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  #261  
Old 02-14-2020, 02:28 PM
WingsOnWheels WingsOnWheels is offline
 
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Location: Plano, TX
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Quote:
Originally Posted by DanH View Post
The manual states 5 to 10 degrees, which pretty much matches observation on a lathe.



See Global Controller Configuration Dialog. Nothing set in Megajolt software will have any effect below 200 RPM, when the Ford EDIS module apparently has full control. However, you can set the advance which will be active between 200 and 500 RPM. This is separate from the Big Map.

Point is, there is little value in specifying a mapped advance bin less than 1000. The software will extrapolate for all RPM between whatever is set in cranking advance and the advance value in the first mapped RPM bin.

Example: Clock 10 degrees as planned. Set "cranking advance" to 10. Header the first column on the big map as 1000. Set 35 in all spaces in every column.

Result will be cranking below 200 at 0 to -5, 0 (TDC) from 200 to 500, 600 = 5 BTDC, 700 = 10, 800 = 15, 900 = 20, and 1000 = 25. Everything above 1000 will be fixed 25 BTDC.

I use bins for 1000, 1500, 2000, then 100 RPM increments to 2700.

Dan,

Thank you for the help. I set up the MJ as noted above. I started the engine on the left mag and the brought the EI online. The timing was a good 10 degrees off (per the timing light), so I adjusted to match the 25 degree mark on the rear of the flywheel.

I must have a problem with my installation, i am getting a slight ping when the EI on, and poor running with afterfire (i think) when running only on the EI. I belive I may have my cylinders paired incorrectly. Or have a cylinder dropping in and out.

I need to confirm I have my ignition harness going to the correct coil posts.
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RV-6A #20603
Complete 5/10/19
PP SEL / A&P
I donate every year on my B-Day (in Dec), but donated early in Sep'19.

Last edited by WingsOnWheels : 02-18-2020 at 06:15 AM.
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  #262  
Old 02-14-2020, 02:45 PM
WingsOnWheels WingsOnWheels is offline
 
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Location: Plano, TX
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Ok, using the Pmag manual for reference (same coil), looks like I swapped 2 and 4, that explains a lot.
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Colin P.
RV-6A #20603
Complete 5/10/19
PP SEL / A&P
I donate every year on my B-Day (in Dec), but donated early in Sep'19.

Last edited by WingsOnWheels : 02-14-2020 at 04:36 PM.
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  #263  
Old 02-14-2020, 09:00 PM
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skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 774
Default Bearing Fit

Quote:
Originally Posted by lr172 View Post
I suspect Slick had a reason for doing it. However, it goes against industry convention and I would exercise caution following their lead, unless you know why they did it.

FYI, mine has been in service for over 500 hours without a hiccup. The design is similar to the version dan posted. It will be interesting to see what Dan did on his bearings. I am sure his has as many or more hours on it.

Best of luck on the project. FYI, I built two of them and only used one. Happy to sell the extra if you get frustrated.

Larry
Interference fit of both the inner and outer races is really the only way to ensure that engine oil from the accessory case can't seep around the sealed bearing without introducing another seal into the assembly.

Skylor
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  #264  
Old 02-14-2020, 11:23 PM
lr172 lr172 is offline
 
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Location: Schaumburg, IL
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Quote:
Originally Posted by WingsOnWheels View Post
Dan,

Thank you for the help. I set up the MJ as noted above. I started the engine on the left mag and the brought the EI online. The timing was a good 10 degrees off (per the timing light), so I adjusted to match the 26 degree mark on the rear of the flywheel.

I must have a problem with my installation, i am getting a slight ping when the EI on, and poor running with afterfire (i think) when running only on the EI. I belive I may have my cylinders paired incorrectly. Or have a cylinder dropping in and out.

I need to confirm I have my ignition harness going to the correct coil posts.
I made that mistake (mismatched coil connection) and got the same afterfires. You put two pieces of tape on the flywheel; One at TDC and the other 180 opposite. Mark them 1 and 2. Put the timing light on #1 top plug and spin the engine with bottom plugs out and ICO. #1 tape (or whatever you marked for the TDC position) should be in the light. Move light connector to #3 plug and spin again. The other numbered tape should be in light.

You need to be carefull with wasted spark, as both plugs on the coil fire at the same time. If I remember the 4 cyl correctly (I recall FO:1324, but can't be sure), coil pairs are 1/2 and 3/4. You can have similar problems if not paired correctly. When a coil fires, one plug should be in a cylinder that is in compression and the other plug should be on a cyl that is in exh stroke. On a 4 banger it is easy. With the crank set at TDC via the flywheel markings, the two cyl at TDC are on the #1 coil and the two at BDC are on the #2 coil.

Your EI should reference which coil connection is intended for the first plug to fire in the rotation. I would expect it to be labelled Coil 1 or Coil A, as Megasquirt calls it. Vaguely remember this being an outgrowth of the MS code base.

Larry
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Last edited by lr172 : 02-14-2020 at 11:45 PM.
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  #265  
Old 02-14-2020, 11:50 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by skylor View Post
Interference fit of both the inner and outer races is really the only way to ensure that engine oil from the accessory case can't seep around the sealed bearing without introducing another seal into the assembly.

Skylor
The slick mag already has an oil seal on the shaft at it's base that separates the bearing from the accy case. I don't believe any design engineer would trust a bearing with an interference fit to prevent oil migration without an oil seal, especially in a splash environment like the accy case.

It's more likely that their reason was shaft retention. I can't remember if their is a bearing retainer, but guess there is not and they use interfererence fits to hold the shaft in place.
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Last edited by lr172 : 02-15-2020 at 12:00 AM.
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  #266  
Old 02-15-2020, 02:09 AM
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skylor skylor is offline
 
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Location: Southern California
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Quote:
Originally Posted by lr172 View Post
The slick mag already has an oil seal on the shaft at it's base that separates the bearing from the accy case. I don't believe any design engineer would trust a bearing with an interference fit to prevent oil migration without an oil seal, especially in a splash environment like the accy case.

It's more likely that their reason was shaft retention. I can't remember if their is a bearing retainer, but guess there is not and they use interfererence fits to hold the shaft in place.
Ther is no bearing retainer, but you’re correct about the oil seal. The double interference is likely for shaft retention and to ensure the bearing races don’t spin free within their bores or on the rotor shaft.

Skylor

Last edited by skylor : 02-15-2020 at 11:08 AM.
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  #267  
Old 02-15-2020, 11:06 AM
WingsOnWheels WingsOnWheels is offline
 
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Location: Plano, TX
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Quote:
Originally Posted by lr172 View Post
I made that mistake (mismatched coil connection) and got the same afterfires. You put two pieces of tape on the flywheel; One at TDC and the other 180 opposite. Mark them 1 and 2. Put the timing light on #1 top plug and spin the engine with bottom plugs out and ICO. #1 tape (or whatever you marked for the TDC position) should be in the light. Move light connector to #3 plug and spin again. The other numbered tape should be in light.

You need to be carefull with wasted spark, as both plugs on the coil fire at the same time. If I remember the 4 cyl correctly (I recall FO:1324, but can't be sure), coil pairs are 1/2 and 3/4. You can have similar problems if not paired correctly. When a coil fires, one plug should be in a cylinder that is in compression and the other plug should be on a cyl that is in exh stroke. On a 4 banger it is easy. With the crank set at TDC via the flywheel markings, the two cyl at TDC are on the #1 coil and the two at BDC are on the #2 coil.

Your EI should reference which coil connection is intended for the first plug to fire in the rotation. I would expect it to be labelled Coil 1 or Coil A, as Megasquirt calls it. Vaguely remember this being an outgrowth of the MS code base.

Larry
Looks like i have 1&3 correct, I just had my paring wrong. If I swap 2&4 I should be good
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Colin P.
RV-6A #20603
Complete 5/10/19
PP SEL / A&P
I donate every year on my B-Day (in Dec), but donated early in Sep'19.

Last edited by WingsOnWheels : 02-18-2020 at 06:16 AM.
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  #268  
Old 02-15-2020, 10:54 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by skylor View Post
Ther is no bearing retainer, but you’re correct about the oil seal. The double interference is likely for shaft retention and to ensure the bearing races don’t spin free within their bores or on the rotor shaft.

Skylor
A bearing doesn't need to be held, via interference fit or otherwise, in order to not spin. Radial intertial forces keep the the inner or outer surfaces from slipping. In a properly working bearing, there is much less friction in the in race / ball interface than the retaining surface interfaces, so this interface breaks the inertial force first with the mounting surfaces still held by inertial force. That said most bearing companies recommend a few PSI of axial tension on the assembly to insure tiis. It is very standard for only the internal or external fit to be interference and not both. This improves bearing life.

Larry
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Last edited by lr172 : 02-15-2020 at 10:59 PM.
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  #269  
Old 02-16-2020, 07:39 AM
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DanH DanH is offline
 
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Best to use a good reference for any design incorporating bearings. A glance at the SKF catalog says they needed 24 pages, with tables, to properly specify radial bearing fit. I'm just sayin'...
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  #270  
Old 02-17-2020, 05:39 AM
WingsOnWheels WingsOnWheels is offline
 
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Just to follow up, after I swapped the 2&4 positions on the coil, everything is working great. I have to do more ground testing, but eventually it will be ready for flight testing. I set up two maps, one with a flat 25 degree advance to match the mag. The second has an advance curve similar to the recommendations from SDS. Once I am flying I can start to play with the curve and performance.

I did most of the wiring for a second system while I was installing the first. The plan is to eventually have a dual EI setup with a dedicated backup battery.
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RV-6A #20603
Complete 5/10/19
PP SEL / A&P
I donate every year on my B-Day (in Dec), but donated early in Sep'19.
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