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Engine Rebuild

In June 2016 ARAMIS started leaking oil from the joint between starter motor  and flywheel housing.


There should of course be no oil in the flywheel housing so the crank oil seal was immediately suspect.  Nevertheless, the engine was still running well for a 50-year old based 1930s technology.


We decided that separating the gearbox and block was necessary to investigate the problem.







We had worked on the engine in situ before, notably to fixed a slipping clutch (due to a fractured pin holding the clutch plates) and to re-stuff the stuffing box, which required the engine to be moved forward.  We therefore knew that with a sturdy beam over companionway entrance and using the main-sheeting system as a block and tackle, we could move all 250kgs of the engine into the cabin.


[We always carry the supporting beam with us in case we need to make an engine intervention whilst traveling]


With the engine/gear boxed separated. We soon identified the problem.


A tube delivers oil under pressure from the end of the crankshaft to the main bearing in the gearbox.  This tube is sealed by two O-rings and has a very small, almost pinhole, that controls the volume of oil arriving at the bearing.




This small tube gets a special mention in the engine service manual.


The photos right show the removal of the tube and all important cleaning of the pin-hole


Sure enough, this hole had become blocked and because the sealing o-rings had perished and flattened, the oil, under pressure was finding its way past the o-rings and in to the flywheel housing.


Whilst we could have simply unblocked the hole and replaced the o-rings, we assumed that all other "rubber" components in the engine might also be in a poor condition and therefore a full rebuild was necessary to ensure long-term reliability.

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The engine was therefore removed in bits and stripped down.


We managed to do this without a crane/hoist.  We used the boom for the two heavy sections, the block and flywheel.  We estimate that the flywheel alone was some 35kg !


Once striped, we checked the crank journals and cylinders for wear.  


Everything was well with in specification and showed remarkably little wear.


We now started looking at the parts required for a full rebuild.  These may be summarised as :


- Oil seals and o-rings

- Bearing shells and thrust washers

. Compression and locking washers

- Gaskets

- Piston rings


The rebuilt would include :


- decoking cylinder head and exhaust manifold

- de-scaling all water ways

- honing cylinders to accept new piston rings

- grinding in the valves


We also felt it prudent to recondition the injector pump and injector assemblies, including new nozzles.


The estimate for the reconditioning (excluding labour) was some €3,800.



The offending oil transfer tube - component #1

250kgs of premium Swedish cast-iron!



In view of the cost and age of the engine, we considered replacing it with a new unit and looked at Sole, Nanni and Betamarine options.  


Compared with the reconditioning costs, the cost of a new engine was very reasonable.  The problem we had was that all modern engines are high-speed, a necessary requirement to meet emmision regulations.  Even with the longest reduction gears available we could not get a new engine to match the propeller fitted to Aramis. A new engine therefore meant a new smaller pitch higher speed propeller.


Moreover, we could not find such a propeller that would fit the existing propshaft.  This meant a new shaft that in turn meant a new bearings/stuffing box and a new Cutless™ bearing.  All this, plus the costs of a crane lift and hard-standing in the marina during the work.


This additional cost, plus the desire to keep ARAMIS original led us to commit to the rebuild.


We also noted that a modern engine of the same power would weigh some 100kgs less than the Albin AD2 on Aramis.  This sounds like a great saving, however we were worried about removing this weight that would have been considered by Richard Carlson in his design.


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One of the most painful tasks was cleaning the many layers of paint of the castings.  This was eventually achieved by chipping away with a light pointed hammer.  Following further cleaning and degreasing we treated the castings with a phosphoric acid corrosion protection.


The photo on the right shows two castings before and after treatment.


We used hydrochloric acid to descale the waterways.  These were in a terrible state with only pinhole clearance in some key areas, for example between the head and exhaust manifold. We rather doubt that the waterways were clean during the previous rebuild circa 1995.


The block and head were probably both several kilos lighter after the descaling process.


Once thoroughly rinsed and dried, the waterways were also given an anti- corrosion treatment.


The single most expensive item in the rebuild was reconditioning and recalibrating the injector pump.


We are most thankful to Sheaf Diesel Services in the UK for "keeping alive" these old injection systems.  Not only did the pump come back as new, they were most helpful when we had a few reinstallation hiccups.

Castings before and after anti-corrosion treatment

The injector pump after some extreme TLC from Sheaf Diesel Services

Shiny reconditioned holders and new injector nozzels.

Once reassembled, we had to consider the protection that was to be applied to the engine.  We suspect that the original engine was treated externally with a Zinch Chromate red oxide primer.  Internally, still largely intact we could see a greenish primer that we suspect was also zinc phosphate based.  Sadly (but probably with due cause) such poisonous paint products are not available in Europe.  Elsewhere in they world they are available to licenced professionals and in some places freely available.


Rather that send the engine for painting to Korea (and a few other places) we went with an available Zinc Phosphate based primer and compatible enamel top coat from Titan in Spain.



The rebuilt engine after two coats of zinc phosphate primer an two coats of enamel

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The original motor was painted in a slightly metallic lighter green. This paint is still available from however for expediency, we used a "Volvo" green and a compatible zinc phosphate primer from Titan paints.  Still, it was closer to the original than the yellow applied during the 1995 rebuild.

AD2 old

Extracts from the service manual. We wish that the engine had been this clean during our intervention!