Is my ignition timing pointer set right?

[SavannahSatellite]

OK I need help, I have a 70Satellite with a 400 from a 72. I have been trying to set the timing at least to factory which is 5btdc. The thing is when I hooked up my timing light up it initially read right at 20btcd,with 0degrees of advance on the gun and engine idle at 1000rpm. I tried adjusting the distributer to get it closer and the engine won't stay running. Now I know that the holley 850dp is way to big but that's what was on it when I bought the car and I don't have the money yet to swap it out but I should be able to get it to run, it was for a while till I messed up and put mid grade in it, that's when the problems started. Its all premium now. What I'm wondering though is the timing numbers on the engine, could they be off and if so is there a way with the engine in the car and not removing the head for me to find and reset the guage for tdc so I can properly set the timing?

 

[themechanic]

This video may explain a lot.

[video=youtube;UYGU7mTwsZc]http://www.youtube.com/watch?feature=player_detailpage&v=UYGU7mTwsZc[/video]

 

[Hemirunner]

20 would have been fine. You sure don't want 5!!

 

[rev.ronnie]

Put a piston stop in on #1 & remove all the other plugs.

Slowly rotate till the piston hits the stop. Mark the balancer.

Slowly rotate, counterclockwise till the piston hits the stop. Mark the balancer.

Split the difference between the two marks and that will be TDC.

 

[brasil]

x2! Works for me everytime. A 100% bullitproof method to check TDC

 

[SavannahSatellite]

Ive seen tha video but thank you. The reason I am trying to go with 5 before top dead center is because that's what the service manual says. If it should be more can some one explain why? 20 seems extreme. I will say that my knowledge of timing and when things should happen is limited but that just seem way to early. I have looked up a lot of articles and watched videos but none of the really get into detail about why you need the spark when you need it maybe understanding that would help. thank for the posts yall.

 

[66Satellite_in_NC]

You want the spark to be set initially for it to fire when the piston is at the top of the intake stroke, too early and you have pre-detonation which is not good for the motor/piston. Too late and the piston is already on the downward stroke and it will have lost the ability to harness all of the power from the ignition of the fuel.

 

[70rr-brian]

20 seems extreme.

Actually, the difference between 5 and 20 isn't as much as you might think. If my math is right, at 900 rpms, that means the spark is happening 2/1000ths of a second sooner at 20 versus 5.