New engine or cylinder head M13A

My 52 plate Jimny that I have had for the last 5 years has suddenly developed a noise coming from the front right hand side of the cylinder head. Its a distinct tap tap tap noise. If I need to replace the whole engine or the cylinder head where is the best place for a refurb engine ? 

Many km or miles on it?
if it is low milage I would fix it depending on the cost.
You will know your own service history but if you buy a second hand engine it is most likely unknown.

I would consider changing it out to a m16 just as well.
No big task for anyone with average/good mechanical skils or if you can get it done cheap by a garage the engine swap would not cost much more if you swap to a m16.
engine/parts cost would be the same or so.

Hi there, good point about not knowing the history on a second hand engine. I am the second owner on mine with a good service history and 60,000 on the clock so maybe a rebuild is the route to take.

Maybe start by having the fault diagnosed, discussing rebuild or replace seems a bit extreme for what is being described as a "tap tap tap" noise.

Its quite a loud tapping noise that came when the car was at tick over. She has been so reliable over the years I guess I might been panicking a bit and should have a closer look before giving upon the engine.

If it is quite loud and came on suddenly, there may indeed be an acute problem that needs immediate attention. 60k miles is not really sudden-failure territory, but then again, stuff happens.

Is the tap at engine speed or half engine speed? The latter is more likely to be valvetrain-related, the former perhaps bottom-end.

It sounds like you have already spent some time under the bonnet listening, so I assume you have already ruled out external problems like the fan belt or an exhaust leak at the manifold.

If you are mechanically inclined, it may be useful to remove the valve cover for a look. Beyond that, having it under the microscope at a knowledgeable garage would be prudent, as @fordem says -- and soon.