Getting ready to finish the briggs build tomorrow and i have a question . The cam i'am using is a dyno 107SS recommended timing is 32-34 degrees . The ARC flywheel says with a stock key it will be at 30 degrees . I have bought offset keys #2 #3 #4 I really don't understand them . How much will each one move my timing or which one do I need to be in the 32-34 window ? And which direction does the key install ?
Timing ? On my flat head build
- Thread starter David wulf
- Start date
- Tags build flat head timing
Use any of those keys. Notch on left. When putting flywheel on, make sure the flywheel is all the way against the key on the left side of the flywheels notch. Torque to spec. I almost always go a bit over on torque especially with a notched key since there is now a gap on the right side of the flywheel notch. Not enough torque and it could slip.
The number of the key is the number of degrees. For yours, 2 = 32, 3 = 33, and 4 = 34.
The number of the key is the number of degrees. For yours, 2 = 32, 3 = 33, and 4 = 34.
In case you need a pic.
Timing is Everything - Basic Kart Ignition Explained, Part 2 - Article by John Copeland
Timing is Everything - Basic Kart Ignition Explained, Part 2 - Article by John Copeland
The ARC flywheel you have is a nice piece. I believe they have rare earth magnets in them. Briggs coils retard as rpm increases. Some coils have more resistance than others and tend to retard less. The numbers on offset keys is not the amount they advance the timing. Back when I was racing the STOCK 5hp. briggs class on gas we usually ran a #3 or #4 key with a stock briggs flywheel. This was probably less than 30 degrees. I would start with a stock key in the flywheel you have and go from there. There are better ways to set the timing on these but it is more involved.