Dragula

Just fired the beast up and it ran real good during the break-in procedure....showed about 13:1 air/fuel at 2000-3000.
Problem comes with the idle. I can't get the thing set right.
When I put the carb back on, I left the idle speed the same as the original 383ci, backed the idle mixtures out 1 1/2 turns, and fired her up. Once it started, it would die without the pedal in a bit. I screwed in the idle speed screw until it would run by itself without dying, but it still would only idle reliably at 1200 RPM.
This sounds funky with the relatively mild 274 duration cam in the 383ci. Especially since I had to screw in the idle speed a ways to get the 1200. I backed it down and tried plpaying with the idle mixture to no avail.....it would stumble, die, and sometimes backfire leaving flames in the carb body to be put out with a wet towel
Anyways, has the higher airflow through the engine due to the custom y-pipe and 4" exhaust require me to open the idle speed and uncover the transfer slot? Below that 1200 RPM level, I had relatively NO adjustment with the idle mixture screws. (I haven't taken the carb off to check the slot yet.)
The SA 770 has power-valve blowout protection, but should I stick a new power valve in it to be safe. I know the power valve won't usually effect idle since it is tied to the primary circuit.
No vacuum leaks (since when I unplug a hose it surges a bit showing it to be a rich idle, maybe due to the transfer slot and dripping fuel from primaries I haven't looked in yet due to the popping, but when I attempted to lean it out in an attempt to get more air it would backfire and catch fire like an S.O.B)

Hey Jester.......give me some suggestions.
Should I order some of the pre-drilled throttle blades from Holley and try those?

Odyssey

I'd say double check your timing.

onebad82z

iTrader: (7)

I always go a bit rich on the crews when I fire a new motor...I would go out around 2 turns from bottomed.Then recheck your timing like said above.I had the same issues with my current motor when I broke it in and after all was said and done..my timing was too far retarded.I advanced it and all was good..car idled dead steady at 850rpm.

Jester

Doesn't sound to me like a carb problem. I'll just about guaruntee you either the timing and/or valve lash is off. The backfire that shows up at low rpm's is the clue there.

Just FYI, a blown PV will very much effect your idle. In fact..you're lucky if a car with a blown PV idles at all...but thats not your problem.

Dragula

Thanks y'all.........after dealing with all of that I realized I never dialed the timing back in to 38 BTDC.
It is probably too far retarded like y'all said. I will stick a new power valve in just to be safe.

89formula#1

ok guys i droped my dist. in 8 degrees btdc and when i shot the timing light it was at 8 on the timming marker. nowto adjust my timing witc way woudl i go to advance it? to a lower number such as 4 or 5? also u guys are talkin about 34 degrees? how do u come up with this number and how do u tell u have that much? thanks guys

Dragula

Okay, I re-adjusted the timing to where it was before....38 total with 17 initial all in by 2800 RPM. Still no decent idle when in drive.

Do you think it might be because I took off the vacuum advance can? This is the only thing I have done differently. I'm at a loss now, so I put the cannister back on and will be trying it again today.

A friend of mine said that my distrib might be 180 degrees out of alignment. I am pretty sure it is not, besides, the engine wouldn't run if it was 180 degrees off, correct?

I am thinking that maybe when the automatic transmission load is put on it, it doesn't advance enough without the vacuum advance cannister. What do you guys think?

89Formula#1, advancing makes the number larger, so from 8 go higher. Retardiing makes the number smaller towards 0 degrees BTDC (or just TDC).
To advance the distrib, turn it counter-clockwise, retard turn it clockwise.

Dragula

Still sux.
I have tried everything from 10 degrees initial to 20 degrees.
The higher initial it runs better, but still won't hold idle when put in gear.
Any other suggestions?

crazynights

iTrader: (3)

Dragula,
Your dist. could be off some teeth. So what your reading on the timing mark is not the actual reading of the firing. I'd start from the beginning and bring her up to #1 firing stroke. Check your rotor to see where she's pointing. If it's pointing 100% in the right direction you can rule that out. Then I'd try to put the advance can to see if it changes anything, its' really not that difficult and it's something you can rule out if it still acts the same as before, but I'd try the #1 compression stroke and see where that rotor is pointing.

Dragula

I have had the distributor in and out 4 times, re-doing the curve, so I know it is lining up right.