I've been playing with the idle speed on my 79 302 since it was (admittedly) set too high when I got it. Right now, it idles in park with NO compressor on at about 1150-1200. Drops to about 1100 or so in park with the compressor on. With NO compressor, it drops to about 750-800 in drive and 650-700 in drive with compressor on. In drive, with compressor on it feels like it wants to die, but only did once when the engine was warm. It seems like quite a drop from park to drive. Is what what everyone else is experiencing?
When i had automatic in mine i had it set to 1000 rams. I wonder if there is something else going on.
I had an...A/C fast idle solenoid...on my 302. it bumped the idle up 200 RPM when I turned the A/C on... you may need a little more stall in your converter...
Hmmm, my idle drops when I turn on the compressor. Maybe I don't have the solenoid or it isn't working. Either way I have near future plans to upgrade my intake and carb... Is my 268H cam also messing with the idle?
Likely at least if you have a stock converter... I went with a 2000/2200 converter on my Comet for that very reason and my cam has a little less duration...
I'll check into that... May be something I need to learn to deal with until I can get around to thinking about the converter...
that cam isn't big enough to need an aftermarket converter to keep from stumbling with an AC on. You have fuel mixture and/or timing issues going on there.
X 2 on the above two posts. You may need more spark advance and/or more (richer)fuel mixture. It should idle without dying in gear with the A/C on
Alright fellas I finally got ahold of most of the things I needed in my garage to do some testing. This may be a long-winded post but bear with me. This is a 79 302 from a Granada, installed in 77 Maverick clone that looks mostly like a 72. The engine came with all the EGR stuff but that was all removed. Stock intake and Autolite 2100 carb. Comp cams 268H cam with the following specs: Operating Range: 1500-5500 RPM Duration Advertised: 268° Intake / 268° Exhaust Duration @ .050'' Lift: 218° Intake / 218° Exhaust Valve Lift w/1.6 Rockers: .456'' Intake / .456'' Exhaust Lobe Separation Angle: 110° I checked the vacuum at the "T" behind the carburetor by removing the "top" of the T that goes down to the transmission. Hooked up my gauge and had about 14.5" at the 1000 RPM idle I'm set at. This was with the vacuum advance disconnected and plugged at the distributor. I checked both fuel mixture screws (what a pain!) and both are about 2 rotations out and didn't seem to affect vacuum to any appreciable extent. Timing was at 8* so I slowly advanced it and now sits at 20*. I have the idle set at 900 and it sounds pretty good. Going into gear drops it to about 700 and still sounds pretty good. At 8*, 700 was rough and it would stumble every few seconds and recover. Now no stumbling. At 20*, in D, 700 RPM, when I hit the AC, it drops to 600 and is pretty rough, stumbling a lot. Though it didn't die in my garage, I suspect it will at a red light knowing my luck. At the above settings, at 900 RPM in park, I was getting about 17-17.5" of vacuum WITH the brake booster plugged off. With the brake booster hooked back up, I lost 1" on the vacuum gauge. Spraying the plastic joint with carb cleaner did not affect the idle. Does anyone have anything else to try given this information? What I haven't done is disconnected ALL vacuum systems to determine if there is any sort of leak, I was more of piddling today. I DO plan on swapping out the intake and carb to a 4 bbl but in the mean time I'd like to figure out why I'm dropping an extra 100 RPM with the AC on and why 600 rpm is so rough/dying. Thanks!
In spite of what the other posters have said, I'm still going with a looser converter and NO DOUBT will have to idle that cam at about 800 RPM with A/C on & in gear... If you want it to idle smoothly at 600 RPM in gear you'll have to swap cams... Here's what Comp says HYDRAULIC FLAT TAPPET: Good for daily driven performance vehicles. Mid-range power. Slightly lower gears. Mild rough idle. Hyd Hyd 1500-5500 31-218-2 268H
Thanks for your input sir. The rough idle is fine and I'm not stuck on 600 I just think it revs too high in park but maybe it's supposed to. What I'm more interested in is how my vacuum readings and timing sound to yall?
850 to 900 RPM at idle (Neutral/Park) is fine. Dropping 100RPM with the A/C on is to be expected unless you have the solenoid to increase it when the A/C is switched on. A friend of mine has the Comp 268H in his Maverick with a stock converter. No problems whatsoever. 20° initial timing is a bit much. At your altitude (Louisiana), you should be more around 12° (factory setting was 6°). If adjusting your air/fuel mixture screws is not making any changes, something is wrong. Check the float level on the carb while you're tinkering.
