Description

International Harvester Farmall Cub, International Cub Lo-Boy Technical Manual

If you are pulling a head on a Farmall Cub without the factory specs, you are gambling with a cracked block. I have seen it happen. Backyard rebuilds using aftermarket Chilton numbers that are off by 10 ft-lbs – then the gasket blows the first hot day. Don’t be that guy. This International Harvester Farmall Cub, International Cub Lo-Boy Technical Manual is the original Blue Ribbon Service publication from IH. 32 pages of page-1-to-32 factory data, no reprints, no third-party guesswork.

Engine Cylinder and Crankshaft Specs – Page 6

You get the crankcase cylinder block dimensions, cylinder head bolt patterns, and crankshaft journal tolerances direct from the IH engineers. The Crankshaft section on page 9 lists main bearing clearances and end play. Camshaft lobe lift numbers? Page 9. Timing gear backlash? Page 10. If you are rebuilding the bottom end, you need these numbers. The manual also covers connecting rods, pistons, pins, rings, and tappets. Everything is in imperial – inch-pounds and foot-pounds. No metric conversions. That matters when your torque wrench is calibrated in ft-lbs.

Nut and Bolt Torque Specifications – Page 15

Page 15 is the one page you will dog-ear and get greasy. It lists torque values for cylinder head bolts, main bearing caps, connecting rod nuts, flywheel bolts, and more. Don’t trust a forum post. Trust the page that came from the IH factory. I keep a copy of this page laminated in my toolbox for when a Cub rolls in with a weeping head gasket. One torque value wrong and you are chasing oil leaks for weeks.

Electrical System: Battery Ignition and Magneto

The electrical section covers the battery ignition unit, magneto, generator, cranking motor, and voltage regulator. If your Cub is hard starting, the magneto timing procedure on page 20 will save you from pulling wires randomly. The manual includes a diagram of the light circuits and the storage battery specs. Don’t chase phantom electrical gremlins – follow the OEM procedure.

Fuel System, Governor, and Carburetor Adjustments

Carburetor settings, air cleaner maintenance, manifold torque, governor adjustments – all on pages 20-22. The governor section is critical. If you set the idle speed wrong, the tractor surges under load. The manual gives you the linkage specs and spring tensions. Also covers the fuel system checks for sediment bowl and fuel lines. If your Cub runs uneven, go to the carburetor page. Don’t skip the air cleaner oil bath maintenance – page 21 tells you the correct oil level.

Chassis: Clutch, Brakes, Transmission, and Final Drive

Engine clutch adjustment, brake relining specs (page 26), transmission gear ratios, differential shim selection, final drive pinion depth – all in the chassis section. The front axle and steering toe-in spec on page 31 is critical for tire wear. If you are pulling a Manual Transmission apart, the gear tooth contact patterns are shown. The power take-off and belt pulley sections (pages 31-32) include shaft diameters and keyway dimensions. Even the drawbar and hitch dimensions are listed. This manual covers every bolted-on assembly.

Why OEM Factory Specs Beat Aftermarket Copies

Aftermarket manuals often reprint data from a 1970s copy of a copy. I have seen aftermarket “International Harvester Cub” manuals that list the wrong cylinder head torque sequence. This is the original IH Blue Ribbon Service manual – the same one dealership techs used in the 1950s-60s. The pages are scanned from an actual factory copy. You get the correct footnote warnings, like “Do not exceed 32 ft-lbs on the oil pan bolts” – stuff that third-party editors delete because they think it’s clutter. Clutter saves engines.

Need a parts breakdown? Check the McCormick Farmall Cub Tractor Parts Catalog TC-37A for exploded diagrams and part numbers. For the H30B industrial version, look at the International Harvester H30B Operators Manual – Factory Specs, 74 Pages. And if you are working on a later Cub Cadet lawn tractor, the International Harvester Cub Cadet Tractor Service Manual – OEM Factory Specs will cover the OHV engines.

Standards for thread specifications and materials come from SAE International Standards. The manual references SAE grades for bolts – you can trust the fastener specs.

FAQ – Common Questions About This Manual

Does this cover both the Farmall Cub and the International Cub Lo-Boy?

Yes. The manual covers both models – same engine, same chassis with slight variations noted in the final drive and front axle sections.

What torque values are included on page 15?

Page 15 lists cylinder head bolts, main bearing caps, connecting rods, flywheel, timing gear cover, and oil pan. Values are in foot-pounds. Also includes a note on re-torquing after initial heat cycle.

Is this a reprint or a scan of the original manual?

It is a high-resolution scan of the original International Harvester Blue Ribbon Service manual. Every page is legible, including the fold-out diagrams. No text has been removed or edited. This is not a third-party reprint – it is the factory document.

Can I use this to rebuild the entire Engine from crank to cam?

Yes, the Engine section covers the cylinder block, crankshaft, camshaft, timing gears, connecting rods, pistons, rings, pins, and tappets. You also get the lubrication system details. You will need a separate parts catalog for part numbers, but all clearances and specifications are here. Page 6 through page 15 gives you everything for a full rebuild.

Access the Factory Manual and get the right numbers on your workbench before you turn a wrench. Your Cub will thank you.