During the three seasons since new, the heat exchanger has developed small corrosion pits at the front cap for the tube stack. The tube stack itself and the inside of the heat exchanger were fine. To their credit, Vetus sent a complete new heat exchanger without any discussion whatsoever. It looks slightly different from the original one.
The o-rings for the end caps are 61×2.5. The end caps of the new heat exchanger are brass instead of the original plastic.
As with most new engines, it does not have any sacrificial zincs. All the manufacturers claim that the alloy shall withstand corrosion. Well, I’ve fitted zincs anyway…
Old heat exchanger
New heat exchanger
New. Aft end cap.
New. Fwd end cap.
Old. Corrosion of housing at o-ring.
To our great relief, the engine started on the first try and ran perfectly. We did a one-hour test-run (keeping below 2000 rp, in compliance with the manual’s instructions for breaking in) and were very pleased with the very low noise and vibration level.
The speed achieved with the Vetus M4.17 in the HR41 (42 bhp, 12 tons) was almost identical to the speed achieved with the Volvo D2-40 in the HR35 Rasmus (38 bhp, 7 tons). 5 knots at 1500 rpm, 5.5 knots at 1700 rpm and 6.3 knots at 2000 rpm.
The engine replacement is now complete. In total it cost double the purchase price of the new engine, which included not only the new engine and transmission but also the work and material of the following;
- installed new sound proofing of engine room
- replaced all hoses
- replaced entire exhaust system
- replaced prop shaft, cutlass bearing and propeller
- installed Bullflex between transmission and prop shaft
- installed instrument panel with analogue gauges
- installed engine control (single handle Teleflex)
- replaced electrical diaphragm bilge pump
- replaced water pressure pump
- installed extra fuel filter (Racor)
- installed sea water strainer
- cleaned and painted engine room
The new Vetus M4.17 is considerably smaller than the old Volvo MD21, making all service points much easier to reach.
Many thanks to Jonas at www.joinme.se for the excellent job; done at the agreed price and finished on time!