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Mag Timing Laser

Ironflight

Ironflight

VAF Moderator / Line Boy
Mentor
Like many, I enjoy the odd toy tool now and again, so I recently picked up one of those little lasers that clamp to the ring gear and give you a very accurate timing mark on the crankcase split. It's been sitting in the drawer for a couple weeks, so when I changed oil yesterday, I was all excited to clamp it in place and see how it worked!

Of course, as soon as I took the cowl off, I went "Doh!!", and slapped my forhead...I had forgotten about the forward baffles being in the way between the ring gear and the case - I guess I was just visualizing my old Grumman setup. I had also checked the timing on the engine before final baffle installation....

Anyway, this appears to be a small obstacle either with or without the laser - what techniques do people use to make sure the timing mark on the flywheel is lined up with the case split line with the baffle in between? carefully measure and transfer a line? Drill a small hole in the baffle? Surely you don't remove the baffle every time you want to check timing..... :confused:

Paul
 
Use the alternate index on the starter with the marks on the front of the ring gear...

You do this from the front of the engine.

Deene.
 
Light Bulb beginning to glow now....I've always wondered what those marks were for!!

I never stop learning....Thanks!

Paul
 
Can you elaborate on the alternate timing marks.
I've never heard of alternate timing marks.
Have the same set up as Paul and the same laser timing light.
It been in the drawer for a year. Thought I'd have to drill a hole into the baffling.thanks.
 
I just did my timing.

I marked the front of the ring gear with a sharpie for TDC and 25BTDC.
Then I fold the front baffle rubber down and hold it there with 2 clamps either side of centerline.
I then draw a line up the center of the rear baffle and forward baffle with a sharpie [extending the engine case split line].

I gunsite the whole lot together and get a very accurate timing indication.
Worked very well for me.
 
Ironflight said:
Like many, I enjoy the odd toy tool now and again, so I recently picked up one of those little lasers that clamp to the ring gear and give you a very accurate timing mark on the crankcase split. It's been sitting in the drawer for a couple weeks, so when I changed oil yesterday, I was all excited to clamp it in place and see how it worked!

Of course, as soon as I took the cowl off, I went "Doh!!", and slapped my forhead...I had forgotten about the forward baffles being in the way between the ring gear and the case - I guess I was just visualizing my old Grumman setup. I had also checked the timing on the engine before final baffle installation....

Anyway, this appears to be a small obstacle either with or without the laser - what techniques do people use to make sure the timing mark on the flywheel is lined up with the case split line with the baffle in between? carefully measure and transfer a line? Drill a small hole in the baffle? Surely you don't remove the baffle every time you want to check timing..... :confused:

Paul
Click to expand...

Does anybody know where can I purchase one of these small laser timing lights? I tried McAviation but their web page is unavailable.

:cool:
 
There is a hole in the nose of the starter, takes a piece of 1/16" round stock-----such as a drill bit, or at least a piece of one.

It will become a pointer for a second set of alignment marks on the front of the flywheel, which are correctly offset so they match the starter location at the same time the case split matches the alignment marks on the rear of the flywheel.

Try it, you might like it.

Here is a photo Google found for me.

20130720_timing_mark2.jpg
 
Last edited:
Mike S said:
There is a hole in the nose of the starter, takes a piece of 1/8 round stock-----such as a drill bit, or at least a piece of one.

Here is a photo Google found for me.

20130720_timing_mark2.jpg
Click to expand...

Slight addition to Mikes post to avoid future confusion.
The hole is 1/16" diameter, not 1/8". It takes the smallest bit in a common drill bit set. In the image above, it is the hole shown closest to the 25 degree mark on the ring gear, not the other larger one to the right.

Bill, thanks for setting folks straight on this, my bad :( corrected my prior post Mike
 
Last edited by a moderator:
For engine running timing verification:

One can fashion a temporary wire pointer which points to and is close to the top aft side of the ring gear. This can be "calibrated" by rotating the engine until the tiny hole in the starter is aligned with whatever mark one wants to use, then bending the wire to align it with the appropriate spot on the top aft side of the ring gear. Marking the alignment point on the ring gear with a sharpie makes seeing the mark when the strobe is on it easier.

Caution is advised... it takes two people to do this!
 
Mike S said:
There is a hole in the nose of the starter, takes a piece of 1/8 round stock-----such as a drill bit, or at least a piece of one.

It will become a pointer for a second set of alignment marks on the front of the flywheel, which are correctly offset so they match the starter location at the same time the case split matches the alignment marks on the rear of the flywheel.

Try it, you might like it.

Here is a photo Google found for me.

20130720_timing_mark2.jpg
Click to expand...

Been there, done that but still looking for the laser timing light.

;)
 
Android/iPhone

They seem to be the answer for everything these days. As is said "There's an app for that".

I timed my mag using both the traditional flower pot method and using an iphone inclinometer app and a similar android app. I simply taped the phone to the prop hub with enough duct tape to ensure it wasn't moving.

I first found tdc and zeroed the app. then backed the prop until I had the necessary 25 btdc. sanity checked that against the timing mark on the starter and it was dead nuts.

then set the mag.

then rotated the engine through and used the buzz box against the app to verify the timing to within .1 of a degree.

just for grins then had a local magneto expert use his traditional flower pot. Best he could get was +- 1.5 degrees.
 
Hole in the baffle

Paul,

I drilled an appropriately positioned hole in the baffle to allow the laser to shoot through. I fill it with a screw and self-locking nut when not in use.

Cheers,

Vac
 
I use a laser level. One that projects a straight line on a wall, floor or whatever. Place it on the boot cowl pointing forward and line up the split line in the case. The line will project forward to the ring gear, prop and hangar door....

Works great, and you probably have one in your toolbox already.
 
I made a pointer out of scrap 0.025" and attached it to the front baffle. Crankshaft TDC was carefully set and the pointer bent/adjusted so it was at the TDC mark on the flywheel. Been using the pointer for several years....works great. I'll recheck it every other condition inspection or so to make sure it is still valid.
 
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