Laser timing pointer

[carusoam]

If you want to take the legal route to doing maintenance, you may want to quote the engine manufacturer's specifications and the Maintenace Manual's method of measuring.

The engineering route does indicate that there is other solutions that work.  A wise engineer would want to define why he would want to go there.

There are many people that pursue STCs to do these things.  Some are here at MS.

RobertGary, what are you trying to do?  Change the timing of your engine from 20 to 25°? Or is this a theoretical discussion?  I like both!

just wondering,

-a-

Edited October 12, 2015 by carusoam

[Andy95W]

Then you tell him you are unable to give him 25.0 degrees.  You can't charge extra for a job your cannot measure to the expected precision. If all you can do with a flower pot is +/- a half degree Then that's what you can do.   You can also buy a timerite and charge and extra 40$ to get the timing deadass. I'd pay extra.  It likely takes less time since there's less error of measurement and repeated adjustment of the mags to get them exact. 

Byron-  I'm sure you have customers that you enjoy working with and you also have customers who are a pain in the ass. I know which category I'd put one that insisted on timing accuracy to 2 decimal points.  Frustration and irritation slows work progress and costs more in hours.

The whole subject reminds me of owners I'm really glad I don't have to deal with anymore. 

 

[jetdriven]

And who is to say that 25.0 is better than 25.4? Certainly Lycoming never gave us a preference. They only gave us 2 mathematically significant digits. So if you want it set to 25.0 you just made that last digit up yourself. 

 

-Robert 

I called lycoming on this and they said 25 degrees.  Not 25 +/- 2 degrees like Continental does but 25.  No tolerance.   So to me that's 24.5 to 25.5. 25.0 being in the middle of that. Would I expect 25.0?  No.  But 24.5-25.5 is reasonable. I've set the timing a degree off and the CHt runs 20 or 30 degrees hotter leaned in cruise.  

[jetdriven]

Byron-  I'm sure you have customers that you enjoy working with and you also have customers who are a pain in the ass. I know which category I'd put one that insisted on timing accuracy to 2 decimal points.  Frustration and irritation slows work progress and costs more in hours.

The whole subject reminds me of owners I'm really glad I don't have to deal with anymore. 

 

you simply say you cannot perform the timing job to 2 decimal places. I don't think there's a person in this earth that would expect two decimal places.   They probably want it to a half degree. I don't think a flower pot is that precise... But that's me 

The best  you can do it +/- 1 degree and let them decide.  

I work on my own plane and I do what I'm told on others' planes.  Some people are particular but it's usually the "don't bend the nose gear" and don't do 5-minute full power runups on my 421 without the cowl on.  Yes i have seen this.  Smoke was coming from the cylinders when he shut it down because the paint was burned off. 

Edited October 12, 2015 by jetdriven

[Andy95W]

You are much better at customer relations than I ever was!  I'll bet the owners you work with are glad to have you. 

[jetdriven]

I don't work with owners.  I do what I'm told to the best of my ability.  But some things I cannot do because I don't have the proper tools.  

[DaV8or]

I am not sure you can absolutely say for certain using the mark 1 eyeball and the marks on the starter gear that you have precisely set it at 25 and not really 26 or even 23. You can sure think you can, however, but you are giving up some efficiency if you are not spot on. I imagine those that race the planes use this tool or one similar. But if being close is all one cares about, then so be, just be close. Personally, I prefer precision when it comes to engine setup and flying. And really, since you are trying to figure out how to locate where 25 deg. (or more likely 20 on a factory reman that you have) is by asking about mounts for a lazer pointer, why not just get this tool instead of a "rig"? It really doesn't cost much and it also allows you to measure things like flap settings, etc. I have one, and it really takes less time to get it right on than my old method of using fishing line extended along the case centerline which was "sorta" close...An A&P was convinced after he swore he nailed 25 deg and was off by 3 deg. when we first played with it. He now owns one.

Yep. The device really works. In my case, I had my IA do the finish inspection on my mag install and he set the timing with his dangly, pointy tin cup thing and I watched. The needle on that thing was pretty sticky and it could stick maybe one to three degrees off. He kept tapping on it to try to get it to settle. Well for my type A personality and the fact that I'm flying this thing and paying for it, I was not satisfied.

I didn't want to insult him because he declared it perfect, so later I bought this machine, followed the easy instructions and got truly perfect. After actually working with the Rite System, I have total confidence in it's accuracy. I is very sensitive, but easy to use. About 5 engine hours later, the plane went for annual at LASARl. I didn't participate this time, but they said nothing to me of the timing being off. 

IMO, anybody contemplating getting any kind of timing device for themselves, this is the only one to get.

[RobertGary1]

RobertGary, what are you trying to do?  Change the timing of your engine from 20 to 25°? Or is this a theoretical discussion?  I like both!

just wondering,

-a-

I just need to replace my pointer. Also, Slick just recalled recently manufactured mags and have asked me to send them back. So I'm thinking about it at the moment. 

-Robert

[N201MKTurbo]

You would need some kind of micrometer device to move the MAG finely enough to get it to 10 millidegrees. Even after you did that it would probably be off by quite a few millidegrees after a few hours of flying. 

Considering that the IO 360 can be set to either 20 or 25 degrees depending on which year, data plate or SB you care to pay attention to. It doesn't seem like a small fraction of a degree is that important. 

All this his being said, I'm neurotic about timing mags. The last time I sent my dual mag out for overhaul, I redid the internal timing because the overhaul shop didn't do it good enough for me. And when I time them to the engine, I probably get them within 1/10 of a degree using my hack saw blade. Getting it any closer isn't the fault of the hack saw blade, it is the ability to reposition the MAG any finer then that.

[Guest]

If you don't like flower pots you could use one of these, 

http://www.skygeek.com/ats-i200b18k.html

Clarence

[Shadrach]

I've timed a number of Lycoming engines over the last decade or so. All of the methods listed in this thread work fine. I prefer a straight edge for it's simplicity. It's easy enough to verify TDC on the starter ring with a plunger. If TDC is indexed properly, then 20° and 25° are indexed properly.

Edited October 12, 2015 by Shadrach

[RobertGary1]

If you don't like flower pots you could use one of these, 

http://www.skygeek.com/ats-i200b18k.html

Clarence

From the "There is always a way to spend more money" files?

 

-Robert

[DaV8or]

I've timed a number of Lycoming engines over the last decade or so. All of the methods listed in this thread work fine. I prefer a straight edge for it's simplicity. It's easy enough to verify TDC on the starter ring with a plunger. If TDC is indexed properly, then 20° and 25° are indexed properly.

Then there is me, who's data plate now reads 20 degrees and there is no index mark for 20 degrees. Neither a hack saw blade, or laser would do me any good.

[mike_elliott]

Then there is me, who's data plate now reads 20 degrees and there is no index mark for 20 degrees. Neither a hack saw blade, or laser would do me any good.

but the rite systems timing indicator would...

[RobertGary1]

Then there is me, who's data plate now reads 20 degrees and there is no index mark for 20 degrees. Neither a hack saw blade, or laser would do me any good.

You could probably find someone (l ike me ) who has both marks and count teeth. 

-Robert

[Shadrach]

Then there is me, who's data plate now reads 20 degrees and there is no index mark for 20 degrees. Neither a hack saw blade, or laser would do me any good.

Interesting that you don't have both as our birds are only a year apart at most. One could easily find 20° by measuring the distance from TDC to 25°and using 4/5ths of that.  Did you have the timing rest to 20° or was it the previous owner? Why would your A1A need to be set at 20° while mine performs beautifully at 25°?  I have often thought the retarding to 20° merely minimizes a symptom of some other issue. Are your CHTs chronically high?

Edited October 12, 2015 by Shadrach

[DaV8or]

but the rite systems timing indicator would...

And that's just what I used. Part of why this tool is so great.

[DaV8or]

Interesting that you don't have both as our birds are only a year apart at most. One could easily find 20° by measuring the distance from TDC to 25°and using 4/5ths of that.  Did you have the timing rest to 20° or was it the previous owner? Why would your A1A need to be set at 20° while mine performs beautifully at 25°?  I have often thought the retarding to 20° merely minimizes a symptom of some other issue. Are your CHTs chronically high?

Somebody before me changed it to 20.  I have no idea why. I think it was trendy to do so back in the day I don't know? If anything, my CHTs are chronically low.

[RobertGary1]

Lycoming changed it to 20 to reduce CHTs in situations where people probably were not managing the engine correctly or had poor baffling. This is at the expense of harder starts. Those of us with new Lycomings have no choice. Those with the older A1As can choose to follow the original data plate or move to 25 based on the Lycoming optional SB is my understanding. But once the data plate changes your legal options decrease. Although I know some FSCs that will just use the old timing anyway. 

 

-Robert

[jetdriven]

You can undo Lycoming SI 1325A and reset the timing to 25 degrees. Its optional and some people dont want it on their engine.  It involves changing the magneto for a different part number which has a different lag angle on the impulse coupler and restamping the data plate.  There are no other changes.