Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSGMC1989MAGNAVAN 5.7 K, 3L80/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE MECHANICALMECHANICAL7.4L V8 - VINS [N,W]ENGINE SPECIFICATIONSPISTON/PIN/RING SPECIFICATIONS
1989 GMC Magnavan 5.7 K, 3L80/M40
Piston/Pin/Ring Specifications
1989 GMC Magnavan 5.7 K, 3L80/M40SECTION Piston/Pin/Ring Specifications
PISTONS, PINS & RINGS SPECIFICATIONS
| Application | In. (mm) | ||
|---|---|---|---|
| Piston | |||
| Clearance | .003-.004 (.08-.10) | ||
| Diameter | N/A | ||
| Pins | |||
| Diameter | .9269-.9271 (23.543-23.548) | ||
| Piston Fit | .00025-.00035 (.0063-.0088) | ||
| Rod Fit | .0013-.0021 (.033-.053) | ||
| Rings | |||
| Ring No. 1 | |||
| End Gap | .010-.018 (.25-.46) | ||
| Side Clearance | .0017-.0032 (.043-.081) | ||
| Ring No. 2 | |||
| End Gap | .016-.024 (.41-.61) | ||
| Side Clearance | .0017-.0032 (.043-.081) | ||
| Ring No. 3 (Oil) | |||
| End Gap | .015-.055 (.38-1.40) | ||
| Side Clearance | .0050-.0065 (.127-.165) | ||
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.