Stroker Motor / Static Angle / Help Needed

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Off Road
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Stroker Motor / Static Angle / Help Needed

#1 Post by Off Road » Thu May 24, 2018 12:17 am

I built a stroker motor using a Hotrods +4 mm crank and oem cylinders.

I did one heat cycle and decided that I would check the Static Angle in the Zeel when I did the next heat cycle.

I started by finding TDC on the Left cylinder, which is a little tricky due to the large dwell with the stroker crank
I rotated the crank CCW until the dial gauge just touched TDC, and marked a line on the stator.
I continued rotating the crank until the piston passed TDC and then turned the crank CW until the dial gauge just touched TDC,
and marked a 2nd line on the stator.
The distance between the 2 lines was about 2 mm, I assumed TDC would be in the middle of the 2 lines.
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Re: Stroker Motor / Static Angle / Help Needed

#2 Post by Off Road » Thu May 24, 2018 12:28 am

I used the formula in the Zeel instructions and calculated that 17* BTDC = 1.58 mm BTDC.

I turned the crank CCW until the dial gauge just touched TDC, then turned it CW until the piston dropped 1.58 mm, and marked a line on the stator.

I marked a second line on the stator, 2 mm to the right of the first one.
I Assumed that 1.58 mm from TDC would be in the middle of my 2 lines.
I marked this line and labeled it “1.58”.
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Re: Stroker Motor / Static Angle / Help Needed

#3 Post by Off Road » Thu May 24, 2018 12:28 am

Programmed a flat curve of 17* into the Zeel and started the bike.
With a static angle of 34* in the Zeel, the line labeled “34” lined up with my mark on the engine case.
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Re: Stroker Motor / Static Angle / Help Needed

#4 Post by Off Road » Thu May 24, 2018 12:29 am

Then I changed the static angle in the Zeel to 50* (the maximum value allowed) and the line labeled “50” lined up with my mark on the engine case.

Using my dial gauge I determined that the “50” line is 4.25 mm BTDC which works out to 28.2*.

This is 11* more advance than I should have.
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Re: Stroker Motor / Static Angle / Help Needed

#5 Post by Off Road » Thu May 24, 2018 12:30 am

The next day I found TDC on the Right cylinder, and marked 2 more lines on the rotor.

The first line at 1.58 mm BTDC (which should be 17* by my calculations)

A second line at 4.25 mm BTDC (which should be 28* by my calculations)



At an idle, (with a static angle of 50* and a flat curve of 17* in the Zeel), the line marked 17* (4.25 mm BTDC) lined up with my mark on the engine case.

When I changed Zeel ignition curve to 6*, the line marked 6* (1.58 mm BTDC) lined up with my mark on the engine case.
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Re: Stroker Motor / Static Angle / Help Needed

#6 Post by Off Road » Thu May 24, 2018 12:30 am

1 – I haven’t read of anybody having this problem, so I’m thinking that I’ve made a mistake somewhere.
If anybody has any thoughts, ideas or opinions, I’d love to hear them.

2 – For my last test, I programmed 2 flat ignition curves into the Zeel.
One curve at 6* and the other curve at 17* BTDC.
At an idle the bike ran much smoother using the 6* curve. When I switched to the 17* curve, the idle increased by 200 rpm, and the bike ran a rougher, and every once in a while it would cough or miss.

3 – If, not very likely, but if I have done everything correct, and an advance of 6* programmed into the Zeel really is 17* BTDC, then the Minimum advance that I can ever have is 11* BTDC, when I program the Zeel for an advance of 0*.

4 – So, according to my calculations 1.58 mm is 17* BTDC.
In order to get the 1.58 mm line to line up with my mark on the engine case, I had to retard the ignition by 16* (changing the static angle in the Zeel from 34 to 50), and I had to further retard the ignition curve by 11*, for a total of 27*.
This would have me believe that the first few times that I started the bike, I was running an advance of 44* BTDC.

5 – Before I retarded the ignition, I noticed something interesting/scary when I was starting the bike.
I would kick it over 3 or 4 times and then on the next kick, I would get ¾ of the way through the stroke, and the engine would just Stop. Instantly, just like the piston hit a solid object.
Scared the shit out of me the first time it happened.
After it did this, it would usually start on the very next kick.
Since I’ve retarded the ignition, it hasn’t done this anymore.

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Re: Stroker Motor / Static Angle / Help Needed

#7 Post by kenny » Thu May 24, 2018 6:10 am

I think you are confused between advance and retard.
To retard the ignition you make it fire later ie 20 - 10 degrees BTDC
To advance the ignition you make it fire earlier ie 10 - 20 degrees BTDC

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Stroker Motor / Static Angle / Help Needed

#8 Post by cbrian » Thu May 24, 2018 3:22 pm

OR

I had issues getting my Zeel up and running properly. I documented my trials on my Aprilia build thread http://www.apriliaforum.com/forums/show ... ast-Hybrid on page 4. I found that the aftermarket supplier "Fast from the Past" had a great excel spreadsheet that could calculate your advance for you. (http://www.fastfromthepast.com/ignitions) All you had to do is plug in a few variables, rod length being one of them. It took me a couple of tries with the advance of the pickup plate to get it right.
Last edited by cbrian on Sat May 26, 2018 8:07 am, edited 1 time in total.

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Re: Stroker Motor / Static Angle / Help Needed

#9 Post by RuZty » Thu May 24, 2018 7:10 pm

Not sure why you are using a static angle of 50, your stator plate looks stock, which should give an angle in the mid 30's. Also be aware that the Zeel has 2 options for triggering, one that reads off the front edge of the trigger and another that reads off the trailing edge at RPM below the first point on your program, so depending where you set your first point this could be adding a variable that you didn't know was there (ie. if it is set to +/- instead of +only and your first point of your 'flat' curve is at 2000rpm, there will be a step in your curve below 2000rpm). There is also compensation for delay at higher RPMs, make sure you don't have a goofy value set there. Make sure you haven't switched the pickup wires as this will reverse the pulses, adding similar confusion.
When you changed the static angle from 34 to 50 it behaved correctly by waiting 16 more degrees to fire, since you had added that to the reference point. Static angle relates the pickup signal to TDC so the unit knows how long to wait after the signal to fire at the programmed point, which is referenced to TDC, not the pickup position. This is also why you can't program more than your static advance because it can't start counting an offset from an input it hasn't seen yet. If you want more advance than your static amount you need to add it mechanically by moving the pickup CW by slotting the backplate holes.
Not sure if you have seen this; http://www.fastfromthepast.com/PDF/static_angle.pdf" onclick="window.open(this.href);return false;

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Re: Stroker Motor / Static Angle / Help Needed

#10 Post by Off Road » Sun May 27, 2018 2:32 am

Hey Kenny,
The last change that I made in the Zeel, was to go from 17* BTDC down to 6* BTD C.


Thanks to Rusty and cbrian for the link to the static angle pdf at fastfromthepast. I had not seen that before.
When I put my rod length (115) and stroke (58) into the spreadsheet, it says the 1.58 mm BTDC is 17*.
The same value that I get in my spreadsheet.

I read the instructions in the pdf and I'm pretty certain that I have done everything correctly.

I was not impressed when I read the last sentence in the instructions:
“Too big static angle is not good solution, because it decrease ignition advance stability (do not use static angle greater then 45deg if not necessary).”


RuZty wrote:Also be aware that the Zeel has 2 options for triggering, one that reads off the front edge of the trigger and another that reads off the trailing edge at RPM below the first point on your program, so depending where you set your first point this could be adding a variable that you didn't know was there (ie. if it is set to +/- instead of +only and your first point of your 'flat' curve is at 2000rpm, there will be a step in your curve below 2000rpm). There is also compensation for delay at higher RPMs, make sure you don't have a goofy value set there. Make sure you haven't switched the pickup wires as this will reverse the pulses, adding similar confusion.
Thaks, that's interesting information.
I'll check the pickup wires and change the first point on my flat curve to 500 rpm.


I haven’t had a chance to work on the bike all week, but I have the next couple of days off, so I’ll look into it further

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Re: Stroker Motor / Static Angle / Help Needed

#11 Post by Off Road » Mon May 28, 2018 3:26 pm

With a Zeel Static Angle = 34* and a Zeel Ignition Curve = 17*
The ignition fired when the piston was >8.15 mm BTDC which calculates to >44* advance.


With the Zeel Static Angle = 50* and a Zeel Ignition Curve = 17*
The ignition fired when the piston was 4.25 mm BTDC which calculates to 28* advance.


With a Zeel Static Angle = 50* and a Zeel Ignition Curve = 6*
The ignition fired when the piston was 1.58 mm BTDC which calculates to 17* advance.
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Re: Stroker Motor / Static Angle / Help Needed

#12 Post by Off Road » Mon May 28, 2018 3:26 pm

I checked to make sure that the pickup wires were correct. They are.
When I looked at the connector I realized that I'm using the stator & rotor off the old motor that I took out of this bike.

I changed the ignition curve in the Zeel so that the 1st point is 6* at 1000 rpm. (The minimum rpm value allowed)

Nothing changed.
A static angle of 50* and an advance setting of 6* still fires the ignition at 1.58 mm BTDC

I then changed the Zeel static Angle from 50* to 45*.

With a Zeel Static Angle = 45* and a Zeel Ignition Curve = 6*
The ignition fired when the piston was 2.6 mm BTDC which calculates to 22* advance.
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Re: Stroker Motor / Static Angle / Help Needed

#13 Post by Off Road » Mon May 28, 2018 3:27 pm

Then I changed the Zeel Ignition Curve from 6* to 1*.

With a Zeel Static Angle = 45* and a Zeel Ignition Curve = 1*
The ignition fired when the piston was 1.58 mm BTDC which calculates to 17* advance.

As I expected, a static angle of 45* with an ignition curve of 1* gives the exact same timing as
a static angle of 50* and an ignition curve of 6*.
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Re: Stroker Motor / Static Angle / Help Needed

#14 Post by Off Road » Mon May 28, 2018 3:27 pm

I dicovered that the Zeel allows you put in negative numbers for the ignition advance.

So I changed the Zeel Ignition Curve from 1* to -1*.

With a Zeel Static Angle = 45* and a Zeel Ignition Curve = -1*
The ignition fired when the piston was 1.2 mm BTDC which calculates to 15* advance.
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Re: Stroker Motor / Static Angle / Help Needed

#15 Post by Off Road » Mon Jun 11, 2018 2:50 am

In my last picture, there were a couple of lines on the Stator that I didn’t talk about..
They are marked “T” and “L”.

Line “T” lines up with the mark on the stator, when the Trailing Edge of the rotor Magnet is still covering the circular center part of the pickup,

Line “L” lines up with the mark on the stator, when the Leading Edge of the rotor Magnet is completely covering the circular center part of the pickup,

I don’t know if the pulse coil is triggered by the Leading or Trailing edge of the magnet, so I marked both positions.

“If” the leading edge of the magnet triggers the Zeel, then the distance between Line “L” and TDC, should be my Static Angle.
The earliest that the ignition can be triggered is when the leading edge of the magnet is over the pickup.
If there is zero delay in the Zeel, then it would fire the ignition at this time.

I marked these lines so that I could compare them to the stock motor that I have.

If you look at the distance between TDC and the leading edge of the magnet on the Stroker motor, you’ll see that it is about the width of 1 finger.
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