Engine replacement for a Westerly Discus advice

[Peter Q]

Hi all,

The engine on my Westerly Discus has been condemned and needs replacing. As it happens I was planning an engine replacement in the near future but it has unfortunately been bumped up the priority list!

At this early stage I have two questions:

(1) Manufactures

What has been removed is the original Volvo 35hp unit and where the boat is located at Essex Marina with Volspec on site replacing it with a new Volvo seems an obvious thing to to do. However, they are not cheap and are there other manufactures that I should be looking at before I make the decision?

My requirements in the the following order are:

- reliability
- availability of spares (not just locally but thought the UK, channel islands, the rest of Europe and the Nordics)
- ease of maintenance
- cost (note that this is behind the above requirements!)

Note that I will not be fitting the new engine myself.

(2) Engine size

The 35hp unit that has been removed seemed if anything a little more powerful than necessary. I found that the previous engine was rarely used above tick over, even motoring out of the Crouch at about 4-5 knots. Obviously extra power can be very useful motoring against the tide into the wind if needed in an emergency. Volvo currently only make a suitable 30hp or a 40hp unit so should I go up or down in size? A complication is that in all probability a new propeller will have to be fitted and I intend to fit a feathering prop which would obviously benefit from a little extra power. Also being a safety conscious chap I am inclined not to go down in power. I would be grateful to hear from anyone that has been through this process, particularly with a Discus or similar sized (33ft/10m) boat, for some advice.

Many thanks.

PQ

 

[alahol2]

Bump for a new user lost in the ether.

I am quite sure you will be advised to have a look at Beta engines. Based on Kubota engines spares are readily available all over the world. Beta themselves are superb at after sales service and advice.

 

[Tranona]

A Beta or Nanni 35 would be a good choice. It is a heavy boat at over 6.5tons and although a Volvo D1 30 would do the job, the Kubota based engines are 4 cylinder. Availability of spares is not a problem on either of those two brands, or for Yanmar or Volvo. Generally speaking Nanni and Beta are the preferred engines for replacements, because they concentrate on that market so are usually easier to fit and more competitive on price.

The important thing is to appraise the whole installation as you will probably need to use a new propeller (unless you have one where you can change the direction of rotation) and take the opportunity to overhaul or replace all the anciliaries.

 

[ex-Gladys]

Don't assume that an engine of the same manufacture will fit easier... A friend replaced a Volvo with a Volvo in a Sadler 34 and electrical connection/alternator and exhaust had all changed sides.....

 

[prv]

Generally speaking Nanni and Beta are the preferred engines for replacements, because they concentrate on that market

+1

Volvo and Yanmar are geared up to supply the big boatbuilders, and sell the odd replacement engine on the side. Whereas I don't think any major builder fits Beta engines from new, their whole business is selling to people doing exactly what you are. The base engines are Japanese Kubota used everywhere in generators, diggers, small tractors, etc with corresponding spares availability, and the conversion for marine use is done just outside Gloucester.

Pete

 

[Robin]

We had a 1978 Westerly 33 centre cockpit ketch, same boat as the Discus. we had a Mercedes OM636 42hp which IIRC was the same 4 cylinder engine as the Volvo as the one we removed went as spares for one of those I think. We wanted to retain a similar 4 cylinder engine for boat resale value purposes. We chose a Volvo MD22L 4 cylinder 50hp which was lighter and lower profile than the hunk of iron it replaced. The extra hp was never essential but worked very well. We had to repitch the prop and this made it less of a drag an added bonus. I don't know if that Volvo MD22L is still available but it was a Volvo green panted version of the Perkins Prima 50hp. My alternate choice at that time would have been a Yanmar and coincidentally that was what our next boat had, a 4 cylinder 4JHE 44hp, best engine we ever owned..


When we re-engined our W33 the Volvo fitted easily onto the existing bearers without need for significant mods other than new mounts and as I mentioned was lower height overall made access even easier from the front in the main cabin even without lifting the cockpit floor access hatchThat new engine gave 6kts at a silent 2,000rpm cruise and a very consistant 0.43 gph fuel consumption, better than the original.

 

[Tranona]

MD 22 has gone. It was an old BL Montego engine so dates from the 1980s. Replaced in the Volvo range by a D2 55 which is a different base engine.

Beta or Nanni 35 would be my choice out of what is on the market now, probably a Nanni because it is blue.

 

[KAL]

Our Discus was supplied from new by Westerly with the Mercedes OM626 mentioned in post #6 above. It really is the most fabulous engine. 56hp of oomph with solid, dependable reliability. Granted, a Beta is newer, but the Merc is the same engine that powers the refrigeration unit of the big refrigerated lorries that ply their trade up and down the motorways of Europe day in day out for hours on end; testament to their reliability and robustness. Parts are also available almost universally because of this.

If you wanted to explore this possibility, get in touch with Manfred at Westfield 4x4 in Lancs. He is, arguably, the UK's resident expert on the marinised version and can supply you with a new or recon unit which is hand build from scratch. He also carries all the necessary parts and spares and is a veritable fount of knowledge which he imparts freely over the phone if you ever have a problem.

One thought: have a chat with Manfred. He may not agree that your engine is kaput. Even if it is, he will probably be able to recondition it for you or take it in px for a replacement.

The Merc won't necessarily have the latest tech, but it is an engine which has proven itself over tens of millions of hours and it is not likely to let you down.

Good luck in your search, anyway.

 

[Tranona]

One thought: have a chat with Manfred. He may not agree that your engine is kaput. Even if it is, he will probably be able to recondition it for you or take it in px for a replacement.

The OP currently has a dead Volvo fitted to his boat not an MB (see his original post). Whilst an MB is as you say an excellent engine it is way OTT for the boat, and only fitted originally because there was few other sensible 4 cyl engines available and Westerly were already fitting the MB to the 36' range where it was suitable. The Discus does not need more than 35hp and the Beat/ Nanni 35 would be an excellent choice, although the slightly bigger and more expensive Volvo or Yanmar 40hp engines would be OK.

 

[BabaYaga]

- availability of spares (not just locally but thought the UK, channel islands, the rest of Europe and the Nordics)

Because this comes so high up on your list, I would say Volvo or Yanmar.
At least here in the Nordic countries the others are far, far behind in this respect. (speaking as a Beta owner.

 

[RAI]

Expect any engine change to cost a lot more than the engine itself. I replaced a Volvo with a Yanmar and the total bill was about twice the engine price. As you are not doing it yourself, it might be worth asking the people who will do it what they recommend. If they have much experience in re-engine-ing boats, then they may well have good advice. Personally, after Volvo and Yanmar experience, I would be looking closely at Beta.

 

[sailor211]

we have a W33 and occasionally think about changing the engine. A refurb OM636 is a silly price compared with a Beta or Nanni and the marine parts will be easier to come by. The Volvo total cost was not much more when I talked to a installer.

I did talk to a prop man who said the limitation on size meant the prop could not deliver more than 30HP so 30Hp at the prop would be the biggest engine require. A fellow owner who fitted a sole 30HP agreed with this. I also doubt that the original engine was fueled to produce more than 30HP which is what the manual the for marine market. And at 30 years old I bet it delivers a lot less. so I would tend towards the 30-35 Hp engines.

I would not expect to work the engine hard enough to need spares other then belts filters etc.

If there was not too much other work like propshaft, prop and exhaust etc I would consider a M Power.

 

[Robin]

we have a W33 and occasionally think about changing the engine. A refurb OM636 is a silly price compared with a Beta or Nanni and the marine parts will be easier to come by. The Volvo total cost was not much more when I talked to a installer.

I did talk to a prop man who said the limitation on size meant the prop could not deliver more than 30HP so 30Hp at the prop would be the biggest engine require. A fellow owner who fitted a sole 30HP agreed with this. I also doubt that the original engine was fueled to produce more than 30HP which is what the manual the for marine market. And at 30 years old I bet it delivers a lot less. so I would tend towards the 30-35 Hp engines.

I would not expect to work the engine hard enough to need spares other then belts filters etc.

If there was not too much other work like propshaft, prop and exhaust etc I would consider a M Power.

FWIW when we had our w33 back around 1988, we had the original OM636 rebuilt completely but 2 years on the oil pump drive ( brand pump new fitted in rebuild) sheared and the motor seized solid. As stated in #6 we re-engined with a Volvo MD22L50hp which proved excellent. I did a lot of research on prop sizes and did the calculations myself as well as getting results from both Volvo and Perkins ( who sold the same engine as their Prima 50hp. We got the prop size spot on I believe as it would just pull max revs in gear under load. We reduced the existing prop size dia by 1 inch IIRC and it was pitched up a tad too which actually gave it less total drag when under sail. Shaft rpms as well as shaft horsepower go into the prop equation and aided the continued use of existing gear in our case. A self pitching prop like a Bruntons sadly will not fit in the space between cutlass bearing and rudder on the W33/ Discus.


For sure we never really used the 50hp but we could have if really encountering a bad headwind/sea. However we did go 'up' through Alderney race against a NE7 when it coped admirably despite the seas being very roughnonchalance. I actually remember backing off a bit as my teeth were clenched so hard against the crash bang wallops it was giving me a headache! We normally cruised at 6-6.5kts under motor at 2,000rpm and 0.43gph but it would do 8kts if asked to, against a foul tide entering/exiting Poole for example. Water skiing was not an option...

BTW the Mercedes )OM636 was originally a generator engine designed around 1938 and used at the North Pole I was told, it was not a marinised Mercedes vehicle engine nor a refrigerator power generator. It was built under licence in Spain. The Om626 referred to by another poster's reply may be a totally different beast altogether.

 

[sailor211]

BTW the Mercedes )OM636 was originally a generator engine designed around 1938 and used at the North Pole I was told, it was not a marinised Mercedes vehicle engine nor a refrigerator power generator. It was built under licence in Spain. The Om626 referred to by another poster's reply may be a totally different beast altogether.

interesting . My Mercedes OM636 handbook shows various options including the marine and 180 car option

 

[Robin]

interesting . My Mercedes OM636 handbook shows various options including the marine and 180 car option

My information was from the Mercedes specialist repairer in Poole who rebuilt the engine totally for us first time. Our engine had a user cleanable instead of replaceable cartridge oil filter, hardly an automobile type feature. It also had a tiny 25A alternator, cars usually had 50A ones even then. Not that it matters one iota:nonchalance:. THE MD22L we replaced it with, a Montego overhead camshaft automobile diesel, marinised by Perkins and painted green by Volvo,who also added their own gearbox and Bosch electrics was far better, but as pointed out elsewhere is no longer available anyway. Whilst The Mercedes was good, it was irritating in needing the glow plug heaters to start, as it was indirect injection, unless hot whereas the Volvo with higher compression direct injection never did so even in the depths of winter.


Engine horsepower is a bit like anchor weights, you rarely hear anyone saying they wish they had bought a smaller one, but often hear the reverse. and, however suitably matched a boat re-engined with a smaller than original motor my lose a little of it's resale value

 

[PetiteFleur]

I re-engined with a Beta 25hp, to replace a BMC 1500 in my Moody33. I looked at all the makes and settled on the Beta for the following reasons, sea water pump at front of engine so very easy to replace impeller, included an oil pump for engine oil change, excellent price, they made the engine feet to suit my bearers for a modest extra cost(so saving me having to replace the bearers), spares kit included in price, excellent aftersales service - spares delivered next day etc etc. Again I was limited on prop diameter and the recommended engine size was 20hp but they were doing a special offer on the 25hp.
The Nanni is similar and some say is better marinised. I also had to have a new prop, shaft, waterlock, non drip shaft gland, exhaust hose, swan neck and I also fitted superior sound insulation.

 

[prv]

Engine horsepower is a bit like anchor weights, you rarely hear anyone saying they wish they had bought a smaller one

<raises hand>

I'm increasingly thinking I should have gone one size smaller on my anchor

Pete

 

[Robin]

<raises hand>

I'm increasingly thinking I should have gone one size smaller on my anchor

Pete

There's always one!:nonchalance:

 

[charles_reed]

Whilst I re-engined with a Yanmar (2GM to 3YM) I would think the advice already given to the OP to look first @ Kubota-base engines, will save his pocket and prove perfectly satisfactory.

 

[jonrarit]

Not sure if it's been suggested already but the OP could also consider a reconditioned like for like unit.

After weighing up the options when we did it, it was the cheapest & easiest route ....same exhaust, controls, loom & gearbox. The last engine lasted 30 years so no reason why the replacement shouldnt do the same.