Vetus VH4.65 good&reliable? Tune it to VH4.80 without gearbox ratio adaption

[CaptainRivet]

Hi all,

Is a vetus VH 4.65 a good and reliable Engine?
The Hyundai H100 2.6D D4BB is the base Engine which Vetus then marinize. The Hyundai is known and proven simple Diesel engine and is widely used in a lot of Pickups, busses, Transporter, Vans, Mini Trucks especially in 3rd world countries due to simple,robust,easy to repair.
The Vetus too or did they screw up the marinization? Also you will never have to do a overhaul of the engine, I get a low mileage D4BB for 500$ and a new for below 3000$ so no overhaul makes sense as a good used or even a new block and head is cheaper then rebuild.

You can also easily tune the Vetus VH4.65 =65hp to a VH4.80=80hp. Only 3 differences: bigger diameter exhaust elbow, bigger impeller pump and rev limiter is raised from 3000RPM to 4000rpm. The additional 15hp just comes from reving higher, there is no difference till 3000rpm between the two engines.
But the 4.80 has a different gearbox ratio to account for that. I assume if I keep the 4.65 gearbox ratio then engine will rev higher but the extra 15hp won‘t change anything like top speed.
Can I get around that by buying a different folding prop with eg different pitch or size?
Maybe not 100% like original 4.80 but if it’s 90% is ok for me. I am a total noobie on that gear ratio and Propeller stuff..
Impeller pump and elbow need to be changed anyhow and the fixed standard prop i want to replace by a folding prop. so tuning/modifying it is just the price difference from 4.65 to 4.80 parts but it won‘t make sense if I need to change the gearbox to get the benefits of the extra 15hp.

[Roboreeves]

Hi CaptainRivet

I have the exact same question and dilemma. Did you manage to find out any more?

Rob

[CaptainRivet]

Originally Posted by Roboreeves

Hi CaptainRivet

I have the exact same question and dilemma. Did you manage to find out any more?

Rob

which question and dilemma do you mean, there are several above?


Modifiying to 80hp and keeping the 65hp gearbox? Yes you can do it with a different prop to somewhere in the 80 till 90% range compared to the 80hp gearbox.
but you need a professional that calculates you what prop size, pitch...you need now depending on your spezific boat. I was told the following: on a light boat the loss low down and higher diesel consumption is neglectable and you get significantly more top speed. But if you have a heavy displacment boat then the loss at low RPMs is very noticeable (means you need to rev higher for the same speed) which also results in more diesel consumption and speed gain is not much.


But it is worth to just get the 80HP parts (bigger elbow and impeller pump) just as spare part instead of the 65h parts even without raising the rev limiter as this is optimises the engine cooling I was told.

If propeller is not due and 65hp ellbow and pump is good, its not worth modifiying in my eyes. But both are wearables/maintenance parts anyhow so just stock the 80HP parts and swap when 65hp fails, then try rising the rev limiter+different prop. If you get more speed with nearly same diesel consumption, good but if not you optimised cooling which is important too and just swap the old prop back on.

But I didn't buy this boat with the Vetus engine so I didn't try but I would have done it.

[Roboreeves]

Good point, there were several questions in your post! Thank you for your reply. I am considering re-engining with the 65hp but when I saw the 80hp was the same engine I wondered what was so different it justified £1000 (roughly) more.



When you mentioned the gearbox difference I did wonder about that. I have to re-prop anyway and this sounds like a cheaper way to have some extra power. That said, the power curves below 3000rpm look identical and would I really want to run the engine that faster than that. I just thought better to have it than not.

My boat is quite light, an aluminium Ovni just under 48' overall. I am replacing a Perkins Prima M60 that itself was rated at 60hp at 4000rpm. I thought it seemed underpowered in rough seas past Gibraltar so I wanted a little extra.


This leads to another thing, I do not want a turbo charged engine particularly and there is little choice in that power range. Volvo, Yanmar and Nanni are turbo. The Beta 60 looked ideal but that is only 56hp and there seems to be a big cost difference to their 50hp for 6hp. It actually only leaves Vetus 65 as far as I can see.


No one replied to your reliability question. From what I have read they did have some heat exchanger problems but Vetus have upgraded this now. I cannot see why the Vetus should be a problem in any other area.


Anyway I waffle, sorry. You post is very useful because I would think it would cheaper even from new to buy the 65hp because the parts to upgrade must be cheaper than a thousand pounds!



There is a down side, it comes with a hydraulic grearbox so I will need to find a way to break the prop shaft when sailing. Nothing is ever straight forward.