318 Timing

[gold75duster]

I have just installed a edelbrock 600 cfm carb and edelbrock intake on a stock 318 75 Duster and am having troubles getting it dialed in.

I am having the car slightly hesitate. It just doesn't seem to be wanting to go like it should.

I tried various timing adjustments and currently have it set at 5 degrees advanced which seems to be were it idles the best. Is anybody running the same or a similar set up that has had better luck with a different timing setting?

I have tried to set the air / fuel mixture but no matter how much I tighten the air / fuel mixture screws on the primaries and secondaries I can't get the motor to stall.

Any ideas? I am at 3500 feet above sea level. Am iI looking at swapping out jets / rods to get this thing to run right.

I am a novice at this so any help would be greatly appreciated.

Thanks

 

[Flatlander]

Welcome and good question. I'm sure someone will have the answer.

My eddy on a 273 is running rich, still messin' with it.

 

[gold75duster]

Thanks Flatlander.

Another question for anybody out there:

I just took it around the block and it idles at first but misses under load and smokes a lot and sputters on start up (too rich?).

It is equipped with the electronic ignition. Can anybody tell me if it has vacuum at idle or not?

There are two ports on the Edelbrock carb one for distributor advance with vaccum at idle and one without. I have tried both but can't seem to get it sorted out.

I think I am playing with too many variables and need to start eliminating them systematically.

Is is safe to assume that once I figure out the vacuum / no vacuum at idle and get the timing set up propoerly that then I can start trying to adjust the carb?

 

[Demon 408]

You will need a timing tape or dial back timing light to check timing and a vacuum gauge and tach to adjust carb.

If the car ran good before you put on the new carb/intake then why did you adjust the timing? Where was it set to and can you set it back to that setting?

Make sure you don't have a vacuum leak (another good use for vacuum gauge). Possibility if you didn't get new intake or carb sealed correctly. If you have a vacuum leak the gauge will flutter all over the place.

Timing at 10 BTDC would be a good start, check with vac adv unhooked/hose plugged and engine at curb idle speed. As long as it does not ping or want to kick back when cranking you may be able to get 12-15 BTDC. Check your total timing, you don’t want over 34/35 degrees, again with vac adv unhooked/hose plugged engine at 3200 RPM when checking total. On where you should connect vacuum advance; you will get different opinions on this one. My opinion is to connect it to a carb port that has vacuum at idle.

You have your idle screw (not mixture screws but the screw on the side connected to the linkage) turned in to far that's why your idle mixture screws are not working. Get your timing set first and then your carb. Vacuum leak will make it impossible to get carb adjusted properly.

Good luck.

 

[gold75duster]

Thanks for the advice Demon 408.

I had to pull the distributor as it the o ring was shot and it was leaking oil down the back of the engine. I marked everything and was carefully to put it back to close to where it was but I am figuring with the new ingition box and carb / intake the original timing may not be right for this new set up?

Which port should I be connecting the vacuum gauge to measure vacuum? I am assuming the one on the carb for vacuum advance at idle?

Thanks

 

[Demon 408]

Thanks for the advice Demon 408.

I had to pull the distributor as it the o ring was shot and it was leaking oil down the back of the engine. I marked everything and was carefully to put it back to close to where it was but I am figuring with the new ingition box and carb / intake the original timing may not be right for this new set up?

Which port should I be connecting the vacuum gauge to measure vacuum? I am assuming the one on the carb for vacuum advance at idle?

Thanks

I don't think this new set up will necessarily change your timing requirement, depends what it was set to before. But for now I would put it back to where it was for a starting point and to eliminate one possible problem. Connect the vacuum gauge to the port that has vacuum at idle, if you have the carb off the car this will be the port that enters the throat of the carb below the throttle blades (manifold vacuum).

The following link will help with reading vacuum gauge. Remember though, low vacuum readings are common with large overlap camshafts. But I beleive you are running a stock cam so you should have normal vacuuum reading.

http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm