Ignition Timing settings

[heinkeljb]

For those who have been reading all the threads as they come up - like me - I know, Sad.

Actually I have learnt a lot about these vehicles doing that!

There was a question relating to a canted over Dynastart. This was caused by a previous owner not having a long enough power cable for the Dynastart to Solenoid run, so the Dynastart was rotated to allow for the shorter cable.

This presented two problems:

1: The Dynastart was now at a strange angle in the clamp so making the two poly belts run at an angle - not good from them. Easily solved by re-fixing the Dynastart fan shroud in the correct place as dictated by the little locating peg. Longer power cable needed.

You might ask why this is important. Well, the Dynastart fan shroud has an ignition timing mark cast into it and this needs to be vertically above the crank shaft in order to allow you to set up the ignition timing correctly.

When the Dynastart fan shroud is correctly positioned, the mark on the crankshaft pulley and the mark on the shroud line up one above the other.

Ignition timing is set thus:

1: Turn crank clockwise until lefthand piston is at top dead center (TDC) - when viewed from back of the Haflinger.
2: Both Crank shaft pulley mark and Dynastart fan Shroud marks should be in line with each other.
3: Open distributor cap
4: Set points gap to 0.20mm as it should be on maximum opening at this point.
5: Rotate crank shaft anti clockwise 1/4 turn
6: Rotate crank shaft clockwise until the timing mark on the pulley wheel is 5 - 7 mm from the the mark on the shroud.
7: Using either a multimeter or a battery and bulb, Rotate the distributor until the points just open.
8: Tighten things up
9: Engine should now start and run as this is the basic starting point for the ignition timing.

Fine tuning can now be done - As with all petrol engine that have a few miles on them, there is wear in all sorts of places which can affect the running of the engine. So now you have a combination of Carburetor and Ignition timing settings to play with until you get the engine running the way you want.

John

[heinkeljb]

Now we come to a relevant question:

The manual I have states the ignition timing to be 5 - 7 mm before TDC.

How can this be? We are talking about something which rotates and so setting should be in degrees not mm which is for straight line measurements.

Possibilities:

1: There is a translation mistake between the original German manual and my English manual and that it is in fact 5 - 7 DEGREES. That would be easy to live with.
2: That is is "supposed" to be in mm and that you are supposed to measure using a ruler the 5 - 7mm in a straight line between the two timing marks. It is possible that at the diameter of the crank shaft pulley that both DEGREES and MM are the SAME in terms of distance.

Actually, my engine started and ran when I set it up using the second possibility. I then used a strobe and my ear to adjust the timing to get it to run smoothly. I did not have to adjust things a lot, so it pretty close if you go by the above.

Hopefully, the above will allow people to at least get their engines running if the only issue is ignition timing.

John

[AustHaflinger]

As they say - In doing things there is right way, the wrong way and the British way - well as far as Haflinger timing goes maybe this saying should be changed to "there is right way, the wrong way and the Austrian way".

Yes it would be nice to sort it out.

Garry

[pathfinder700ap]

Hello,

it is definitely a distance of 5 - 7 mm between the two marks. It is also stated like that in the german manual - and that's nice, because crank angle degree would certainly be hard to measure or require conversion to arc length.

In younger manuals, the nominal distance for the ignition timing setting was reduced to 2 mm:

I am not sure why this was done. I heard a rumor that with increasing fuel quality, the duration of burning had decreased, but I can't confirm this theory.


Kind regards,
Constantin

[heinkeljb]

Thanks Constantin,

I am glad the German manual also lists it in "mm".

I have had several engine which list the timing in degrees and it is easy to use a timing disc marked in degrees to match the requirement. Some required you undo the crank pulley nut and place a timing disc (marked in degrees) on the shaft and do the nut up hand tight and then carry out he timing task. Others just list it and leave it to you to figure out how you do it!

The problem I have with the Haflinger way is that at what angle do you hold your ruler / tape measure / dividers in order to get the 5 - 7 mm and now 2mm distance? My engine was fitted in 1983 and was obviously on of the last ones from the factory as it does not have an "official" engine number, instead PW of Ward fame has hand punched a number with a center punch! So maybe I should see if 2mm works better.....

John

[Julian B]

John - can one not just measure 5-7mm (or 2mm) around the circumference of the Dynastarter pulley wheel?

I took it from Constantin's remark that the reduction from 5-7mm to 2mm was more to do with a change in thinking by SDP over time rather than a change in the way they designed & built the engines, but I may be wrong ...

[heinkeljb]

Julian,

I was thinking that there are a couple of ways of measuring the timing distance based on how you do it and that each would give you a slightly different result.

It probably isn't that big a difference in what is essentially a "sloppy" mechanical system, but it you measured the distance using a ruler and held the ruler horizontal to the ground i.e. parallel to line of the crank shaft / con rod center line, you would get a different distance than if you used a piece of wire, for instance bent to follow the curve of the pulley. With the amount of "play" in the whole system, I doubt you would even notice the difference if you set the engine up using the two different ways!!

As you can see, I am not talking about a huge difference in the resulting gap, but it might be enough to make a difference to the way your engine runs. - that's why it is better to use a strobe to do your timing or to use a rolling road and gas analysis to get the output right.

The Static timing is just that - Static, whereas a running engine is dynamic.

Sorry, this is getting very theoretical. Early engine had a hand adjustable timing system so you could alter the timing as the engine was running to get the best out of it. Modern engines with electronics do the same thing. Our engines are stuck in the middle with a crude mechanical regulating system, which I have to say works quite well when set up correctly!

I hope I haven't confused anyone over how to set their timing. The static way (which ever figures you use) should get your engine running if timing is the only issue.


John

[AustHaflinger]

I am going to get an engraver and mark the fan 2mm from the TDC mark and then in future time the ignition using a strobe light. Will save a lot of mucking around and it is as it should have been from the start.

Garry

[Julian B]

John, even on a pulley the size of that on the Haflinger the difference (in rotational degrees) between 5-7mm around the circumference and a 5-7mm straight line across two points at the edge must be so impossibly small that I really can't think it makes any difference. I'd have thought that it would be less than the thickness of a line (and certainly less than the width of the embossed timing mark on the pulley). All the more so when one uses the later 2mm.

That said, this thread has been very useful for me as I will need to improve my timing & mixture settings in the next few days as whilst the engine is running well I am not convinced that it is delivering all of the power that it could be.

[heinkeljb]

I agree it is a moot point, but all I was trying to do was point out that it could be measure in different ways even though we now believe that it is a straight line measurement in mm's.

Gary,

Use some tip-ex to put a white background on the fan housing and as small as you can manage in the pulley wheel notch. make black marks every mm on the fan housing strip of Tip-ex. Run the engine with the strobe attached. Make a note of how many mm marks off TDC the strobe lines things up at. Then you can make a permanent mark on the fan housing witch matches your current well setup engine.

John

[pathfinder700ap]

John,

frankly speaking, I feel like things are being artificially complicated here. I agree about your theoretical concerns about the measurement techniques, but practically, this is negligible.
This thread somehow brings back to my mind the story about the valve covers which could be "improved" by adding four holes & plugs for adjusting the valve lash...


Kind regards,
Constantin

[Julian B]

4: Set points gap to 0.20mm as it should be on maximum opening at this point.

John, on Constantin's scan above it says the contact gap should be 0.40mm - where did you get the 0.20mm from?

Julian

[heinkeljb]

Probably thinking of valve clearances!

John

Still think the bolted on pipe going from the rocker box cover(s) to the crank case makes what would otherwise be an easy / quick task into one which forces you to do more work than you need to.

[heinkeljb]

Just been looking through the repair manual I have to see if that has the points gap listed, but can't find it there - so only place it appears to be listed is in the operators manual.
As it happens looking in the "Group ): Technical Data" section near the beginning of the repair manaual and came across the follwing information:
Ignition Timing: 4 Degrees 30 Minutes before TDC i.e. .2756" (7mm) before TDC measured at the double fanbelt drive pulley. So we do have a degrees and a linear measurement for the ignition timing. I shall have to get the strobe out again and see what mine is set to.

John