Hello everybody,
just a newbie question about my restored (with engine rebuilt) XK140: is a “ratt-tt-tt-tt-tt” noise in the background normal?
also, there is black smoke from the exhaust, is this normal while cruising at low speed and with some stops when driving it in the city? engine fits weber carburetors, maybe to ‘greasy’ for low speed cruising or could be the sign of any issue with the engine?
Thanks in advance
I would say the sound should not be a Rattatta and the exhaust should not be black smoke, sounds like you need to get the car to a carburettor specialist to set the chokes on the Webers.
My first thought is valve clearances too large. Listen with a mechanic’s stethoscope or there is the old long screwdriver in the ear trick, handle in your ear, tip held against the engine at various places to find the noise.
I uploaded a video on youtube where you can hear what I mean…if I mean something which makes sense 
Hi Dante,
No comment on the noise but the black smoke is the carbs are too rich. Do you know what the spec’s are for the Webers - model, jets etc.?
Best
Keith
Ciao Dante,
have you checked if your exhaust headers sealed well at the head (e.g. checking for black soot deposits next to the gasket)? At low rpm a small exhaust leak can be confusing with a tapping noise…
You may want to try reducing the “idle jets” by one step (i.e. 5) to run a bit leaner at low revs, and check the outcome on the spark plugs… but eventually jetting and setting the webers perfectly is achieved more easily using tools.
Check the generator pulley. That’s what was wrong with my 150. Also check fan blades. One of mine was bent and hitting the shroud.
Pat H.
If Webers are set up correctly, no.