Replacing Perkins 4108 with equivalent YANMAR 4JH45 or Volvo D2

[leakysump]

I have always found my 4108 (on a 46 sailboat) incredibly reliable at starting but it is a 1985 model and the issue for me is not wearing out but corroding out. I had it fully reconditioned in 2003 and I do less than 50 hours a year, but the corrosion is such that I now need to replace the Bowman radiator and heat exchanger (£1000 !) and I worry corrosion has likely affected other parts of the engine. I fancy a new and quieter replacement and am looking at the usual suspects - Yanmar , Beta and Volvo. My question Is how have owners found these makes a) resistant to corrosion, and b) ease of bleeding the fuel system (something not so simple on the Perkins). The Yanmar 4JH45 is the front runner at the moment so if any owners can help please…

 

[leakysump]

Another issue I have with the Perkins is the difficulty of access to bolts holding the radiator to the engine. Actually the task of bleeding the fuel system has not been revisited since I upgraded the fuel filters to spin on type a few years ago so perhaps that is a less important point of comparison

 

[leakysump]

Any issues of awkward access for maintenance with the Yanmar or indeed the Volvo D2 or Beta 50?

 

[Refueler]

Sorry to hear you are moving away from the Perky .....

I too had Heat Exchanger corrosion - the pipes inside fell apart. It was on my 4-99 - the basis of the 4 series engines.

Solution ? Removed the Heat Exchanger and converted to raw water cooling. She ran for years till boat got flooded when I was away for most of the year ... after draining boat .. drying out what we could ... checked engine oil in sump and appeared water free. 2 weeks later engine seized.
What to do ? Few years before I'd replaced bearers, coupling etc. .... so did not fancy replacing all that lot again ... so got offered a scrappy 4-107 ... which dropped straight in.
Raw water cooled again .....

That engine has been running sweet as sewing machine for years ... Diesel mechanic pal of mine - sadly passed away after accident when a car fell on him .... gave it a real good check few years back and was amazed how good it was - especially when I told him it was a scrappy.

Basically owner of a Rustler decided similarly to you that the old 4-107 needed swapping out. It was a touch smoky and he had offer of a nice Beta.
It sat on a pallet at back of shed in the yard for a few years - then offered to me ... 250 quid ... a rough brush up ... throw a bit of fuel at it - fired up literally straight away.
Deal done and fitted.

That engine has been through storms ... crossed Baltic number of times ... through Swedish Islands etc.

As I say - sorry to hear about your 4-108.

I would suggest you don;t let it go cheaply ... regardless of what some here may say - those 4 series are still worth money. Plenty of Inland Waterways ... coastal workboats etc. still use them. If you were over here - I know a coupled of people who would take it ...

 

[Tranona]

Beta would be my choice. All service points on the front or high up if on the side. Depending on the displacement of your boat a 38 or 43. The latter is a larger engine (2l rather than 1.5) but slower revving and may be more appropriate. Rather than looking at the Perkins as the "base2 better to start from scratch and determine the optimum propeller to drive the boat then work back to the best engine/reduction box combination. You will almost certainly need a new propeller anyway. for example i have just re-engined a boat that needed a 17" propeller and although the Beta 25 had just enough power to achieve hull speed, it would not drive bigger than 16" so I chose the 30 which will give me cruising speed at 250rpm lower and a bit more ultimate speed.

 

[Arcady]

FWIW I replaced a 4.108 a few years ago with a Mitsubishi based Vetus M4.45. It’s available in various versions but I chose the naturally aspirated 42 hp version. I know the 4.108 is sometimes said to produce 50 hp @ 4,000 rpm, but I know of no-one who does that. I shudder at the very thought of the Perky thrashing around at that speed. At a more modest 3,000 rpm, the Vetus output is slightly higher at 42 hp. The electric fuel pump makes it a doddle to bleed and I found the after sales service excellent. I have no connection: just a satisfied customer. See here: Vetus M4.45 Mitsubishi Engine 42Hp FWC TMC60A 2:1 (Vetus M445A602A)

 

[MikeBz]

Volvos suffer from hear exchanger corrosion - see this thread Volvo Penta Heat Exchanger corrosion poll - please help. I’ve heard that other makes do as well but not seen pictures.

 

[leakysump]

Refueler, thanks for that. Very interested to hear you running salt water through the cooling system without any problems . Maybe no need for me to worry about possibility of corrosion damage elsewhere than the Bowman heat exchanger then?

 

[leakysump]

Tranona , thanks for that. Yes I view the Perkins 4108 as in reality a max 36 hp at 3200 rpm and in practical terms continuous cruising max of 2800 rpm so rather less than even that! But it has always been reliable and pushes me along at around 6 knots while also running a 160ah Balmar Alternator on dual pulley belts, so a low powered work horse

 

[leakysump]

Arcady, thanks for that. I regret I would not go for a motor with an electric fuel pump as I like the once it starts it will go forever whatever happens to the batteries etc flooding etc

 

[leakysump]

Thanks MikeBz . That writes Volvo off then! Does the D2 also have radiator removal bolt positions with impossible access? I don't think a plastic/fibre gasket would prevent corrosion around the 4108 Heat Exchanger inlet & outlet pipes and heat exchange enclosure - the corrosion seems very widespread around there. Those pipes themselves are rubber

 

[Tranona]

Suspect you are worrying overmuch about potential corrosion of the heat exchanger and piping. All modern heat exchangers are a mix of metals and some (like the Beta) need to have anodes and do not have problems if the anode is changed according to the schedule. The Volvo has to my mind an undeserved reputation for HE problems which I suspect is more to do with the vast numbers in service than a high incidence of problems, not helped by the high price of replacements. However the "problem" which is related to the interface between the HE and the exhaust elbow is invariably related to coking up of the elbow as a consequence of poor running - not enough continuous use and not running at higher loads. In other words typical yachty intermittent use at low loads followed by long periods of no use. You do not find these problems on heavily used engines such as on charter yachts. My 2030 (essentially same HE design as the D2) ran 3500 hours as a charter boat and still had its original HE and elbow.

Not sure what you mean by "radiator". The cooling system on modern engines is different from that used 40 years ago on the Perkins. The HE and exhaust is all in one bolted to the side of the engine. The seawater comes into it via hose at the front and exits at the rear to be injected into the exhaust outlet. Some designs have a header tank for the engine coolant, others not with a filler/pressure cap directly on top of the HE.

As mentioned in relation to the Vetus, many engines now have electric fuel pumps because the engines on which they are based have them and are self bleeding. If you have a dedicated engine start battery it should always be fully charged so that if the engine is running the pump will always work so I think your fears are unfounded. Anybody who has struggled with the horrible lever operated diaphragm fuel pumps will bless the use of an electric one!

Current engines (all makes) are just in a different league from the 4/108 as indeed they should be. All the engines that would suit are based on Japanese industrial engines (even Yanmar) which power all the construction and agricultural equipment we see around us that run for hours that far exceed any marine use except full time commercial use. They are still low specific output mechanical engines (apart from the electric fuel pump on some) except for Volvo which is still mechanical but has an electronic control panel grafted on using a rather crude solid state interface - although there are tens of thousands in use and despite some manufacturing problems a few years ago seem to work just fine.

You really can't go wrong with any of the mainstream engines. They have been refined over the years to be reliable and long lived, They each have their own features that some people like and others dislike, but in reality they will all do the job. As I suggested earlier the starting point is the propeller - determine the size that achieves hull speed comfortably then look for the best combination of engine and reduction to drive the propeller. The propeller does not care what is driving it - just the amount of power and shaft speed, but at the other end there are issues to consider. Service points, fit in the space, availablity of service and support etc may influence the choice of specific brand. Not a lot of difference in price from one to the other, but always room for a deal including getting some value out of your old engine.

 

[leakysump]

Tranona, thanks. My Perkins 4108M has the HE you describe with a filler cap on top and bolts directly to the exhaust ports of the engine (radiator was definitely the wrong term). It is in fact the Bowman PE180 Heat Exchanger. You have an interesting and unusual view on choosing propeller first. My view is more conventional in that I choose the max size/weight engine for dimensions of engine compartment (always horribly restricted in a sailboat) and existing mounting stringers that is practical for maintenance access and does not deviate in weight too far from the original design installation , and then find a prop suitable for that engine & boat. But it is always useful to hear other views. I do see how electric pumps would be wonderful for bleeding the fuel system!

 

[Tranona]

Tranona, thanks. My Perkins 4108M has the HE you describe with a filler cap on top and bolts directly to the exhaust ports of the engine (radiator was definitely the wrong term). It is in fact the Bowman PE180 Heat Exchanger. You have an interesting and unusual view on choosing propeller first. My view is more conventional in that I choose the max size/weight engine for dimensions of engine compartment (always horribly restricted in a sailboat) and existing mounting stringers that is practical for maintenance access and does not deviate in weight too far from the original design installation , and then find a prop suitable for that engine & boat. But it is always useful to hear other views. I do see how electric pumps would be wonderful for bleeding the fuel system!

Somewhat surprised that you find my "view" unusual as it is the mainstream way of determining what engine to fit! This is probably the best book on the subjectamazon.co.uk/Propeller-Handbook-Installing-Understanding-Propellers/dp/0071381767

I spent most of my working life around marine engines in small boats and as you can imagine I have seen loads of poor or inappropriate installations because people start from the wrong end. When you are spending £10k+ and the knowledge of how to get the best out of that expenditure is readily available surely it makes sense to use it? Your criteria are really a non issue because the correct engine will fit in the space occupied currently by your 4/108 - all the engines are smaller and lighter - although reduction in weight is not significant in a boat of the size of yours!

However, in reality the size of propeller you can use is often compromised by the space available so it is quite legitimate to determine the power required to achieve displacement speed for a given waterline and displacement then calculate a propeller size to achieve that using one of the many programmes available. In general terms the larger the diameter the better, but larger diameters need slower shaft speeds so the reduction ratio is critical - but of course that also depends on the maximum revs of the engine. So for example a Beta 38 has a maximum of 3600 and a 43 2800. The common 2:1 will give a shaft speed of 1800 on a 38 and 1400 on a 43. As with my example earlier on my current project there is a choice between running at different engine speeds for a given cruising speed, although fuel consumption will be essentially the same. While there is an argument for running small diesel engines hard as this reduces the chances of exhausts coking up, if the propeller is correctly sized, continuous running speed should be around 50% of power which on most diesels is between 60--70% revs. So, if I had chosen a 25 my cruising speed of 5.5 knots would have required 2500rpm, and the 30 would be 2200, both within the guidelines but the lower engine speed is much more restful!

There is quite a bit of leeway around the optimum first because you have adjustment to the prop by way of the number of blades and the pitch and because engines come in relatively wide HP bands, particularly at the lower end of the HP range - for example Volvo go 13, 19, 29, 40hp and essentially the same shaft speed so you end up with installations that are either underpowered or overpowered. However when you get into the sort of power bracket and displacement range you are in the choice is much wider because you have a greater range of power and shaft speed as options. Ignoring the potential constraint of clearance to swing the prop you have a chance a decent chance of getting close to the optimum.

 

[Refueler]

I always find it interesting when people start recc'dg what brand of engine .....

Various Volvo engines are rebranded Perkins

Many of the 'Japanese' engines are rebranded from same manufacturer - with a spattering of Chinese 'input'.

We only have to look back at Honda - Kubota - Beta - etc.

Because OP was interested in that my engines have been changed to run Raw Water cooled ... there is one factor that is important to note.

HE indirect cooled engines should run at higher temp than Raw Water cooled ... this gives better combustion and energy return. With the coolant having Anti Freeze in - there are additives to clean etc.
But Raw Water cooled must be run at lower temp - to avoid the heat causing salts and other to deposit out from the water. Perkins and other brand manuals explain this.
Theoretically - we should regulate water flow thriugh the engine by use of the seacock - setting the flow to produce a temp. But I don't do that .. I have my seacock fully open and let my engine run cooler .... I have no thermostat - its really a HE item and better to remove when Raw Water cooled.

Each winter I pass Anti-Freeze through the engine for lay-up. I watch / catch the outflow to check what it looks like and whether crud etc. is expelled. So far for near 20yrs - that outflow is still 'clean'.

On Heat Exchangers ... my hydraulic gearbox - the HE on that failed for same reason as the Engine one ... but may years later. The pipes inside just fell apart. I was on a Baltic cruise and I was refilling gearbox every run between stops with oil. Basically - the oil was going to HE to be cooled but because pipes were failed - water and oil was mixing ... losing it out exhaust. The water being from the engine cooling.
Back home - I removed HE and gave to my pal at Metal works. He was not impressed by the design and metals used. A cylinder with many small pipes set inside ...
He took the cylinder and built a new set of pipes - less in number but larger bore - in a metal more suited to our environment.
I fitted that in 2011 ... and its been absolutely gold ....

He did offer to make me a similar for the engine - to re-instate indirect cooling ... but that would mean sourcing gear to complete .... engine runs fine as is ...

 

[leakysump]

Refueler thanks - very interesting. I like my fresh water coolant running hot as it passes through a hot water tank transfering its heat to create hot water for showers!!

 

[Refueler]

Refueler thanks - very interesting. I like my fresh water coolant running hot as it passes through a hot water tank transfering its heat to create hot water for showers!!

Absolutely ... I would too.

Just passing on about Raw Water system .... many people are not aware of the running temp difference.

 

[PCUK]

Sorry to hear you are moving away from the Perky .....

I too had Heat Exchanger corrosion - the pipes inside fell apart. It was on my 4-99 - the basis of the 4 series engines.

Solution ? Removed the Heat Exchanger and converted to raw water cooling. She ran for years till boat got flooded when I was away for most of the year ... after draining boat .. drying out what we could ... checked engine oil in sump and appeared water free. 2 weeks later engine seized.
What to do ? Few years before I'd replaced bearers, coupling etc. .... so did not fancy replacing all that lot again ... so got offered a scrappy 4-107 ... which dropped straight in.
Raw water cooled again .....

That engine has been running sweet as sewing machine for years ... Diesel mechanic pal of mine - sadly passed away after accident when a car fell on him .... gave it a real good check few years back and was amazed how good it was - especially when I told him it was a scrappy.

Basically owner of a Rustler decided similarly to you that the old 4-107 needed swapping out. It was a touch smoky and he had offer of a nice Beta.
It sat on a pallet at back of shed in the yard for a few years - then offered to me ... 250 quid ... a rough brush up ... throw a bit of fuel at it - fired up literally straight away.
Deal done and fitted.

That engine has been through storms ... crossed Baltic number of times ... through Swedish Islands etc.

As I say - sorry to hear about your 4-108.

I would suggest you don;t let it go cheaply ... regardless of what some here may say - those 4 series are still worth money. Plenty of Inland Waterways ... coastal workboats etc. still use them. If you were over here - I know a coupled of people who would take it ...

Amazing. My 4107s went through corroded cylinder liners, cracked heads, broken crankshafts and constantly breaking Jabsco drive shafts. Both engines were as bad as each other and would fail within weeks of each other. Raw water cooled wet liners are a recipe for disaster. Luckily, you have an engineering angel on your shoulder.

 

[Tranona]

I always find it interesting when people start recc'dg what brand of engine .....

Various Volvo engines are rebranded Perkins

Many of the 'Japanese' engines are rebranded from same manufacturer - with a spattering of Chinese 'input'.

We only have to look back at Honda - Kubota - Beta - etc.

That is somewhat misleading. The origins of the engines are pretty clear as I explained earlier, and at the same time suggesting you can't go "wrong" with any of them but that there are sound reasons for choosing one rather than another. Actual power, choice of gearboxes, layout of service points, location and style of exhaust, availability of parts and service for example. Also some engines have electronic components - Volvo have an electronic interface with the control panel and Yanmar of this size is common rail injection which may influence choice. While the base engines may in some cases be the same (Beta and Nanni use Kubota, Vetus and Sole use Mitsubishi for example) the detail of the marinisation is different which may make one a better choice in a particular installation than another. Nobody makes raw water cooled engines now except the venerable Yanmar 1GM a design that dates from the late 1970s.

BTW your last sentence in the quote does not make sense - Honda don't make inboards or base engines and the relationship between Beta and Kubota is simple - Beta is an authorised mariniser of Kubota engines, along with Nanni and Westerbeke.

 

[leakysump]

Tranona thanks. I am aware of the formulas for prop selection but the science is extremely complicated and I prefer to tinker around close to the choices of the yacht designer. I have a neighbour who is a leading professor of hydro dynamics (particularly wave motion) and he told me when asked for selection advice that he felt unable to offer an opinion because the topic was so complicated. In my case my hull is rarely clean on account of the enormous cost of haulout charges these days . Furthermore different conditions demand different choices and it is usually a compromise. Recently I left Poole Harbour with a full incoming tide and struggled to make progress just more smoke as I pushed the revs up. I now do short handed sailing and rely more on the prop to make better progress against a sea when the wife is eager to get to a pontoon. My boat started life with a Martec 17 x ? twin bladed folding prop which after many years of blue water service flew off under hard reverse into a force 7 during dock manoeuvring. Replaced it with a Gori similar 18x13 and recently after the Poole Harbour experience switched to smaller Flexifold similar 17 x 11 . Each have their benefits under different conditions of sea state and hull state. I would rather re- focus the discussion on engines and tendency towards corrosion and maintenance accessibility