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  #1  
Old 04-10-2021, 09:04 PM
ArlingtonRV ArlingtonRV is offline
 
Join Date: Feb 2005
Location: Marysville, WA
Posts: 567
Default LASAR Timing Help

I am having difficulties timing my LASAR mags, well, just the left one.

A little history. I bought the airplane a few years ago and shortly thereafter sent both mags out for IRAN. I installed and timed them per the T-300 manual and had no problems. I have checked and adjusted the timing a couple of times since with no problems. This time, problem.

I started with step 3.9 on page 17 and noticed that the timing was off by a couple of degrees. I then back tracked to step 3.6 on page 14 and TDC was off by a couple of degrees. I realigned it per step 3.6 and got it back to TDC. When I got to step 3.7 and rotated the engine backwards until the "LEFT BKR PT" turned off then rotated forward until it turned on the base timing was off by a couple of degrees. I backed off the prop again for another try and the light wouldn't go off no matter how much I turned the prop. The right mag worked as advertised.

The first thing I tried was to put all new AAA batteries in the test box and try again.

I once again went back to square one and tried again starting at step 3.6. The the same thing happened. The light went out once, but when I tried to back it off to repeat the process it won't go off at all.

This concerns me as it would seem to indicate that the points are closed all the time and that would seem to be a bad thing.

Has anyone encountered this before or know what it could mean or how to rectify it? Thanks
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  #2  
Old 04-10-2021, 11:44 PM
Taltruda Taltruda is offline
 
Join Date: Oct 2017
Location: Las Vegas, NV
Posts: 843
Default

I'm unfamiliar with the lasar mags, but aren't they similar to Slicks in how they time? Does the left mag have an impulse coupling? And if so, are you turning the prop until it clicks and then back it up to start timing it. Also check that the mag key is on both, and that the clips are on the right terminals, and ground is on a good ground.
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  #3  
Old 04-11-2021, 12:24 AM
Stevea Stevea is offline
 
Join Date: Jun 2008
Location: San Jose, CA
Posts: 126
Default LASAR timing

Steve,

I had something similar happen to one of my LASAR mags when went through a re-install and re-time process a few months back. I don’t remember if it was the left or right mag, but after re-installing both mags on the engine (using the timing pin) I could not get one mag set to base timing (25 +/- 3 degrees BTDC in this case), no matter how much I rotated it. The T-300 timing box light would not come on at the correct timing.

Tried new batteries in the T-300, removed and re-installed the mag a couple of times, verified the connectors and cabling were all good……….no joy, could not get the timing set. The opposite mag timing set just fine. Also, the system had been working fine before the mags had to come off the engine for access to oil filter adapter bolts and prop governor bolts (another story).

My “solution” to the problem was to remove the problem mag and replace it with one from my spare set (what…...doesn’t everyone have multiple sets of mags laying around :-) ). The problem mag is still sitting in my closet, waiting for a trip to the IRAN shop, so I don’t know what the real cause of not being able to set the timing was. It had about 400 hours on it when removed.

Anyway, back to your problem. I don’t have the T-300 manual here in front of me, but offhand it doesn’t seem like you are doing anything wrong procedure wise.

When you say it was off a “couple of degrees” at TDC, I assume this means it was outside the 0 +/- 1 degree spec? Same thing with the base timing…..it was outside base timing +/- 3 degree spec? Reason I ask is I can always get mine set to 0 degrees TDC, but the base timing tends to come out 3 degrees higher than nominal (28 rather than 25)…..still within spec, just not the middle of the spec.

One thing to check is verify the connector contacts are clean (no corrosion) and straight (not bent). Make sure you put some of the recommended goop on the connector contacts to prevent corrosion (Nyogel). Also make sure the connectors are fully seated to the timing box.

Let me know if you find the problem and can make it work, or if you just want to hash it over some more.
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  #4  
Old 04-11-2021, 12:32 AM
Stevea Stevea is offline
 
Join Date: Jun 2008
Location: San Jose, CA
Posts: 126
Default lasar mag timing

Tom,

Yes, they are basically slick mags, with some additional electronics. But, they use a different timing box and a different timing procedure than standard Slicks. And, they usually do not have an impulse coupling installed (rare exceptions). Mag key position does not come into play when setting/checking timing.

So, the same, but different
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  #5  
Old 04-11-2021, 05:32 PM
ArlingtonRV ArlingtonRV is offline
 
Join Date: Feb 2005
Location: Marysville, WA
Posts: 567
Default

Quote:
Originally Posted by Stevea View Post
Steve,

I had something similar happen to one of my LASAR mags when went through a re-install and re-time process a few months back. I don’t remember if it was the left or right mag, but after re-installing both mags on the engine (using the timing pin) I could not get one mag set to base timing (25 +/- 3 degrees BTDC in this case), no matter how much I rotated it. The T-300 timing box light would not come on at the correct timing.

Tried new batteries in the T-300, removed and re-installed the mag a couple of times, verified the connectors and cabling were all good……….no joy, could not get the timing set. The opposite mag timing set just fine. Also, the system had been working fine before the mags had to come off the engine for access to oil filter adapter bolts and prop governor bolts (another story).

My “solution” to the problem was to remove the problem mag and replace it with one from my spare set (what…...doesn’t everyone have multiple sets of mags laying around :-) ). The problem mag is still sitting in my closet, waiting for a trip to the IRAN shop, so I don’t know what the real cause of not being able to set the timing was. It had about 400 hours on it when removed.

Anyway, back to your problem. I don’t have the T-300 manual here in front of me, but offhand it doesn’t seem like you are doing anything wrong procedure wise.

When you say it was off a “couple of degrees” at TDC, I assume this means it was outside the 0 +/- 1 degree spec? Same thing with the base timing…..it was outside base timing +/- 3 degree spec? Reason I ask is I can always get mine set to 0 degrees TDC, but the base timing tends to come out 3 degrees higher than nominal (28 rather than 25)…..still within spec, just not the middle of the spec.

One thing to check is verify the connector contacts are clean (no corrosion) and straight (not bent). Make sure you put some of the recommended goop on the connector contacts to prevent corrosion (Nyogel). Also make sure the connectors are fully seated to the timing box.

Let me know if you find the problem and can make it work, or if you just want to hash it over some more.
Thanks for the information. Unfortunately, I don't have a spare, so it looks like I will be sending this one in for test/repair.

Appreciate the help.
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  #6  
Old 04-12-2021, 06:57 AM
RV6_flyer's Avatar
RV6_flyer RV6_flyer is offline
 
Join Date: Jan 2005
Location: NC25
Posts: 3,734
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To me, it sounds like the plastic cam that opens the points is worn. A little wear on the points and the cam could give the indications you list.

How many hours have been put on the mags since the last time the M3611 plastic cam was replaced?

The last LASAR mag I had apart was a 4-cylinder sensor mag that would not work after 2,000 some hours of use. It was very dirty and the cam was worn so much the points would not open and close reliably. (The reason that LASAR sensor mag quit working.) Cleaning, replacing the carbon brush, plastic cam, and re-timing, the mag would work (spark) on the bench when test cap with leads that had a spark cap was installed.
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  #7  
Old 04-12-2021, 02:39 PM
ArlingtonRV ArlingtonRV is offline
 
Join Date: Feb 2005
Location: Marysville, WA
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It has been 3 years and 222 hours since they were in for the 500 hr inspection. There was no mention of replacing the M3611 plastic cam. I have been in contact with Scott at Progressive in Kamloops and he suggested hooking the mag to the test box after it was removed from the airplane. I did so and the light stays on no matter how much the shaft is rotated.

Fortunately, Carl had a spare mag that had been freshly serviced. I installed it and it timed just like it should. The other one is headed to the shop for repair. I’ll post what they find for informational purposes.
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  #8  
Old 06-01-2021, 06:53 PM
ArlingtonRV ArlingtonRV is offline
 
Join Date: Feb 2005
Location: Marysville, WA
Posts: 567
Default The Daignosis

As promised, here is the diagnosis from the repair shop.

There was light corrosion on the terminal of the points that the circuit board lead attaches to which was making the timing light act like the points were always open. We also found some pitting of the contact points which is a bit strange since these points don’t usually get pitted unless the capacitor is unserviceable, and the mags don’t run on the breaker points unless they are in backup mode. In the LASAR magnetos the capacitor is on the circuit board and can’t be tested or replaced. The contact points will be replaced during the repair.

I post this only as a data point in case anyone encounters similar problems.
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