Engine doesn't want to stop!

Post by **hornmeister2000** » Mon Aug 18, 2003 10:40 am

Hi!

I've got a questions about the behaviour of my Moggy's engine. Basically, it's sometimes not too keen to stop running when I turn off the

ignition and I'm not sure why. It runs very well, though. On Saturday I retarded (I think!) the ignition timing by about 2 degrees using the

microadjuster on the distributor, as I was told this was necessary to run on 95 octane unleaded petrol. It has been a bit worse since then.

According to my book, you have to turn the dial clockwise to retard the timing. Now the dial is pointing downwards, so I assume that by

"clockwise" it assumes I am looking at it face-on, so I turned it anticlockwise from above, as I was behind the dial.

I don't know if that's connected or not, but and advice would be appreciated!

Many thanks,

Neil

Post by **Kevin** » Mon Aug 18, 2003 10:49 am

I know it sounds obvious but you dont have your tickover running to fast do you ?

www.xing.com/profile/Neil_Shorney · Post by **hornmeister2000** » Mon Aug 18, 2003 10:52 am

Don't think so. It seems to tick over about right

Post by **ColinP** » Mon Aug 18, 2003 12:44 pm

Is the timing correct (i.e. advance it till it pinks under load, then retard it a smidgen)? If it's too retarded it will run rather poorly. (obviosuly check with the fuel you intend to use - I use Optimax - 98+ octane)
What is the mixture like (check the spark plug electrodes - white is too lean, black too rich)?
The running on problem is caused by the fuel-air mix being ignited by bits of the cylinder head/spark plug which are hotter than normal.
Hence you need to make sure the plugs are clean/new and the right temperature rating.
I recall hearing tales of how running on was a sign of an impending de-coke - the carbon deposits on the combustion chamber glowing red-hot. Maybe that's something you need.

Lastly, if the engine has been driven hard, the bits will be hotter than if it's been treaded gently. Sometimes it will just run on a couple of turns.

Modern cars actually have an electrically operated valve to cut off the fuel supple for idling to prevent this probem.

Colin

www.xing.com/profile/Neil_Shorney · Post by **hornmeister2000** » Mon Aug 18, 2003 12:50 pm

Thanks for the advice Colin. Could you explain what Pinking actually sounds like? I've heard it mentioned so often in relation to unleaded petrol and I understand it harms the engine, but I'm not sure exactly what it is. Basically, I've had the car a month (it's my first 'classic' car) and it seemed to run fine on unleaded with a fuel additive. I was advised to retart the timing 2 degrees in case it was pinking, but I don't know if it actually was, in which case would I be better re-setting the adjuster as it was before? If I knew what pinking sounded like it would be easier! Is it loud? Would I know if I heard it?!

Post by **ColinP** » Mon Aug 18, 2003 1:09 pm

Hmm, how do you describe this?

Pinking is where the fuel/air mixture explodes instead of burning smoothly (but very rapidly). It's most noticeable when accelerating hard at low engine revs (floor the throttle in top gear at 15-20 mph), and sounds like a metallic rattle/tinkle from the engine. This is why it's bad for the engine - the explosion causes excessive force on the pistons/con rods/crankshaft - plus the shock-wave effect.
I'd seriously consider re-setting the ignition timing to the "book" values, and using "super" fuel - there was a long discussion here on fuel grades. IIRC the 95 octane does have a tendency to run-on as well.
Cam - how's my memory?

What engine/model do you have? and how many miles?

Colin

www.xing.com/profile/Neil_Shorney · Post by **hornmeister2000** » Mon Aug 18, 2003 1:13 pm

Thanks for the advice Colin. It's a 1969 1098cc with only 51k on the clock. I assume the noise is loud enough to notice. I'll have a search through the old posts and find the old discussion too, but I don't go far in it so the extra expense of 98 octane isn't too bad. Or I s'pose Valvemaster Plus octane boost has the same effect

Post by **Kevin** » Mon Aug 18, 2003 1:52 pm

Another point is that if the engine is original low mileage and untouched it will not have an unleaded head, and as Colin says its quite distinctive and often noticed when when accelerating up hills as well.
As you are new to Morris Minors it would do no harm to join your local branch which can also be a useful source of advice and help.

Post by **Peetee** » Mon Aug 18, 2003 2:15 pm

Imagine the muffled sound a metal spoon jangling around in a tea mug sitting in your engine bay while you drive.
That's the sound of pinking.

www.xing.com/profile/Neil_Shorney · Post by **hornmeister2000** » Mon Aug 18, 2003 2:24 pm

Thanks for the advice - I'll probably put the timing back where it was before and run it on Optimax or Super Plus. Yes, it is the original unaltered engine with a leaded head, so I'm using Castrol Valvemaster which I've heard good reports about. Also, yes, I think a local club would be useful! Thanks everyone for all your help!

Post by **Cam** » Mon Aug 18, 2003 3:55 pm

Spot on Colin!!

Pinking is one of those sounds that automatically causes me to wince a bit and take my right foot off the gas or change down a gear, our Sierra is terrible for it (run on LRP) but my Rover has never suffered with it (same fuel). Once you hear and recognise it you won't forget it. however having said that, I have been in friends cars and moaned at them for allowing it to pink and they did not have a clue what I was on about!!

If I were you, I would use Castrol valvemaster plus with normal unleaded because you don't have an unleaded head and so need VSR (valve seat recession) protection. Just changing to optimax won't provide this (although it will probably stop the pinking). so you need VSR protection and higher octane fuel. valvemaster plus should do the job a treat!!! oh and reset the timing to what the book says as well (as has been suggested)

Post by **Willie** » Mon Aug 18, 2003 7:58 pm

Now you know what pinking is...it seems that you altered
the timing without having a good reason to do so!
For your guidance the click adjuster on the distributor takes
eleven clicks to alter the timing by one degree. as regards
running on, a tickover which is too fast will not help,on your
low mileage engine(?????) you should be able to set it so that
the red charging light is just glimmering on tick over.
The click adjuster is marked 'A' and 'R'. Standing at the
side of the engine,facing the dizzie you turn the knob anti-
clockwise to advance the timing.

Post by **les** » Mon Aug 18, 2003 10:31 pm

I have a book on the 'A' series engine that suggests the static timing is more suited at 14 degrees btdc, with a distributor cam marked 10 degrees.

Post by **Cam** » Mon Aug 18, 2003 11:50 pm

I always set mine to 8 degrees BTDC (dynamic) and they seem to like it! I think that 14 degrees static is a bit advanced. The owner's manual recommendation of 6 degrees (dynamic) is fairly close.

Post by **les** » Wed Aug 20, 2003 9:37 pm

I agree it sounds too much, my manual says 5 degrees, but I tried the higher setting and it runs sweet, when you think about it the piston is pretty close to the top of its stroke even at this apparently high setting, I wonder how much lower the piston is for an 8 or 9 degree difference.

Post by **Cam** » Wed Aug 20, 2003 10:27 pm

Not much, it hardly moves at all close to TDC or BDC. But those few degrees can make a large difference to the running.