Ignition setting
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
I'd say that 10 degrees initial advance is sufficient for the fuel that you are using. An earlier spark doesn't produce any more power. At idle the early spark will produce more vacuum, but at running speed the vacuum advance and cetrifugal advance are giving you all the advance that you need. You are running a very high Octane rated fuel in a low compression motor, you can't get any more power from the fuel.
Thread Starter
|
Senior User
Joined: Dec 2007
Posts: 269
Likes: 0
okay, so actually there's no real "sweet-spot" , it's a large range..?
Would i set the mechanicat at the most advance capability, to achieve best economy at cruise?
Vac. advance is not connected yet, but i intend to do so.
Would i set the mechanicat at the most advance capability, to achieve best economy at cruise?
Vac. advance is not connected yet, but i intend to do so.
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
Yes, there is a sweet spot, but once you go beyond it there is no advantage. In fact going beyond a certain amount of advance will lead to detonation in a high compression motor with low Octane fuel.
It takes time for fuel to burn, that's why you advance the timing at idle and advance it more at higher RPM. If you advance it too much with fast burning fuel you will get a shock wave banging into your piston on the upstroke. If the fuel burns more slowly (high Octane), you won't get the shock wave, but you won't make any more power, since the energy available is limited.
It takes time for fuel to burn, that's why you advance the timing at idle and advance it more at higher RPM. If you advance it too much with fast burning fuel you will get a shock wave banging into your piston on the upstroke. If the fuel burns more slowly (high Octane), you won't get the shock wave, but you won't make any more power, since the energy available is limited.
Thread
Thread Starter
Forum
Replies
Last Post
93truck
1973 - 1979 F-100 & Larger F-Series Trucks
1
May 20, 2015 12:57 PM
