Lightspeed timing

[DanH]

Originally Posted by rmd

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.

Nope. On the ground it will sound and run just fine with advance in the 40's. At full throttle it may detonate, depending on conditions. However, even then it won't sound or run much different, only feel a little down on power.

[lr172]

Originally Posted by rmd

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.

Another reason to be very careful about where you get your advice and guidance. I run 35* of advance at idle on my 320 to improve idle performance. At 1000 it is back to 23, but find that it helps to get the idle RPM lower, and still smooth, and that is important with FP props if you don't want to float.

[RV8Squaz]

Originally Posted by rmd

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

Yup, its happened to me too. I discovered my timing on the LS to be stuck at 43 deg BTDC.

It was bit insidious in my case. I received my newly repaired engine with new cylinders in the spring some years back. I watched the temps come down during break-in. Just when I thought the break-in was complete, I began seeing the temps go back up. This was coinciding with warming summertime temps. Once I had trouble maintaining CHT's below 380, I knew something was amiss.

I bore-scoped, checked baffling, checked the Vernatherm, etc. Finally something on this site tipped me off to check the timing. The magneto on the right was right at 20 deg BTC, perfect for the angle valve. The LED on the LS also indicated perfect timing. Shot it with the strobe light and voilà, 43 deg BTDC. Not sure if it was in the MAP circuit or not, but there was a capacitor blown in the box. Klaus repaired it for a reasonable price.

That was my 3rd failure with my LS. I've had two of the Hall Effect sensors that go in the magneto hole go bad and the aforementioned capacitor. So I'm not exactly thrilled with it, but I do have 1800 hours on the system. When it works, it works exceedingly well. But when it doesn't, it's game over.