1. Cylinder Block Inspection and Service
Chapter 10
Cylinder Block
Inspection and Service

2. Objectives Analyze wear and damage to cylinder block
Select and perform most appropriate repairs to block

3. Objectives R&R cam bearings, galley plugs, and core plugs
Explain theories of cylinder wall surface finishes

4. Cleaning the Block Disassemble
Remove all core plugs and oil gallery plugs
Remove cam bearings
Hot tank block and flush thoroughly to remove caustic solution and sediment

5. Cleaning the Block Lubricate all machined surfaces
Check block for cracks in cylinder bores and lifter valley

6. Oil and Water Plugs
Must be cleaned after hot tanking to prevent loosened particles from entering engine after reassembly
Use a stiff bristle brush with hot soapy water

7. Oil and Water Plugs Three types of gallery plugs Female plug Male plug
Allen-type plug

8. Oil Jet Cooling
Original intent of the jets on the inside of piston was to provide lubrication to wrist pins
Pistons are prone to increased heat, thus cooling this area is important
Be careful when removing jets to clean the oil galleries

9. Aligning Dowels on the Back of the Block
Dowels align the transmission or transaxle housing to the engine
Aligning dowels should be in good condition to avoid misalignment
Sweet transmission pump area with dial indicator attached to the crankshaft if misalignment is suspected

10. Main Bearing Caps and Registers
Fit in to machined slots in block
Bores are bored at factory with caps in place
Caps are not interchangeable

11. Main Bearing Caps and Registers
Some engines use four or more bolts to support main cap
Some engines use a bedplate for extra strength

12. Main Bearing Caps and Registers

13. Main Bearing Bore Alignment
Repeated heating and cooling of an engine block
Can cause misalignment of main bearing caps
Check main bearing saddle bore alignment with feeler gauge and straight bar
Blocks can be remachined to correct misalignment

14. Main Bearing Bore Alignment

15. Checking Main Bearing Bore Alignment
Coat main journals of crankshaft with Prussian Blue
Install crank and bearings I block
After torquing main caps, rotate crankshaft twice

16. Checking Main Bearing Bore Alignment
Turn engine upside down and rotate engine twice
Carefully unbolt main caps and remove crank
At least 75% of bearing area should be “blued” for acceptable alignment

17. Decking the Block Clean deck surface with a file or whetstone
Remove any nicks or burs that may give false readings
Use a straight edge and a feeler gauge to check block deck for flatness

18. Decking the Block If block shows warpage, block should be decked
Machine shop will use a grinder or milling machine to deck block

19. Inspecting Cylinder Bores
Inspect cylinders for taper and out-of-round wear
Maximum wear is at 90º to wrist pin
Due to lack of lubrication at top of cylinder

20. Inspecting Cylinder Bores
Top of cylinder is subject to high pressure of the piston rings against cylinder wall
When air-fuel mixture is ignited

21. Measuring the Bore Square ring just below ring ridge
Measure ring gap with feeler gauge
Compare this measurement to butt gap measurement taken at bottom of cylinder

22. Measuring the Bore
To determine taper, divide difference between the two gaps by three

23. Deglazing Cylinders with Engine in Car
Rotate crank to BDC
Put a length of hose on bottom of glaze breaker
This prevents it from damaging crankshaft

24. Deglazing Cylinders with Engine in Car
Newspaper at bottom of bore will protect crank from oily grit
It is not necessary to stroke all the way to bottom of cylinder

25. Clean the Block of Grit Hand brush or use air drill
Ordinary cleaning solvent will not lift grit from pores of metal
Check cylinder walls and crankcase for cleanliness

26. Clean the Block of Grit Following cleaning
Grit can often be found in crankcase area just under cylinder bores

27. Reboring Cylinders
Cylinders with excessive or unusual wear or rust should be rebored
Following boring
Cylinders are honed to fit new oversized pistons
Popular oversize
.020", .030", and .040"

28. Reboring Cylinders
Small change in compression ratio will occur when boring

29. Ultrasonic Thickness Testing
Used to check thickness of cylinder walls
Determines if enough material exists in block to safely bore cylinder
Considered a non-destructive tester

30. Ultrasonic Thickness Testing
Can produce sound waves from 500 KHz and 100 MHz
Higher frequencies for thinner materials
Lower frequencies for thicker metals

31. Honing Cylinders Two stones and two aluminum guides on a rigid hone
Ensure guides are not too tight against cylinder walls
As honing of each cylinder is completed
Allow stones to run with very little pressure for several strokes

32. Honing Cylinders
Stroke hone at speed necessary to generate a crosshatch of between 20º and 30º off horizontal surface of block

33. Cylinder Surface Finish
One micro-inch is one millionth of an inch
Higher micro-inch number
Means rougher finish
Average finish recommended
25 to 30 micro-inches

34. Cylinder Sleeves
Cylinder sleeve can be used to fix a cracked, rusted, defective cylinder
Most sleeves come with a 1/8” or 3/32” wall thickness

35. Cylinder Sleeves To install sleeve Bore block
Cool sleeve and heat block
Press in sleeve

36. Final Block Preparation
Clean block with soap and hot water
Oil machined surfaces
Clean all bolt holes
If block has been decked
Bolt holes can be chamfered at top to remove burrs
Clean out galleries with rifle brush

37. Oil Gallery Plug Installation
Coat threaded oil gallery plugs with sealer or Teflon tape and tighten into block
Install press fit core plugs with red loctite
Cross stake outside of core holes with cold chisel

38. Oil Gallery Plug Installation

39. Coolant Core Plug Installation
Clean core holes in block with emery cloth
Put sealer on outside of core plug and drive into block
Lip is just past chamfer when core plug is properly installed on block
Core plugs of same diameter can have different depths

40. Coolant Core Plug Installation