How many degrees timing advance MS 400?

[wilfrie]

Hello! As a tree climber I do like my Stihl MS 400, but I would like to increase the bottom power (torque) a bit more. I opened already the stock muffler, but I would also do a timing advance, since I read it does help as well on a 400.

My question is, how many degrees of advance is save & perfect for the MS 400? I read people do from 4 to 8 degrees on comparable saws (like the 362 or 462), but I couldn't find many information about timing advance on the MS 400. Most people seem to do 5 or 6 degrees, but would e.g. 8 degrees add extra wear to the engine? And has anyone already tried different degrees of ignition advance to find the optimal benefit, since there should be a kind of an optimum technically?

So I hope you can help me and already many thanks!

 

[lehman live edge slab]

So you haven’t done any yet you asked weeks ago already an I told you how to advance it and about how much using the fan blades on flywheel. If you think what I told you was too much or too little then start with less advance and add to it after you try it. Your going to get probably several different answers on how much and still need to decide what your going to use for the number

 

[Mastermind]

7mm at the outer edge of the flywheel.

 

[lehman live edge slab]

7mm at the outer edge of the flywheel.

I told him 1/4” about on outside edge couple weeks ago so pretty similar

 

[Mastermind]

Yep. Same Same.

 

[wilfrie]

Thanks for the replies. I understand that the 5mm you mentioned in your personal message Lehman, the 1/4" (6,35 mm) and 7 mm are in the same scope. But since 1 degree corresponds to 0,9082 mm, those differences in milimeters do matter, because they corresponds almost to different degrees. So e.g. 5,4 mm corresponds to 6 degrees and 7,22 mm to 8 degrees advance. And since the amount of degrees of ignition advance might matter, in terms whether there is an optimum and from what degrees detonation (popping) of the engine occurs, I am interested in experiences of others with different degrees? And from there I can deduce how many millimeters of change in the outside of the flywheel that means.
Or does the difference between 5 and 8 degrees timing advance not matter at all by the MS400 with respect to a power optimum and detonation occurance or extra engine wear?

 

[huskihl]

It’s not an “optimum power” thing. More timing advance typically adds lower rpm power but also holds back some unloaded or less loaded rpm. If you’re cutting 6–8” wood all day, any more timing advance could be hurting it. If you’re cutting 24 inches of wood, then more is probably better

 

[lehman live edge slab]

Another way you could gain some torque is drop a tooth on your rim depending what your running or kind wonder how .325 would run with an 8 pin on a 400.

 

[wilfrie]

It’s not an “optimum power” thing. More timing advance typically adds lower rpm power but also holds back some unloaded or less loaded rpm. If you’re cutting 6–8” wood all day, any more timing advance could be hurting it. If you’re cutting 24 inches of wood, then more is probably better

Ah oké, and do you mean with 'any more timing advance could be hurting', more than 0 degrees? And what do you mean by hurting, and how bad is that? How many degrees timing advance would you advise if you cut mostly between 16-20" mainly hard wood?

 

[huskihl]

Hurting the power for that size wood, not hurting the saw.

I would do what was mentioned before, somewhere between 6 and 8MM of perimeter rotation further counterclockwise. When you are looking at the inside of the flywheel with the key on bottom, you would need to file away a portion of the left hand side of the key

 

[farminkarman]

The last ms400 I did has 10 degrees of timing advance…that translates to a little more than 3/8” of movement at the OD of the flywheel.