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 MANUALSCHEVROLET1987SUBURBAN R20, 7.4 N, 400/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE MECHANICALMECHANICAL6.2L V8 DIESEL - VINS [C,J]ENGINE SPECIFICATIONSPISTON/PIN/RING SPECIFICATIONS
1987 Chevrolet Suburban R20, 7.4 N, 400/M40
Piston/Pin/Ring Specifications
1987 Chevrolet Suburban R20, 7.4 N, 400/M40SECTION Piston/Pin/Ring Specifications
PISTONS, PINS & RINGS SPECIFICATIONS
| Application | In. (mm) | ||
|---|---|---|---|
| Piston Clearance | |||
| Bohn Pistons | |||
| Bores 1-6 | .0035-.0045 (.089-.115) | ||
| Bores 7-8 | .004-.0054 (102-128) | ||
| Zollner Pistons | |||
| Bores 1-6 | .0044-.0054 (.112-138) | ||
| Bores 7-8 | .0049-0059 (.125-.151) | ||
| Pins | |||
| Piston Fit | .00039-.00060 (.0101-.0153) | ||
| Rod Fit | .000003-00121 (.0081-.0309) | ||
| Rings | |||
| Ring No. 1 | |||
| End Gap | .012-.022 (.30-.55) | ||
| Side Clearance | .003-.007 (.080-.178) | ||
| Ring No. 2 | |||
| End Gap | .030-.039 (.75-1.0) | ||
| Side Clearance | .001-.003 (.039-.080) | ||
| Ring No. 3 | |||
| End Gap | .010-.020 (.25-.51) | ||
| Side Clearance | .0015-.0037 (.040-.096) | ||
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.