340 Tuning - I need advice

-
Please bare with me here... If I advance the timing to 20 - 25 will I have pinging problems, and wont that further increase my idle? I have my idle set screw all the way out right now... will I have room for more adjustments? Maybe I am doing something wrong...

Also I don't know how to use a piston stop... any more avalible info on that?
 
Robb said:
Please bare with me here... If I advance the timing to 20 - 25 will I have pinging problems, and wont that further increase my idle? I have my idle set screw all the way out right now... will I have room for more adjustments? Maybe I am doing something wrong...

Also I don't know how to use a piston stop... any more avalible info on that?
Click to expand...

If I had to make a guess, and it is only a guess, I'd say you are way way way off timing. You can't even begin to tune the engine if you not on the idle circuit on the carb - indicated by the fact that no matter how you tune the carb it does nothing ... if I understand you right.

At this point I would disregard your timing marks and set you idle speed screw in till it touches and turn you distributor very very slowly in one direction at a time until you feel the engine settle down - don't even look at the timing light. Are you sure your distributor is not in 180 degrees off? ... because it can go in either way. If no matter how far you turn it makes no difference, than my guess is likely wrong and you have a vacuum leak you have not found yet. If not, at that point, do you have another distributor you can try? Are your wires all good?
 
The wires are new, and I am not sure about being 180 out, but if it is, it has been that way a long time...

I will work on increasing the timing advance tonight and report back.

Thanks Everyone!
 
When you put your finger over the spark plug hole to find compression TDC, is your timing mark in the right spot at the top of the stroke?

Early balancer and late cover, or vice versa, would create some havoc here.
 
crackedback said:
When you put your finger over the spark plug hole to find compression TDC, is your timing mark in the right spot at the top of the stroke?
Early balancer and late cover, or vice versa, would create some havoc here.
Click to expand...

I haven't physically verified TDC yet, but I may need to. Also I think my motor is all 1969 except for the cam and carb. How can I verify?

Update: I spent some time tonight trying to re-time and tune the carb. Going up as high as 20-25 didn't seem to improve much or make it smoother. I wound up at about 15 degrees advance but it still stutters a little. If it is anything like last time it will be real shaky next time I run it...

New question: Is there an air gap setting on the pick up coil???
 
Don't forget to use brass feeler guages and look at the plate as you tighten the hold down as they will move sometimes due to the design.
 
bigdemo1 said:
Don't forget to use brass feeler guages and look at the plate as you tighten the hold down as they will move sometimes due to the design.
Click to expand...

Why a brass feeler guage? That's something new I will have to buy, but just wondering why...
 
Robb said:
Why a brass feeler guage? That's something new I will have to buy, but just wondering why...
Click to expand...
Brass is non-magnetic . (Pick-up coil has a magnet in it)

I would recommend doing a compression check all 8 cylinders (throttle wide open) to rule out any mechanical issues .
 
How sure are you the firing order is right? Specifically 5/7? Should be 1 8 4 3 6 5 7 2 in a clockwise direction IIRC. #1 should be the forward most terminal on the cap, offset slightly to the driver's side. Some caps have this positioned marked with a "1" on the top of the cap.
 
yes I have verified the firing order a couple of times, and I may run a compression check, but wouldn't my vacuum guage show internal problems as well?
 
Robb said:
yes I have verified the firing order a couple of times, and I may run a compression check, but wouldn't my vacuum guage show internal problems as well?
Click to expand...

A vacuum gage will show mainly problems with intake valve but a compression gauge will show a dead or weak cylinder as well as cylinder to cylinder balance then I usually follow up with a leak-down % test to pin-point how bad the valve or ring seal is.
 
Yes your vacuum guage will show internal problems.
 
You must log in or register to reply here.
-

Back
Top