1. Engine Sealing and Reassembly
Chapter 13
Engine Sealing and Reassembly

2. Torque Principles All metals are elastic.
Bolts can stretch and compress.
Stretch applies clamping force.
Too much stretch destroys the bolt.
Bolts torqued to yield never return to normal.

4. Torque Principles (cont’d)
Most torque values are for dry fasteners.
Lubricants increase applied torque.
Visually inspect the bolts.
Use lubricants or sealers as specified.
Tighten in the correct sequence.
Ensure proper fastener is used.

5. Bolt Installation Tips
Threads must be clean and undamaged.
Use liquid sealant or engine oil on threads.
Install bolts in their proper holes.
Run a nut over the bolt’s threads by hand.
Clean bolt and cylinder block threads with a thread chaser or tap.
Tighten bolts to the proper torque specification.

6. Thread Cleaning

7. Thread Repair Overtorquing or incorrect threading will strip threads.
May be repaired using thread insert or Helicoil.

8. Torque-To-Yield Bolts
TTY fasteners are designed to stretch when properly tightened.
Once at yield point the bolt is permanently stretched.
Commonly used as cylinder head bolts.
Torqued in steps.

9. Gaskets Used to provide a positive seal between bolted together parts.
Also act as spacers, wear insulators, and vibration dampers.
Gaskets are used on stationary parts.
Seals are used with moving parts.

10. General Gasket Installation
Never reuse old gaskets.
Handle new gaskets carefully.
Ensure clean mating surfaces.
Use the right gasket in the right position.
Only use sealants when specified.
Make sure all threads are clean and undamaged.

11. Adhesives Used only to hold a gasket in place.
Do not assembly until adhesive is dry.

12. Types of Sealants Aerobic Sealants Anaerobic Sealants
Cure only when exposed to oxygen (air)
Are commonly used to form gaskets
Anaerobic Sealants
Cure only in the absence of oxygen (air)
Are used for thread sealant

13. Types of Sealants (cont’d)
General Purpose Sealants
Available in liquid, brush on, or aerosol types
Ensure sealant is O2 sensor safe
Never use a hard drying sealant on gaskets
Thread Sealants
Used on bolts passing through a liquid passage

14. Types of Sealants (cont’d)
Silicone Sealants
Formed-in-place gasket
Applied to mating surfaces
Room Temperature Vulcanizing (RTV) most common
Too much RTV can be squeezed out and into oil system

16. Antiseize Compounds
Prevents dissimilar metals from reacting with each other and seizing
Commonly used on aluminum parts
Always follow manufacturer recommendations when using

17. Oil Seals Used with rotating parts Three basic types Fiber-packing
Two-piece lip
One-piece radial

18. Oil Seals (Cont’d)

19. Engine Reassembly Clean and lubricate head bolts.
Match head gasket to block.
Place head on block and alignment dowels.
Torque head bolts in sequence.
Lube pushrods and rocker arms.

20. Timing Belts and Chains
Cam and crank alignment is critical.
Follow timing procedures exactly.
Ensure the tensioners apply properly.

21. Methods of Valve Lash Adjustment
Rocker arms with adjustable pivots
Adjustable push rods
Rocker arms with adjustable screws
Adjustable cam followers
Selective shims

22. Adjusting Valve Lash

23. Engine Installation Tips
Always refer to the manufacturer’s service information.
Prime the oil pump prior to starting the engine.
Follow the manufacturer’s computer
relearn procedures if applicable.

24. Starting Procedure Set ignition timing as closely as possible.
Fill fuel tank with several gallons of fresh fuel.
Start engine and run at 1500 RPM.
Run until engine reaches normal operating temperature then shut off.
Recheck all adjustments.

25. Break-In Procedure
Test drive at 30 MPH and accelerate to 50 MPH at full throttle.
Repeat at least 10 times.
Apply loads to engine for short periods.
This helps assure the rings seat.

26. Relearn Procedures
The computer will need to learn the engine condition and make adjustments.
Idle and transmission shift schedules will relearn.
Reset any memory functions such as the clock and radio presets.