Has anyone chaged there engine size?

[wayland]

Hi I have a 42' steel Colvin Gazell sailboat with a bad diesel sabb engine. The repair parts would cost me over $3500.00. What I am wondering will a car engine like the Alfa Remeo Diesel or Volkswagen Diesel have the power to move my boat like 7 knots. Has anyone done any changes like this? Thanks Wayland

[delmarrey]

Automotive diesels are a differant can of worms. The starters are not spark resistant, the fresh water pumps are all iron/alum, the altenators are basic and the paint is really not sooted for marine service.

If you want it to be fresh water cooled you'll have to come up with a heat exchanger as well as a water cooled exhaust.

Other differances maybe the camshaft maybe set up for excelleration vs torque. Mounting brackets would have to be custom made and finding the proper bellhousing to fit the tranny you want maybe a problem.

And then if you need parts ................that's a whole nutter story.

By the time you get it all set up, you'll wish you had just bought the one at the boat show............................_/)

[hellosailor]

There's a subcult that have converted the VW Pathfinder diesel (an air cooled industrial model) in boats, but I have no idea how the hp rating compares to what you have or need.

As Delmarrey says, you can and will have problems with "marinization" issues, including compatible metals, galvanic problems, spark/combustion controls...It can be done, but doing it right will require a lot of investigation and it may not pay off in the long run.

A Saab diesel? I guess they use them in trucks too? Any chance you can get the more expensive pieces from a truck junkyard or dealer? Or are they special marine engine parts?

[wayland]

Have you ever changed to car diesel engine or personally known anyone who did? I would like to know there problems. Car parts are easy to find, Boat parts are very expensive and I know made for boats and saltwater.

[wayland]

Originally Posted by hellosailor

There's a subcult that have converted the VW Pathfinder diesel (an air cooled industrial model) in boats, but I have no idea how the hp rating compares to what you have or need.

As Delmarrey says, you can and will have problems with "marinization" issues, including compatible metals, galvanic problems, spark/combustion controls...It can be done, but doing it right will require a lot of investigation and it may not pay off in the long run.

A Saab diesel? I guess they use them in trucks too? Any chance you can get the more expensive pieces from a truck junkyard or dealer? Or are they special marine engine parts?

Hi, I just bought the Colvin Gazell sailboat knowing the engine needed parts. Somebody pulled the head in the past, Why I don't know. If the car engine sounds to bad I may just buy a new engine. Just testing my car ideal here. Thanks Wayland

[Alan Wheeler]

The biggest issue you have between a boat engine and automotive use is the govenor in the Injector pump. They are very different and work very differently, determining power points in your engine performance very differently. Not saying they don't work, they just don't work quite as well. You know an automotive diesel in a boat when you hear one at idle. It "hunts" or revs intermitently up and down at idle.
Now to the other comment you made about marine engine parts being more expensive. Actually this is not the case. You will find make for make, the parts being ruffly the same. It is just that there are a few specific marine engines out there that have very expensive parts. But there are also some specific engines that are reasonably priced parts as well. The one reason why some parts may tend to be slightly different is going back to the power points in the two differing engines. An automotive engine maybe designed to give max power/torgue points at very different RPMs than a marine engine. This is achieved by several design differences in Injector pump and cam shaft being the major two. This can also mean that other area's of the engine are built ever so slightly different, such as main and big end bearings, as the load is "felt" by these components in a very different way.
I do know of many boats with Automotive engines and I do know many that work just fine. But these engines are the old traditional Fords and Perkins etc. I also know of some boats that have tried the late model Jap Diesels because they are so cheap. In a nut shell, every single one has been a compleate dismal failure in some way.

[delmarrey]

I have the German 1981 VW Rabbit diesel (50 hp) in mine and it does fine. I have around 7000 hours on it with only a head job and new fresh water cooled headers. It gets me up to hull speed at 3200 rpms and the boat weighs in at 7 tons. I been told by others that have them that they will not last in the heavy boats due the the engine mass. They were put in racing boats because they were light weight engines. And I do run a blower in my engine compartment while at hull speed.

Heavy engines can handle the long continous running. The mass absorbs the heat trasnfer. Car and truck engines usually have air passing over them to help them cool. But in a boat they are enclosed with only the blower (maybe) and the air intake drawing in cooler air..............._/)

[ssullivan]

More of a question, but what do lobster boats run? Wouldn't a nice Catterpillar or Kuboda engine work very well? I see a lot of commercial boats with standard type engines routed through vertical pipes and mufflers (where the exhaust isn't mixed with water). Seems to me that a standard engine would do just fine if you do the exhaust in a more standard way, rather than mixing it with the cooling water.

[ssullivan]

More of a question, but what do commercial vessels and lobster boats run? I often see them with vertical exhaust systems and a standard truck muffler. They make a nice throaty sound, like a truck would. Seems like a nice Kuboda or Catterpillar engine would work out so long as you could sort out the heat exchanger situation and possibly do something with the exhaust.

[Boracay]

While other posters are covering the issues of marinising an automotive engine (most marine conversions seem to be of industrial engines) I would suggest that you keep in mind your goals. I mean, what are your plans?
My understanding is the Sabb is a well respected marine engine. If parts are available then fixing it is an option. If it is in pieces then it would probably need to be pulled out and completely rebuilt by a competant shop.
You may care to cost out a repower vs a rebuild.
I am in a similar position in that I have a kaput engine in a largish steel boat.
My options are to repower or to fix.
Either is going to be expensive. Fixing an obscure engine (mine) is a questionable project.
At the moment I have a large number of other tasks and I am not going anywhere soon. An repower at the moment would leave me with an expensive engine being covered in sawdust and epoxy powder.
But then at the moment I am in a reasonably(?) priced, secure, easy access marina becoming very familiar with that old time rock and roll.
So I am planning to do everything else and the last job is going to be the engine. In the meantime it might decide to fix itself...

[SkiprJohn]

Hi Wayland,
I think you got a lot of good answers. Yes, its been done but usually with mixed results. Why not buy that really nice Perkins on eBay? Right amount of hp and rebuilt.
After having gone through what you suggest and written about it in another thread on this forum I recommend you shop around for a good used engine, Perkins or Yanmar. Stay away from Saab or Volvo because of their expensive parts and pieces.
Good luck in your decision.
Regards,
JohnL

[SkiprJohn]

Aloha Wheels,
You've made a very good point. RPM determines hp in my little diesel. If I run it to max at 3600 I get 42 hp. Since that overheats the engine and sounds terrible I usually keep it at no more than 2000 I only get about half the rated hp, say 21. To put my 34 LWL boat at hull speed in calm waters requires 8-9 hp. About 4 hp for alternator, a bit of hp loss for hydraulic trans and belt driven pumps I'd say another 4 that leaves me 3-4hp over what I really need. If I need to kick it up into a wind or tide then I can go at 3000 for quite a time before overheating.
Little engine is ok with me.
Regards,
JohnL

[hellosailor]

Wheels, which makes of late model Japanese diesels have disappointed you?

[Alan Wheeler]

Several adn for many of the extra reasons posted above. But probably the most common one we see down here in NZ is the Nissan LD28 Diesel engine. It is a very cheap 2.8ltr 6 cylinder diesel that is very common and very reliable.(in vehicles) Turbo versions are very easy to find giving a very good power to weight ratio. But as soon as you place them in a boat, it all changes. They smoke like they run on coal, they don't get the power in the right rev range, which means you need to crank the snot out of them and operate up in the 4K RPM plus range. And that is the real minus for any of the Vehicle engines out there. They are all (mostly all) designed to achieve their power and torgue in high rev ranges. Properly designed Marine engiens are designed to operate in much lower RPMS. Even though big commercial engines may have top RPM of say 1200RPM, modern day boat engines still range from 2400 upto 3600 ish. Most Vehicle engiens are happy to run out to 4500 throught to 5 and 6K. They are not designed to stay up there, but when in a boat, they do need to be up there to get the power potential of the engine.

[wayland]

From Wayland,
I want to thank all who replied to my questions about car engines. What I have leaned from the post. Thick diesel engine body handles heat transfer better. Burns fuel better meaning better fuel mileage than gas engines. Diesel engines have more power. Diesel is much safer than gas on inboards. What I will do is fix the Sabb or buy another strong diesel engine. All the good answers here helped me make up my mind.
Thanks to all, Wayland