TM 10-3930-653-14&P Adjustment should be made whole engine Is hot.  After all valves have been adjusted correctly, tighten lock nut  firmly  to secure the adjustment. Valve clearance Intake 0.38 mm Hot (0.015 in) Exhaust (3) CHECKING AND ADJUSTING FAN BELT With  the  engine  switched  off  and  the  hood  up,  push  the belt gently downward.  You should be able to depress it about 10   mm   (1/2   in)   midway   between   fan   pulley   and   alternator pulley by a force of 10 kg (22 lb).  If the fan belt has become slack through wear, loosen the fixing and adjusting bolts, and move the alternator away from the engine.  Thus will eliminate the slack.  Tighten the bolts again, and make sure that the belt has  been  tightened  correctly.    If  tightened  excessively  it  will wear rapidly and also overload the water pump and alternator bearings. Fan belt deflection: 8 to 12 mm (0.31 to 0.047 in) Fig.  4-3.  Adjusting Pan Belt Tension. (4) CHECKING ENGINE ATTACHING PARTS Check engine mounting, carburetor, alternator, starter, fuel pump and distributor for looseness.  If  necessary, tighten. Tightening torque: Engine mounting center bracket-to-body bolt 7.5 to 9.5 kg-m (54 to 69 ft-lb) Engine mounting upper bracket-to-engine bolt 4.0 to 5.0 kg-m (29 to 36 ft-lb) Engine mounting insulator bolt 8.0 to 10.0 kg-m (58 to 72 ft-lb) (5) CHECKING ENGINE COMPRESSION Note:  If this test is to be  performed.    it  should  be  done when  all  plugs  are  removed  for  service  during  basic tune-up procedure. Unless check is made for worn rings or for the cause of low speed, compression check should not be necessary. Fig.  4-4.  Testing Compression Pressure. Test    compression    with    engine    warm,    all    spark    plugs removed    and    throttle    and    choke    opened.        No    cylinder compression  should  be  less  than  80%  of  highest  cylinder’s. Excessive  variation  between  cylinders,  accompanied  by  low speed   missing   of   the   cylinder   or   cylinders   which   are   low, usually   indicates   a   valve   not   properly   seating   or   a   broken piston ring.  Low pressures, even though uniform, may indicate worn   rings.      This   may   be   accompanied   by   excessive   oil consumption. Test conclusion If    one    or    more    cylinders    read    low,    inject    about    one tablespoon of engine oil on top of the pistons with low reading cylinders  through  the  spark  plug  port.    Repeat  compression check on these cylinders. (1) If  compression  improves  considerably, piston rings are faulty. (2) If compression does not improve, valves are sticking or not seating properly. (3) If   two   adjacent   cylinders   indicate   low   compression and  injecting  oil  on  pistons  does  not  increase  compression, the  cause  may  be  a  cylinder  head  gasket  leak  between  the cylinders. Engine oil and coolant in cylinder could result from this problem. 4 - 9