MeridexionWärtsilä absorbed the Sulzer low-speed range, so one engine can be described two ways depending on who built it and when. Get that wrong on an enquiry and you will be quoted for the wrong machine. Here is how to tell them apart before you send anything.
The engine does not care what the invoice says. It cares whether the part fits.
The families you will meet
- Sulzer RTA / RT-flex — low-speed two-stroke, now supported under Wärtsilä.
- Wärtsilä X series — the current low-speed range, electronically controlled.
- Wärtsilä 32, 46, 50DF — medium-speed four-stroke, widely used for auxiliary and dual-fuel.
- Wärtsilä 20, 26 — smaller four-stroke for auxiliary and propulsion.
Medium-speed engines are covered further under auxiliary engine parts.
What is still in production
Put side by side:
| Category | Availability | Notes |
|---|---|---|
| Consumables — filters, gaskets, seals | Widely available, including equivalents | Lowest risk, shortest lead time |
| Wear parts — rings, nozzles, valve parts | Available, sometimes only as equivalents | Material specification must be confirmed |
| Castings — liners, covers, pistons | Available for current families; scarce for older ones | Long lead time, order early |
| Electronic control components | Genuine only in most cases | Certification and software compatibility |
The legacy-number problem
An RTA engine built in the 1990s carries Sulzer part numbers on its drawings. The same component may now be listed under a Wärtsilä number, with a supersession chain in between. Two things follow:
- Always quote both the old and any known new number.
- Ask the supplier to confirm which revision the quoted part corresponds to, not just that it “fits”.
Where the chain is broken, the engine serial number is the key that reconnects it.
Sourcing approach for older units
For engines out of production, work in this order: check remaining stock in the distribution chain, then alternative manufacturers holding the original tooling, then made-to-drawing production. The last route is often the only one for castings, and it needs a drawing rather than a sample. See marine engine parts for the system-by-system view.
What to send
- Engine type and serial number, and the build year if known
- Both the Sulzer and Wärtsilä part numbers if you have them
- Component position and quantity
- Whether genuine or equivalent is acceptable
- Class certificate requirement
The full field list is in the RFQ checklist.
Common questions
Are Sulzer engine parts still available?
Yes for most wear parts and consumables, through Wärtsilä as the successor and through alternative manufacturers. Older castings may only be obtainable made-to-drawing.
Do Sulzer and Wärtsilä part numbers cross-reference?
They do for engines that transferred into the Wärtsilä range, through a supersession chain. Where the chain is incomplete, the engine serial number is used to identify the correct revision.
Can I get class certificates for equivalent parts?
Often yes, where the manufacturer holds the relevant approvals or the part is surveyed by the class society. This should be confirmed before the order is placed, not after production.
Talk to us about this part
One email with the engine details and the part is enough to start. We reply with availability, options and a realistic lead time.