Engine Timing Mark

[3Dreaming]

4 cylinder 4 stroke non-geared engine, all cylinders fire in two revolutions of the crank/prop. So each revolution the impulse coupling(s) will release twice. This should happen only a few degrees before top dead centre. BUT the sound will not tell you which cylinder is getting the ignition pulse so you're still in the dark.

Best just to start from scratch, follow the procedure with the timing pin and install the mag in the right position with cylinder 1 on the compression stroke tdc.

Also note that the firing order of the mag and the engine are different. The wire from mag position 1 goes to cylinder number one, but mag wire 2 goes to cylinder 3, mag position 3 goes to cyl4 and 4 goes to cylinder 2 for the firing order of 1342 (cast into the crank case). Wouldn't be the first time this mistake was made.

The firing order is 1-3-2-4. If he has Slick leads to go with the mags the cylinder number and position are labeled on the leads. That being said I have a set of new leads back in the shop that were labeled wrong from the factory.

Also since this is a newly assembled engine are you sure the camshaft is timed correctly to the crankshaft? As you pull the engine through and it comes up on compression are the timing marks on the bottom when cylinders 1 and 2 come up on compression?

[Robert Lees]

4 cylinder 4 stroke non-geared engine, all cylinders fire in two revolutions of the crank/prop. So each revolution the impulse coupling(s) will release twice. This should happen only a few degrees before top dead centre. BUT the sound will not tell you which cylinder is getting the ignition pulse so you're still in the dark.

Best just to start from scratch, follow the procedure with the timing pin and install the mag in the right position with cylinder 1 on the compression stroke tdc.

Also note that the firing order of the mag and the engine are different. The wire from mag position 1 goes to cylinder number one, but mag wire 2 goes to cylinder 3, mag position 3 goes to cyl4 and 4 goes to cylinder 2 for the firing order of 1342 (cast into the crank case). Wouldn't be the first time this mistake was made.

If you have a new Slick or Bendix harness, the plug leads are stamped with the sparking plug cylinder locations. That has been the standard for some time.
(Not so with Eisemann or Case Mags of course)

[Scott]

The firing order is 1-3-2-4.

I was bound to get it wrong, continental cast the numbers on the case just for me

[Robert Lees]

Some posts about a certain virus moved to a new thread

[Taylorcrafty]

In my opinion, this is by far the simplest accurate way to set mag timing.

https://aircraft-tool.com/shop/detail.aspx?id=RSK-DX

[astjp2]

Recomend you beg borrow or buy a time rite as you'll be lucky to get a good result just by trying to eyeball the timing Mark's on the crank.
https://1.bp.blogspot.com/-KTIKOJgDD...0/DSCN2492.JPG

use a line laser, works real good if you get it to align up on the case halves and the crank.
are you up and running?

[Guest]

Why do you have to set timing to #1 cylinder?

How about setting it to another cylinder (in this case 3 or 4) that fires when the timing mark is aligning with the top side of the crankcase split line where you can better see the mark alignment? The mag fires every 1/2 turn of the prop on and ungeared 4 banger as mentioned earlier by Scott.

Or perhaps that is what you are doing?

Dave

[3Dreaming]

Why do you have to set timing to #1 cylinder?

How about setting it to another cylinder (in this case 3 or 4) that fires when the timing mark is aligning with the top side of the crankcase split line where you can better see the mark alignment? The mag fires every 1/2 turn of the prop on and ungeared 4 banger as mentioned earlier by Scott.

Or perhaps that is what you are doing?

Dave

How would you index the mag for other than the #1 firing position to time it to the engine? Once the mag is installed and timed properly you could possibly check the mag timing in one of those other positions.

[Robert Lees]

If the mag is positioned to fire at cylinder "n" and the engine is positioned at cylinder "n" then it'll work. The number is not relevant.

The No 1 cylinder is the convention; I quite often use another one depending upon whether I can see the crankshaft markings easier from above or below.
Slicks and some Bendix mags may be different...they have a "cheating" hole or mark that aligns them with No 1 cylinder.

[3Dreaming]

If the mag is positioned to fire at cylinder "n" and the engine is positioned at cylinder "n" then it'll work. The number is not relevant.

The No 1 cylinder is the convention; I quite often use another one depending upon whether I can see the crankshaft markings easier from above or below.
Slicks and some Bendix mags may be different...they have a "cheating" hole or mark that aligns them with No 1 cylinder.

Bendix has an indicator mark that is visible when the mag is firing the #1 position, and Slick has a lock pin the aligns it at the #1 position.

[Guest]

You don't need to get an infinitesimally accurate crankshaft position to get the mags installed in the proper firing order.

Since the discussion involved accurate crankshaft positioning I assumed it was only about setting timing (points opening).

I assumed that the mag and harnesses had already been installed and the corresponding firing orders had already been matched.

Perhaps that's not the case, maybe I should have read the thread from the start. Will do that now.

Dave

[Robert Lees]

Bendix has an indicator mark that is visible when the mag is firing the #1 position, and Slick has a lock pin the aligns it at the #1 position.

Well, yes, that was my meaning Tom. Did it come out different from my intended meaning? (I hope the Churchillian language barrier has not stricken).

[3Dreaming]

Well, yes, that was my meaning Tom. Did it come out different from my intended meaning? (I hope the Churchillian language barrier has not stricken).

I was just concurring that Bendix and Slick indeed have means to locate position #1.