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  #11  
Old 11-26-2022, 01:06 AM
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hgerhardt hgerhardt is offline
 
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Quote:
Originally Posted by gasman View Post
The bad news.... you need to remove the prop to adjust the timing!!..:eek......
Nope, you can adjust the timing with the prop installed provided you'll take a few minutes to make a tool: https://www.vansairforce.net/communi...2&postcount=24 Let me know if the pics don't appear and I'll attach them the new way.
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  #12  
Old 11-26-2022, 07:16 AM
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DanH DanH is offline
 
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I'm with Warren. Leave it alone and be happy. If we base on Nigel Speedy's data using a parallel valve 360, the base timing retard will result in lower CHT with no practical performance difference in the common 6K~10K altitude range.
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  #13  
Old 11-26-2022, 09:51 AM
F1R F1R is offline
 
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Quote:
Originally Posted by gasman View Post

The good news.... your timing W/O mp is fine. And the high numbers with mp is out of the range set by lightspeed...but, it's on the good side. I would be happy with that and just fly on.

Any adjustment to get back into spec will need the brain box sent in.
As Warren and Dan have posted. Your timing, as you have verified, is quite fine and you are on the safe side of perfection. All you need to do is fly it.

Last edited by F1R : 11-26-2022 at 09:58 AM.
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  #14  
Old 11-26-2022, 05:30 PM
ge9a ge9a is offline
 
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Posts: 214
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This forum never disappoints. I always appreciate the input.

Based on what I've read here, I'll continue to fly it and continue to watch the engine temperatures closely (I do that anyway).

I'll keep the tools in mind in case I decide to venture down that path (thank you for the info, hgerhardt).

And thanks for including the data/graphs, Dan. Very interesting.

Thanks for everyone's input! That's why it's called Experimental. Always learning!
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  #15  
Old 11-27-2022, 08:48 AM
Kent Ashton Kent Ashton is offline
 
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I have never checked the Lightspeed timing at other than a static, engine-off condition. It is pretty easy with a mag-hole trigger--turn the prop until the LED comes on. With the various crank sensors, the timing cannot be off if the trigger ring or mini-sensor is installed correctly and aligned with TDC. Yeah, the manual mentions using a timing light but I never bother (well maybe I did the first time I installed a system). You can tell if the zero-advance (starting) magnet is triggering at TDC just by pulling a plug and checking the spark. I suppose the advance timing could be off due to some internal defect in the electronic box but I've never heard of that. I've had several of these systems.
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  #16  
Old 11-27-2022, 10:09 AM
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I seem to recall at least one case of a failed MAP sensor resulting in timing advance at high manifold pressure. Card, RV-9? It's here somewhere.

Anyway, with the manifold pressure sensor hose disconnected, the sensor is seeing high pressure, which should result in base timing. The timing light doesn't just check for proper Hall sensor position. It also tells if the MAP sensor is working.
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  #17  
Old 11-27-2022, 10:20 AM
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Carl Froehlich Carl Froehlich is offline
 
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Quote:
Originally Posted by DanH View Post
I seem to recall at least one case of a failed MAP sensor resulting in timing advance at high manifold pressure. Card, RV-9? It's here somewhere. SNIP
Yep - on an RV-7. The MAP circuit failed so timing was 42+ degrees BTDC regardless of manifold pressure or RPM causing CHTs be dangerously high, and this was on both ignitions. Perhaps Klaus had a bad batch…..

I strongly recommend anyone still flying with Lightspeed do this check, along with annual coil and spark plug wire inspections.

Carl
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  #18  
Old 11-27-2022, 10:28 AM
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Toobuilder Toobuilder is offline
 
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As I recall, Lightspeed uses GM style MAP sensors (as does SDS), and after learning of this potentially catastrophic failure mode (hard over to full advance), I adjusted the base programming of my SDS products to ignore this anomalous condition. Since then I have seen one of these GM sensors fail on my system and due to my settings, it was a non-event.
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WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

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  #19  
Old 11-27-2022, 01:39 PM
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Originally Posted by Toobuilder View Post
As I recall, Lightspeed uses GM style MAP sensors (as does SDS), and after learning of this potentially catastrophic failure mode (hard over to full advance), I adjusted the base programming of my SDS products to ignore this anomalous condition.
Different system, same move. Timing advance schedule below is for an angle valve. I don't know what sort of MAP sensor is on the board of the Autosport Labs timing control device I use, but the software allows building the schedule from scratch. It's easy to assign 23 BTDC base timing to a very low MAP line.

Turned out, I hardly ever use this schedule anyway. I have two, inflight switchable, and most of the time it's running on 23 fixed.
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  #20  
Old 11-27-2022, 06:45 PM
rmd rmd is offline
 
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For what it is worth...there is at least one case of the internal timing being off.

My ignition timing display indicated that the Plasma II+ went to 45 or 46° of advance, but the engine sounded and felt fine. Increased CHT seemed to confirm that the timing was too far advanced, but I did check timing with a timing light and followed all of the other trouble-shooting steps Klaus put in his manual.

After performing all of those steps, I gave Lightspeed a call and they told me to send it in for repair. They replaced a capacitor to fix this problem and upgraded some other minor, unspecified components and had it back in the mail the day after they received it. I don't recall the cost, but didn't find it to be unreasonable.

Interestingly, a couple of A&Ps walking by as I tested the timing commented that they thought the engine would really sound and act horribly if the timing was advanced that far. I wasn't smart enough to know one way or the other, but thought I'd pass along the information.

Regards,
Rob
N706DR
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