During the summer of the 2019 the Bavaria 39 Tessa Jane began producing black exhaust smoke and suffering a cut in power from her 2005 Volvo Penta MD2030. Initial investigations covered the standard suspects such as energy issues, blocked exhaust elbow and so on, which resulted in the fitting of your shiny new stainless-steel harrow elbow.
But I was unable to isolate the exact cause before our annual cruise around the Channel Islands and upper France, so we just kept the revs very low while motoring and appreciated our holiday.

However, whilst motor-sailing from St Peter Interface to Cherbourg, the smell of unburnt diesel increased and will increase miles from the west entrance to the harbour we started emitting rather numerous white smoke.

We limped into Chantereyne marina and were luckily able to berth on the hammerhead, which reduced as much time manoeuvring under power and kept the white smoke to your minimum. We obviously had to address this tout-suite hence cancelled our plans to keep onto St-Vaast-la-Hougue and go about investigating a possible faulty or blocked injector.
Surprise breakage
I successfully pulled entry two injectors (of that three), but the aft-most one was surprisingly loose. Diesel injectors really should be fitted with relatively excessive torque, so when I fixed to removing the retaining nut to the fuel leak-off pipe that come with the rear cylinder, I used to be genuinely surprised to see the whole injector rotate as nicely. Inevitably, the result on this rotation was that the particular brass leak-off pipe out of cash.

With the three injectors most pulled, a quick inspection of their ports highlighted that the particular rear injector port appeared to be completely blocked with carbon build-up, and I attributed what causes it to the loose injector. We also noted that there seemed to be a lump of something that looked like calcified carbon still partly blocking the injector opening, but this proved impossible to clear out.

I cleaned the back injector port, and made a temporary repair for the fuel pipe using JB Weld prior to reassembling the system. An engine test confirmed all of us had, at least, ended the billowing white light up.

Due to a not enough brazing equipment on table, which could have been employed to affect a more permanent repair of the leak-off pipe, I decided to visit some local garages and workshops to check out if anyone could fashion some form of repair for me. Sadly, I was out connected with luck.

Plan B therefore was make use of the Volvo Penta Actions Service (VPAS) to source a better part. This was now Friday afternoon before the August bank holiday in addition to we had crew joining us on the following Tuesday ready for the sail back across the actual Channel. VPAS were very useful with identifying the proper part number, locating a local dealer, dealing using translation challenges, and getting them to supply it right to the marina around the Monday. However, I ended up funding 200 Euros for a part you can aquire online in the BRITISH for £50.
With the replacement resource pickup installed and homemade wine stocks replenished we relished a lovely sail back over the channel stopping overnight around Yarmouth, before continuing up on Portsmouth. Engine power has been still slightly reduced, but there is no billowing white smoke a pipe.

I knew I’d should remove the cylinder head so that you can identify the foreign object while in the rear cylinder injector vent, and as the boat can be moving to her cold months home in October, we enjoyed a great deal of weekends in the Solent not having incident.

Getting to the fundamental cause
Once the boat was in her winter home with Hornet, Gosport, I could look into the task of tugging the cylinder head and also investigating further. I removed the injectors as well as sent them off for servicing together with ordering a cylinder brain gasket kit in preparation for what I hoped would have been a weekend-long job. Then I go about removing the cylinder scalp (see the step-by-step guide below) and discovered the true cause of our diminished power.

The engine, which is actually a Perkins unit rebranded by simply Volvo Penta, has pre-combustion chambers. These make the engine easier to begin and also improve gasoline efficiency by partially igniting the fuel from a small chamber, before it gets squirted on the cylinder.

The chambers are covered with conical inserts containing a good number of holes which shape the charge the way it enters the cylinder. The foreign object I’d before assumed was calcified carbon was in fact the remains on the conical cap for that rear cylinder. The best part was it had remained from the pre-combustion chamber and had not entered the main storage container, as I’m sure this will have proved to be terminal for the engine.

The bad news was this was obviously not going in the form of quick fix.

I needed to send the head off into a specialist for repair, so I made contact that has a Perkins specialist who prepared me that while it’s commercially possible to replace pre-combustion chambers in a number of different engines, it was unachievable for this particular serps. For my engine, the cylinder head is known as a single part, so Perkins tend not to make the individual portion parts available.

I searched for a second-hand replacement for two months but eventually was mandated to stump up around £1, 200 for the new Perkins head.

Used to do contact Volvo Penta who seem to insisted their heads tend to be machined differently so I should try a Volvo Penta version (at the very least 20% more expensive). Well I thanked them for his or her advice and then fixed the Perkins head. Until now all is well….
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