Description

When your Allis Chalmers starts knocking or the oil pressure drops to nothing, it’s likely time for new main bearings. These bearings keep your crankshaft properly positioned while handling all the forces from combustion and power delivery. Without good main bearings, your engine becomes scrap metal pretty quick. This standard size bearing set gets your 4-cylinder gas engine back to running smooth and reliable.

What You’re Getting

Complete main bearing set engineered for 138 CID and 149 CID 4-cylinder gas engines
Includes flanged thrust bearing to control crankshaft end play and prevent damage
Standard size bearings for engines that haven’t been machined undersize
TISCO quality construction built to handle the demands of farm work

Built for Real Farm Work

This bearing set fits the workhorse 4-cylinder gas engines found in various Allis Chalmers tractors. These engines powered everything from smaller utility tractors to mid-size row crop machines, handling tasks like cultivating, mowing, and light loader work. Whether you’re restoring an older orange machine or keeping one running that’s been in the family for decades, proper main bearings are essential for reliable operation.

Made to Last

Farm engines work hard under constant load, and main bearings take tremendous stress from combustion forces and rotating weight. These bearings use quality materials and precise manufacturing to provide the oil clearances your engine needs. The flanged thrust bearing design controls crankshaft movement while maintaining proper oil flow for long service life.

Installation Notes

Installing main bearings requires engine disassembly and proper measuring tools to verify clearances. Check your crankshaft journals for wear and scoring before installation – damaged journals may require machining and undersize bearings. Always verify bearing clearances with plastigage and torque main caps to specification. If you’re doing this job, it’s smart to replace rod bearings at the same time.