Service Procedures

CYLINDER HEAD COMBUSTION DECK INSPECTION AND REFACING





Inspect the head surface for nicks, erosion, etc.

Check for head distortion as illustrated.

Limit

Variation: 0.010mm [0.0004 inch] in any given 50.8 mm [2.0 inch] diameter area. The overall end or side-to-side variation limit is: 0.30 mm [0.012 inch].





The combustion deck may be refaced in whatever increments necessary to clean up the surface and maintain the surface finish and flatness tolerances, as long as the combined total of stock removed does not exceed 1.00 mm [0.0393 inch]. The amount of stock removed each time must be steel stamped just above the edge of the combustion deck on the lower right hand corner of the rear face.

A = 1.00mm [0.03937 inch] total
B = 94.00 +/- 0.25mm [3.7008 +/- 0.0010 inch] minimum (reference only)
C = Surface finish 1.5 to 3.2 micrometers [60 to 128 microinches]
D = Identification area for stamping amounts of stock removed

VALVE GUIDES: INSPECTION AND INSTALLATION





Inspect the valve guides for scuffing or scoring.

Measure the valve guide bore.

Diameter Limits
New Minimum: 8.019 mm [0.3157 inch]
New Maximum: 8.029mm [0.3165 inch]
Worn Limit: 8.090 mm [0.3185 inch]

If the valve guide bores are larger than the worn limit, the cylinder head must be machined for service valve guides. New valve guides must be reamed to size after they are installed.

NOTE: If the cylinder head needs service valve guides and valve seat inserts, the valve guides should be installed first.

VALVE GUIDES

^ Intake (Thick wall)
^ Exhaust (Thick wall)
^ Intake and Exhaust (Thin wall)

SERVICE VALVE GUIDES - THIN WALL





Machine the cylinder head valve guide bores to Dimension A.

A = 11.125 +/- 0.013mm [0.4380 +/- 0.0005] in diameter

Service valve guides must be centered with valve seats within 0.35 mm [0.01378 inch] diameter and are to be square with the combustion face within 0.10 mm [0.0004 inch] at 50.0 mm [1.9685 inch] radius.





Install the valve guides as illustrated.

A = Lubricate with oil and press the guides flush to the bottom of the bosses.
B = 12.00 +/- 0.75 mm [0.4724 +/- 0.0295 inch] reference
C = Trim off flush to top of guide bosses if necessary.
D = 8.029 +/- 0.010mm [0.3161 +/- 0.0004 inch]

NOTE: The valve guide bore must be centered with the valve seat within 0.35 mm [0.0138 inch] diameter and must be square with the combustion face within 0.010 mm [0.004 inch] at 50.0 mm [2.0 inch] radius.

SERVICE VALVE GUIDES - THICK WALL





Machine the cylinder head valve guide bores to Dimension A.

A = 14.000 +/- 0.013 mm [0.5512 +/- 0.0005 inch] diameter

Valve guides must be centered with valve seats within 0.35 mm [0.01378 inch] diameter and must be square with the combustion face within 0.10mm [0.0004 inch] at 50.0mm [1.9685 inch] radius.






Install the valve guides as illustrated.

Lubricate with oil and press in the guides to dimension A protrusion above the cylinder head.

Ream the bores to the dimension B size.

A = 12.25 +/- 0.50 mm [0.4823 +/- 0.020 inch]
B = 8.029 +/- 0.010 mm [0.3161 +/- 0.0004 inch]

VALVE SEATS - GENERAL





On cylinder head which have integral valve seats, the seats can be reground once only. Integral seats that have been previously reground must be replaced with service seats.

Seats that have been previously reground should have been identified with one X stamped into the head casting as shown.





Two X's stamped on the head indicate service seats have been Installed. Service seats can be reground.

CAUTION: On the integral seat head, if 0.254 mm [0.010 inch] or more has been removed from the head combustion surface, service seats must be installed.





NOTE: To determine if the head has been previously resurfaced, before calculating valve depth, proceed as follows:

1. Check the rear lower right corner of the head for a stamping that would indicate previous resurfacing (e.g. 0.003).
2. To verify the information, or if no amount is indicated, measure the head height (B).
3. If the head height is 94.75 mm [3.730 inch] or greater, the valve seats may be reground If they have not been reground previously.

CALCULATING THE GRINDING DEPTH (INTEGRAL SEATS ONLY)





After resurfacing the valves and determining that all values meet specifications, install the valves in their designated locations and measure valve depth.





NOTE: The valve depth is the distance from the valve face to the head deck.

Record the depth of each valve (A).

GRINDING THE VALVE SEATS





Grind the valve seats to remove scores, scratches and burns.





Seat Angle
Intake: 30 degrees
Exhaust 45 degrees





Install the valves in their respective bores and measure the depth again.





Record the depth of each valve (B).

Calculate the grinding depth (GD) as follows: GD= (B)-(A)





Grinding Depth Maximum Limit (integral Seats Only)

GD = 0.254mm [0.010 inch]

NOTE: Service valve seats are available for over the limit seats.





Identity reground valve seats.





Install the valves in their designated locations and measure the depth of each.





Valve Depth Limit (Integral and Inserted Seats)

C = 0.99mm to 1.52mm [0.039 to 0.050 inch]

NOTE: Replace the valve if the depth is over the limit.





Apply a light coat of valve lapping compound to each valve and lap each valve to its mating seat.





Remove the valves and clean lapping compound from the valves and seats.





Measure to valve seat width indicated by the lapped surface.

Valve Seat Width Limit

1.50 mm Minimum [0.060 inch] 2.0mm Maximum [0.080 inch]





If required, grind area (A) with a 60 degree stone and (B) with a 15 degree stone to center the seat on the valve face. Maintain the valve seat width limits.

Valve Seat Width Limits (1)

1.50 mm Minimum [0.060 inch] 2.0 mm Maximum [0.080 inch]

INSTALLING SERVICE VALVE SEATS





Inspect the valve guide bores as described in the valve guide section of this manual. if it is necessary to install valve guides, install the guides before installing the service seats.

Valve Seat insert - Pocket Machining Dimensions, Intake Seat

A = 8.029 +/- 0.010mm [0.3161 +/- 0.0004 inch]
B = 10.40 +/- 0.10mm [0.4094 +/- 0.004 inch]
C = 47.00 +/- 0.013mm [1.8504 +/- 0.0005 inch] diameter
D = 0.40mm [0.0157 inch] maximum radius
E = 3.2 micrometers [128 microinch] surface finish

(Valve Seat Insert Part Number 4429854)





Valve Seat Insert - Pocket Machining Dimensions, Exhaust Seat

A = 8.029 +/- 0.010 mm [0.3161 +/- 0.0004 inch] diameter
B = 10.20 +/- 0.10 mm [0.4015 +/- 0.004 inch]
C = 43.650 +/- 0.013 mm [1.7185 +/- 0.0005 inch] diameter
D = 0.40 mm [0.0157 inch] maximum radius
E = 3.2 micrometers [128 microinch] surface finish

(Valve Seat Insert Part Number 4429111)





Valve Seat Insert Staking Tool

Press service seats into the machined pockets. Stake the valve seats into the pockets.





Grind the valve seats lightly to ensure proper seat angle.





Seat Angle
Intake: 30 degrees
Exhaust: 45 degrees





Install the valves in their respective locations and measure the depth.





Valve Depth Limit

C = 0.99 mm to 1.52 mm [0.039 to 0.060 inch]





Apply a light coat of valve lapping compound to each valve and lap each valve to its mating seat.





Remove the valves and clean the lapping compound from the valves and seats.





Measure the valve seat width indicated by the lapped surface.

Valve Seat Width Limit

1.50 mm Minimum [0.060 inch] 2.0 mm Maximum [0.080 inch]





If required, grind area (A) with a 60 degrees stone and (B) with a 15 degree stone to center the seat on the valve face. Maintain the valve seat width limits.

1.50 mm Minimum [0.060 inch] 2.0 mm Maximum [0.080 inch]

REPLACING SERVICE SEATS
To replace service seat inserts, machine the insert in the same manner as if machining out the integral seat. Hold the same tolerances and follow the same installation procedures.