Cylinder Head Measuring

Tools Used

• 10mm and 14mm socket 
• Feeler Gauges - For measuring clearances 
• Valve spring compressor - To allow valves to be removed
• Straight Edge - For measuring how much springs are out of alignment
• Micometer - for measuring taper and ovalitiy
• Ball Gauge
• Square Edge
• Callipers

Head dis-assembled

Valve Inspection and Measurements Taken

• Surface Warpage: Using straight edge across surface of cylinder head I was looking for any bends in its surface measurements were taken in 6 different places across surface with feeler gauge checking gap between surface and straight edge. Maximum warp allowed was 0.15mm
• Valve Stem Measurement: Once valves were removed from head using spring compression tool to close up spring so pin could be removed. Measurements were taken at 3 different areas of valve stem (top, middle and bottom) with micrometer to measure diameter of stem of both intake and exhaust valves.
• Valve Guide Margin: Using feeler gauge width of valve guide was measured according to width of it had to be 0.5mm at most.
• Valve Guide Clearance: Using the ball gauge to measure how much room there is in the valve guide once measurement was taken a micrometer was used to measure the reading from the ball gauge
• Valve Spring Squareness: Measurement was taken to find out how much the springs were out of alignment using a square edge and vernier callipers this can be found out by the amount of space there is in between vertical edge of the square is measured in 2 places and answer is made by minusing the 2 measurements from each other.
• Valve Spring Free length: Measured using Callipers to find length of spring
• Valve Spring Installed Height: Using Callipers again valve is measured in place in head 

Cams and Valves

Camshaft Inspection and Measurements Taken

• Inlet and Exhaust cam lobes: Using a micrometer 5 cam lobes were measured in 2 places to obtain the lift of each lobe
• Shaft ware (out of round and taper): Also measured using the micrometer in 2 directions of the journals horizontally and vertically. journals had to be within 0.05mm 
• Cam shaft run out - Using a Dial test indicator the amount of ware on the bearings was measured it had to be within 0.03mm according to manufactures specification
• Oil Clearance - Using a Plasti-gauge the small amount of clearance needed for the oil to move around was measured with the bolts torqued up to manufactures specification a result of 0.050mm was shown which was within specification of 0.035 - 0.081mm

Cam Shaft on blocks so that run out can be measured

Reason for Measuring Head


Measurements are required to make sure the head is in good order. If these measurments are out they can cause problems like; 

• loss of power 
• a blown head gasket
• valve seating faults
• A loss of compression
• Coolant leaks

These problems can be rectified by replacing warn parts or resurfacing excessively warn areas to correct specification.