Timing Advance 362

I've got the itch to mess with my 362 and try to squeeze some more power out of it. Right now all I've done to it is add a second hole right next to the factory exhaust port. Porting isn't really an option for me right now.

I've read on here that they like somewhere between 5 and 8 degrees of timing added. Just want to make sure I'm doing this right. I don't have a degree wheel or anything like that, but I can do some jr high math.

Flywheel diameter = 4", multiply by pi and circumference = 12.56".

12.56" / 360* = .036 inches/degree....multiply by 6 degrees of timing = .21".

I'm thinking if I make a mark on the flywheel and a mark on the saw case at "stock" timing, then make another mark .21" counterclockwise of that mark that should be my new timing mark. File the key until the flywheel rotates to the new timing mark.

I'm pretty sure this is right, but tell me if I'm wrong.

 

The 362 likes more like 10 degrees of advance. If I were you, I would advance the OD of the flywheel 3/8”. The 362 has a cast-on key on the flywheel. You need to be careful in how you cut the key down.

 

Thanks. I might try 6 first and step up to more if I don't like the results.

I have a small file I'll use to cut the key on the flywheel.

 

I pulled the flywheel this morning and did some filing. I made 4-5 strokes, put it back on and checked how far that got me, remove and repeat. I advanced the flywheel about .275" or about 8 degrees.

I don't have any big wood handy to try it on but the throttle response is noticably better. I cut up a few 5" cants I picked up this morning from the sawmill but that's hardly a test. It does sound a little angrier, and I like that.

 

Printable degree wheels are all over the place online. Just print one out and spray glue it to a piece of cardboard.

 

As I said before, they like .375” of advance on the flywheel OD…and that is ported with a smaller combustion chamber and transfer timing fixed. That all being said, you can go more on an otherwise stock saw.

 

I may go a little more, but I just like tinkering with it and want to test as I go as see what changes.

 

I picked up another load of 5.5" cant cut-offs and this time I stacked them double deep (11") and cut a few to length. Power is noticeably different and saw seems really happy where it is. I think I'm going to leave it alone. It will probably only get better as the mtronic learns more.

 

Thinking about this more today. Never changed timing like this but why wouldn't it work and much easier if your saw is in one piece. Simple math and as long as the crank stays in one spot you have to be able to get pretty close. Even with a degree wheel there could be a small margin of error.
So now the big question? How much timing do I want to add to my 362?

Thanks for the info and sharing this. It will get stored in the memory bank.

 

8 degrees doesn't suck. I might try 10.

The bad news is the key is on the flywheel so you can't go back to stock without a new flywheel. The good news is the flywheel is interference fit to the crank so the key doesn't really do much other than alignment. If you went too far you could back it off some without a new flywheel

 

If you ever want to go back to stock timing, just take the flywheel back off. When you re-mount it, just keep the flywheel up against the other side of the key by applying some clockwise pressure on the flywheel. Then tighten the flywheel nut to draw the flywheel back onto the taper.

 

FWIW, here is a ported MS400 with 10 degrees of timing advance:

 

The taper keeps the flywheel form spinning on the crankshaft, not the key. Its only for timing the engine at the factory or if being removed. I've had saws, 3 now, with the key removed to get them timed correctly after changing them to electronic ignition. None have slipped.

 

That's what I said. Flywheel is interference fit (friction fit, press fit).

 

I guess in my morning stooper, waiting on my coffee, I missed that.

 

Well, I was going to mention this but in the past when I said this others would tell me I don't know what I am talking about, so I kept my pie-hole shut.
You can leave the key out, use some lapping compound on the end of the crank and lightly lap the flywheel to the crank, you should see the crank and flywheel will get that even greyish color around the entire surface.
Clean the crank and flywheel well ( brake clean , acetone , lacquer thinner ) and blow it dry. You want no oily residue of any kind. Install flywheel and torque to spec.
I have done it this way countless times and not once have I had an issue, some of these things have certainly seen 20k plus RPM in the RC car world.

 

Just one thing I was thinking about with this.
The drawback I see is you don't know where the timing actually is. Sure, you can advance it " x" degrees by doing the math but where is it in relation to actual TDC?
Not saying it actually matters but to me it would be nice to know. So, without a degree wheel this is kind of an unknown.

Again , not that it matters but the engine guy in me would be curious where it actually is.
And I am still going to keep this method in my mind for future use if need be.

 

I think the only thing you could do is set the piston TDC and see where the magnet on the flywheel is relative to the coil. You might be able to measure timing if you could figure out exactly what part of the magnet sparks the coil. To your point, the stock timing number is kind of irrelevant unless you were trying to install a flywheel without a key.

 

If you really want to know where your ignition timing is at, you gotta use something like a dial back timing light. You would also need to mark flywheel fin and a spot on the case that corresponds to TDC to dial back to.

 

Got the saw into some hard maple today. Really made a big difference. I'd need a bar longer than 20" to really be able to use any more power. Before it wouldn't hold RPM in wood that hard but now I can lean on it pretty hard before it loses any.