TR4/4A Engine Issues Again--I'm Hearing Things

[KVH]

It seems I regularly have the opportunity around here to show my age and declining state of mind. Here we go again:

My 4A is finally running well, and fairly smooth. However, when at operating temperature, and while idling, there is a sound coming from the engine reminiscent of a whirring cooling fan. I have such a fan on my other vehicle (also a 4A) but none on this car. The sound is coming from the upper part of the engine, maybe the valve cover. It's not a pinging, clicking or ringing sound. But more like the whirr of a fan or jet engine.

Any ideas of things not inside the confines of my mind?

 

[TomMull]

Generator? Water pump? Use a long screw driver as a stethoscope (or a stethoscope). Tom

 

[texbears3]

Dont' rule out the tensioner for the time chain. Use your stethoscope on the chain cover. Two have briken on my 4A over the years. One time is pierced the chain cover.

 

[Geo Hahn]

Easy enough to rule in / rule out the generator & water pump -- just run it briefly w/o the belt and see if the sound goes away.

I agree it could be the tensioner - did have a sort of whirring noise when it was broken and touching a stethoscope to the timing chain cover removed all doubt.

 

[DougME]

Old piece of garden hose works well too for locating noises.

 

[GTP1960]

I was having a hard time tracking down an intermittent chirping noise that sounded something like a circular saw slightly connecting with the side of a cut.
turned out it was a harmonic vibration caused by the carburetor heat shield at certain idle speeds.
the intermittent nature of these things is the challenge. Hard to recreate the event on your terms.