Part Five: Ignition Timing

[Sty57]

Will Coil gap affect timing?

 

[Rob Stafari]

@Coolcraigster26 This would be a good place to start reading.

 

[MustangMike]

Will Coil gap affect timing?

Yes, the tighter the gap, the more advance, but not by much. I use a piece of flashing .010 to set my coil gaps (I shaped it to the flywheel curve).

 

[moby x]

how many degrees does a 560xp550 ignition. does anyone have the answer? thanks

 

[Adirondackstihl]

how many degrees does a 560xp550 ignition. does anyone have the answer? thanks

360

 

[MustangMike]

I have found that several of my saws (definitely not all of them) run better with less muffler mods, and some of the 066/660s prefer a modified baffler (rather than a fully removed baffle).

Several members have stated that is because the porting (to the cylinder) was not done right, but I'm starting not to buy that. Other members have inferred that I'm full of Sh**, but I have documented this to my satisfaction several times.

Don't know why it took so long for the anvil to hit me in the head, but all of a sudden it seems real obvious that it is likely related to ignition timing. After all, when ever we used to open up the headers on our cars, substantial timing advance was required.

I guess if you are looking to make a work saw that does not "bite you" on start up, you may prefer a bit less timing advance and a more restrictive muffler.

I think I'm also going to advance one of my Asian 440 big bores more than .020 off the key and see what happens.

I think I've been conservative (on purpose) with the timing advance on most of my saws.

I welcome anyone else's thoughts/comments on this.

 

[Motorhead]

I have found that several of my saws (definitely not all of them) run better with less muffler mods, and some of the 066/660s prefer a modified baffler (rather than a fully removed baffle).

Several members have stated that is because the porting (to the cylinder) was not done right, but I'm starting not to buy that. Other members have inferred that I'm full of Sh**, but I have documented this to my satisfaction several times.

Don't know why it took so long for the anvil to hit me in the head, but all of a sudden it seems real obvious that it is likely related to ignition timing. After all, when ever we used to open up the headers on our cars, substantial timing advance was required.

I guess if you are looking to make a work saw that does not "bite you" on start up, you may prefer a bit less timing advance and a more restrictive muffler.

I think I'm also going to advance one of my Asian 440 big bores more than .020 off the key and see what happens.

I think I've been conservative (on purpose) with the timing advance on most of my saws.

I welcome anyone else's thoughts/comments on this.

Moderation,Is key to a long life

 

[Mastermind]

Other members have inferred that I'm full of Sh**

Harrumph !!!!!!!!

 

[Mastermind]

Just messin wit ya Mike.

I never......ever leave a baffle in any muffler if I can get it out. But......like anything any one of us does, there are pros and cons to these mods. I have no opinion to share on anything anymore. I just make my living by porting saws. I'm not an expert on it......it's just what I do.

 

[00wyk]

I thought it might have been me, but I can swear that after making a simple .025 cut on my 044's flywheel that the exhaust sounds much louder now. But I don't have any way to measure it. But I guess that might explain the muffler thing if it were true...if...

 

[Mastermind]

Maybe......just maybe......

These mods could possibly work all together?

Maybe?

 

[Deets066]

Does ignition advance make a saw run hotter? If so, why?

 

[Mastermind]

Does ignition advance make a saw run hotter? If so, why?

I have no idear.

I bet @Redbull661 has stuck a thermometer up one's ass to see though.

 

[MustangMike]

These mods could possibly work all together?

And that is the key.

Randy, there are many things that I can't explain, I just try to learn what works, and knowledge is the asset of this forum. But your previous post had far too much modesty in it!

Two of my 77 cc saws recently did very well in the Upstate NY GTG competition. I did not port either of them, so I can't take credit. The 460 was ported by Dr Al using port timing numbers from you (thank you kindly), and the Hybrid was done by CFB. I did carburetor testing on both saws after I got them, and both of them run a little bit stronger as a result. The 460 did not improve at all with the HD-11 carb (I timed cuts in Hickory for the testing), but loved the HD-50 carb. NONE OF MY OTHER SAWS LIKED THE HD-50 CARB, but that 460 runs about 10% stronger with it. Conversely, the Hybrid loved the HD-11 carb. (In fairness to CFB, he wanted to put one on but did not have one at the time).

I can't explain why my MOFO 460 loved the HD-50 and none of my other saws did. The HD-11 (with the richer jet) is easier to explain, the high revving Hybrid benefited from the richer jet, where as most of my other saws just didn't need it.

I'm just glad I discovered what these saws like, and I go with it. Now I'm worried that when I advance the timing on my Big Bore that the RPMs will pick up and it will also need an HD-11! (I still have an HD-11 and HD-50 NIB).

 

[Redbull661]

haven't gone to extremes on the keys/advance. and i've only done this on the 661. Plus this is with the flir. Not the thermocouple. All that said doesn't seem like much? I think the most interesting thing from these results is how the max RPM changes. and of course the times

 

[MustangMike]

Thanks for that Julian!

 

[Mastermind]

But your previous post had far too much modesty in it!

I wasn't trying to be modest.

What I was hoping to convey was that there are so many variables between the saw, the wood, the chain, and the operator, that there really isn't any blanket statements about anything that really hold up. What helps one day might hurt the next depending on weather conditions, or because a rino farts in Africa. These days I'm content to just do my job and stay away from the drama of the "discussions".

 

[Hedgerow]

I have no idear.

I bet @Redbull661 has stuck a thermometer up one's ass to see though.

He did, but it was just his normal 98.6 degrees.

 

[MustangMike]

Some of the things I have noted over the past couple of years:

I never leave the 660 baffle stock, but a 1/2" hole in the back sometimes results in a saw with more torque than when the baffle is completely removed. I have found this to be true on 3 different saws so far, you can notice the difference when you lean on them (two with Cross P+C, one with a 066 jug).

I did a muffler mod on my brother's stock 460 and removed the baffle. The saw lost torque, so I advanced the timing and it really picked up.

I opened up the dp muffler cover on one of the 440 BBs I did. The saw sucked fuel like crazy! I put a unmodified dp cover back on it and the saw is just as strong and a lot better on fuel.

I don't claim to be any expert, I'm just trying to share what I have noted and I welcome any explanations.

 

[Mastermind]

He did, but it was just his normal 98.6 degrees.

Repped.