Chevy 3.1L Cam Bearing Bore Issues - Engine Builder Magazine

Chevy 3.1L Cam Bearing Bore Issues

Some of the later roller cam 3.1L blocks for the ’93-’94 Chevy VIN M are showing up with oversize cam bearing bores that appear to have been caused by spun cam bearings.

If a new cam bearing is installed in a bore that has been damaged, it will spin in the block, cut off the oil to the cam, and cause an immediate failure.
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Inspect the cam bores in all of the late 3.1L castings (10137093/ 10191737/ 24504089/ 24504150/ 10224227) very carefully, paying special attention to the #2 bore that seems to be the most prone to failure.

If the cam bore is oversize, there are only two choices:

1) You can either knurl the O.D. of the cam bearing to get enough press fit, or 2) you can junk the block.

 For more information about GM’s V6 engine family, read Doug Anderson’s article from the March issue of Engine Builder here.

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Before installing cam bearings, make sure to chamfer any oil holes and clean up back grooves of any sharp edges.

Engine Builder and Engine Pro present Shop Solutions in each issue of Engine Builder Magazine and at enginebuildermag.com to provide machine shop owners and engine technicians the opportunity to share their knowledge to benefit the entire industry and their own shops. Those who submit Shop Solutions that are published are awarded a prepaid $100 Visa gift card. Submit your Shop Solution at [email protected]. You must include your name, shop name, shop address and shop telephone number. Submitted Shop Solutions not published will be kept on file and reevaluated for each month’s new entries.

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