Just want to double check my timing. I have a 68 block with aluminum heads and a 268 comp cam. I have heard to put it at 12°. Is that good for this combo?
thanks
Each combo is different. Some of us run 20-24. Set it to what runs the best. If it still cranks at 12 ( it should), it's fine as long as your total timing does not cause the dreaded "ping"
Yeah, back it off if you get pinging. Sometimes aftermarket heads have better chambers than stock so one might actually run less advance than w/ stock heads. Going up into the 14 degree range may necessitate premium gas. If you dont need preium already, dont start buying it just for a little timing.
I believe its a motorcraft dizzy with single points and vacuum advance.
Am I doing it correctly by unplugging the vacuum hose and setting the timing at 12° at idle speed or do I need to increase the RPM's ?
Its been a while since I last adjusted the timing on a car.
I have a Mallory Unilite dizzy on the shelf somewhere and will install that at a later time.
initial timing is your timing with no vacuum or centrifugal advance, at around 1500 rpm's or thereabouts. whats supposed to happen with a vacuum advance is that as you rev your engine and increase load on acceleration the vacuum advance will start to advance your distributor to your total timing, which is usually around 30-40' advanced. this helps give you more performance. a mechanical advance does the same thing, it just uses the speed of the distributor as a guide to advance the timing. you need to set initial timing with the hose off of the distributor that way you dont get any advance. newer cars are the same way, its just that the computer controls the advance. historicmustang is right, total timing is most important. thats why alot of people lock out there timing with a total advance.
chech you total timing when you check / adjust your initial.
Say if you set your initial at 12* (with the hose off the vacuum advance.
then put the hose back on, hold the rpm's around 3500rpm, read your timing.
(this is your total timing)
should read between 34-40?
each engine requires a little different timing, I cant tell you exactally what it should be.
You should start a post asking what your total timing should be. List all of your engine parts etc. etc. Im sure someone has a set up similar to yours and they can reccomend a total timing number.