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| 3800 Bearing Question (Page 1/1) |
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Lou6t4gto
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MAY 06, 06:31 PM
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when these engines (3800SC, 1999) were made at the factory, were ALL the Bearings exactly STANDARD. Or did they actually "SIZE them" (std, .001,002, ect,) and are they stamped on the back ? thanks
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fieroguru
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MAY 06, 11:02 PM
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GM builds everything to production specs and uses STD bearings for each application. Anything with a 001, 002, 010, 030, etc is aftermarket and a sign that someone else has been inside the engine before.
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Lou6t4gto
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MAY 07, 01:20 AM
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So, Std "premium" replacement bearings Should be the ticket. (almost No Wear on the originals) OR is it better to leave the" originals" in it ???
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olejoedad
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MAY 07, 07:04 AM
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'Almost no wear' is not a good indicator when it comes to bearings.
You must measure exactly to determine journal OD, bearing ID, and determine concentricity and journal taper.[This message has been edited by olejoedad (edited 05-07-2019).]
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Lou6t4gto
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MAY 07, 01:14 PM
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DID, the Crank has NO WEAR. bearings look like if you had just rebuilt the engine and run it about 1000 miles,no scores,some of the first gray film is still on them. yes it is original
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olejoedad
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MAY 07, 01:30 PM
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If that is the case, I would leave the originals.
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fieroguru
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MAY 07, 01:39 PM
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| quote | Originally posted by Lou6t4gto:
DID, the Crank has NO WEAR. bearings look like if you had just rebuilt the engine and run it about 1000 miles,no scores,some of the first gray film is still on them. yes it is original |
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As a general rule, assume nothing. Measure and verify.
You should measure the journals in several locations and at several locations to the 0.0000" and compare this to the published specification for diameter and roundness. That will let you know if it is still within spec or not, and if not, how far out.
Visual appearance of bearings is only good to verify bad (not good). Just because they "look good", doesn't mean they have the proper bearing clearance with the crankshaft. You can use some plastigage to check the bearing clearance and verify it is within spec for your particular engine.
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