Finding firing point

ChuckZZ

Member
We all know that flathead coils retard as RPM goes up and the only dependable way to properly set timing is to find and mark the flywheel with a timing light. But at what RPM do you make the mark?
 

flattop1

Dawg 89
The mark is a reference point .
Depending on what your after or how you want to set the timing .
Most use static , so at an idle or roll over speed if using a starter .
Now if you want 34* at 6000 rpm its a little more complicated .
 
We all know that flathead coils retard as RPM goes up and the only dependable way to properly set timing is to find and mark the flywheel with a timing light. But at what RPM do you make the mark?
You want it at (or near) peak torque ~4000 rpm on a stocker. That's where ignition timing is most critical.
The mark itself is just a reference. The actual firing point is as the trailing edge of the magnet is directly under the right hand most edge of the D shaped pick-up module (located under the coil body.) Most builders will simply place their chalk mark on the flywheel at the right coil leg for easier visibility.


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🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
32 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
You want it at (or near) peak torque ~4000 rpm on a stocker. That's where ignition timing is most critical.
The mark itself is just a reference. The actual firing point is as the trailing edge of the magnet is directly under the right hand most edge of the D shaped pick-up module (located under the coil body.) Most builders will simply place their chalk mark on the flywheel at the right coil leg for easier visibility.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
32 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
Does this hold true on gas?
 
Some will disagree with this and some won't. I don't really care.
I worked at building Nascar race engines back in the day. All timing was set at 3600 rpm. Racer car engines timing advances up to 3500 RPM and keep the same timing up to 7 or 8,000 . Since you never race below 4,000 The timing does not really make a difference unless you idle a lot.
Now with the Flathead coil your problem is the opposite It retards as rpm increase. So if you set it 36 static it will retard down. How much is different with different coils . So set the point of fire at 4,000 Preferably on a dyno or under load of some type. Then set the desired timing on the engine. And I don't mean set your timing at 36 degrees by the actual firing point. Some coils retard as little as 2 degrees and some 6 degrees. It was always referred to as blueprinting the timing. All your are doing is getting the engine to fire at the correct time while you are racing. Not idling.
Now on the animal. Static timing is good. It does not retard.
 
Thank you Brian. Hey do you stay pretty busy during the winter? I have an idea but I need someone like you to complete the couple things I'm not able to pull off due to lack of machines and of course lack of skill an as ability. If you had time could you do some work on a 3 hp? Wanting to deck block, install guides, weld and chamfer lifter area, align bore and hone cylinder correctly, as well as all other places needing honed. Also set timing up correctly like you were just explaining. Possibly some other things that I'm sure I am missing. I'm sure your wondering why all this on a 3 horse? Well I kinda like em. I have plenty of raptors on the shelf from bone stock to a supposed national level. But that's been done b4 plus they are to tall to fit in frame, and I hate to admit it but for this mini bike I have it's has to much donkey behind it to even enjoy it. Hope you can help.
 
Thank you Brian. Hey do you stay pretty busy during the winter? I have an idea but I need someone like you to complete the couple things I'm not able to pull off due to lack of machines and of course lack of skill an as ability. If you had time could you do some work on a 3 hp? Wanting to deck block, install guides, weld and chamfer lifter area, align bore and hone cylinder correctly, as well as all other places needing honed. Also set timing up correctly like you were just explaining. Possibly some other things that I'm sure I am missing. I'm sure your wondering why all this on a 3 horse? Well I kinda like em. I have plenty of raptors on the shelf from bone stock to a supposed national level. But that's been done b4 plus they are to tall to fit in frame, and I hate to admit it but for this mini bike I have it's has to much donkey behind it to even enjoy it. Hope you can help.
If it's anything like the past couple of years, I doubt it, but don't rule us out. We can do all that, it's just a matter of how long you care to wait for it. I keep telling myself that i want to "slow down" a bit, but it never seems to work out that way. :)
 
If it's anything like the past couple of years, I doubt it, but don't rule us out. We can do all that, it's just a matter of how long you care to wait for it. I keep telling myself that i want to "slow down" a bit, but it never seems to work out that way. :)
Do you have a shop rate or a standard charge for each service preformed?
 
Do you have a shop rate or a standard charge for each service preformed?
Yes, we have rates for installing valve guides, align boring, honing, assembly, etc.
Lawn mower shops charge $60 - $80 / hr shop rate and don't have any of the equipment that race engine builders have; mills, lathes, VGS machines, flowbenches, dynos, etc. They simply shortblock everything.
But if we (or any kart engine builder) charged an hourly shop rate, no one could afford these engines. :)
 
We all know that flathead coils retard as RPM goes up and the only dependable way to properly set timing is to find and mark the flywheel with a timing light. But at what RPM do you make the mark?
Most do....but not all ;) and then there are a few that will numb your arm when you grab the 18" long zip tie to pull the plug boot off...just sayin'
 
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