What is the idle set on 85 GT

[MY 85 GT]

I had the idle set at 1000 rpm's it seemed a little high now i have it set at 850 -800 rpm's it seems low to me...the car sound nice it has a nice exhaust note for stock exhaust...u know thats what the sticker says to adjust it to also..it is a 5 spd...so does these cars have a lopey sound to them stock...i mean when it was at 1000 rpm's it seemed to have no lopey sound almost like it was idling to high ....now it seems to drive fine no problems but im just wondering if that is normal the car has a slight rumble tis way and shakes a little at idle not a bad shake...lol like it has a cam in it...so is that ok?

 

[battyice]

800 rpms should be fine. Your car should idle smoothly with a stock cam. If you are concerned with the lope/shake and you know that the camshaft is stock, I would start looking at your ignition components.

 

[MY 85 GT]

All the ignition parts are new..if i bring the idle up to 1000 rpm's its smooth as glass...only when its around 800 or so it has that lopey feel to it....but as soon as you give it gas its smooth as silk.....im wondering if it has something to due with fuel..i have a 650 cfm carb and a carter high volume fuel pump 120 gallons per hr with a max rate of 6 psi...so im thinking it could be running a little rich at idle???

 

[85_SS_302_Coupe]

As long as you're sure it's only 6psi then the fuel pump isn't going to cause it to run lean. Have you done any jetting to the carb? Have you checked for vacuum leaks? That'll make it sound lopey. Have you adjusted the curb idle yet? What kind of 650 is it (Holley, Edel, Barry Grant, vacuum secondary/mechanical secondary, choke or no choke) I usually have mine idling around 6-700rpm...i like mine pretty low. As long as it doesn't stumble off idle then there's nothing wrong with 800. There's nothing wrong with 1000 either, that's pretty typical for most engines.

 

[battyice]

What type of carb are you running?

In any case, you need to adjust the idle fuel/air mixture screws. Most carbs will run out-of-the box but need to be fine tuned.

A vacuum guage is argueably the best way to adjust the mixture screws. With your idle speed set, you connect the guage to a manifold vacuum source and adjust the mixture screws in equal amounts until you achieve the highest vacuum level. Re-adjust the idle speed as necessary.

If you don't have a vacuum guage, you can do the same thing by watching the tachometer/listening to the engine speed.

Make sure your engine is at operating temperature (with choke open) before you adjust anything.

One more thing, what is your ignition timing set at?

 

[MY 85 GT]

Sorry its an edelbrock thunder series 650 cfm electric choke....the carb was set with a vac gauge thats the only way i set them...i put in a sifter set-up spring that was it didnt touch jetting or metering rods yet....My timing is set high probably around 18 degrees BTDC....i think i will re-adjust the carb today when i get home i drive 25 miles mostly highway so it will be warmed up alot...so i will check it..I have no bogging ..no hesisation...just idles a little lopey....at 800 rpms...like i said if i have it at 1000 rpms its smooth....

 

[battyice]

What did you do with the factory emissions/egr when you swapped to the Edelbrock? Make sure you don't have any vacuum leaks.

All in all it sounds like you have everything set up pretty good. Might just be the nature of the beast.

Just out of curiosity, why did you ditch the OEM holley?

 

[85_SS_302_Coupe]

I think it should be fine. Unfortunately my advice stops when it comes to Edel carbs...never had one.

 

[MY 85 GT]

What did you do with the factory emissions/egr when you swapped to the Edelbrock? Make sure you don't have any vacuum leaks.

All in all it sounds like you have everything set up pretty good. Might just be the nature of the beast.

Just out of curiosity, why did you ditch the OEM holley?

It had an edelbrock 600 cfm on it when i bought it i put the 650 cfm on it.....`i might go over it again this evening to make sure its adjusted perfect.... i just hope it gets a little smoother at idle it kinda sounds like it has a cam now tho...lol

 

[Fast63]

How much vacuum do you get at an idle? I have mine idling at 750 rpm, seems to do well there.

My experience, with the OEM carb: It is a piece of stinking junk. Sure, it might have worked great coming off the factory floor, in 1985, but they don't age well at all. I tried everything, including two rebuilds to get my factory one to work right, and it never did. I even bought a remanufactured one from holley, and I am still not happy with that one. That's my guess as to why the OEM carb was ditched for the edelbrock.

Regarding your question about how lopey it is, what do you call lopey? The stock cam doesn't lope, but it doesn't purr with one constant tone that never changes either.

 

[MY 85 GT]

Thanks guys for the info ..I went home last nite and re-adjusted the carab again...with the vac gauge..i have 20" of vac at idle..i adjusted it for the highest level of vac the idle now is about 950 and it runs very smooth now...when i mean lopey sound i meant like it has a hot sound to it ...but like like a big cam...just a nice tone to it and before i re-adjusted the carb it was running rough now its running smooth....i just wish i could get the idle down a little more but i think the stock linkage is holding it back from me getting an adjustment...the idle screw is off the carb stop a hair so thats how i know its the stock linkage holding the idle higher any way to adjust that??

 

[curtisboyte]

wish i could help, i never have had a edelbrock carb either, When i replaced mine i went back with Holley. Let us know what you find. Thanks

 

[Fast63]

If your idle screw is off the stop and it won't idle any lower, there is something wrong. Can you push down on the throttle arm to make it idle lower while the screw is off the idle stop?

 

[MY 85 GT]

If your idle screw is off the stop and it won't idle any lower, there is something wrong. Can you push down on the throttle arm to make it idle lower while the screw is off the idle stop?

If i push the carb linkage down it will idle lower if i take the linkage off i can adjust it to an idle speed so i know its not the carb i think the stock linkage is holding it back...i wish i knew how to get some play in the stock linkage..then i can adjust the carb stop from there....