Ignition Timing and Carb setting

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rustybolts21

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I have a Series 3 petrol with electronic ignition and a Zenith 36IV carb.

What should I set the ignition timing at with a strobe light?

I've searched the forum and found several different answer. One of which is 'by ear' but I don't know what would be the right sound!

Also, how many turns out is a good place to start with the Idling Volume Control Screw on my carb?

Any help would be gratefully appreciated.
 
On the crankshaft pulley you should find a small 'v' cut into the back edge. Behind that there should be a piece of metal which goes to a point and will be located at about the same level as the top centre of he pulley.

Use a bit of chalk or Typex on both, and that should give you your ignition timing.

I always found it best to screw the fuel adjuster right in and then turn it back about 2 1/2 turns.

Hope this helps.
 
Thanks for the reply Old Sea Dog.

I'll set my fuel adjuster at 2 1/2 turns out.

What setting do you suggest for the ignition timing e.g. TDC, 3oBTDC, 3oATDC etc? when using a strobe light.
 
Once you have got it to fire up consistently, then I would static time the ignition to the mark at 3 BTDC.

Start your engine up at that and then slowly turn your distributor. It should speed up until it gets to the point where doesn't like it, and then back it off a couple of degrees.
 
Hi I'm also looking to set up my timing and idle etc after rebuilding my carb and fitting electronic ignition.

Is the dynamic setting also 3 BTDC or is that just for static? I can't use static timing due to my electronic ignition I've fitted. Thanks for any help.

Did you get yours sorted Rustybolts21?
 
Another method for setting timing is the use of a vacuum gauge.

Plug the gauge into the intake manifold on a warmed-up engine with the distributor loose enough to rotate. Start engine and turn distributor till you get a maximum vacuum reading, then back till the reading drops an inch of vacuum on the gauge or so. This is not unlike the "by ear" version above but gives you a quantitative measurement to work against.

Done it this way for years and had good luck wioth it. Best part is you're actually measuring the engine's efficiency as an air pump (which is what it is after all) and setting the ignition to work with the real-time state of the engine.
 
34 of my 35 years with series Land Rovers where with diesels.
From memory I think I used 3 degrees before TDC as a static setting and 6 degrees at around 1500 rpm with the strobe. You do need to make sure the vacuum advance is working on the distributor to do it this way.
 
Hi today I tried to set the timing on the car but it is running very badly. In the end I had to give up for the day.

I have the 25d dizzy with the little wheel/knob on the side that can also be adjusted.

I put the strobe timing light on but I didn't know whether to set the timing with the vac advance pipe removed or not?

As I can't get the car to idle at low revs such as 500rpm I'm struggling to know what to set the timing to and whether the vac should be on or off?

Thanks for any help with this...
 
Oldseadog said:
Remove the vac pipe and static time as explained previously, then replace it and fine tune from there.
Click to expand...

Hi thanks. So vac off and can I still use the strobe? I can't static time due to elec ignition. But if I strobe time do I still do it to 6BTDC or is it different somehow on the front timing chain marks when doing dynamic? I've now found my Haynes but it doesn't mention dynamic timing... Thanks for the help.
 
i have mine set to 6 btdc and it runs sweet if it pinks back it off a little but you should be ok and that is with a strobe
 
jockmurray said:
i have mine set to 6 btdc and it runs sweet if it pinks back it off a little but you should be ok and that is with a strobe
Click to expand...

Hi thanks - so is yours set at 6btdc with a strobe running at 500rpm with the vac advance off? Also is it 2.25 engine petrol like mine?

My strobe is just a 'normal' one that can't dial in timings etc.

Thanks again for the help.
 
You may find that your distributor can take a lot more advance than the book says - depending on its age and the state of the springs you may find that anything upto 12 degrees (or even 15 if you use 98 ron) will work. Some newer lucas dissy's have quite differnt advance curves. The best thing is to keep advancing until you hear it pinking. and then back off a degree or so. To do this set to say 12 then drive on a gentle up hill slope at around 30mph in top, if you hear something sounding like marbles on a glass table that's pinking.

I tend to run with a little pinking as I find it picks up better and uses a little less fuel. Many people say this will cause you to blow holes in pistons but I've so far had no problems.
 
pinking is the petrol igniting early which can make the engine run hot i dont run mine at 500 rpm i run it at 750 and yes i set it using the 6 degree mark on the bottom pulley with vac off i am aslo running a powerspark ignition kit from simon bbc and the thing pulls like a train in as much as a series canhope this helps regards dave
 
Oldseadog said:
Once you have got it to fire up consistently, then I would static time the ignition to the mark at 3 BTDC.

Start your engine up at that and then slowly turn your distributor. It should speed up until it gets to the point where doesn't like it, and then back it off a couple of degrees.
Click to expand...
Hi there,
Sorry for butting in here but my 72 S3 is a bit blowy, lacking power and can conk out on idle. I reckon it’s timing so I ask, Can you simply turn the distributor by hand and listen to the engine? Oh I hope so......
 
6BTDC is the starting point, I guess from the thread that you have a fixed set of replacement points and not a complete distributor like I have (123 Ignition) .. so my advantage is that there is an LED that lights to indicate the firing position, so by turning the distributor I can set it.

I found however that the best spot is a little off 6BTDC as there must be wear on the components i guess.

As for the Zenith, I hated mine and could never really get it set to where it ticked over evenly, it was either ticking over ok but running with a massive flat spot at about 45MPH or refused to tick over but the flat spot was virtually gone.. so I bit the bullet and fitted an SU conversion and BINGO! not only does it idle but also pulls in all gears even at low speed.
 
On the crankshaft pulley you should find a notch at near TDC, and a pointer fitted to the timing box just above it.
Turn the engine by hand until the two line up (I use a dab of Typex on both to make them easier to see), and then turn the distributor, without the cap on, to where the points just begin to open, with the ignittion on and a lamp between the points.
Gently nip up the clamp.
She should fire up once you replace the cap.
Once she has fired up, you can then manually turn the distributor fior the final setting, as outlined above.
Hope this helps.
 
Simon Perks said:
6BTDC is the starting point, I guess from the thread that you have a fixed set of replacement points and not a complete distributor like I have (123 Ignition) .. so my advantage is that there is an LED that lights to indicate the firing position, so by turning the distributor I can set it.

I found however that the best spot is a little off 6BTDC as there must be wear on the components i guess.

As for the Zenith, I hated mine and could never really get it set to where it ticked over evenly, it was either ticking over ok but running with a massive flat spot at about 45MPH or refused to tick over but the flat spot was virtually gone.. so I bit the bullet and fitted an SU conversion and BINGO! not only does it idle but also pulls in all gears even at low speed.
Click to expand...
An SU makes a massive difference!! Brings the engine to life!!
 
Thanks for all the responses. Had a wee look today and seems like I need the choke on for it to run without stalling. It’s in the garage next week so as a temporary fix I thought I’d just up the idle rate. No difference.... still stalled without the choke. So then thought, if the choke makes a rich mixture, I’ll adjust the mixture on the carb...... fully closed, fully open.... no difference in how the engine sounds. A friend reckons it’s idling using main jets (really low) and there might be an issue with the idle jet.... who knows. It can wait till it’s in the garage.... or I might just drive it to the skip (with the choke on of course).
 
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