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P-mag Timing Explained

N941WR

Legacy Member
Axel, thank you for the picture!
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I also set the timing of the PMAGS and configured the "B curve" as shown below. Set the Max engine RPM to 2816, dropped the Max Advance to 33.6 deg and subtracted 1.4 deg on the curve shift. Will play around with this once I get more familiar with it. For now the instrument will remain off along with ADSB since I have to get back in the cockpit. Trying to minimize the info coming in that is not required.
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This is a great picture of our new EICommander EIC32 that Axel posted on his Fast Back thread.

I am writing the following to help explain how the timing should be set on engines running P-mags.

This seem to be especially important for those running angle valve engines (IO-360, 390, & 400's).

The following assumes the P-mag timing marks are set at the TDC. All examples for standard 8.5:1 compression parallel valve engines. Below will be some numbers for angle valve engines.

Everything I describe below can be configured with either an EICoimmander, with the EICAD program available from Emag Ignitions, or by clocking the ignitions as described in the Emag Electronic Ignition Installation & Operating Guide available here.

Displayed in this picture it the timing configuration page from the new EICommander EIC32. This is a custom "C" configuration that Axel has made and sent to his P-mags.

First, the standard P-mag "A" jumper in configuration has a the following settings:
RPM Max (Rev limiter): 3328 RPM's
Advance Shift: 0 - This equates to 26.6 degrees before TDC.
Max Advance: 35.0 degrees before TDC.

Max RPM;
Axel reduced the point where the P-mags will stop firing to 2816 RPM's. This is good because should he have a prop governor failure, the P-mags will limit the overspeed to this number and help him avoid an engine overhaul.

Advance Shift:
By setting the Advance Shift to a -1.4 degrees, the high power timing setting will be 25.2 degrees BTC.

Max Advance:
The Max Advance is exactly what is sounds like. As the manifold pressure drops off with altitude and throttle setting, this is limits how far the P-mags will advance.

RMSD:
Run Mode Start Delay allows the engine to delay firing the sparkplugs for a set number of revolutions. Zero is the desired setting. If you change this to two (2), the engine will make two complete revolutions prior to firing the sparkplugs. If this is set to any value other than zero (0), the engine will pump raw fuel out the exhaust ports, which will light off with a bang once the ignition comes on line. Thus we highly recommend it be left at zero (0).

LED:
The allows you to turn on and off the external LED. Leaving it set to "SENS" allows you to see the LED turn red, yellow, and green as required to set the timing. In the newer EIC32, we do not allow this to be changed.

A few comments about P-mag configurations:
1. We have not heard of any Lycomings where the P-mags should be run on the "B curve" (no jumper). The "B Curve" starts firing the ignitions at 30.8 degrees BTC and advances out to 39.2 degrees.

2. The configuration Axel has selected appears to work very well for Parallel valve engines. We have enough experience with it to say that in a typical installation, this will reduce the CHT's 10 to 20 degrees F and increase speed a few knots over the standard "A" - jumper in configuration.

3. If you run an angle valve engine (IO-360, 390, 400, etc.) that requires a 20 degree timing, neither the "A" nor "B" curve should be used when the P-mag's timing mark is set to TDC. Using either of these configurations could damage your engine.

There are three ways to set the timing for these engines. One is to "clock" the ignitions, similar to how the timing is set with a standard magneto. Contact Emag Ignitions for details.

The other two options are to create a custom configuration with either an EICommander or the free EICAD program from Emag Ignitions.

Again, this assumes you have set your timing mark to Top Dead Center.

Advance Shift:
-7.0 will cause the P-mag to fire at 19.6 degrees BTC during high power operations such as takeoffs.

Max Advance:
29.4 will limit the maximum, lower power advance to this value.

These engines should never be set at TDC and then run with either the jumper in or jumper out. Either of these configurations may damage your engine when the TDC mark is set to Top Dead Center.

CHT cooling on angle valve engines seems to be much better than parallel valve engines. Do not take acceptable CHT's as an indication that all is OK with your engine while running excessive advance in your angle valve engine.

If you have a high compression engine, consult your engine builder for the proper timing advance.

As always, feel free to contact me off line, if you have questions. I am more than happy to help protect you and your engine. I don't care if you are an EICommander customer or not, I am happy to help.

Either Angle or Parallel Valve engines:
Finally, if you have a new engine, or a newly overhauled engine, I recommend you set the Max Advance number to equal your high power timing number for the first 10 hours +/-. This way, if you experience high CHT's for the first ten hours or so, you know the issue isn't a result of your timing advance and is probably the result of a baffling leak. After your CHT's drop, then change the Max Advance number as appropriate for your engine.

Clocking your P-mags:
Emag Ignition's preferred method of setting the timing is to not use the EICAD program but rather "clock" the timing mark. This achieves the same things as adjusting the internal timing values with either the EICAD program or the EICommander.

Emag Igntion's 114 manual said:
CLOCKING: Set timing with the engine positioned slightly after TDC (1-6 degrees). Greater offsets will produce greater retard (less aggressive advance).
This does not require you to purchase any hardware (USB to serial connectors, EICommanader, etc.) or install the EICAD program on your computer. It accomplishes the same thing by moving the initial firing point and should be accomplished with the jump installed between P-mag pins 2 and 3.

Remember, the goal is to fire the spark plugs at the point recommended by your engine builder, any way this is accomplished is beneficial to you and your engine.

DB9 Connectors:
The following image is what I recommend to builders who install P-mags and plan on adjusting them with either the EICAD program or adding an EICommander later on (If you are going to start with an EICommander, wire them as recommended in the EIC manual. As stated above, it is not required, if you plan on "clocking" the ignitions to achieve optimal timing. This will allow you to connect to the P-mags with a PC from inside the cockpit and should you later decide to install an EICommander, you can make a simple wiring harness to join both P-mags to the EIC.
"No jumper" is depicted because the drawing assumes you are going to customize the P-mag configuration. If you elect to run the standard "A Curve", place the jumper at the DB9 plug.
vh6jxu.jpg


Hand Proping:
Do not hand prop your plane, unless you have been trained in the fine art of hand propping.
If you expect to need to hand prop your aircraft, contact me off list (include your email address), and I will send you a wiring diagram on how to wire in a 9 volt battery to one P-mag.
 
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Bill - u mention the free EICAD program from Emag. As I mentioned to u months ago, I?ve not been able to get that program to work. Interested to know if anyone has been able to use it. I can get it displayed on my computer but I get no readings. I?ve resorted to adjusting my timing by offsetting half a tooth from TDC. If someone says the program works I?ll try it again. Maybe I?m doing something wrong.
 
Bill - u mention the free EICAD program from Emag. As I mentioned to u months ago, I’ve not been able to get that program to work. Interested to know if anyone has been able to use it. I can get it displayed on my computer but I get no readings. I’ve resorted to adjusting my timing by offsetting half a tooth from TDC. If someone says the program works I’ll try it again. Maybe I’m doing something wrong.

I use an old Windows 10 computer and USB to DB9 converter. I suspect your issue was either with your computer and/or your converter.

What is most important is that you have adjusted your timing appropriately, which it sounds like you have done.

One thing to keep in mind is that your "rev limiter" is at the factory default, which is over 3300 RPM's. This should never be an issue, I hope.
 
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I got the Eicad program to work but it took trying several different USB to serial adapters and some port assignment tweaks.
 
I got the Eicad program to work but it took trying several different USB to serial adapters and some port assignment tweaks.

Can you share with us which adapter worked for you and what settings you had to tweek?
 
Can you share with us which adapter worked for you and what settings you had to tweek?

Trendnet adapter from Amazon
https://www.amazon.com/dp/B0007T27H8/ref=emc_b_5_t

I'm not a computer whiz but what happened was the computer assigned the adapter to port #23 I think and I had to go into control panel (Windows laptop) and change that port assignment to port 4 as the EICAD seems to only recognize ports 1-4. Fortunately there was nothing assigned to port 4 that would have conflicted. Rebooted and it worked and I could use the program and read the Pmag parameters just fine.
 
For those who are going to change their P-mag configurations with the EICAD program available from Emag, you have to contact them to get access to the programs.

They have a Version 3 & Version 4, but have some minor bugs and my preference is version 3. Both work fine.

I suggest the following process:

1st. Download the EICAD program from Emag, either version.
2nd. Make a custom wiring harness, as described by Emag, and connect it to P-mag pins 1 (Ground), 2 (Receive), and 3 (Transmit). (Remember that P-mag pin 2-Rreceive must go to receive on the DB9 send pin 2 and P-mag pin 3-Transmit must go DB9 receive pin 3.)
3rd. Connect to the P-mag with your PC, start the program, and make sure it connects.
4th. Make your desired changes.
5th. Using something like the "Snipping Tool", save a screen shot of the new configuration and put a printed copy in your engine logbook.
6th. Cycle the power to the P-mags and pull up the configuration in the EICAD program to verify they were accepted.
7th. Change the configuration of your other P-mag as described above.
8th. DO NOT install the jumper. With a custom configuration, you want your P-mags to run on the recently modified B configuration.

If you need to reset the TDC mark by blowing in the tube, do so after you have changed the configuration, if needed, as described in the manual.

Good luck!
 
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One additional benefit of getting your timing set properly is that your engine will operate more effectively, meaning more speed or better fuel burn.

Either way, it is critical that you set your timing properly.
 
Moderators, I'll suggest Bill's post should be a sticky. The suggested base timing and max advance values (Post #1) are well supported.

Parallel valve: base 25.2 degrees BTDC, max 33.6 (25 max 34)

Angle valve: base 19.6 BTDC, max 29.4 (20 max 29)

Although the post describes how to achieve those settings with an EI Commander or EICAD, the stated values apply to any ignition brand...and we have folks out there doing really dumb things with timing.
 
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Good timing

For this post...

Just reinstalled my Pmags today and am struggling somewhat with EICAD to set the advance shift to -1.4 degrees. It seems to take when I send the configuration to the Pmag, but when I power down and power back up, restart EICAD and read the configuration - the advance shift shows positive 12 point something degrees.

Called Emag but the tech that answered could not answer my question - but did duplicate the settings and readings I am seeing on the bench there.

Anyone know if this is just a bug/limitation of EICAD? I really would like to confirm the advance shift. I would prefer not to set the base timing advance mechanically.
 
Yes, there is a bug in the display indication. But it's just in the display. If you go one 'click' negative from '0', it will set the advance correctly at -1.4, even though on a subsequent check, it displays incorrectly.

I had this explained from Brad some time ago. I would think they'd want to clean up the code, but apparently, not done yet.
 
Yes, there is a bug in the display indication. But it's just in the display. If you go one 'click' negative from '0', it will set the advance correctly at -1.4, even though on a subsequent check, it displays incorrectly.

I had this explained from Brad some time ago. I would think they'd want to clean up the code, but apparently, not done yet.

Thanks. Bug in EICAD makes it impossible to verify that advance shift was set to what you uploaded.
 
Thanks. Bug in EICAD makes it impossible to verify that advance shift was set to what you uploaded.

I recommend you use Version 3 of the EICAD program. Once you make and save your change, exit the program completely, start it up again, and query the P-mags to verify your configuration.

Here is a screen shot I took after configuring a friend's 114 series P-mags with the EICAD V3 program

wtt6e1.jpg


If you are going to use this program to change the settings on your P-mags, DO NOT change the "LED MODE" setting. As stated above, this controls the LED and if you turn off the LED, it will be very difficult to set the timing as the LED will not light up.
 
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Thanks!

I appreciate the suggestion. The Technician at Emag thought you would know the answer. Now to obtain V3 of EICAD.
 
V3 V V4

I had the same issue. Changed with V4 and verified with V3. Took a while of frustration to figure that out.
 
I just reset the timing to 1.5 degrees after TDC, as recommended by Brad at EmagAir when I questioned him about making my ignition a little less aggressive. This results in a corresponding retard of all position references - start up firing position as well as the bottom and top of the variable range - and this is with the jumper in, so ?A? curve. My advance shift should now be 25.1 and the max advance should be about 33.5. This is a less aggressive curve for my IO-360 with 9:1 compression, but what is recommended by Superior for my engine (25 degrees for high power settings). Resetting the timing was much easier than wiring up a harness to enable EICAD or EIC. I don?t have the wider range of choices for spark advance, but is a more simple way to accomplish what I was after. If any of this is wrong, or I am mis-interpreting how this works, please sound off (Bill R.?).

My Pmags are new and running V40 software so there is a built in 4 degree retard for starting when the mag is timed to TDC. Mine will now fire at 5.5 after TDC on start, and that is fine according to Brad. I have a light weight Whirlwind 200RV prop, so this will help prevent kickbacks during engine start if I have a low battery.
 
I just reset the timing to 1.5 degrees after TDC, as recommended by Brad at EmagAir when I questioned him about making my ignition a little less aggressive. This results in a corresponding retard of all position references - start up firing position as well as the bottom and top of the variable range - and this is with the jumper in, so ‘A’ curve. My advance shift should now be 25.1 and the max advance should be about 33.5. This is a less aggressive curve for my IO-360 with 9:1 compression, but what is recommended by Superior for my engine (25 degrees for high power settings). Resetting the timing was much easier than wiring up a harness to enable EICAD or EIC. I don’t have the wider range of choices for spark advance, but is a more simple way to accomplish what I was after. If any of this is wrong, or I am mis-interpreting how this works, please sound off (Bill R.?).

My Pmags are new and running V40 software so there is a built in 4 degree retard for starting when the mag is timed to TDC. Mine will now fire at 5.5 after TDC on start, and that is fine according to Brad. I have a light weight Whirlwind 200RV prop, so this will help prevent kickbacks during engine start if I have a low battery.

My understanding is the "A" curve is fixed and cannot be changed at all, the only way for any changes to be made is via the "B" curve with jumper out.
 
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My understanding is the "A" curve is fixed and cannot be changed at all, the only way for any changes to be made is via the "B" curve with jumper out.

That is correct. The "A" curve can not be changed. I believe Scott positioned the timing marks not at TDC but 1.5 degrees after TDC before using the standard procedure for timing the Emags. Scott, can you elaborate?
 
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Scott,

You should be good to go.

With you indexing the P-mags 1.4 degrees, not starter teeth, you should be fine.

Let us know if you see a drop in CHT's. The couple of knots increase in speed is difficult to measure. (I did it by changing the P-mag configuration in flight; same air, same temp, etc.)

For starting, when version 40 came out, they started firing the plugs at 4.2° after TDC when below 200 RPM, based on our request to eliminate kickback issues associated with lightweight props. With you clocking the P-mags, firing at 5.6 for starting won't hurt anything.

Please document what you did in your engine logbook and how you did it.

My only concern with using the clocking method is that if someone else works on the engine, they may just download the manual and reset the timing mark to TDC.

I had a conversation with an RV-14A builder earlier this week about this. Their engine builder clocked their P-mag and test ran the engine. After installing the engine, the builder reset the P-mag to TDC, not knowing/understanding what it should be.

Regarding the EIC, it does much more than just allowing you to set the configuration of your P-mags, think of it as an engine monitor for your ignition.
 
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PMAG Timing

A few comments about P-mag configurations:
1. We have not heard of any Lycomings where the P-mags should be run on the "B curve" (no jumper). The "B Curve" starts firing the ignitions at 30.8 degrees BTC and advances out to 39.2 degrees. My personal belief is this was designed for very low compression engines, such as a small Continental.

So now I'm confused. I have dual PMAGS (Ver 114 with the latest software) on an IO-360 BIA engine. If the "B curve" start timing is 30.8 degrees BTC, what would the "A curve" starting timing be? Is it the same?
 
So now I'm confused. I have dual PMAGS (Ver 114 with the latest software) on an IO-360 BIA engine. If the "B curve" start timing is 30.8 degrees BTC, what would the "A curve" starting timing be? Is it the same?

As Ray's post above mentioned, this is covered in my first post.

The "A curve" starts firing at 26.6 degrees BTC and advances out from there as manifold pressure drops off.
 
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Please note that I changed the initial post to clarify that the timing configuration I recommend can be achieved by leaving the jumper in and clocking the P-mags as described on page 13 of the Emag Ignition manual.

You can get to the required timing without purchasing a USB to serial connector, loading software, or buying an EICommander.

Clocking is an acceptable method of complying with your engine manufacture's recommended timing configuration.
 
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Yes, I timed the mags at about 1.5* after TDC with the jumper still in, which slides the ‘A’ curve to the right. This means that on start up, the mags will fire 1.5* later than when they were timed at TDC (5.7* vs 4.2 with V40 on 114 mags). This also means the advance shift will fire 1.5* later (25.1 vs 26.6), and the max advance will be 1.5* later also (33.5 vs 35.0). The ‘A’ curve is the same as before, but it is de-tuned a little to be a little less aggressive. The variable timing starts to become more advanced at the same place - about 25” MAP and continues its linear shift until about 22” when it’s at the max advance - about 33.5* in my case now.

This all assumes I’m good at setting my timing mark at 1.5* after TDC. I didn’t have a propeller protractor to do this, so my method of measurement might be a little crude. I did this timing change yesterday and haven’t flown it yet to see what the result is. I don’t have CHT issues, in fact, my engine runs very cool, but my reason for making a change is because of what I’ve read on this site about overly aggressive spark advance, and reports/recommendations from Axel and Bill. I’ll try to get some numbers when I can, and see if I can find a protractor around here to more precisely set my timing.
 
Scott,

I wouldn't call it "detuned" but rather "properly tuned".

Our experience and that of our customers indicate that you should see slightly more powered but with cooler CHT's.

Good luck, we are all like looking forward to seeing your numbers.
 
I?ll try to get some numbers when I can, and see if I can find a protractor around here to more precisely set my timing.

You dont need a protractor. Use the teeth on your fly wheel and some simple math to get better accuracy. Assuming a 149 tooth wheel, 360 degrees divided by 149 teeth = 2.4 degrees per tooth.

erich
 
Eric,
That?s what I did, but it seems a little crude because I?m dealing with less than a full tooth. I?m probably pretty close though.
 
Eric,
That’s what I did, but it seems a little crude because I’m dealing with less than a full tooth. I’m probably pretty close though.

Better to err on the safe side and go "too retarded". Its the initial advance of the Pmag curve that's the spooky part, but fortunately that high power range just happens to be the most insensitive to ignition retard WRT power output. Reference my flight testing at 100% in the Rocket: a timing sweep from 20 to 30 degrees had ZERO effect on power output (IAS), but the temps sure went up at the high advance.

Mechanically spoofing the timing to a retard certainly pulls some off the high end which is likely to hurt your LOP efficiency, but that's a reasonable trade for increased detonation margin IMHO.
 
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PMAG Timing

A few comments about P-mag configurations:
1. We have not heard of any Lycomings where the P-mags should be run on the "B curve" (no jumper). The "B Curve" starts firing the ignitions at 30.8 degrees BTC and advances out to 39.2 degrees.

I've been running the "B curve" timing on my IO-360B engine for the last 1620 Hrs. The only times I've seen high CHT's is when I try to do aggressive full power climbs at gross weight on a hot day (or after taxing for too long, then taking off).

So after I read this tread, I decided to try running the engine with the timing set to the "A curve - jumper in". Note that I'm running the Sensenich metal cruise prop (85 pitch). Here is what I noted as differences:

? The CHT?s definitely ran lower by 25*-30*. Max temps in cruise was under 300* (high 290?s). We did not see any CHT overheating on climb out today (at the same full load point), but the outside temps were only in the mid 50?s, so it probably wouldn?t have happened anyway.

? The EGT?s were definitely higher at about 100* hotter, or around the low 1400* temp point (engine leaned). This is an indication that there is fuel still burning when the exhaust valve opens. I noted that during the slow leaning process, the EGT?s went well over 1500*?.

? Fuel burn was higher by about .5 gal/Hr. I was not able to get the same RPM?s at the ?B curve? gal/Hr. leaning point. An indication of less power??

? Take off RPM was only 2290 RPM, a bit lower than when the ?B curve? timing was used. I interpret this as an indication of less available power.

? The engine did idle at a lower RPM, almost stalling and definitely below the PMAG power output RPM (which then required ship power to keep them running).

So, overall, I?d say that there was a loss of performance for the lower CHT's. Tomorrow I?m going to remove the jumper and take some more numbers? I might also try retarding the timing manually somewhere in between the two PMAG curves.
 
I've been running the "B curve" timing on my IO-360B engine for the last 1620 Hrs. The only times I've seen high CHT's is when I try to do aggressive full power climbs at gross weight on a hot day (or after taxing for too long, then taking off)….
A couple of questions for you:
1. Is this a 180 hp parallel valve engine or 200 hp angle valve?
2. What compression ratio are you running?
3. What is the manufacturer's recommended timing setting?
 
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I've been running the "B curve" timing on my IO-360B engine for the last 1620 Hrs. The only times I've seen high CHT's is when I try to do aggressive full power climbs at gross weight on a hot day (or after taxing for too long, then taking off).

So after I read this tread, I decided to try running the engine with the timing set to the "A curve - jumper in". Note that I'm running the Sensenich metal cruise prop (85 pitch). Here is what I noted as differences:

• The CHT’s definitely ran lower by 25*-30*. Max temps in cruise was under 300* (high 290’s). We did not see any CHT overheating on climb out today (at the same full load point), but the outside temps were only in the mid 50’s, so it probably wouldn’t have happened anyway.

Climb CHT reduction is probably the #1 reason to retard timing, lower mechanical stress (avoid high stress due to higher gas pressure at TDC) being #2.

• The EGT’s were definitely higher at about 100* hotter, or around the low 1400* temp point (engine leaned). This is an indication that there is fuel still burning when the exhaust valve opens. I noted that during the slow leaning process, the EGT’s went well over 1500*….

This is a p-V (pressure -volume) diagram for a research engine at 1200 RPM, borrowed from Taylor's Internal Combustion... The X-axis is cylinder volume, with TDC on the left. The Y-axis is cylinder pressure. I've added some notes; the only variable is ignition timing.

Spark%20Advance%20PV%20Diagram.jpg


Note that when ignition is delayed, peak pressure is indeed reduced, as noted above. Pressure later in the stroke, around exhaust valve opening, is higher. Cylinder volume is the same at exhaust valve opening for any ignition timing, so higher pressure means higher gas temperature.

Pressure and temperature are proportional when temperature is expressed in degrees Kelvin. Here the reported EGT increase was 100 F. Given a jump from 1400F to 1500F, or from 1033K to 1083K, the required pressure increase at valve opening is only about 5%.

• Fuel burn was higher by about .5 gal/Hr. I was not able to get the same RPM’s at the “B curve” gal/Hr. leaning point. An indication of less power??

Just to clarify, fuel burn became higher when the mixture knob was adjusted to get the same RPM you would have expected with more advanced timing? That too would be an expected result.

• Take off RPM was only 2290 RPM, a bit lower than when the “B curve” timing was used. I interpret this as an indication of less available power.

Good data point. How much lower?

• The engine did idle at a lower RPM, almost stalling and definitely below the PMAG power output RPM (which then required ship power to keep them running).

Expected, but that's just a stop screw adjustment.

So, overall, I’d say that there was a loss of performance for the lower CHT's. Tomorrow I’m going to remove the jumper and take some more numbers… I might also try retarding the timing manually somewhere in between the two PMAG curves.

It's all a matter of weighted compromise.

My compliments sir. Keep bringing that data.
 
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PMAG Timing

A couple of questions for you:
1. Is this a 180 hp parallel valve engine or 200 hp angle valve?
2. What compression ratio are you running?
3. What is the manufacturer's recommended timing setting?

1. 180 hp parallel valve engine
2. 8.5:1
3 25* BTDC
 
PMAG Timing

Climb CHT reduction is probably the #1 reason to retard timing, lower mechanical stress (due to higher gas pressure at TDC) being #2.

........


It's all a matter of weighted compromise.

My compliments sir. Keep bringing that data.

Dan,
Good explanation. I've been toying with the idea of installing an EI Commander so that I can get better real time data, and be able to more quickly making timing changes. I've got an extra 3.125" hole in the panel just for that device. Maybe Bill can chime in and tell me which device would be better in that location.
Running the engine on the "B curve" yesterday gave me the distinct impression that there was less power overall. The take-off RPM on the "B curve" was 2290 RPM, and about 2350 running on the "A curve", so, with a fixed pitch prop, to me that is showing less power.
Can't fly today as the weather here is terrible. I'll try and get a few more data points during the week.
 
The take-off RPM on the "B curve" was 2290 RPM, and about 2350 running on the "A curve", so, with a fixed pitch prop, to me that is showing less power.

Agree, about 4 HP less. I suspect you can get it back if you lean just a little.
 
Dan,
Good explanation. I've been toying with the idea of installing an EI Commander so that I can get better real time data, and be able to more quickly making timing changes. I've got an extra 3.125" hole in the panel just for that device. Maybe Bill can chime in and tell me which device would be better in that location.
Running the engine on the "B curve" yesterday gave me the distinct impression that there was less power overall. The take-off RPM on the "B curve" was 2290 RPM, and about 2350 running on the "A curve", so, with a fixed pitch prop, to me that is showing less power.
Can't fly today as the weather here is terrible. I'll try and get a few more data points during the week.

Fred, the EIC is designed for the 2-1/4" hole, so you will need to buy an adapter. Putting it on your panel will allow you to make adjustments, preferably on the ground.

The no jumper "B curve" starts firing at 30.8 degrees, which is a good amount more advance than your engine was designed for.

The jumper in "A Curve" starts at 26.6 degrees, which is still a bit more advance.

You must have some really efficient baffles, or bad CHT probes. Most (I)O-360's in a Van's cowl tend to run very close to 400 degrees at full power, if not over 400 in climb and only cool down in level flight.

A number of our customers, myself included, have experienced lower CHT's and slightly higher speeds by lowering the "A curve" by 1.4 degrees. This means that their P-mags will fire at 25.2 degrees for take off and a max advance of 33.6 degrees in cruise.

I am surprised that your cylinders run as cool as they do.
 
Dan,
Running the engine on the "B curve" yesterday gave me the distinct impression that there was less power overall. The take-off RPM on the "B curve" was 2290 RPM, and about 2350 running on the "A curve", so, with a fixed pitch prop, to me that is showing less power.
Can't fly today as the weather here is terrible. I'll try and get a few more data points during the week.

Am I miss reading this post or your earlier post? Your earlier post, at least the way I read it, indicates a lower RPM of 2290 with the A curve and a higher RPM with the B curve.

I did experiment some with the A and B curve and some custom curves as well with my IO360-M1B in a 7A and found the difference between the A and B curve was little and not worth the higher CHT. The B curve was a bit better up high and the penalty down low was a bit higher CHT which would push my CHT to 400 and above if I kept climbing at full power. Like the above post, I am impressed with your CHT numbers. My baffles weren't anything like DanH work but I would say much above average.
 
Mehrdad,

Just to be clear, are you talking about the parallel valve engine in your -7A, which you have since sold?

The angle valve engine in your -14A seems to cool much better than the parallel valve engines for some reason and that engine requires 20 degree timing. Since you have an EIC in your 14A, creating a custom configuration that sets the timing correctly should be fairly easy.
 
Hi Bill,
That is correct and I am planning on experimenting with different curves with my new IO390. Currently I am using the "A" curve without any modifications but I have set the timing with about 5 degrees retard of TDC on the flywheel when I set the timing on the PMAG which brings it to the manufacture suggested 20 degree.
 
Hi Bill,
That is correct and I am planning on experimenting with different curves with my new IO390. Currently I am using the "A" curve without any modifications but I have set the timing with about 5 degrees retard of TDC on the flywheel when I set the timing on the PMAG which brings it to the manufacture suggested 20 degree.

Great! I just wanted to make sure you were not damaging your engine.

Since you have the EIC, it is really easy to create custom configurations and send them to the P-mags, as you know.

Feel free to call, if you have any questions.
 
One D-sub connector?

The EIC has one male D-sub connector. How do I wire two P-mags to interface?

I have already wired up two D-subs, one for each P-mag, to interface to use the EICAD program initially.
 
The EIC has one male D-sub connector. How do I wire two P-mags to interface?

I have already wired up two D-subs, one for each P-mag, to interface to use the EICAD program initially.

Jeff, just make a Y adapter that comes from each DB9 connector to the DB15 connector required by the EIC.

Did you bring the tach line to each of the DB9 connectors? That is required.
 
TACH INPUT

Yes, I brought both tach inputs to each the separate DB9's.

So, each separate P-mag is distinguishable when Y-wired to one DB9 connector brought to the EIC?

Is that also the case when connected to a PC?
 
So, each separate P-mag is distinguishable when Y-wired to one DB9 connector brought to the EIC?

Is that also the case when connected to a PC?

The two DB9s are connected to a DB15, which connects to the EIC. You could, optionally, connect them directly to the DB15 but would not then be able to connect individually to a PC, if later desired.
 
Ray is correct.

The PC USB to serial converters are DB9 connectors. You can plug a PC in to either P-mag, as needed.

Had you wired your P-mags to one DB15 connector and wanted to use a PC withe the EICAD program, you would have to make a reverse Y cable to go from the DB15 to two DB9 plugs.
 
This all assumes I?m good at setting my timing mark at 1.5* after TDC. I didn?t have a propeller protractor to do this, so my method of measurement might be a little crude.

Scott (and Bill),

So, I?m about to embark on installing the 2nd Pmag on my aircraft (have been running 1 on the left/Slick on the right for the last 3 years) and I am following the information on this thread closely and intend to set the timing up on BOTH as you did and as Bill recommends (1.4* shifted).

Regarding measurement of that 1.4*, would a circular protractor, downloaded, printed out and attached to the flywheel be (perhaps) a more accurate way of measuring?

This website:

https://www.blocklayer.com/protractor-printeng.aspx

...Allows you to create a template up to 30? in diameter. My thoughts would be to print an appropriately sized, anti-clocked, circular protractor, attach it to the flywheel and then use it as accurately as I can to set the mags after moving it 1.4* after TDC.

More or less accurate than counting teeth or am I being overly detail-oriented in this? Just count teeth, set the mags and it?ll be fine?

Thanks,

Rob S.
 
Rob,
That protractor should work as long as the printed copy is true. You should check it with a simple plastic protractor. Another possibility would be to use your cell phone with an angle finder app, or level app. My iPhone has one. Tape it to your prop at TDC, zero the digital readout on the app, and then move the prop 1.4*. Make sure you go the correct direction (counter-clockwise looking at it from the front - aft), so you are retarding the timing v.s. advancing it.
 
Rob,
That protractor should work as long as the printed copy is true. You should check it with a simple plastic protractor. Another possibility would be to use your cell phone with an angle finder app, or level app. My iPhone has one. Tape it to your prop at TDC, zero the digital readout on the app, and then move the prop 1.4*. Make sure you go the correct direction (counter-clockwise looking at it from the front - aft), so you are retarding the timing v.s. advancing it.


Brilliant!

In 30 seconds, I downloaded and installed a free protractor app that will do the trick just as you described!

Outstanding tip, Scott! Thanks!!

Rob
 
Not past TDC?

Unless I?m missing something, I?m pretty sure the 1.4 shift is done through the Emag program and not by setting the actual past TDC. For the 0-360s I think it?s reccomended to electronically shift the curve 1.4 via the software while timed at TDC. So as long as you have a TDC mark, you shouldn?t need to do any of this protractor measuring. Electronically shifting the curve 1.4 via the software is not the same as timing the Pmags to 1.4 past TDC.



Scott (and Bill),

So, I?m about to embark on installing the 2nd Pmag on my aircraft (have been running 1 on the left/Slick on the right for the last 3 years) and I am following the information on this thread closely and intend to set the timing up on BOTH as you did and as Bill recommends (1.4* shifted).

Regarding measurement of that 1.4*, would a circular protractor, downloaded, printed out and attached to the flywheel be (perhaps) a more accurate way of measuring?

This website:

https://www.blocklayer.com/protractor-printeng.aspx

...Allows you to create a template up to 30? in diameter. My thoughts would be to print an appropriately sized, anti-clocked, circular protractor, attach it to the flywheel and then use it as accurately as I can to set the mags after moving it 1.4* after TDC.

More or less accurate than counting teeth or am I being overly detail-oriented in this? Just count teeth, set the mags and it?ll be fine?

Thanks,

Rob S.
 
Unless I’m missing something, I’m pretty sure the 1.4 shift is done through the Emag program and not by setting the actual past TDC. For the 0-360s I think it’s reccomended to electronically shift the curve 1.4 via the software while timed at TDC. So as long as you have a TDC mark, you shouldn’t need to do any of this protractor measuring. Electronically shifting the curve 1.4 via the software is not the same as timing the Pmags to 1.4 past TDC.

Wick,

Go back to page 1, first post and scroll down to where Bill talks about "clocking" the mags....

That's what is being discussed here...physically advancing the engine 1.4* past TDC and then setting the timing of the Pmags there via the instructions found in their manual.

Measuring and setting that 1.4* is what I'm using the protractor for.
-Rob
 
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