Let's talk ignition advance

[fwdvw]

I'm trying to choose a distributor for my EG. I don't have access to the EG figures but trying to figure out if there is a better distributor curve to seek and how to interpret the data.

So for the US here are the choices

(RPM then degrees advance)

055 905 205AA Vac advance and retard
1980 Carb’d

1100-1400 Advance begins
2100 15-19
5000 26-30

049 905 205Q Vac advance and retard
1980-1982

1050-1400 Advance begins
2200 15-20
4000 22-26
5000 26-30

049 905 205R Vac advance and retard
Canadian

1100-1400 Advance begins
2200 15-20
5000 26-30

049 905 206B Vac advance
1983 Cars

1050-1400 Advance begins
2200 15-20
4000 22-26
5000 26-30

026 905 205D Vac advance
JH GTI

1050-1300 Advance begins
2600 15-19
4500 22-26

027 905 205F Vac advance
MkII Golf

1100-1350 Advance begins
2600 12-17
6000 23-27

I am leaning toward the 049 905 296B since it has multiple advance steps.

I noticed that the Canadian Distributor, the GTi and the Later MKII distributor do not mechanically do a lot of advancing though out the range. Any insight into this? Also there are vacuums advance figures too which i think also complicates the characteristics. Any real performance need for retarding?

Does anyone have the advance figures for the EG distributor 067 905 205 for comparison?

[ny_fam]

Now for those specs you listed: are those final numbers based on initial advance? or measured from zero?
If measured from zero - some of those would be running like 36 degrees total at 5k and up(the JH one has 6 degrees initial advance)

For performance you'll want more advance earlier under 4k. You could just lock it at low 30's and not worry about how much the distributor advances.

[fwdvw]

Bentley says "Degrees Advance at the Crank shaft" so I'd think its based upon the Zero Degree mark on the flywheel.

So it doesn't look like there is very much advantage from most of the distributors since around 4000 RPM's most are maxing out up to 22-26 with some advancing more at 5000rpm.

If we were to nit- pick, It still looks like the 049 905 206B is advancing more at lower RPM's than the JH GTI distributor, and advances more after 5000 RPM's.

049 905 206B Vac advance
1983 Cars

1050-1400 Advance begins
2200 15-20
4000 22-26
5000 26-30

How do we consider the Vacuum advance figures? Do we add them to the advance at the RPM's?

[WaterWheels]

The data you posted is not real clear that I can tell. Is it a mix of vacuum and mechanical advances? If you can point me to the source I can look for myself I guess. That there are RPM ranges listed does not mean there are steps in the advance. That is part of the confusion as it is posted. The mechanical advance is a constant thing and does not happen in steps. It may start at a certain engine speed, most often it does, and continues to add advance as the engine speed increases to a point. That point is either where a stop limits the advance or the springs are stretched to their limits. The vacuum advance is also a constant process. Just as vacuum changes based on the load placed on the engine so does the ignition advance change. The two are combined in a single distributor to give a smooth transition under all possible conditions.

If I was to pick one for the 1.6L GTi engine I would pick the 026 905 205D. Unless you have to go through tough emission inspections or inspections where tampering is checked, I would stay away from the dual vacuum units (ones with retard).

[sw5]

[sw5]

And, for good measure,

[sw5]

[sw5]

[sw5]

[fwdvw]

The data you posted is not real clear that I can tell. Is it a mix of vacuum and mechanical advances? If you can point me to the source I can look for myself I guess.

The Source is from the Robert Bentley. For 1980 to 1983 VW Rabbit (Golf). So your feeling is the JH distributor curve is an improvement over the other curves? I would also think so but the information indicates there might be some other alternatives to look at.

The Vacuum advance figures are not included but I'll have to digest the information. Its starting to look a little more logical.

Smog should not be a problem here as I think the JH disti will still pass, but what i am concerned with is the fact that 95 Octane is not even close to what we can get in the US, so pre-ignition may be an issue.

Other option would be to use a Knock Sensor ignition, but that would not pass visual during inspection, and I am concerned about the knock sensor location on the block. Ever use a knock sensor ignition on an earlier small block in the UK or Russia?

[fwdvw]

And, for good measure ....

This forum is the BEST!!! You guys have so much to contribute thanks so much.

This proves to me that spending time and money on obtaining a "True" EG distributor is a waste since we got the very same type of Distributor in the US.

Looks like the 049 905 206B is a very close match to the EG 067 905 205. I'll do some more study on this, and need to check if My 1983 Jetta has this distributor or not.

[WaterWheels]

The Source is from the Robert Bentley. For 1980 to 1983 VW Rabbit (Golf). So your feeling is the JH distributor curve is an improvement over the other curves? . . . but what i am concerned with is the fact that 95 Octane is not even close to what we can get in the US, so pre-ignition may be an issue.

Other option would be to use a Knock Sensor ignition, but that would not pass visual during inspection, and I am concerned about the knock sensor location on the block. Ever use a knock sensor ignition on an earlier small block in the UK or Russia?

I don’t own a Bentley for Golf I models and I can’t remember seeing any data in my other manuals, English or German, that’s why I asked. Yes, I feel that the distributor I indicated would be best, of the ones you listed, for a performance stand point. To be honest it would not matter if I were doing the build as I adjust every mechanical distributor myself to suit my needs. Keep in mind that factory ignition distributors are not set for pure performance but a compromise for all driving conditions, fuels and economy. If it is normal daily driving you seek then try to get the curves as close to the original as possible (or do it yourself).

Smog is really not an issue if you can tune around it, but rather strict controls where they check numbers or are good at visual inspecting. I have no idea what, if anything, you are up agains but some places have tough inspections, an engine swap would be a fail. Just something to keep in mind if it relates to your situation. 95 octane fuel is also no big deal as mid-grade should be fine and if you do happen to have a slight problem then the advance curve can be altered or the static timing cut back a little.

You should have no problem installing a knock sensing ignition. In many places if the modification is an “up-grade” or to a newer management system it is allowed as it will run cleaner, or should. Like engine swaps, a new engine in and old car is often OK while an old one in a new car is a no-go. And yes, I have installed knock sensor ignitions on many different engines, 1.6L included.

[fwdvw]

.....To be honest it would not matter if I were doing the build as I adjust every mechanical distributor myself to suit my needs.....

I'd be interested is seeing how you modify this. Is it complicated? Care to walk us through what you do?

[WaterWheels]

I'd be interested is seeing how you modify this. Is it complicated? Care to walk us through what you do?

Complicated depends on one’s skills I guess. I would say it is a little time consuming but most things that are not off the shelf tasks seem to be so. It’s also not something “everyone” will want or need to do. For most people the factory ignitions are just fine the way they come installed in the car. This type of work is more geared towards racing, “improving” performance and matching mix-matched advance curves. Full electronic ignition systems are not “re-curved” in this manner so only people with mechanical/vacuum distributors will qualify, less and less of them now days.

Walking someone through the process would be rather long and pictures really would help a lot too. There are different designs of distributors also which would cause branching off for this persons situation and that persons, makes it even longer. Then of course there will be the people who jump in saying “well my chevy or ford looked or worked different . . .” which again would cause problems. I suggest you do a search on the Internet, yeah Google or some other search engine is what I’m suggesting if that offends anyone. There will be long detailed write-ups and nice clear pictures. I’m sure there will be information for many different brands of cars and maybe even Volkswagens. It is just a matter of applying the information to the distributor you are working with.

I’m not one for writing up step by step procedures for a few different reasons. One is the information has already been posted all over the Internet. Another reason is that I don’t do this kind of thing and there sure as shootin will be someone who jumps in yelling that I missed something. Another reason is that if I did do something like that I would have to include pictures and I’m not going to maintain any picture links. But the real or big reason is that I just don’t feel like taking that much time for something already out there. But if you have questions “about” doing it I will address them so long as it is not going to be a “how to” thing. Hope that does not bother you too much.

[TyeGTI]

I have heard the old school, back yard, red neck way is remove the vacuum advance, run 91oct gas, and turn the disturber until the engines starts to ping then turn it back slightly and call it done. My car is running 9degrees advanced at idle, it doesn't start or run well it's cold but. It is a Canadian 84 JH not running an O2 sensor.