Marinising A Vehicle Engine

[Biggles]

Hello

 

Am I missing something? When I look at modern NB engines they tend to be of Japanese decent. All I can see is instead of having a radiator there is a skin tank for the cooling. I know often there is additional weight added to the flywheel as well and of course the bell housing to the gearbox.

 

So disregarding ancillaries like extra 12v & 240v alternators, and hydraulic pumps what else is there that makes a standard vehicle engine marinised?

[Guest]

Hello

 

Am I missing something? When I look at modern NB engines they tend to be of Japanese decent. All I can see is instead of having a radiator there is a skin tank for the cooling. I know often there is additional weight added to the flywheel as well and of course the bell housing to the gearbox.

 

So disregarding ancillaries like extra 12v & 240v alternators, and hydraulic pumps what else is there that makes a standard vehicle engine marinised?

The heat exchanger/exhaust manifold is one of the most expensive parts I am told. My friend marinised an Isuzu for his last boat which made a good conversion, but it cost quite a lot for the bell housing, engine mounts, heat exchanger etc. I note that for his present (third) fitout that he has bought an engine/box ready to drop straight in.

[Ex- Member]

Hello

 

Am I missing something? When I look at modern NB engines they tend to be of Japanese decent. All I can see is instead of having a radiator there is a skin tank for the cooling. I know often there is additional weight added to the flywheel as well and of course the bell housing to the gearbox.

 

So disregarding ancillaries like extra 12v & 240v alternators, and hydraulic pumps what else is there that makes a standard vehicle engine marinised?

 

That's about it, and sorting out the engine mounting framework, some people marinise their own engines, I think you can get kits to do it also. But you have to chose the correct engine not all are suitable. I always thought a Mercedes 190 2.0 diesel would make a good engine, pretty well bulletproof. But I think it would only pay doing it on a used engine, the time you mess about marinising a new engine it would probably been as cheap to buy it marinised in the first place, plus you would have the waranty.

[Biggles]

Used engine would be what I am thinking. So suggestions on suitable units of the 70hp range would be good. Thinking widebeam power now.

[NB Esk]

A lot will depend on how much work you are able to put in yourself, & to some extent, the position of the engine in the boat.

 

 

On the ex-plant engine above, I made the gearbox to engine adaptor plate (bellhousing) as well as some other work.

The engine won't be tucked away in a cocooned installation, so a water cooled manifold is not as important...

[Biggles]

The plan would be to put under a cruiser stern. Does the exhaust have to be water cooled then?

 

The amount of work I'd be willing to do would be dependent on the savings to be made. I am an engineer and welder by trade, but not a motor engineer of any note.

 

Things like engine mounts would be no problem, and I would look for an engine that has bell housing and gearbox options availiable.

[alan_fincher]

Off repeated advice is to not overhead cam engines in a canal environment.

 

This would seem to rule out many of the newer automotive engines, and explain why older push rod type engines are still regularly marinised.

 

I agree with what others have said - even if you have the requisite skills, marinising your own is by no means a no-brainer. To do it properly, and produce something equivalent to a proper marine engine, the parts do seem to be surprisingly expensive.

 

Even for a widebeam 70HP seems rather OTT to me.

[Biggles]

Are the Jap engines push rod then. It was my understanding that timing belts were the problem due to rusting of the sprockets during periods of non use. Would the same apply if the timing was done by chain on an OHV.

 

Is 70 to much for a widebeam, bearing in mind at boat running it probably would not reach max HP.

 

Keen to learn anything on the topic of marinising.

[NB Esk]

Are the Jap engines push rod then. It was my understanding that timing belts were the problem due to rusting of the sprockets during periods of non use. Would the same apply if the timing was done by chain on an OHV.

 

Is 70 to much for a widebeam, bearing in mind at boat running it probably would not reach max HP.

 

Keen to learn anything on the topic of marinising.

 

Keep an eye on ebay. Occasionally, there are ex army gen sets for sale. Because they run in an enclosed cabinet, they are often *marinised*.

 

There may be governor issues, so check for suitability...

[lazyboy]

Japanese engines that are marinised are mainly from the dumper truck, excavator, small tractor or water pumping set market. You should look for an engine with a Variable speed governor, Heavy SAE4 flywheel housing and 7.5 inch flywheel arrangement. Be especially aware of hydraulic pump adaptors in the front end gear cover as they make the fitting of anti vibration mounts very awkward. The Isuzu 70hp in particular is marinised from the Isuzu industrial engine model 4JGPK .

[Biggles]

Japanese engines that are marinised are mainly from the dumper truck, excavator, small tractor or water pumping set market. You should look for an engine with a Variable speed governor, Heavy SAE4 flywheel housing and 7.5 inch flywheel arrangement. Be especially aware of hydraulic pump adaptors in the front end gear cover as they make the fitting of anti vibration mounts very awkward. The Isuzu 70hp in particular is marinised from the Isuzu industrial engine model 4JGPK .

 

 

Very interesting. Thanks