water.
The theory and it works is when air borne since there is no load on the props there NO WAY to build boost. The rapid idle to full tricks the governor and for split seconds the governor goes to full throttle and dumps in fuel, those quick spurts of fuel would keep heat in the cylinders and keep some boost on the turbo.
If you doubt that watch Buzzi throttles, he works harder than you think!
Jake brakes or things like that can't react fast enough to do what I describe above - I firmly believe that running a raceboat in rough water is a "feel" thing, you have it or you don't. Just because you could run a gas boat didn't mean you could run a diesel boat!
