Petrol

[Cyril]

Ok thanks. Any suggestions as to why the car is still jerky?
Its been serviced and timer been corrected and new spark plugs.
Its not a major issue as the car still drives but I notice it.

[liammonty]

Hi Cyril,

Sorry to hear you're still having problems. It's so difficult to say what would be causing it without being there, but it sounds to me like something to do with the ignition system, especially if it's just been serviced. There are a lot of dodgy ignition parts out there these days unfortunately, so it could be that an old component has been replaced with a new, bad one perhaps. Also, if the points have been set wrong it could cause it, so an easy first check would be the points gap. If the timing's been adjusted as well, there's always the possibility that it's not been set quite right. If the problem started after the service, chances are that it's due to something that was done in the service. Good luck tracing it!

[Cyril]

No its actually much better after the servicing, they did not replace any ignition parts.
What is "Pinking"?

[liammonty]

Probably no need to worry about it, but pinking is pre-ignition of the charge of air and petrol in the cylinder; that is, where it ignites slightly before it should do, and doesn't burn smoothly. It's due to the ignition timing being too far advanced (i.e. the spark happening too soon) for the type of petrol you're using, and it can cause damage to the engine. You can normally hear it, and it sounds like a jingling noise (if you can imagine someone hitting a piece of metal really fast and lightly with a hammer, it's a bit like that). You'll normally only hear it when the engine is at lowish revs, and working hard (like driving up a hill in a high gear). Lower octane fuel (i.e. normal unleaded vs super unleaded) makes it slightly more likely to happen, but if it happens, it is cured by setting the timing correctly, which is why back in the 80s when unleaded started coming in, people used to have to get the timing adjusted on their cars when changing from higher octane 4 star to unleaded.

I hope that makes some kind of sense!

[bmcecosse]

You DO NOT want to use 'Super' Unleaded - whoever told you that just has no idea ..... And please - don't waste money on silly additives...they really really are not necessary. Unless - you intend to regularly hammer the car on the M/way - then you should add Tetraboost additive - which contains genuine tetra-ethyl lead, and effectively makes the fuel 'leaded'. Note - you must not put this stuff anywhere near a catalyst.... Meantime - set the exhaust valve gaps at 15 thou - and check/reset every 3000 miles. You won't have any problems. The 'unleaded' caper is seriously over-egged.... don't worry about it - and just use 95 grade fuel - it's more than adequate for a standard A series.......

[rogerowen]

You DO NOT want to use 'Super' Unleaded - whoever told you that just has no idea ..... And please - don't waste money on silly additives...they really really are not necessary. Unless - you intend to regularly hammer the car on the M/way - then you should add Tetraboost additive - which contains genuine tetra-ethyl lead, and effectively makes the fuel 'leaded'. Note - you must not put this stuff anywhere near a catalyst.... Meantime - set the exhaust valve gaps at 15 thou - and check/reset every 3000 miles. You won't have any problems. The 'unleaded' caper is seriously over-egged.... don't worry about it - and just use 95 grade fuel - it's more than adequate for a standard A series.......

The use of 'Super Unleaded' was sanctioned by a certain Morris Minor Specialist in East Sussex!!!!???***

[bmcecosse]

Exactly.......tells it's own story really.......and not for the first time......

[customjob]

Hi Cyril, standard unleaded (95 RoN) or super plus unleaded (97 - 100 Ron) is fine for a moggie, as regards it's kangarooing around it maybe that the timing has not been set correctly recheck it or have rechecked.

[simmitc]

Hi Cyril, I think that we've done the petrol issue to death. If the car is still jerky then perhaps a new topic describing the symptoms would be helpful, then we'll chip in with ideas for solutions.

[MrDodo]

I've conducted an experiment over the past 1,100 miles/5 months and have been using Shell Nitro+ to see if this improves the fuel economy. The results a marginal improvement of 0.7MPG - not enough to justify the 8p/litre premium and certainly within the margin of error given that I wasn't driving in controlled conditions.

[bmcecosse]

Fuel economy always improves during summer..... Easier cold starting/faster warm up/thinner oil - and therefore less use of 'choke' and 'warming up'. And then better driving conditions - less wind and rain to battle against - no need to run heater fan/wipers/lights - all of which use power and therefore fuel. My diesel modern improves by ~ 4 mpg in summer over winter running. I suggest your improvement of only 0.7mpg actually represents an increase in fuel burned !

[MrDodo]

I was trying comparing to a similar set of figures summer (if I don't do a longer run out of town the London traffic will crush any improvements). Though as I said it hardly been a scientific test. I'm quite happy with around 40MPG from my '65 1098 convertible.

[JOWETTJAVELIN]

Anything like "Super unleaded", "Premium", "Extra", etc is just a waste of money. Stick to regular unleaded, the car will be fine. If you do a lot of high speed motorway work then I recommend Valvemaster, but, as I noted in my original reply, opinion is strongly divided on the need for it. On what we all agree is that you do not need anything more exciting than standard unleaded petrol.

In the case of our engines, yes. But if the engine was designed for Premium grade fuel then you will not get the best performance from the engine if you fill up with Regular grade. The A Series in its earlier incarnations was designed to run on poor quality fuel, as has been said already, but later versions specified a minimum of 95 RON for the 1098cc unit and 97 RON for some versions of the 1275cc. This is certainly the case for the A Series in the Allegro, for example, and the performance definitely suffers if driven on the 95. Conversely, if a cheaper grade were available in this country, the early Minors would happily run on it, I'm sure.

So yes, Premium grade petrol is a waste of money for a Moggy engine.

Incidentally, some people would like to tell you that 'all petrol is the same as it all comes from the same refinery'. This is utter rubbish, as the stuff you buy from the supermarket is not refined to the same level as the branded fuels, nor does it contain the same level of additives.

then you should add Tetraboost additive - which contains genuine tetra-ethyl lead, and effectively makes the fuel 'leaded'. Note - you must not put this stuff anywhere near a catalyst....

Could you please explain what you mean by 'catalyst' in this instance, as it has me stumped!

[taupe]

Cat converter.. they are ruined by lead in the fuel.

[lambrettalad]

there is a range of each star rating e.g. petrol isn't homogeneous,therefore petrol at the lower end of the scale is cheaper leaving the refinery ,and goes to the cheaper end of the market