When should a valve be replaced due to margin thickness wear?

When the valve head has been worn down to 0.5 mm (0.020 in) in margin thickness, replace the valve.

What is the camshaft end play specification and limit?

Camshaft end play is 0.03 - 0.31 mm (0.0012 - 0.0122 in), measured with the thermostat housing and gasket installed; the limit is 0.15 mm (0.059 in).

What special tools are used to install the valve oil seal and to what depth?

Tools KV10109500 and KV10107500 are used, driving the seal to 14.8 - 15.2 mm (0.583 - 0.598 in).

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Nissan Micra Cylinder Head Inspection & Assembly - Valve & Camshaft Specs EM-14

Cylinder head inspection and assembly page with valve dimensions, spring checks and figures

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Cylinder head inspection and assembly procedure covering valve dimensions, spring squareness and camshaft end-play with figures.

AI caption April 2005 · Photo 68 of 412

This is page EM-14 of a Nissan engine (EM) service manual section covering cylinder head inspection and assembly. The left column completes inspection procedures: valve dimensions must be checked against S.D.S. specifications, the valve must be replaced when the head margin thickness wears to 0.5 mm (0.020 in), and the grinding allowance for the valve stem end surface is 0.2 mm (0.008 in) or less. Valve spring squareness must be less than 2.0 mm (0.079 in) out of square, and free length and tension values are referenced to the S.D.S. The right column details cylinder head assembly: installing the valve oil seal using special tools KV10109500 and KV10107500 to a seated height of 14.8-15.2 mm (0.583-0.598 in), installing valve components and the camshaft oil seal, oiling and installing the camshaft with the front face knock pin orientation shown for No. 1 cylinder at TDC compression, and measuring camshaft end play with the thermostat housing and gasket installed — specification 0.03-0.31 mm (0.0012-0.0122 in), limit 0.15 mm (0.059 in). Illustrations SEM188, SEM288A, SEM994, and SEM013 support each procedure.

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Frequently asked questions

When should a valve be replaced due to margin thickness wear?: When the valve head has been worn down to 0.5 mm (0.020 in) in margin thickness, replace the valve.
What is the grinding allowance for the valve stem end surface?: 0.2 mm (0.008 in) or less.
What is the valve spring out-of-square limit?: Less than 2.0 mm (0.079 in).
What is the camshaft end play specification and limit?: Camshaft end play is 0.03 - 0.31 mm (0.0012 - 0.0122 in), measured with the thermostat housing and gasket installed; the limit is 0.15 mm (0.059 in).
What special tools are used to install the valve oil seal and to what depth?: Tools KV10109500 and KV10107500 are used, driving the seal to 14.8 - 15.2 mm (0.583 - 0.598 in).