Whine from engine

[NoviceM]

1970 morris 1098 engine.
Runs fine but....recently on tickover, a high-pitched whine (spelling?) Comes from engine.....and I cannot find it. Seems to be coming from centre line (in line with rocker cover).
When engine has warmed up sound disappears. I have tried engineers stethoscope still cannot find source of sound. I have oiled distributor including heel of points.
Any ideas.?
Garry

[Bill_qaz]

Try running(short period) without the fan belt. This will eliminate the water pump and dynamo or alternator, whichever is fitted.

[NoviceM]

Good idea thanks, will try tomorrow morning.
Cheers Garry

[michael4]

Often this can be the alternator (if it has one) when under load after starting. Goes away as the load drops.

[philthehill]

Make sure that the fan belt is tight. If you have an alternator fitted the belt needs to be very tight. The correct tensioning should be a 8lbf applied to the belt at midway between crankshaft and alternator pulley should give a deflection of 6mm.
If it is the fan belt slipping a slight coating of talcum powder on the fan belt helps considerably.