Automotive / Engine Components
Cylinder Head Installation Guide for Toyota 1PZ, 1HZ, and 1HD-T Engines
A technical guide for installing the cylinder head on Toyota 1PZ, 1HZ, and 1HD-T engines, including procedures for measuring piston protrusion and selecting the correct cylinder head gasket.
Quick answers from the manual
Quick answer
- To install the cylinder head, you must first measure the piston protrusion for each cylinder, calculate the average, and select the appropriate cylinder head gasket (hole/cutout 1, 3, or 5) based on the largest measured value. p. 1, 2
Key actions
- Measure piston protrusion p. 1
- Select cylinder head gasket p. 2
Problems and fixes
Piston protrusion is not as specified
Remove the piston and connecting rod assembly and reinstall it.
p. 1Technical specifications
| Parameter | Value | Meaning | Pages |
|---|---|---|---|
| 1PZ/1HZ Protrusion | 0.405-0.655 mm | Acceptable range | p. 1 |
| 1HD-T Protrusion | 0.475-0.725 mm | Acceptable range | p. 1 |
Where to find it in the PDF
- Piston Protrusion Measurement p. 1
- Gasket Selection Tables p. 2
Table of contents
Manual images
Click an image to enlargeQuick Guide: Piston Protrusion and Gasket Selection
This document outlines the critical procedure for measuring piston protrusion and selecting the correct cylinder head gasket for Toyota 1PZ, 1HZ, and 1HD-T engines. Proper gasket selection is essential for engine integrity and performance.
Measuring Piston Protrusion
Before installing the cylinder head, you must measure the piston protrusion for each cylinder to determine the correct gasket thickness.
- Preparation: Clean the cylinder block solvent. Set the piston of the cylinder to be measured slightly before Top Dead Center (TDC).
- Measurement Setup: Place a dial indicator on the cylinder block and set it to 0 mm (0 in.). Ensure the measuring tip is square to the cylinder block gasket surface and the piston head.
- Measurement Procedure: Find the point where the piston head protrudes the most by slowly turning the crankshaft clockwise and counterclockwise.
- Data Collection: Measure each cylinder at two places. Make a total of ten measurements for the 1PZ engine or twelve measurements for the 1HZ and 1HD-T engines.
- Calculation: Use the average of the two measurements for each cylinder to determine the protrusion value.
Protrusion Specifications
The acceptable piston protrusion ranges are as follows:
- 1PZ and 1HZ: 0.405-0.655 mm (0.0159-0.0258 in.)
- 1HD-T: 0.475-0.725 mm (0.0187-0.0285 in.)
Note: If the protrusion is not within these specifications, you must remove the piston and connecting rod assembly and reinstall it according to the service manual.
Selecting the Cylinder Head Gasket
After determining the largest piston protrusion value, select the appropriate gasket based on the hole or cutout number.
1PZ Engine
There are three types of supply gaskets available (hole numbers 1, 3, and 5). Select the gasket based on the largest protrusion value:
- 0.455 mm (0.0179 in.) or less: Use hole number 1
- 0.456-0.555 mm (0.0180-0.0219 in.): Use hole number 3
- 0.556 mm (0.0219 in.) or more: Use hole number 5
1HZ and 1HD-T Engines
There are three types of supply gaskets available (cutout numbers 1, 3, and 5). Select the gasket based on the largest protrusion value:
- 1HZ (0.455 mm or less): Use cutout number 1
- 1HZ (0.456-0.555 mm): Use cutout number 3
- 1HZ (0.556 mm or more): Use cutout number 5
- 1HD-T (0.525 mm or less): Use cutout number 1
- 1HD-T (0.526-0.625 mm): Use cutout number 3
- 1HD-T (0.626 mm or more): Use cutout number 5
Manufacturer information
Toyota Motor Corporation
Practical help
Common problems
Piston protrusion out of specification
Remove the piston and connecting rod assembly and reinstall it according to the service manual (pages EM-86 and EM-108).
Before use
- Clean the cylinder block solvent.
- Set the piston slightly before TDC.
- Ensure the dial indicator measuring tip is square to the cylinder block gasket surface.
- Measure each cylinder at two places.
- Calculate the average of the two measurements for each cylinder.
Specs in practice
- 1PZ/1HZ Protrusion Range
- 0.405-0.655 mm (0.0159-0.0258 in.)
- 1HD-T Protrusion Range
- 0.475-0.725 mm (0.0187-0.0285 in.)
Images and diagrams
- The diagrams illustrate the measuring points on the cylinder block for different engine models.
- The gasket selection charts show which hole/cutout number to use based on the measured protrusion.
Model compatibility
- Gasket selection differs between 1PZ and 1HZ/1HD-T engines.
- Only three types of supply gaskets (1, 3, 5) are available for replacement, despite five types being installed at the factory.
Manual page author
Emily Carter
User documentation editor
Prepares concise manual descriptions and highlights the most useful setup, operation, and maintenance information for readers.