Oliver Tigre Mk3 Bolt Pattern: What Engines Will Fit and How to Make Others Work
The Oliver Tigre Mk3 Has Its Own Mounting Footprint
If you have a model drilled for an Oliver Tigre Mk3 and want to run a different engine, no PAW or AM diesel drops straight in without modification. The Oliver Tiger — made in Nottingham by J.A. Oliver Engineering from the early 1950s — uses a crankcase design with lug positions unique to the Oliver family. No other production engine in the common British or European range shares them.
That said, there are practical routes around this, and the right one depends on how much work you want to do on the airframe.
Why British Diesels Don’t Share Mounting Patterns
British model diesel manufacturers of the post-war period — PAW, Oliver, ED, Frog, AMCO and others — each worked to their own drawings. There was no agreed standard for bearer hole spacing or lug geometry. A PAW .15 (roughly 2.5cc) and an Oliver Tiger Mk3 (2.5cc) are both British diesels of near-identical displacement, but their mounting holes sit in different positions.
The same applies to AM (Effzett) engines from Germany. Independently designed, independently tooled. No cross-compatibility.
A note on the name “Tigre”
The engine sometimes appears as “Tigre” rather than “Tiger” — it is the same engine. “Tigre” is the Spanish and Italian form of “Tiger” and shows up on some export versions and in wider European community usage.
Engines in the 2.5–3.5cc Range Worth Considering
If you are sourcing a replacement diesel for a crash-prone return to control line, here are the realistic options:
- PAW .15 and PAW .19 — still made in the UK, these are roughly 2.5cc and 3.1cc respectively. PAW diesels have a solid reputation for reliability and a reasonable tuning range. They won’t match the Oliver mounting holes, but they are the easiest British diesel to buy new. The .15 and .19 share the same crankcase, so bearer dimensions are identical across those two sizes.
- AM Effzett diesels — a German-made series popular in Europe, available in 2.5cc and 3.5cc. Good engines, but new examples can be harder to track down than PAW. Different mounting to the Oliver.
- Oliver Tiger (current production) — J Oliver Engines continues to make the Tiger series. If you want zero fuss with the existing mounting holes, a current Oliver is the obvious answer. Current production maintains the original lug layout.
- OS and Supertigre diesels — Japanese and Italian alternatives exist in the displacement range, though new stock availability varies and in practice they are harder to find than PAW in the UK. Different mounting patterns again.
How to Fit a Different Engine into an Oliver-Drilled Mount
Two approaches cover most situations:
Adjustable engine mounts
Control line specific mounts with slotted holes let you shift the engine position to suit different lug spacing. If the lug positions are reasonably close, a small amount of filing on the slots can bring them into alignment. This approach preserves flexibility — if you switch engines again later, you haven’t committed to one drilling pattern. For someone expecting ground strikes, that matters.
Redrilling the bearer
If you have chosen your replacement engine, drilling new holes in the bearer is straightforward. Fill the old holes with a hardwood plug or epoxy first, especially if the new positions are nearby. Many older models have been redrilled more than once without structural issue.
Get the engine physically in hand before drilling. Place it on the bearer, mark the holes directly, then drill. Published dimensions from forum posts are a useful sanity check, but minor variations between production runs are common enough that physical marking is more reliable than numbers alone.
Practical Notes for Returning to Control Line
Expecting crashes during a return to the hobby is realistic, not pessimistic. Running a current-production engine makes more practical sense in that situation than hunting a vintage Oliver: spare parts are available, props are easier to source, and you won’t be gutted if it hits the deck hard. PAW is probably the most accessible choice for someone in the UK right now.
One other thing worth checking before any flying: the model’s leadout geometry and control line fittings. A lot of problems on re-entry to the hobby come from worn or misadjusted hardware rather than the engine itself.