Cylinder Block Service
WARNING: This page is about a different car, the 1992 Geo Metro, 1991 Geo Metro, and 1990 Geo Metro. However, it is still accessible from the selected car via links, so may be relevant.
- Using feeler gauge and straightedge, check cylinder block head surface warpage. If warpage exceeds specification, repair as necessary. See ENGINE SPECIFICATIONS tables at end of article.
- Cylinder bore diameter is measured at 1.96" (49.8 mm) and 3.74" (94.9 mm) from top of cylinder bore. Different sized cylinder bores are used.
- Cylinder bore can be identified by No. 1 or No. 2 stamped on deck surface in accordance with cylinder location. See Figure. Cylinder block must be bored if taper or out-of-round exceeds specification. See ENGINE SPECIFICATIONS tables at end of article.
MAIN BEARING BORE SPECIFICATIONS
| Letter Stamped On Cylinder Block | Diameter In. (mm) |
|---|---|
| A | 1.9291-1.9294 (49.000-49.006) |
| B | 1.9294-1.9296 (49.006-49.012) |
| C | 1.9296-1.9298 (49.012-49.018) |
1990 MAIN BEARING JOURNAL DIAMETER SPECIFICATIONS
| Number On Crankshaft Counterweight | Diameter In. (mm) |
|---|---|
| 1 | 1.7714-1.7716 (44.994-45.000) |
| 2 | 1.7712-1.7714 (44.988-45.994) |
| 3 | 1.7710-1.7712 (44.982-44.988) |
1991 MAIN BEARING JOURNAL DIAMETER SPECIFICATIONS
| Number On Crankshaft Counterweight | Diameter In. (mm) |
|---|---|
| 1 | 1.7616-1.7618 (44.744-45.750) |
| 2 | 1.7614-1.7616 (44.738-45.744) |
| 3 | 1.7612-1.7614 (44.732-44.738) |
MAIN BEARING SELECTION (STANDARD BEARINGS)
| Cylinder Block Letter | Crankshaft Number | Bearing Color Code |
|---|---|---|
| A | 1 | Green |
| " | 2 | Black |
| " | 3 | No Color Code |
| B | 1 | Black |
| " | 2 | No Color Code |
| " | 3 | Yellow |
| C | 1 | No Color Code |
| " | 2 | Yellow |
| " | 3 | Blue |
BEARING THICKNESS SPECIFICATIONS
| Color Code | In. (mm) | |
|---|---|---|
| Standard Bearings | ||
| Green | .0786-.0787 (1.996-1.999) | |
| Black | .0787-.0788 (1.999-2.002) | |
| No Color Code | .0788-.0789 (2.002-2.005) | |
| Yellow | .0789-.0790 (2.005-2.008) | |
| Blue | .0790-.0791 (2.008-2.009) | |
| Undersize Bearings | ||
| Green & Red | .0835-.0836 (2.121-2.124) | |
| Black & Red | .0836-.0837 (2.124-2.127) | |
| Red Only | .0837-.0838 (2.127-2.129) | |
| Yellow & Red | .0838-.0839 (2.129-2.131) | |
| Blue & Red | .0839-.0840 (2.131-2.134) | |
MAIN BEARING SELECTION (UNDERSIZE BEARINGS)
| Finished Journal Diameter Cylinder Block (1) | Block Letter | Bearing Color Code | ||
|---|---|---|---|---|
| 1.7612-1.7614 (44.732-44.738) | A | Red Only | ||
| 1.7612-1.7614 (44.732-44.738) | B | Yellow & Red | ||
| 1.7612-1.7614 (44.732-44.738) | C | Blue & Red | ||
| 1.7614-1.7616 (44.738-44.744) | A | Black & Red | ||
| 1.7614-1.7616 (44.738-44.744) | B | Red Only | ||
| 1.7614-1.7616 (44.738-44.744) | C | Yellow & Red | ||
| 1.7616-1.7618 (44.744-44.750) | A | Green & Red | ||
| 1.7616-1.7618 (44.744-44.750) | B | Black & Red | ||
| 1.7616-1.7618 (44.744-44.750) | C | Red Only | ||
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