Morris Minor ignition timing confusion

[lewis s]

Hi everyone, yesterday was spent fitting an electronic distributor to the girlfriends Moggy Minor, and everything was ok up until setting the timing up with the strobe. I had the vacuum advance pipe disconnected, and set the timing up with the strobe to the recommended 3 degrees b.t.d.c as described in the Haynes manual. The car seemed to run ok but was pinking under load ( i think that's what i could hear, have never heard it before). I then had another go with the strobe and trial and error and is now not knocking but is set at 10 degrees b.t.d.c.

Is this due to modern fuels or am i doing something wrong? What would you normally expect it to be set to? Ive not had a go at timing before so this is all new to me really.

Thanks in advance,
Lewis

[kev b]

Did you fit complete new disributor or just a module to replace the points? If you are still using the old ,worn distributor then it probably has weak centriugal advance springs,this would make the timing over advance as the revs rise, causing pinking. I would back the timing off gradually until the pinking stops. Try revving the engine and watching the timing marks ,does it advance smoothly or bounce about madly? When was the last time the distributor was lubricated? Is the mixture correct?

Edited by kev b on Thursday 30th December 18:52

[ROOODBOY]

Yeah, might not be timing related.

Have you checked the carburettor dashpot has enough oil in it?
If it hasn't, that can make it run lean under load and cause pinking, and make it run a bit rough generally.

[kev b]

Good thinking Rooodboy. I would also check the vacuum advance diaphragm is not split this might make the mixture slightly weak.
Also the idle speed must be correct or your strobe will read incorrectly. If you don't have a rev counter then set the idle speed as slow as poss. then increase it when you have finished.

Edited by kev b on Thursday 30th December 19:20

Edited by kev b on Thursday 30th December 19:20

[lewis s]

Its a complete new distributor, and unfortunately could not rev and look at the same time as the timing marks are in a ridiculous position next to the sump

I will have a look again with the idle turned right down, but it does idle quite low anyways. I have just been given a gadget though which can tell you the engine speed so i will try and get some batteries for it and see what it is idling at. What should it idle at when setting the timing and why would it make a difference?

And the dashpot has recently been topped up when i serviced it.

ETA

The car seems to run and accelerate smoothly and the plugs are a nice tan colour so i think the mixture is correct.

Edited by lewis s on Thursday 30th December 20:00

[wildoliver]

Assuming the rest of the engine is set up correctly totally ignore the "factory" ignition setting, wind it forwards till it pinks then wind it back a tiny bit.

[skeggysteve]

wildoliver said:

Assuming the rest of the engine is set up correctly totally ignore the "factory" ignition setting, wind it forwards till it pinks then wind it back a tiny bit.

I agree.

The distributor on the A series is driven by a shaft that is driven by the camshaft that is driven via a chain by the crankshaft.
In that lot there is going to be a lot wear!
So your timing marks on the crank pulley and timing chain cover are only going top be a rough guide.
To be honest timing an A series, even when new, was always easier 'by ear' than using the timing marks!

[Pigeon]

Third vote for advance until pinks then back off a tad. That's how I always used to do mine... find a hill of the right gradient so you can floor it in top at about 35mph without it accelerating very much, and set it so it's just on the edge of pinking when doing that. And the "tad" is easy on a Moggy with the vernier knob on the distributor

[davepoth]

Another vote for "advancing till it pinks and back off a bit".

There's so much about that engine which is not as per the factory spec (distributor, plugs, mixture, fuel, coking in the cylinder head etc.) that the factory timing is almost guaranteed to be wrong.

Idle on that car should be about 750rpm I should think. Basically anything that turns off the ignition light and doesn't make the engine wobble on the mounts should be ok.

[kev b]

Armed with this new information I will add my vote to the last post. Incidentally have you notced an improvement in performance? My then girlfriend, now wife had a Moggy in the 1970's ,adding a SPARKRITE ignition box made more difference to power and economy than any of the other mods we tried.

[NHK244V]

Can't remember the last time i used me timming light? allway advance till pink then back off but be aware sometimes this can cause a slow turing motor when cold, it'll sound/feel like the battery is flat

[skeggysteve]

NHK244V said:

...but be aware sometimes this can cause a slow turing motor when cold, it'll sound/feel like the battery is flat

If you have advanced so far that it makes the started motor struggle or 'stall' then you have advanced to far.

[lewis s]

Ok more questions

Managed to go out this morning and found a big hill. I advanced the timing and took a run up, and the engine sounded nice and strong. Advanced it a bit more and not much difference and no signs of pinking. I kept on advancing and got to the point where it had a lumpy idle but it still was'nt pinking up the hill. What am i doing wrong here? This is getting a bit annoying :/ Ive just set the distributor so it is idling highest and is pulling well but i want to get this as accurate as i can!

Just checked it on the strobe again when i got home and is now around 4 degrees b.t.d.c

[lewis s]

Anyone?

[chard]

4 degrees @ tickover with the vacuum advance removed will not be far off, if it's not pinking it will be safe. Why not try a little more advance if it pinks back it off a touch. It's the only way to time the engine properly fuels are very different now to when the the designers set the timing marks.

I run my Alpine a touch retarded just in case of lower octaine fuels.

Edited by chard on Sunday 9th January 21:59

[lewis s]

bks, i know what ive done now

[chard]

lewis s said:

bks, i know what ive done now

What??

[lewis s]

chard said:

lewis s said:

bks, i know what ive done now

What??

Ive been turning the distributor the wrong way

[wildoliver]

It does seem to be causing some confusion.

I know everyone including me has said advance till it pinks then back off slightly, but if it ends up that you start losing power having advanced the ignition and it still isn't pinking the aim isn't to hit that point just before pinking, it's purely that is usually where the max power is. If you have lost the power by going too far (never known an engine get to that point without sounding like a rattling chain.) then just wind it back till it feels right. The gist of the post was don't pay too much attention to the manuals setting and a strobe. View them as starting points not much more.

[chard]

lewis s said:

chard said:

lewis s said:

bks, i know what ive done now

What??

Ive been turning the distributor the wrong way

We've all done it at some point