Set timing with strobe

hi all, i checked the repair manual and it says the timing for my car is 7* btdc. i set it with the strobe and then noticed in the book that 7* is the setting for static. does that mean its wrong what i did. is it different setting with strobe light which it is on my mgc.

Hullo Robert,

You must do the initial setup in static mode, i.e. with the engine off. If you haven’t done this before, you can use a multimeter set to ‘continuity’ alarm, or a trouble light. The former is done with the ignition off and the latter with the ignition on. The advantage with the light is that you only need it placed somewhere where you can see its glow. So you can work above and below freely.

Turn the crank around slowly to align with the 7° mark for No.1 pot (Jag 6?), then rotate the distributor until the points just open as witnessed by the multimeter or light. Make sure the points are cleaned and gapped correctly first.

If you try setting this with engine running, you will have errors imposed by the vacuum advance and the centrifugal advance depending upon rpm.

There is a current debate or discussion, that it is better to run these older engines on a higher advance, maybe + 2 or 3, to suit modern fuels. I will fiddle with this a bit later (on a colleague’s car - because it is easier to work on) as it can have a few positives like improved power and economy and possibly slightly cooler running as insufficient advance can replicate a weak mixture. In principle, it is generally recommended to advance as far as you can before ‘pinking’ occurs. It is something to do with the burn rate for modern fuels being different to provide more thorough combustion, and therefore economy.

I hope this helps.


By the + 2 or 3, I mean this to be above the static, hence up to 9 or 10. You can’t do any harm with extra advance provided it is not causing pre-ignition ‘pinking’.

… and vacuum line can be disconnected for the check-up, so only centrifugal advancer might (but shouldn’t ) come into equation…

How does one set static timing when installing electronic ignition such as Pertronix, accuspark or powerspark? The method using a bulb across the points wont work?

Turn it until it sparks.

It should. All you’re doing is opening the switch.

I must admit I have not tried it.

I thought the electronic ignition modules had a little iron core with a coil and magnet in the plastic ring on the dizzy shaft.

As the magnet whizzed by the iron core a little voltage is induced and that opens a transistor.

I thought there would need to be some speed to make it induce the voltage.

Everyday a learning day.

I’ll investigate.

Classically, these have been Hall Effect triggered. Having said that I don’t know exactly how the noted units work. The Hall Effect produces a potential difference (which can be measured and used per this application) in a static magnetic field. It does not require an inductive effect which comes from changing currents (like alternating current) or relative movement between components.

Oh! Thank you. Very interesting.

I’ll report back.

I didnt intend to be this late reporting back.

My distributor was damaged, a wreck, albeit it did run. I binned it and bought a new Accuspark complete dissy, despite assurances that it would fit a 240 it doesnt really as the 240 uses a side entry cap. They sent a further set of leads with 90 boots on the dissy end, better but still a bit rubbish.

So I have the accuspark dissy with my original side entry cap and leads. Its clearly sparking. I have those flashy light up things on the plugs.

Its spitting bqck through the carbs. I thought that meant ignition was too late, so advanced it some more. No joy.

Seems where ever I have the dissy in ita approx 30 degrees or so that it will rotate it wont run.

I’m going to whip 5 plugs out, leave no1 in with my timing light, see if I can find out where it is firing.

Side entry cap confuses as its not a case of movibg the leads round 1 position IYSWIM.

Despite the fact that you now have an electronic dizzy you can still statically time it using a test lamp if you wish. The 123 dizzys come with the lamp (LED) built in. Did your Accuspark come with these instructions? It might be the best starting point? I have an Accuspark module in my Morgan and did the timing this way. FWIW.

Thank you for trying to help.

I think you are suggesting that the accuspark will creat a voltage as I rotate the dissy by hand causing the accuspark to pass the magnet in the plastic ring on the dissy shaft?

So I could put my front crank pulley on its 8 deg timing mark, a voltmeter across the red and black wires from the accuspark and I’d see a voltage as I rotate the dissy body?

That what you mean?

Not really.

Consider that the electronic guts of your dizzy are actually just an on/off switch, like your points.

So if you use a test light, it should come on as soon as the switch goes off, just like opening the points.

A caution about the Accuspark units. Despite what they say, the advance curve may not reflect the original curve for your car. One I bought for an E type was miles out with much faster advance and it topped out nearly 10 degrees above the stock curve.

At minimum I’d check and plot its curve using a dial back timing light, or you can get it mapped by anyone who repairs distributors.

Unless your old distributor is totally unusable I would strongly suggest you send it off and get it properly rebuilt to original spec. This is not expensive, and will give you the proper advance curve for your engine.

I had a lengthy conversation with a distributor rebuilder recently, who has experience with redoing over 20K units. Not only is it important to re-establish all the mechanical aspects of the distributor, but modern fuels differ markedly from what was available when the car was new, and the advance curve should reflect that. Just restoring the distributor to original specifications will not necessarily give a proper curve for modern fuels. There are more than 50 additives now available, the mix varying extensively by brand. You will likely have far more initial advance than stock.

I have had mixed results with electronic distributors, having tried Crane and Pertronix. I have some cars still running on them, others on points. This particular rebuilder told me he considered supplying them, but found the power losses and incremental advance delays to be unacceptable.

I also recommend you have your original rebuilt with points. Seems archaic, but so is the presence of a distributor in modern engines. If the body is cracked from the wreck or from overtightening of the pinch clamp, it can be fixed, probably important if it’s a 22D which are getting harder to find. I think the DMBZs might be less so.

Thank you chaps for your inputs. Much appreciated.

The original dissy is wrecked, at some point it seems something, maybe a balance weight, exited through the main body.

I just pulled the accuspark dissy out to do some bench testing.

Connected it to my meter with the red and black leads.

With the meter set to buzz and on a range of ohm settings up to 200k it seems to be open circuit. I spun the dissy slowly by hand, maybe too slow. But could not incite anything other than open circuit.

I also checked to see if spinning the shaft by hand induced a voltage, I cound not see any response. Maybe too slow.

Oddly I noticed 2 very small clicking sounds from within on each rotation. Two. Not 3 or 6. Two. Thats curious.

Fuck it I’m goung to buy a set of points.

Most of the new electronic ignition kits rely on a Hall effect signal. You will not be able to read it on the bench with a standard volt/ohm meter. Vacuum advance should have no effect at idle. If it does, your throttle plate is bent or something really out of whack. Most mention static timing as you should set the timing before any centrifigal advance starts. Most distributors do not start advancing until above idle. If they did advance earlier, it would be very difficult to have a stable idle as timing effects idle speed. Hook up your timing light, set it at 10 degrees BTDC and enjoy the drive. This setting does not apply to the later emission distributors as they have a much wider mechanical advance curve.

Hi Dick

I kinda thought that would be the case, but the posts above led me to check if I could.

I’ve binned off the iea, I’m going to revert to points. But I still need a replacement dissy.

I don’t think you have said where you are from, but I have the impression you are in the UK? If so, I have a friend who is happy with Distributor Doctor - no experience with him myself, but you might see if he has a spare for your 240 or can do something with what you have.