Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 2010 4/4 sigma pinking

Can anyone out there please give me some advice I have a 2010 4/4 1.6 Sigma powered Morgan and it has given the sound of pinking when driving on over run or whilst driving especially when in 4th and 5th gears. (More noticeable when the engine is warm)
The car runs like a dream other than this noise and it is starting to become a worry.

When I purchased the vehicle it was soon taken back to the dealer that I got it from to try to find the cause. I was told that it is a known trait of the sigma engine and was often mentioned on Ford forums but I have not been able to find anything about this when I've looked.
I have no reason to doubt the mechanics and experts from the centre that I got the car from as their reputation is almost legendary and while the car runs well I still would like to know if something is a miss with my beautiful Morgan or if it is something that I will always have to put up with.

So has anyone experienced anything like this or can point me in the direction to a possible fix to this annoying pinking please.

Do you use highest octane petrol?
I try not to get below 98 octane.

I assume you get plinking at low rpm. Try to avoid anything below 2500 for acceleration.
5th gear is for highway rolling only.
The (my) Sigma likes high revs!

Different petrol might help but at least check the ignition timing, probably too far advanced and might need retarding a bit even if it means backing off from the standard setting a few degrees.

It's not good for engines so best to get checked.

The ECU is fed by the crank angle sensor the position of the engine in it's revolution. From that it looks at temperature, vacuum, engine speed, etc., etc. The ECU then sets the ignition timing.

You cannot change the ignition timing on that engine by twisting a distributor.

It could be a faulty knock sensor assuming it has one.

My best guess would be to find an engine tuner with a rolling road that specialises in these engines and who knows their "special features".

You will not sort it with a reasonably priced code reader.

A Ford Engine Specialist is my opinion. No idea at all about who that would be

I would echo Hannes' thoughts here - are you sure you're using enough revs? These are modern engines and don't appreciate being lugged around at low revs, remember they are designed to spin up to 7k revs or more, and the sweet spot for power is in the 3-4k region.

Also as Hannes says, put decent petrol in it, none of this supermarket rubbish, Shell V-Power or BP Ultima is what your P&J deserves, nothing less.

But if you're revving it and putting good petrol in, then maybe a RR session would be in order as Eddie says.

You don't normally get pinking or knocking on the over run and in normal driving conditions. It usually only occurs when the engine is under load. Mind you top gear in an urban street could have the engine lugging and I would nearly always be in 4th under those conditions.

There is a good article in Wikipedia: https://en.wikipedia.org/wiki/Engine_knocking

I suspect you may have some other cause for the knocking noise. Can you try to describe exactly what you hear with a comparison to some other easily identified sound?

Thank you all for your input I have always gone for the best fuel and it does feel if I Change gear too early then it is more noticeable but it sounds just like the engine is pinking in the traditional way that you would get on an engine with a normal traditional ignition system (points n condenser type) even the senior from the Morgan workshop referred to it as pinking if I had to describe it I could say it sounds like a death rattle or a very cheap set of castanets and it's always noticeable if you change up too early.
Perhaps a RR is the answer this I will have to look into.

Just a thought but if all the obvious causes check out ok then how is your coolant concentration? Are you using say over a 50% mix by any chance? The higher the ratio of coolant to water the poorer the heat transfer. If you have an elevated head temp with localised hot spots and hot plugs that might be causing the pre-ignition. Perhaps you could try a reduced ratio over the summer?

Thank you fo your reply

So what speeds would you be using 5th gear please?

Thanks in advance

I will look into this thank you.