Technical information

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Workshop Manual_3 - 4 LD_cod. ED0053025560_4° ed_ rev. 03
Disassembly / Reassembly
Valve housings and seats
3LD 450, 3LD 451/S, 3LD 510, 3LD 510/S (mm);
A = 34.99 ÷ 35.01 C = 30.99 ÷ 31.01
B = 35.10 ÷ 35.12 D = 31.10 ÷ 31.12
4LD 640, 4LD 705, 4LD 820 (mm):
A = 42.99 ÷ 43.01 C = 36.99 ÷ 37.01
B = 43.12 ÷ 43.14 D = 37.10 ÷ 37.12
Drive the seats in the housings and mill at 45°.
Valve seat grinding
After milling, grind with ne emery paste in engine oil bath.
The S sealing surface shall not exceed 2 mm.
Embed valves D after grinding for 3LD 450, 3LD 451/S, 3LD
510,
3LD 510/S = 0.55 ÷ 1.05 mm; for 4LD 640, 4LD 705, 4LD 820 =
0.45 ÷ 0.95 mm.