It has recently been announced that there are oversize outside diameter cam bearings available for 1985-2003 Cummins L10 & M11 engines. This new bearing will allow a single repair operation to many engine blocks, which will put many unserviceable engine blocks back into service.
These engines have been prone to engine failure related to cam bearing movement during engine operation. Generally, the cam bores were enlarged to such a degree that it was necessary to install a sleeve in the affected cam bore. The standard cam bearing was then pressed back into the bore, in effect putting a sleeve inside a sleeve. This process did not make the repair permanent in many instances, as many engines suffered subsequent failures. The new .170″ (4.3 mm) wall thickness bearing combines both processes into one and should allow a reliable repair for many otherwise discarded blocks.
This bearing combines the thickness of the Cummins supplied repair sleeve p/n 3824894 and standard cam bearing p/n 3820566 into one component. This oversize bearing has almost twice the wall thickness as the standard cam bearing.
To install the new bearing, first determine a .0020″-.0025″ interference fit before align boring the camshaft housing bore. This bushing p/n MCB7025 is currently available from one aftermarket supplier. Contact AERA for an update of suppliers of this type of bearing.
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