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Mis-Aligned Blocks Can Lead To Warranty Blindsiding
By Roy Berndt
This month in Core Corner we will provide you with information that should help you avoid either an improper identification or a potential warranty that could easily blindside you. Kind of a good news/bad news scenario.
Let’s start with the blindside warranty possibility, aka: bad news. It has to do with the 2.2L Chevrolet block casting 24576035. This block came on the scene in 1997. The problem reported out in the field has been with the crankshaft position sensor (CPS) mounting boss. The boss face to which the sensor mounts is flat and should not have a compound angle.
However, some mis-machined blocks seem to have found their way into the remanufacturing core market. If these are used, the CPS will contact the crankshaft trigger wheel, an integral part of the crankshaft casting with notches cut into it. To function properly the CPS requires a specified air gap. So now what was thought to be a perfectly remanufactured engine will not run; that is a bad thing.
The CPS boss is nearly dead center of the left side of the block. In Figure 1, you have to look hard, but you can see the mis-machined boss that has a partial fade away angle toward the cylinder head deck. Attempting to adjust the CPS on the mis-machined blocks has produced unsuccessful results such as oil leaks and improper crank signals.
Since installing the CPS would be one of the last actions taken during an engine installation, you can see how frustrated both the technician and the remanufacturer would become once they realized the problem.
Let’s move on to the good news. This concerns the 3.0L inline four-cylinder 181 cid Chevrolet one-piece seal crankshaft of recent manufacture (we believe that it occurred in 2000). The back end of the crankshaft appears unfinished. More often than not, to see that type of an unfinished flange would lead you to believe that it is not viable, or perhaps, an unfinished reject from OE (see Figure 2). Not so, it is the latest version of this crankshaft, manufactured in Mexico. Apparently, GM changed the style of "bolt-up" for both marine and industrial applications so the pilot hole was no longer required. When providing this crankshaft to a customer be certain that you’re aware of the type he/she has. The earlier full pilot hole one-piece seal crankshaft will work for the later non-finished, but not the other way around.
Well there you have the good and the bad news; hope this helps, and happy building!