Repowering from Gas to diesel

S

Salacia

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Hi Folks

I live in Scotland and the price of gas over here is getting to the point where my boat is going to be sitting in the garage next year rather than being used so I am considering changing my 3.0l 2007 mecruiser to a diesel. I don't know if this is possible and whats involved has anyone got any thoughts or has anyone done this?

The other thing I am considering is running on biodiesel as a guy I know has all the gear to make it and I can make it for next to nothing. I know the cars run fine on this but not sure about the boats again has anyone any experiance of this?

Thanks in advance

Rob
 
S

Salacia

Petty Officer 2nd Class
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Messages
132
Re: Repowering from Gas to diesel

After some research a cummings 1.7TD may be a option
Salacia said:
Hi Folks

I live in Scotland and the price of gas over here is getting to the point where my boat is going to be sitting in the garage next year rather than being used so I am considering changing my 3.0l 2007 mecruiser to a diesel. I don't know if this is possible and whats involved has anyone got any thoughts or has anyone done this?

The other thing I am considering is running on biodiesel as a guy I know has all the gear to make it and I can make it for next to nothing. I know the cars run fine on this but not sure about the boats again has anyone any experiance of this?

Thanks in advance

Rob
Click to expand...
 
Bondo

Bondo

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Re: Repowering from Gas to diesel

Salacia said:
After some research a cummings 1.7TD may be a option
Click to expand...

Ayuh,.... I'm guessin' you've got an Alpha drive, 'n I've never seen a diesel motor, with an Alpha drive...

All I've seen, were with Bravo drives...
 
S

Salacia

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Re: Repowering from Gas to diesel

Bond-o said:
Ayuh,.... I'm guessin' you've got an Alpha drive, 'n I've never seen a diesel motor, with an Alpha drive...

All I've seen, were with Bravo drives...
Click to expand...

Yep it's an Alpha 1 second gen.
 
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Capt Ken

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Re: Repowering from Gas to diesel

It won't work with an alpha drive. Bravo yes, alpha no.
 
QC

QC

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Re: Repowering from Gas to diesel

Well . . . I would say the Alpha/Bravo thing has to do more with what his speed expectations are. In the UK he may simply want to putter around the canals, so output (input) would not be a big deal. That assumes you could get an Alpha to shift properly, which may be what Bond-o and Capt. Ken are focused on.

For the economic side of it I made the attached spreadsheet a little while ago, just formatted for UK units (litres and pounds).

Also, note that it is in .ods format (Open Source), but you can save as an .xls and use it as a normal Excel file, but it should also open as is with Excel.

Just change the Yellow cells. I put in one pound per diesel and petrol litre. Key things are daily fuel use, days per year, and the cost of the repower. Typically, unless you use fuel at a commercial rate (daily and a lot) it probably won't make pure economic sense.

Where in Scotland are you?
 

Attachments

  • UK Diesel Payback Calculator.ods
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S

Salacia

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Re: Repowering from Gas to diesel

QC said:
Well . . . I would say the Alpha/Bravo thing has to do more with what his speed expectations are. In the UK he may simply want to putter around the canals, so output (input) would not be a big deal. That assumes you could get an Alpha to shift properly, which may be what Bond-o and Capt. Ken are focused on.

For the economic side of it I made the attached spreadsheet a little while ago, just formatted for UK units (litres and pounds).

Also it is in .ods format (Open Source) you can resave as an .xls and use it as a normal Excel file, but it should also open as is with Excel.

Just change the Yellow cells. I put in one pound per diesel and petrol litre. Key things are daily fuel use, days per year, and the cost of the repower. Typically, unless you use fuel at a commercial rate (daily and a lot) it doesn't make pure economic sense.

Where in Scotland are you?
Click to expand...

Thanks QC I am in Glasgow on the west coast. The kids tend to ski a lot and I can rack up ?100 a time so a few outings like that and a two week vacation soon add up.
 
QC

QC

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Re: Repowering from Gas to diesel

I've spent some time over there. Stayed in Largs I think it was. Edinburgh too, but thinking of the West coast. Plug your numbers in. I think you'll still be surprised. I think I used 10O liters. What are you paying for diesel and petrol now? You buy road fuel, right? I ask because I don't know your off road tax rates for fuel. Sadly, I do know how high your road fuel taxes are... ;)
 
Don S

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Re: Repowering from Gas to diesel

Some diesels have been used with the Alpha drives. The idle of the diesel is usually rough enough that a shift interrupt switch is not needed.
Some of todays diesels may not have that rough idle, and therfore can't be used with the alpha drives,
Some of the Cummins 1.7 diesels have been used by Mercruiser. Does the one you are looking at fit that profile, who knows.
 
r.j.dawg

r.j.dawg

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Re: Repowering from Gas to diesel

If I'm not mistaken the Mercruiser/Cummins 1.7 was designed as an inboard. Came with its own tranny/drive (much like a v-drive). Not sure if a coupler is available for mating to a stern drive.
 
Don S

Don S

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Re: Repowering from Gas to diesel

Yes, there are part numbers for sterndrive couplers.
Untitled2.jpg

There is also diagrams for the shift cable brackets for the drives lower shift cable, but no indication if for Alpha or Bravo.

Either way, adapting a diesel to a gas sterndrive is going to be an uphill battle. Especially if you don't have a flywheel housing for a sterndrive, and the 1.7 didn't have that either. What it did have is a jack shaft setup.
 
QC

QC

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Re: Repowering from Gas to diesel

Yep, and that's why the discussion starts with the money. You can buy a lot of petrol for the cost of even a few of the parts. If you have to actually buy an engine too, then it gets worse. There are exceptions, and the UK has the highest priced fuel in the world bar none, so maybe. Still very hard with most pleasure uses.
 
H

HT32BSX115

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Re: Repowering from Gas to diesel

QC said:
Yep, and that's why the discussion starts with the money. You can buy a lot of petrol for the cost of even a few of the parts. If you have to actually buy an engine too, then it gets worse. There are exceptions, and the UK has the highest priced fuel in the world bar none, so maybe. Still very hard with most pleasure uses.
Click to expand...

Money is the key here. There's plenty of examples of small automotive diesels in boats. I especially like the VW TDI engines. Here's 2 examples.

A V-6 3.0L engine: http://www.youtube.com/watch?v=fFBAtGeQIJw&feature=related one has to fabricate a flywheel housing and coupler connection.

And a 4.2L V-8 TDI in an inboard with a Velvet drive I presume.... http://www.youtube.com/watch?v=zWLf_BqZzv4&feature=related


The V-8 is claimed to be 350hp.

VW has a complete family of direct injection diesels from 3 cyl to 4,5,V- 6,8, and 10 cyl engines All are proven reliable engines.

Why Mercruiser and Volvo don't take advantage of these is beyond me.... We're still stuck with ancient GM V-6 and V-8's
 
Don S

Don S

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Re: Repowering from Gas to diesel

Why Mercruiser and Volvo don't take advantage of these is beyond me.... We're still stuck with ancient GM V-6 and V-8's
Click to expand...

Volvo has been building it's own diesels for a hundred years, why would they use a VW diesel?

Mercruiser is the one that doesn't make it's own diesel and uses Cummins exclusively.
 
H

HT32BSX115

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Re: Repowering from Gas to diesel

Don S said:
Volvo has been building it's own diesels for a hundred years, why would they use a VW diesel?

Mercruiser is the one that doesn't make it's own diesel and uses Cummins exclusively.
Click to expand...

They've also used VW diesels in cars.. One particular Volvo car came stock with a 2.4L turbocharged VW diesel back in the 80's. Evidently VW supplies engines to MANY OEM's worldwide
 
Bondo

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QC

QC

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Re: Repowering from Gas to diesel

I bet 30K.
 
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