Distributor curve

[CamaroAdam73]

I want to handle the carb issue's after timing if possible, i feel like it's going to be a headache.

I made some more progress today, i gained almost an whole turn out (Richining) with the idle mixture screws before the gains in vacuum/ RPM stopped. I got the vacuum signal at idle (1150RPM) up to almost exactly 14. The signal still wonders but by NO MORE than 0.5" of vacuum. The RPMs went up by 200 to a total of 1300RPM, i dailed it back to a high 1100.


I dialed the vacuum advance back like the instructions said and idle quality suffered. Going Two turns at a time i ended up dialing it back to maximum to achieve best idle results. Is this band-aiding another problem??


After adjustments were made, it runs strong but tries to stall sometimes if i let it idle down. Example, i turned around down the road aways and when i had it in reverse the RPM's dropped down to 500 and it stalled out.

I also noticed when going into gear now i go from 1100 RPM to 600 RPM in gear. I feel like the drop in RPM is letting the dist mechanical advance fall off, timing retards, and engine stalls. Am i right?

Back to the carb issue, i don't have the primary choke pull off installed, i tried to get the secondaries to open today while the car was in park i revved it up to 4000RPM and the flaps didn't budge, arg.

 

[Fox80]

It kind of sounds like you might have more of a problem with the carb, than the timing. Dialing the vacuum advance down for idle isn't bandaiding anything, your motor may not want all the advance at idle. you could try taking a little more out of it to see if it will help the stalling problem, or now that you have the dist set-up correctly you could try the ported vacuum source as well. Your motor may not like the load of being in gear when the vacuum advance is pulling more timing into it. The ported source will apply almost no vacuum to the dis at idle. I think tho that your problem is in the carb, and I am a rookie carb tuner at best so I won't be much help to you with that. I just keep playing with them until it gets better or I have to ask for help, a buddy of mine is a master with carbs.

 

[CamaroAdam73]

I'll try dialing back the vacuum advance again but the engine runs strongest at idle when the advance is in its max position, most advance supplied.

Before i start on the carb ill try ported just to see how it acts

 

[Fox80]

It makes sense that it wants the max timing at idle, most motors do. Going to ported will make the motor suffer on off idle performance. If it were me I would leave the dist where it is and keep playing with the carb

 

[pontiacgp]

takes a few seconds to try it ported so why not try it. If it doesn't help then it takes a few second to change it back

 

[DoubleV]

I also noticed when going into gear now i go from 1100 RPM to 600 RPM in gear. I feel like the drop in RPM is letting the dist mechanical advance fall off, timing retards, and engine stalls. Am i right?

Maybe, but you shouldn't be into your mechanical advance at idle anyway. If you are your idle's too high and/or your mechanical advance is coming in too quickly.

Back to the carb issue, i don't have the primary choke pull off installed, i tried to get the secondaries to open today while the car was in park i revved it up to 4000RPM and the flaps didn't budge, arg.

They usually don't open like that because there's no load.

Maybe I missed it but what carb are you running and what are your engine specs? If you're running the stock compression ratio ( which is under 8:1 ) that's not helping you any considering the size of your cam and the fact it's specifically made to have a choppy idle ( ). If you didn't degree the cam, then that could be making things even worse.

 

[Fox80]

They usually don't open like that because there's no load.Maybe I missed it but what carb are you running and what are your engine specs? If you're running the stock compression ratio ( which is under 8:1 ) that's not helping you any considering the size of your cam and the fact it's specifically made to have a choppy idle ( ). If you didn't degree the cam, then that could be making things even worse.

I agree, your cam and comp. ratio will decide what the motor wants for timing at idle or any rpm. The idea of hooking it to the ported source will tell you if the motor doesn't want much timing at idle, that may be the way to make it run ok if your combo is not quite right. A well built motor with properly matched parts for strong street power usually will run its best with idle timing with manifold vacuum hooked up at around 22-24 degrees, but as Double V stated maybe your combo doesn't match up as well so might take some playing around to see what it wants

 

[CamaroAdam73]

Engine specs..
Olds 403
.040 Over
C/R should sit in the low 9's

350 Rocket heads from 69, had them CC'ed, 66CC
Stock valve sizes
Mild port work

Cam
http://www.compcams.com/Company/CC/cam- ... =1463&sb=0

Lift : 491 / 476
Duration: 278 / 296
Range 2000-5800

Intake
Edelbrock 3711 performer low rise
Range idle - 5500
Dual plane

Ignition
Stock dizzy recurved, DUI DYNA MOD ignition module/ coil.
Moroso adjustable vacc advance
Moroso Pickup

Carb
Factory 800 CFM 403 Q-jet, built to this motors exact specifications

When i built this engine i took allot into consideration and tried to match up specs as best i could with help.
I did degree the cam when i built the motor. I was recommended the cam i have, i would have gone with something less choppy but its what I've got now and i like it.

Tomorrow i'll know my total timing, and what the curve is doing. I'll try ported vacuum and see what the car does in gear. To me 1100RPM seems like a high idle but that's what i was told to set it at and i get a good vacuum signal around 1000RPM.

 

[Fox80]

1,100 is not unheard of for an idle speed for a car with an automatic, the cam you have will probably hinder idle quality. Even the generic rpm range given will show you that off idle performance will not be the absolute best, but you should still be able to get it to run fine

 

[pontiacgp]

I would think 1,100 idle would affect the braking on the car. When i went with a manual it was notice the improved braking without the transmission pushing the car and my idle with the automatic was a little over 700