Chapter 4: Engine Overhaul
Covers the tail end of Chapter 3 (exhaust manifold/pipe systems, sections 32-33) plus the full Engine Overhaul chapter (Engine Specifications through Crankshaft & Cylinder Block, sections 34-41). Engine is the 4A30, in SOHC (16v, naturally aspirated) and DOHC (20v, intercooled turbo) states of tune — our truck is the DOHC turbo variant with a 3-speed automatic (3A/T), 4WD. SOHC/DOHC differences are called out explicitly in each section; engine-overhaul clearances and torque limits are precision-critical and copied exactly where legible.
Numbering note
The front-of-manual table of contents (printed p.7-9) numbers this material as sections 32-41. The in-body chapter divider (printed p.77) instead numbers the same material 42-49 and continues a different sequence than the front matter for later chapters. This site follows the front-matter numbering (32-41) per the assignment; treat “42-49” as an internal inconsistency in the source document, not a typo to correct.
Sections
- Exhaust Manifold (SOHC/DOHC) — printed p.73-74. Removal order, oxygen sensor removal tool.
- Exhaust Pipe System (SOHC/DOHC) — printed p.75-76. Muffler/front pipe/center pipe removal order.
- Engine Specifications & Details — printed p.78-79. Full clearance/torque/wear-limit spec table, cross-checked against later maintenance-note restatements.
- Required Tools (Engine Overhaul) — printed p.80-81. Special service tool list with part numbers.
- Rocker Arm & Camshaft — SOHC — printed p.82-85. Manual valve lash adjustment (0.14mm/0.20mm cold — 0.006in/0.008in), camshaft inspection.
- Rocker Arm & Camshaft — DOHC — printed p.86-87. Hydraulic lash adjusters — no manual adjustment.
- Cylinder Head & Valve System — SOHC/DOHC — printed p.88-97. Head bolt torque (64±5 N·m / 47±3.7 ft-lb, both engines), valve/seat/guide specs.
- Oil Pump, Oil Pan & Front Case — printed p.98-101. Applies to all variants; sealant bead specs, oil pump clearance limits.
- Pistons & Connecting Rods — printed p.102-107. Applies to all variants; ring/bearing identification, connecting rod bolt spec (flagged).
- Crankshaft & Cylinder Block — printed p.108-113. Applies to all variants; main bearing torque (52±2 N·m / 38±1.5 ft-lb, both engines), SOHC vs DOHC bore/clearance specs.
Printed p.114 is blank in the source scan (page-number footer only) — no content recovered, likely a section break before Chapter 5.
Consolidated flagged items — verify before use
Every spec, torque, or figure below could not be confirmed with full confidence from the OCR and is individually flagged in its source file. Do not use any of these numbers for an actual build without checking a clean scan of the printed page first.
Conflicting values (two OCR passes disagree)
| Spec | Reading A | Reading B | File |
|---|---|---|---|
| Cylinder head total height | 109-109.1mm (spec table, p.78) | 108.9-109.1mm (maintenance note, p.91) | 34, 38 |
| Valve spring free height | 41.15mm (spec table, p.78) | 41.5mm (maintenance note, p.92-93) | 34, 38 |
| Cylinder distortion limit | Below 0.01mm (spec table, p.79) | 0.1mm (maintenance note, p.113) | 34, 41 |
| Cylinder head bolt torque, kgf·m figure (DOHC diagram) | (8.5) — diagram fragment, p.95-96 | 6.5kgm — clean prose, p.91 & p.97 (both SOHC and DOHC) | 38 |
Illegible or unmappable (single garbled source, no clean restatement found)
| Spec | Raw fragment | File |
|---|---|---|
| Camshaft height (Intake/Exhaust, Limit/Replace) | 33.81mm / 33.31mm / 33.88mm / 33.38mm — row/column order lost, appears identically in two places | 34, 36 |
| Exhaust manifold torque-to-fastener mapping (SOHC/DOHC) | T=18(1.8), T=44(4.5), T=29(3.0) ×2, T=27(2.8) — balloon-to-fastener mapping lost | 32 |
| Exhaust pipe system torque-to-fastener mapping | T=13(1.3), T=23(2.3), T=20(2.0), T=44(4.5), T=5.9(0.6) — balloon-to-fastener mapping lost | 33 |
| Oil pump body distortion, replace figure | 0.35mm — only in spec table, no independent restatement | 34 |
| Crankshaft endplay, replace figure | 0.04mm — smaller than the limit range’s own lower bound (0.05mm); likely misplaced OCR | 34 |
| DOHC camshaft housing cover bolt torque | ”T-71” fragment, no units/context confirmed | 37 |
| Oil pan / front case bolt torque-to-fastener mapping | T=9(0.9), T=11(1.1), T=19(1.9), T=44(4.5) | 39 |
| Connecting rod bolt torque (possible torque-to-yield) | “13±2 4m” initial torque + “+80°-84°” rotation angle — digits unconfirmed | 40 |
| Connecting rod bearing color-code-to-pin-diameter mapping | Brown / No Color / Blue-White vs. 35.995-36.000mm / 35.985-35.995mm / 35.980-35.985mm — row alignment lost | 40 |
| Main (crankshaft) bearing color-code-to-diameter mapping | Same structural loss as connecting rod table above | 41 |
| Flywheel / drive plate bolt torque-to-fastener mapping | T=10(1.0), T=74(7.5) ×2, T=11(1.1), plus one internally inconsistent “T=10(1.1)” fragment | 41 |
| ”Oil Screen (Bravo Van)” component note | Unclear whether this is a variant-specific part not applicable to our truck | 39 |
Confirmed with confidence (corroborated by a clean restatement elsewhere in the chapter)
- Cylinder head bolt torque: 64±5 N·m (6.5 kgf·m; 47±3.7 ft-lb) — same for SOHC and DOHC.
- Main bearing cap torque: 52±2 N·m (5.3 kgf·m; 38±1.5 ft-lb) — same for SOHC and DOHC.
- Rocker arm shaft lock-nut torque (SOHC only): 9±1 N·m (80±9 in-lb).
- Valve clearance, cold (SOHC only — DOHC is hydraulic): Intake 0.14mm (0.006in), Exhaust 0.20mm (0.008in).
- Piston pin press force: 4900-10,780 N.
- Connecting rod (big end) bearing clearance: 0.10-0.25mm (0.004–0.010in).
- Crankshaft journal oil clearance: 0.02-0.03mm (0.001in).
- Piston-to-cylinder clearance / cylinder boring allowance — SOHC (non-turbo) 0.02-0.04mm vs. DOHC turbo (our truck) 0.03-0.05mm (0.001–0.002in both).
- Oil pump rotor clearance 0.06-0.18mm (0.002–0.007in), side clearance 0.04-0.11mm (0.002–0.004in), outer/body clearance 0.10-0.17mm (0.004–0.007in).
- Valve margin, valve length, valve seat oversize diameters, valve guide oversize diameters — all corroborated between the spec table and maintenance-note restatements.