Repower questions

Then with the lower specific fuel consumption of the diesel I would say that your fuel bills for the diesel will be roughly 70% of the outboard bills. Personally I don't like floating around on the water in a plastic coffin together with a load of gasoline; have you seen what is left of a grp boat after a gas fire?

I would stick to the diesel concept; single engine, avoid the heavy stuff and design for a decent prop size, we will assist you with that when you have homed in on a suitable engine/transmission combination!

Got to leave you now, its late here and I'm preparing for an early morning, search training the dogs. Back on sunday, bye bye!

 

What about these specs?

Engine type: 6,599 cc (6.599 L; 402.7 cu in) V8 turbo
Bore x Stroke: 4.06 in (103.1 mm) x 3.90 in (99.1 mm)
Aspiration: Turbocharged & Intercooled
Valvetrain: OHV 4-V
Compression: 17.5:1
Injection: Bosch High Pressure Common-rail
Power / Torque: 310 bhp (230 kW) @3000rpm / 590 lb·ft (800 N·m) @1600 rpm
Head casting is 8gf1
Block casting is #22351021213
Weight: 849 Lbs.

 

The VW car engines really are only 265 lbs each. Mine were approx 360 lbs with gearbox, bell housing, heat exchanger manifold and raw water pump.

 

I spent several hours yesterday at boat shops trying to pin down a path.

A single inboard with a kicker is the cheapest easiest way to go forward using the same gear in the boat now.

Outboards on a bracket seemed like a good option. But when I looked at OB yesterday I saw that too is bull of pitfalls. Twin 115 or a single 225 and a kicker are about the same price. But then the rigging and controls etc push it up near 19K. I found a pair of Merc 200 offshore for a great price, but the dealer said they may or may not be a good deal. he says about 8K to rebuild them to make them reliable. And they may not end up great after all that.

A GM 6.5 seemed to be a good path. But now that I look for them, there are not many for sale. And the updates to make them reliable ( ie cooler) is pretty spendy and gets me back up in the price.

I posted the specs for a GM Duramax 6.6 above. It is only 850lbs and may be able to run on the current gear? Didnt get an feedback on that yet. These are twice the cost of the 5.9 Cummins but almost 400 lbs lighter. If they can run on the current gear, this would turn into the quickest path.

Failing the above, Im back to the 5.9 and modifying per the above reccomendations.

 

Read Baeckmo's post #31 again, regarding fuel cost and dangers.
I wish to add that the design life of outboards is extremely short.
In the industry this is called Mean Time Between Failures or MTBF. For an outboard 50 hours is regarded as normal (one summer season), from a diesel you may expect 10 or 20 times more.

 

Those diesel hp figures are for very occasional use if you want them to last any amount of time.

I thought the D-Max weighed 1000 lbs??

VW Marine rates the 4 cyl TDI to about 70 so they last and don't have warranty issues.

If you want 250 hp for short periods of time what about a Cummins 3.9 BTA ...it's 2 cylinders lopped off a 5.9.

Marine versions had 250 hp, but one could easily get a lower hp one and do an injector swap and tweak the boost a touch.

Guys get 700-800 hp out of them with a ton of boost...

725 pounds I think,rebuild kit for $500

 

6.5 diesel $5,800.00 http://www.automotix.net/engines/65dieselengine.html

 

Actually they do a bit better than that.
VW offers a 1.9TDI as an industrial engine with 86 hp continuous rating.
For passenger cars they go much, much further. The top end is the BPX or BUK model, adapted for the Seat Ibiza, delivering 158 bhp @ 3750 rpm.
Models with up to 148 bhp @ 4000 rpm are used extensively in the Ford Galaxy and VW Sharan.

 

CDk ..wonder why they rate the industrial higher than the marine?

As you know those car ratings are just peak,I should know as I had a TDI 150 that was modded to 300+ hp.
I certainly wouldn't run it for long at that,though

 

I will stick my neck out a little because I am short on details so maybe others could fill in some blanks and offer their thoughts. Since crowsridge is back to considering a single/kicker using a large single diesel what about reinforcing the transom and hanging a Merc Bravo II on his rig? It would seem to me that would be a much more straight forward job although it would use up some prime cockpit space if it is mounted directly at the transom. Or the engine could be moved forward and turn the drive via a jackshaft like Albermarle uses on their boats.

My recollection is the Bravo II can turn a nice big aluminum propeller so should match up OK with a diesel and not have the corrosion issues that the Bravo IIIs have with the dual stainless props.

 

Did a quick search and found Bravo II props up to 18.75" diameter three bladed and 18.5" four bladed.

 

One of the pitfalls of my job working for the railroad is all the down time. Either waiting for trains to get by, or like today. 10 hours of driving. That gives me wayyyy too much time to think and go back and forth on things. I left part out of my post this morning on the way out the door. Cost wise, the twin VW is still in the hunt.

For those of you with inboards. How often to you foul a prop with a crab rope etc? And if you did, would you get both of them? This is the argument my sons give agains inboard, aside less room.

I just cant get over the hump of having one fuel type, non explosive etc..

They tried to sell me a Verado 225. Brand new 2008, 8.5K. BUT then its $3500 for the controls. But whats the point of going wireless, if I have to run controls back to a kicker anyway? Plus the bracket and rigging, Im back at 15+K for power. That defeats the purpose of this project once again. To see if I can build this and much less costly than new.

 

Wow, nationwide search CL and Ebay and not a single 3.9? That doesnt sound promising...... I got the 849 lbs off the GM website. Not very many of them either. I can get a nice clean one local for 4K. Thats just under what the VW twins will cost.

 

VW Marine has been shifting its focus to the 5 cylinder engines, offering a range from 55 to 165 hp, all based on the same engine. That is probably a management decision, not an engineering one. They only have one TDI-4 at this time and never developed newer variants.

The industrial division is another VW owned company, with its own strategy.

 

So if I use the TDI 1.9's, and the 14" props, what is the ratio? I thought the 2-1 was for the 5.9? There are lots of 1-1's and I found a rebult pair of 1.5-1 with all hardware incl. props for a good price.

Thanks!