Many parts are available either as "new-old" original stock or as modern reproductions. Let me know if originality is desired — I do have a stock of new-old original parts or excellent used parts.
When we talk of Cletrac to Oliver HG's, OC-3's & OC-4's we are really talking about two engines and their variants: four cylinder Hercules IX-series gasoline engines; and three cylinder Hercules GO/DD130-series engines and their variants (see next page).
Cletrac HG's began life in 1939 with the 3 in. bore Hercules IXA-3 engine, succeeded by the 3-1/8th in. bore Hercules IXK-3 in 1940 (both with thermosiphon cooling).
In Feb. 1950, the 3-1/4 in. bore Hercules IXB-3 was introduced, coinciding with the dropping of the name 'Cletrac' from the HG's decals. This engine was equipped with a water pump for greater cooling capacity.
Important note: IX-series engines before serial number 1285103 were equipped with babbited bearings. They are expensive to renew and cannot be replaced with modern insert bearings.
Oliver OC-3's were all equipped with the same 4 cylinder, 3-1/4 in. Hercules IXB-3's as used in late Oliver HG's. Note though that re-engined machines may house variants of the IXB-3 engine - read your tag and the stamp on the side of the block under the cylinder head. For example, 'SL' means it has sleeves, 'LB' means long bore (longer stroke).
Tip: When you email, text or call with questions or enquiries about engine parts, tell me your machine and/or engine model and serial number.