David

I think you were spot in Spitfire 6 when you mentioned ignition timing. I checked and found mine was way out to the tune of almost 10 degrees for some unknown reason. Returned it to 11degrees BTDC and the car is going fabulous with a great burble coming from exhaust at idle. I think that as a final step adding to the actions I have already taken, re-adjusting the ignition timing has made all the difference. Thanks for the idea. Very much appreciated. 😀👍

Forgot to add, yes it is a Lucus PI system as opposed to EFI.

Hi, Thanks Spitfire 6. I had not thought of checking the ignition timing. I’ll do that later and see what a difference it makes. It is indeed a sucking noise I’m dealing with. Could I just confirm what you mean by ICV? 🙂👍

Yes John, it is.

Hi Pete, Thanks for your thoughts. Fairly sure it’s not the Fan Belt. I forgot to add to my original message that when initially looking for the source of the noise, Fan Belt was disconnected and the engine run briefly showing the noise continued despite the disconnection. That way, the Water Pump, Alternator and Fan Belt were all eliminated in my mind. When I run the engine at idle with the pipe disconnected from the Air Valve and then, separately, the large flexible tube from the Air Filter to the Log, it was clear the noise was coming out of the Air Valve Pipe. I have also checked the 4 balancing pipes between the Manifolds for any splits and nothing is evident. Becoming more perplexed as I go. 😕 Any more thoughts as to what I can look at next would be more than welcome. 🙂👍

Hi My 1973 TR6 PI (CR Series) makes a annoying 'Chuf, Chuf' noise when idling and I would appreciate knowing if anyone has come across this before? The 'Chuf, Chuf' noise comes from the Air Valve pipe and that means the sound is amplified when it travels via the pipe into the Air Intake Manifold (Log). I have taken the following steps in trying to track down the problem but with no success. Compression Test completed (dry) and 140psi across all 6 cylinders Valve clearances checked at 0.0010in. All Manifold bolts both inlet and exhaust checked for their respective tightness/torque. WD40 sprayed around manifold gasket and Air Valve to see if any air leakage and nothing is evident. Throttle Butterflies checked and when engine is idling they are closed and I am unable to get 0.002 a gauge past showing no gap between the Butterflies and the Bores. All links re fuel pipes, connections to Injectors etc checked and nothing is loose Gromit seals checked and all replaced re the Insulating Block for each injector. Coming to the end of what I can think of now. Does anyone have anything they can suggest I try next? Cheers David