Manifolds, Cylinder Head & Valves

l)If the new valve guides are replaced, ream the valve guides to the dimensions given in specifications.

m)If the valve seat inserts are to be replaced, take a fine cut, if necessary, from the bottom of the counter bore, to ensure a square seat for the replacement insert. (See fig. 10&11) n)Thoroughly chill the new valve seat inserts at -60 0 C in dry ice before installation. This prevents metal scraping from the side of the counterbore, ensuring full contact of the insert on the bottom and side of the counterbore. After installation inserts peen over the edge of the inserts around it’s entire circumstance. The inserts should be recessed in the Head 0.006” to 0.014” o)Reface the valve seats to the correct angle seat that are too wide after refacing should be narrowed by grinding the top edge of the seat with a stone of a similar angle (15 0 angle preferred). Refer Fig. 14 p)Mount a dial indicator on the pilot shank and check that seat run out does not exceed 0.003”. q)Reface the valves but reject valves that grind down to a fine edge. r)Using carborundum paste lap-in the valves. Ensure that all carborundum paste is removed from the valve and valve seats after lapping. Excess paste must be removed with a cloth and the head washed in the solvent and blown dry with compressed air. s)Check the valves in their seats using engineers blue. A complete ring of contact must be shown on both faces. t)If the end of the valve stems are found to have developed indentation (due to constant hitting of rocker arm) the same should be removed by fine grinding the tips and removing sufficient metal so as to give flat & smooth finish. However either valves or the rocker arms which have deep indentations should not be salvaged.

When using carbon dioxide or dry ice, strictly adhere to instructions to avoid injuries. Do not touch deep frozen parts with bare hands.

4f.ASSEMBLY :

a)Coat the valve stems with clean engine oil and install them in their original position.

b)Install the valve spring seat and valve seals.

c)Install valve springs and retainer. Using valve spring compressor, compress the spring and fit the new collets.

d)After assembling the valves, ensure that the valve depression below the cylinder head mating face is as per the following specifications :

Inlet0.89/0.480.035/0.019

Exhaust1.20/0.780.047/0.031 e)Install the injectors and tighten the nuts to the specified torque. f)Check to see if nozzle protrusion will remain specified limits after rework. Nozzle protrusion of 1.8 to 2.3 mm ( 0.070” to 0.090” ) is to be ensured.

4g.INSTALLATION :

a)Apply a light coating of clean engine oil to the cylinder head mating face and install new gasket.

b)Install the guide studs as shown in Fig.15 in the cylinder block to hold the gasket in place and ensure the correct alignment of the cylinder head while installation.

c)Install the cylinder head d)Install the centre rocker arm lever shaft bracket on cylinder head and insert the long bolt. e)Remove the guide studs then insert the remaining bolts. f)Tighten the bolts progressively in the order shown in Fig.4 to the specified torque. g)Remove the long bolt from the centre valve rocker arm shaft bracket and remove the bracket. h)Install the push rods in their original position.

Before installation the cylinder head check cylinder sleeve protrusion.

If protrusion is not within specification remove the sleeve and follow the complete procedure.

NOTE: Be sure there is no oil i.e. the bottom cylinder head bolt holes to prevent hydraulic lock when the bolts are torqued.