Part Five: Ignition Timing

[Mastermind]

Well since you brought up spark plugs has anyone ever played around with different temp plugs with the modded saws. In the automotive racing we would play with our plugs temp depending on if the engine was na or turbocharged or even on nitrous.


Sent from my iPhone using Tapatalk

I have not. I run NGK BPMR7A plugs in all my saws.

 

[Chainsaw Jim]

I like to think I'd rather have the spark plug fail before the motor when overheating. I don't believe hotter rated plugs spark hotter, they spark when hotter.

 

[Simondo]

Notice I said "as far as I know".

I enjoy these type of threads because we all get the opportunity to learn. When I did the first M-Tronic saws I did not advance the timing because I thought the system was controlling advance. Other guys reported that they were seeing good results with timing advance on these models......so, of course, I tried it. They responded just as well as any other Stihl did.

So, I've come to the conclusion (right or wrong) that the system cannot alter timing beyond the retard that is built in the coil for easy starting.

Yea...i picked up on the ..."as far as i know" . Unlike me you have experimented while working on them and can draw your conclusions from results.

 

[Deets066]

Here is a real good example of when you have too much timing

 

[Deets066]

@Hedgerow's 64 comes to mind here too, except his runs really well in the cut. Out of the cut it sounds like a limited saw

 

[Simondo]

What is the thought here...are saws coming from factory set at the key ...a little retarded ...on the money...a little advanced ?? What is the start point as the outcome seems to always be to advance.

 

[Mastermind]

What is the thought here...are saws coming from factory set at the key ...a little retarded ...on the money...a little advanced ?? What is the start point as the outcome seems to always be to advance.

Like all the other stuff we've talked about, there just isn't any one answer. I don't advance most Echo saws.......or Dolmars. Not too many Huskys either. Almost all the Stihls I do get advanced.

 

[cobey]

290's need advanced. .. all of them

 

[cgraham1]

I recently had an old timer who's built "thousands of saws", tell me that advancing the timing is a retarded thing to do.

 

[cgraham1]

I recently had an old timer who's built "thousands of saws", tell me that advancing the timing is a retarded thing to do.

Same guy that told me every saw should get an "aftermarket heavy duty crankshaft".

 

[moparnut88]

@Hedgerow's 64 comes to mind here too, except his runs really well in the cut. Out of the cut it sounds like a limited saw

My ported 562 does the same thing. Sounds like a limited saw out of the cut but runs like an animal in the cut. The harder u feed it the harder it pulls.


Sent from my iPhone using Tapatalk

 

[Mastermind]

I recently had an old timer who's built "thousands of saws", tell me that advancing the timing is a retarded thing to do.

Same guy that told me every saw should get an "aftermarket heavy duty crankshaft".

This "old timer" probably should stop talking before he shows everyone just how ignorant he really is.

 

[srcarr52]

Effects of timing... nothing else.

No advance.

Just right.

 

[Hedgerow]

No hard, fast rule on timing advance.
Not sure how there could be, as there are so damn many variables!

On the 066 alone, how many coils and flywheels did Stihl use.
Any got auto advance? Any with none?
I got no idea..
Did Stihl send em out from the factory with a simple 14 degree BTDC? 20? Pfffttt..
Who knows really??

I do know on the last 066 I worked on, I had to advance the flywheel a full 24 degrees before it would bite me on start up. Never did pop at full throttle. Quit biting around 18 degrees. Sooooo.... How many degrees total was it after I advanced it 18 degrees?

I got no idea, but it ran like a real saw. Turd burger when it came in the door.

Muffler first, then timing advance.
Timing made a bigger difference than the extra port and baffle removal.

 

[Hedgerow]

What is the thought here...are saws coming from factory set at the key ...a little retarded ...on the money...a little advanced ?? What is the start point as the outcome seems to always be to advance.

Should be sparking BTDC even from the factory. Just not "optimal".
I think they do it to give the saw better manners for starting purposes.

 

[Hedgerow]

Like all the other stuff we've talked about, there just isn't any one answer. I don't advance most Echo saws.......or Dolmars. Not too many Huskys either. Almost all the Stihls I do get advanced.

I think the 13,600 coil out of the 7900's has a steep timing advance built in.
But since I can't prove that by di-secting the damn thing, I'll just have to call it a theory.
I hate those damn 272 coils.

 

[sunfish]

How do you like the one I did for you with stuffers?

Good? Bad? So-so?

I'm not allowed to use the words here to describe it.

Very Very Impressive to say the least!

 

[Mastermind]

I'm not allowed to use the words here to describe it.

Very Very Impressive to say the least!

That's good to know. I kept detailed notes on that saw......as I had a good feeling about it.

 

[srcarr52]

No hard, fast rule on timing advance.
Not sure how there could be, as there are so damn many variables!

On the 066 alone, how many coils and flywheels did Stihl use.
Any got auto advance? Any with none?
I got no idea..
Did Stihl send em out from the factory with a simple 14 degree BTDC? 20? Pfffttt..
Who knows really??

I do know on the last 066 I worked on, I had to advance the flywheel a full 24 degrees before it would bite me on start up. Never did pop at full throttle. Quit biting around 18 degrees. Sooooo.... How many degrees total was it after I advanced it 18 degrees?

I got no idea, but it ran like a real saw. Turd burger when it came in the door.

Muffler first, then timing advance.
Timing made a bigger difference than the extra port and baffle removal.

How are you checking the timing? Just looking where the magnet lines up with the last leg of the coil or are you actually putting a timing light on it?

 

[Deets066]

I think the 13,600 coil out of the 7900's has a steep timing advance built in.
But since I can't prove that by di-secting the damn thing, I'll just have to call it a theory.
I hate those damn 272 coils.

What didn't you like about the 272 coil?