Nissan 13201-1KC0A Valve Intake

Begin by scraping away all traces of old gasket material from the cylinder head, followed by removing carbon from the combustion chambers and ports, and washing the cylinder head thoroughly with paraffin or a suitable solvent. Next, scrape off any heavy carbon deposits from the valves and use a power-operated wire brush to clean the valve heads and stems. Carefully inspect the cylinder head for cracks, coolant leakage, and other damage; if significant defects are found, a new cylinder head should be obtained. Check for distortion of the cylinder head gasket surface using a straight-edge and feeler blade, and if distortion exceeds specified limits, consult an engine reconditioning specialist regarding machining options. Examine the valve seats in each combustion chamber; severely damaged seats will need renewal or recutting, while slightly pitted seats can be ground-in with fine valve-grinding compound. Assess valve guides for wear by inserting the relevant valve and checking for excessive side-to-side motion; if movement is excessive, measure the valve stem diameter and renew the valve if worn, or renew the valve guide if the stem is not worn. If valve guides are renewed, recut or reground the valve seats afterward. Inspect each valve head for pitting, burning, cracks, and wear, and check the valve stem for scoring and wear ridges; renew any valve showing signs of damage. Measure the valve stem diameter at several points using a micrometer; significant differences indicate wear, necessitating renewal of the valve(s). If valves are satisfactory, grind them into their respective seats for a smooth, gas-tight seal, using fine grinding compound unless the seat is badly burned or deeply pitted, in which case a specialist should inspect the components. Perform valve grinding with the head supported upside-down, applying valve-grinding compound to the seat face and using a suction grinding tool on the valve head, lifting the valve occasionally to redistribute the compound. If coarse grinding compound is used, work until a dull, even surface is achieved, then switch to fine compound until a smooth finish is produced. After grinding, wash off all traces of compound with paraffin or a suitable solvent before reassembling the cylinder head. Examine valve springs for damage and discoloration, noting that checking their condition accurately requires special equipment; however, a rough assessment can be made by comparing the free length of the springs with a new one. Stand each spring on a flat surface and position a square alongside it. If any springs are damaged, distorted, or have lost tension, obtain a complete new set, as it is standard practice to renew valve springs during major overhauls. Additionally, renew the valve stem oil seals regardless of their apparent condition.

This is not an operation that is carried out according to the maintenance schedule, but it is recommended if either the noise from the valve gear is heard or if efficiency is decreased due to wrong clearances. Starting with the handbrake, follow it with jacking the frontend of the car and placing it on the axle stands, then you proceed to the removal of the right-hand road wheel and the front right-hand wheel arch liner. Next, turn the cylinder head a little and do the same with the cylinder head cover drawing all the 8 valves, labeling them as inlet or exhaust and numbering them 1 to 8. Continue rotating the crankshaft until the several valve data of No 1 cylinder are 'jiggling or 'rocking' to perform clearance check of both valves of No 4 cylinder at the same time. To adjust the valve clearances, leave the feeler blade of the right thickness in place because inlet valve and exhaust values are not equal. After inspecting No 4 cylinder, rotate the engine through 90 degrees to BOS to inspect No 3 valves and continue with the valve inspections in this sequence. For adjustment we will need a micrometer or dial gauge. If a valve clearance is different from the set figure, the cam follower should be altered, adding the thickness of any cut out cam follower, due to wear. To work on the cam followers, it is necessary to first take out the camshaft and then work separately on each follower to eliminate confusion. Determine the thickness of the follower as per the given and achievable clearances with the needed changes. To replace a follower, remove it to be reconditioned,ically lubricate the new one and refit it in the cylinder head before re-fitting the camshaft, cylinder head cover, wheel arch liner, roadwheel and then lowering the car on the ground.