TIAGO

1.05L REVOTORQ ENGINE 120 Inspection : A. Cylinder Head : Checking Cylinder Head Mating Surface : 1. Using a straight edge and feeler gauge, check evenness of cylinder head parting surface with crank case. If unevenness exceeds specified values, replace cylinder head. 2. Permissible unevenness of cylinder head mating surface-0.030 mm (Length wise). 3. Permissible unevenness of cylinder head mating surface-0.015 mm (Cross wise). Note : Cylinder head top and bottom surface re- machining in service is not permitted. B. Valves : 1. Check valve leakages by pouring gasoline on valve head. Gasoline must not seep past valve seat. 2. Valves with burnt heads, excessive scoring and wear on stem should be replaced. 3. Check valve seat run out with respect to valve stem. If it exceeds specified limit replace valve. No attempt should be made to straighten bent valves. 4. If valve is free from any other defects except worn out seat, then only it can be rematched on valve grinding machine as follows:  Clamp valve on grinding machine jaws as close as possible to valve head.  Adjust grinding angle on graduated scale to achieve correct valve seat angle.  Feed valve slowly towards grinding wheel until wheel just touches valve head.  Grind at low feed until valve seat is just clean all around. NOTE: After grinding, valve head thickness should not be less than 0.85 mm. C. Valve Guides : 1. In case of valve stem sticking in valve guide bore or Excessive clearance between them, remove valve guide From cylinder head using drift (Part No.2868 5890 06 05). 2. Check the condition of valve guide oil seals. 3. Check valve guide bore diameter in cylinder head and if necessary, ream valve guide bore in cylinder head to next over size. 4. Install matching size valve guide in cylinder head using drift (Part No. 2868 5890 06 05) and spacer (Part No. 2653 5890 06 01). 5. Fit Valve guide oil seals D. Valve Seat : 1. Check valve seat height with respect to cylinder head mating surface. Replace valve seat inserts if they are worn out beyond specified limit. 2. Cut exhaust and inlet valve seats with a general 45 deg. cutter. Note : Valve seat must be absolutely faultless and without any chatter marks 3. If necessary lap the valve seats to a smooth and even finish by using suitable hand pump grinder or a lapping paste and valve itself. 4. Smear valve seat with carbon blue. Install valve in guide and turn it slowly under axial pressure. 5. Contact line on valve seat must be around entire circumference at equal width. 6. Distance between narrow diameters of valve face to contact line should be minimum 0.5 mm. 7. Check for leakages through valve seat by pouring gasoline on valve head. Gasoline must not seep past valve seat. E. Valve Seat Insert : 1. For removing valve seat inserts from cylinder head use suitable boring machine. Bore old insert thin (About 0.5 mm thickness) and then pry it out. 2. Alternatively use a suitable turning tool to cut an annular groove into valve seat insert and then pull it out with a suitable puller. In order to avoid damaging machined cylinder head mating surface with crank case, place any soft protective sheet metal under supports of puller. 3. Measure valve seat insert bore diameter in cylinder head. 4. If boring and prying is done carefully without damaging valve seat insert bore in cylinder head, fitment of an oversize valve seat insert will not be necessary. 5. Re-machined valve seat insert bore in cylinder head must be exactly at right angle to cylinder head mating surface with crank case. 6. All specified dimensions should be strictly maintained to ensure proper interference of valve seat insert in its bore.