Static timing point is 5 degrees BTDC +or -1 on the 1.3 Polo.

 

Measuring this with a timing light requires avoiding any other source of advance before BDTC, 

On my GK I'm meant to disconnect the temp sender and run at 2000 to 2500 rpm.

G40 PY is similar. It should then have 5 degrees advance.

 

With modified engine I reckon you need less advance because fuel mixture flows in faster.

But only when pistons moving faster as ignite and burn period stays the same.

 

Can I set static timing by finding TDC (where Hall probe crown changes from gap to vane for cylinder #1)  and rotating dizzy 5 degrees clockwise.

Then turn engine crank to line up the ignition Z point a timing lamp would show apparently still and realign tiny amount (for any timing belt cam end slack?.

 

With a 50mm radius dizzy at bolts I reckon the movement at circumference is 2.2mm from TDC to 5deg BTDC.

 

5 degrees of 360 * circumference. ( 2 * pi * r)

Because cam turns at half speed of engine divide by 2.

 

5/360.0 * 2 *  3.14 * 50)/2 = 2.2mm 

 

Edited 23 July, 201610 yr by dvderlm

ive got an advance timing light ...drive round here and we can time it up if you want , can dial in any setting you want

Ta, but It's the making it drivable again part that's my problem.

 

Think I've been running rich cause timing too advanced, so not enough power at idle.

This then carbon fouled the plugs and shorted the coil secondary.

 

 I measured 14 degrees at idle with my light before the other problems, but the Dignition has its own ideas.

I am trying to help but I don't know why your car is undriveable and if it is modified. I am guessing your ECU is at fault and your ignition/fueling is not as it should be. At the moment I can only suggest a programmable ECU such as Megasquirt or Amethyst. Have you got a thread about your car that I can look at?

Regards

Phil

Main mod is larger inlet valves (but not massive) and re-ringed.

 

It would start and drive but was revving too high once warm (not airleak) and not enjoy over 4000 rpm much, now rings alomost run in.

Plugs were sooty, though only short journeys.

Think the high rev crapness was pinhole leak in pipe to fuel pump - now sorted.

Been trying some warmer plugs (NGK BP6 heat range), but still got soot once I got idle speed back down by moving dizzy too far advanced.

 

I've been trying to use an Aldon Amethyst, but found I had a burnt out coil secondary (a Flamethrower).

The Amethyst needs static timing point right, then I can play with the ignition map.

 

I'll point the timing light at it tomorrow and use a lambda gauge.

 

I know Megasquirt, but I have looked over the Amethyst website and I don't know which version you have: 1: Vacuum dizzy 2: TPS 3: Boosted. If you have the vacuum version the advance in the dizzy has to be locked and the Amethyst works out how the advance curve works. The TPS has an advance curve worked out on throttle position I am guessing. I am presuming that you don't have the boosted version. If you have the TPS version does that need calibrating so the Amethyst knows the difference between 0% and 100% throttle? From your previous post I am presuming again you are using a stock ECU and injection. It is a great idea to drive with Lambda gauge. At idle it should run a little  rich simply because airflow is not that efficient. The perfect air fuel ratio for petrol is 14:7 but if you are seeing 12:1 or worse at any point in your fuel table then your plugs will foul. Hotter plugs will help but will heat your engine up a bit. One way to find out where your plugs are fouling, if you have a tachometer,  is to drive where you think the plugs are fouling, push in the clutch and switch off the ignition without locking the steering, coast to a stop and pull the plugs. I don't need to say this has to be done on quiet roads. Also can somebody plug in the laptop and watch the ignition curve while you are driving? Generally when the engine is lightly loaded it will handle more advance for instance at idle and light throttle cruising conditions. I don't know if this helps.

Regards

Phil

Ta. Locking the dizzy is my issue. Dignition has a Hall sender, so I need to set it 5 BTDC for the Amethyst before mapping

 

That means rotating the crown so vane at right point.

I tried using the offset feature from a TDC point, but I fear I went advance, not retard direction.

Docs are not very clear.

"Changing the offset allows the entire map to be advanced or retarded without altering its shape. The offset can be either positive or negative (i.e. either an advance or a retard"

 

I can use the Amethyst NULL map and watch when LED turns on, with engine crank at Z point.

But I want to confirm I'm allowing for belt slack. 

Pretty certain that point natches 2.2mm from TDC point at circumference of  Dizzy.

Or, can I set TDC as signal point and use +5 as offset for 5 BTDC?

 

Too many wiresto fit the wideband lambda gauge in that heat.Timing light confirms the 5 degree static position at 2000rpm with the Dignition, but it's way happier at 13 to 14 degrees hot idle  900rpm, otherwise with only 5 degrees advance idle speed is lumpy at 550rpm (292 cam as standard in the GK) and slowly dies (plug foul?).  

If I fool the Dignition which has manifold pressure map by applying 15psi vacuum it is really happy.

 

Was trying boost Amethyst on NA car, but with no adjustment for vacuum/pressure yet. It has 3 mapping points for vacuum beginning at -0.5 bar and 5 points for boost, but can just do centrifugal style mapping based on RPM. That is Vacuum/Boost pipe unconnected. 

 

Edited 25 July, 201610 yr by dvderlm

I know it's an expensive option but I using MSD 6BTM ignition that when connected to a turbo engine will retard ignition up to an adjustable 3 degrees of timing retard. Since installing it on my stock engine it has made such a difference to the running of the engine. I have only put it on the stock engine to prove its reliable. Any MSD or similar ignition will work. The spark is that powerful that it runs smoothly from cold after about five seconds of running on the autochoke carburettor. I am only suggesting this because it may get you around plug fouling while the rest is being sorted out. I also have a self build Megasquirt 3x which will run fuel and ignition. I am starting with a stock ignition except with the MSD with plans to convert to distributorless in the future. There is a bit on line about Megasquirt on Golfs so it may be worth a look. So I'm suggesting starting from scratch with an ECU that will allow you to tune fuel and ignition together. I don't know how you would lock the dizzy. Give Amethyst a ring and see if they can talk you through it. Belt slack will be minimal so I think it's not worth worrying about. The boost Amethyst if based on RPM will not take into account engine load so it should alter ignition if connected to manifold vacuum. Amethyst should help with this. There must be a signal from the lambda that you can run an AFR gauge on. This is the only way you can prove your air fuel ratio in real world driving unless you have datalogging of some sort. A Megasqirt 1 or 2 may be enough for you. Good luck with this.It will be interesting what you ultimately end up with.

Just tried the Amethyst in the dark (after connecting up in bright sunshine) with a test lamp (5w bulb to positive) rather than coil and no laptop connected to USB. On 2nd try the test lamp lit once and stayed on rather than flashing while cranking. Could not see the LED flashing for Hall sender signal confirmation either but poor view of engine bay so I suspect my bodged microtimer distributor connector is not connected properly (or I dislodged a wire in the dark).

 

I have got a proper connector from VW Heritage now, so I can try that.

 

New ECU from scratch...

Wondering about Nodiz Pro but need to find a sensible trigger wheel for the Polo aux pulley with crank bolt access retained.

Doh, had dislodged the Hall sender earth connection.

 

So set crank timing mark to Z pointer at 5BTDC. Then rotated dizzy with Amethyst Null map to get its LED to turn on and off with distributor cap off so could check the number 1 sparkplug lead matching rotor position. Then fine tuned until waggling the rotor arm which has a slight play could turn Amethyst LED on and off. Loaded a map with 0 advance at 500rpm and 5 advance at 1000 into Amethyst. Checked the test 5W bulb would flash when cranking and connected Amethyst coil wire to coil negative. No joy, kept adding 1 degree until at +5 static, +7@500rpm =12 advance the engine kicked back on the starter stopping it turning...

Retried with Dignition at this point. Instant start.

Deep thought how spark stops engine turning. Obviously igniting way too early while piston rising slowly.

 

Reason. I had the Amethyst trigger edge as Falling. I had reckoned that when the Hall sender is unshielded it is sending some volts, when shielded falls to zero.

Set trigger edge to Rising. Rechecked with Null map.

 

At +5 static +5@500rpm  =10 and it started and ran.

 

Updated map to max +27@3000rpm with +7@500rpm and fairly straight graph slope based on a 16 point Microsquirt map for 10.5 to 11.4 CR, but no vac advance compensation.

 

Wow.

 

So there's just the issue that the coil appears to be powered if I stall, until I turn off at key fully. Explains the old coil burnout.

And tomorrow using the Lambda to check carb jetting and adding some vac advance.

 

Lambda sensor and AFR gauge wiring still feels daunting. I will fit it for mid-range and top-end tuning. Now I only care about idle and low to mid progression.

 

So resorted to the good ol' Colortune. Yep loads of yellow flashes at idle. Wound the idle mixture screw right in and engine continued to run!? Removed idle jet. Restarted and it still ran!!

So it's been idling on a progression hole (or two) while the timing was out of whack. In my attempts to get control back from the Dignition advancing timing too much due to reduced vacuum I had slowed it by going over-rich. Backed off idle speed screw to close throttle plate down. Double checked cold-start circuit and accelerator pump jet for any enrichment/leak using Blutak and cold start spray.

 

Careful adjustment on mixture screw and air bypass and got Bunsen blue on all cylinders. And now slightest touch on accelerator pedal and revs rise gently and smoothly, no cough, no hesitation.

Added 5 degrees advance at 7.5psi vacuum  = -0.5 bar on the Amethyst. Tried with some vacuum advance at 3.6psi = -0.25bar but collective inlet pulses are not really smooth enough, even through an anti-pulse valve or a fishtank pump one-way valve.     

Edited 31 July, 201610 yr by dvderlm
14.7psi = 1 bar

1. My Amethyst Boost map on NA engine. Might not work for your engine

//Polo GK (from microsquirt http://www.useasydocs.com/theory/spktable.htm)
// CR 10.5:1 to 11.5:1

// Copyright 2016 dvderlm

// Permission granted to use without restriction.

// NO WARRANTY WHATSOEVER

// Hall sender with rising edge trigger

// Static timing at 5 BTDC

 

CYLINDERS         4
REVLIMIT          6800
ADVLIMIT          32
OFFSET              0
//         rpm   5-10-15-20-25-30-35-40-45-50-55-60-65-70
CENTRIFUGAL      7,08,11,16,21,26,27,27,27,27,27,27,27,27
//         psi   -7-3-0+3+7+12+15
VACUUM            5,0,0,0,0,0,0,0

Edited 31 July, 201610 yr by dvderlm

On ‎31‎/‎07‎/‎2016 at 16:28, dvderlm said:

//         rpm   5-10-15-20-25-30-35-40-45-50-55-60-65-70
CENTRIFUGAL      7,08,11,16,21,26,27,27,27,27,27,27,27,27

Still raced a bit when really hot engine. is now

7,3,8,16, ....rest as above.

 

This gives easy start, slower idle and stabilisation of idle speed like when engaging clutch with negligible throttle at a junction.

1500rpm and 40mph in fifth now made a bit smoother with

7,3,9,16,...

 

If I plot the line that's straighter. Best spark time versus engine speed increase (centrifugal with no vacuum advance) s surely nearly linear up to a maximal  diminishing returns point. 

 

Tried 2 degrees at 1000rpm but I found engine running a bit hot on the hottest September day not enough advance.

After reading this http://forum.polomagazin.de/thread.php?threadid=41911&threadview=0&hilight=gk+polo&hilightuser=0&page=2

and understanding some of it, I'm now using

CENTRIFUGAL 8,2,13,22,27,30,32,32,32,32

(a steeper curve at lower revs and much more advance at top end)

but with 6 degrees VAC advance at -7.5psi and 3 degrees at -3.6psi and max summed advance of 33.

 

Think I can lean the idle now.

 

Edited 13 September, 201610 yr by dvderlm

So much for typ86 steep early advice over on polomagazin.de

"Ich würde dann vom Standgas bis 4000 nicht gleichmäßg steigen, sondern untenrum schneller steigen, obenrum langsamer steigen, so dass Du bei 2500 schon bei ca. 24° liegst."

Maybe 24 is a BTDC figure not an advance on 5 degrees static?/

 

Despite momentum 99 fuel leaning idle was not great. A bit like surging lean but actually sounded like misfire under load from 2000 to 3000. Probably pinging but the induction and exhaust too loud to hear the distinctive tinkle sound. At least only at low-ish revs. Hopefully no harm done. I'm going back to more linear climb up to 2500 like Microsquirt3 suggests BUT carry on up to 32 for high end.

CENTRIFUGAL 8,2,11,17,22,27,32,...

and maybe more VAC advance.

Back to the rich idle and a little but more VAC advance and it's good. In cooler fog, not hot sunshine...

And reading the FAQ for Amethyst I finally understand the offset field. I could have done it all relative to TDC not 5 degrees.

 

 

Should I set static advance to TDC, or the manufacturer's setting?

They both work equally well.  If you use the manufacturer's setting, then the map can be entered simply by copying the figures from the workshop manual.  If you use TDC, you will also have to type the static advance figure into the "offset" box.

 

Runs way better in cold weather... so too rich. Lean it out and increase the advance even more?

http://forum.theimpclub.co.uk/viewtopic.php?f=10&t=30567&p=292312&hilit=dhla#

 

This is from a 1040cc Imp engine on twin Dellortos. 100 is full throttle W.O.T and 0 is closed throttle plates max vacuum.

 

 

 

I suppose that's something like

CENTRIFUGAL       4,8,13,17,21,24,27,30,31,31,31,32,32,32
VACUUM            8,2,0,0,0,0,0,0

on Amethyst
and 44 advance limit for my static 5.

Imp is a wedge and GK is bowl in piston cross flow combustion chamber. Similar max advance says Dave Andrews.

This is my newest map. Much more vacuum advance and a bit more "centrifugal" advance at 1000 and 1500rpm.

 

The dash tacho over reads so I thought 2000rpm -ish was okay. In fact that's more like 1800rpm, so the slope was not steep enough. I've now leaned the idle with mixture screw and it's pulling much less sluggishly a need the idle vacuum has gone up a bit so all good. Now needs the choke for first few hundred yards.

Hey, just wanted to drop you a line from across the pond and say thanks for this! Really interesting.

 

I'm converting my emmkay2 to GTI engine with DIS and have been hacking the stock ecu to get to the timing map. I have it, but the values are messed up.

 

I'm also familiar with the dignition in the GK. If you want, I can post the stock timing map. Oh and I'm German, so if you need anything translated, let me know.

 

Cheers

Steiny

 

P.S: Off the top of my head I want to say the max advance on the stock map of the GK is 32 or 36 degrees. I would not subject that engine to 49 degrees, you will have knock that you can't hear over the solid lifters! Be careful, don't break your engine!

Edited 8 December, 20169 yr by SteinOnkel

Fabelhaft! I lived in Germany and exported my Polo too.  

You need to look out for Mark Croxford who's taken his Polo "Huyi" stateside.

https://500px.com/photo/151447917/beautiful-sunset-at-bugapaluza-by-mark-croxford?ctx_page=1&from=user&user_id=12854571

https://huyitravels.wordpress.com/about-huyi/

 

 

I've overclocked a Dignition , but not made any adjustments for reduced vacuum with it. Being able to attach a USB cable and control things from a computer is nice, but I can only make single degree adjustments with the Amethyst. I've learnt that you need to sort out ignition to get idle and progression right. But then adjusting fuelling opens new opportunities to change ignition.

 

Do you have the Dignition map as numbers? The diagram in the SelbstStudienProgramm Heft 48 is annoying to convert to other units. I wrote a small Python function to do the interpolation but it's hard to work out the slope at some critical points.

 

 

 

Edited 8 December, 20169 yr by dvderlm

21 hours ago, SteinOnkel said:

P.S: Off the top of my head I want to say the max advance on the stock map of the GK is 32 or 36 degrees. I would not subject that engine to 49 degrees, you will have knock that you can't hear over the solid lifters! Be careful, don't break your engine!

36 BTDC (30+6)

 

I'm at max advance 33 on 5.0 static so 38.

And I'm using Momentum 99 RON octane.

 

The SSP diagram (https://www.clubpolo.co.uk/forums/topic/303127-na-ignition-maps/?do=findComment&comment=2456403)

has 5 degrees at 0rpm , but 0 degrees at 960 rpm, so it must be additional advance, not raw BTDC..

Using a straight edge like a clear ruler, the high plateau [from 2520 rpm and 564 millibar vacuum) is at 30 advance on 5 (+-1) static.

That's why GK wants Super98.

Manifold sensor and Dignition let me run 95 unleaded and gavegood economy with twin choke Weber DMTL before latest Tuningwahn.

 

Edited 9 December, 20169 yr by dvderlm
l/100km with Weber

Not sure that 49 BTDC at high vacuum is that huge or bad. The high vacuum is because the throttle plate is closed. So cylinder filling is poor.

Big V8 can have 56BTDC at max vacuum if manage 36-ish at 2600rpm without detonation.

 

http://www.mopar1.us/engine2.html