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Author Topic:   Warming up until Car will idle
posted June 17, 2003 06:57 AM
I just rebuilt my motor, a Chevy 406.
Before rebuild in about a minute the motor would idle on it's own.
This car is a stick.
Last night the car went for near 5 minutes and still didn't idle on it's own.
No I didn't check the timing or idle speed yet. I beleive it's the same as last time right know.
With the new rebuild I install a single plane Torker II intake, and a pair of 220cc Pro heads.(did have dual plane high rise boat intake with a pair of 461 heads)
Would this take bigger jets, more or less timing, or more idle speed?
Just looking for things to check

posted June 17, 2003 01:11 PM
Seems like just about anything you do when induction or exhaust are involved requires alittle bit of tweaking.I went from a 4 hole 1/2 spacer to a open 1" and had to reset idle speed.I would get my basic stuff set up idle speed and timing then try it to see how it runs before any major changes.

posted June 17, 2003 02:28 PM
With a race motor, what kind of idle does everyone set them up for.
I believe I set it for about 1,000 rpm.
Does this sound right?

posted June 17, 2003 06:02 PM
i have mine at 1200. anyway i'd look at my float level or maybe fuel pump.

posted June 17, 2003 06:30 PM
Your idle will be dependant on if you run a stick or auto .If your advance isn't locked on the distributer and you have the Idle set to high it might be advancing timing at an idle.I run a stick and it idles about 1200 and I use the mechanical advance in the distributer.I don't know if there all the same, I run msd dist. with msd box and the tach seems to have trouble reading below 1000.(auto meter 5")

posted June 18, 2003 07:04 AM
50cc more intake port= lots less low rpm signal to carb. Open plenum intake= LOTS less all around signal to carb. Your idle will definitely have to be reset, and assuming you had a pretty good tuneup before, you will probably have to go richer on main jet(start about 6% richer, 2 Holley sizes). Total timing will stay the same (37deg). The open intake will want a lot of advance just above idle. Have it all in by 2500 or so, if you are not doing that already. As dirtracer7 said, take care of your baics first. Here's a thought re: idle speed: the lower it is set on the track, the better engine braking you will have entering the turn. Ever see that flame out of the pipe when a Cup driver picks up the throttle (not the trailing throttle flame, everybody has those). A dime to a dollar, they are set up to close throttle blades completely on turn entry.

posted June 18, 2003 08:03 AM
monster is right on the closed throttle blades will help the car turn on entry by dragging the rear tires and you will need less braking. that's why you hear the cup guys revving the crap out of their engines during the pit stops.....if they were to let it idle, it would probably die.

posted June 18, 2003 09:16 AM
I do have a performance distributor, but I do have the vacuum advance still set-up.
Should I also plug the vacuum port on the distributor and just use the weight's on this.

I was thinking the open intake would take some more idle speed.

posted June 18, 2003 10:51 AM
I would do away with the vacuum advance right away. And i would also lock up the mech advance but that is my personal preference. As for idle speed i would not go any lower than 1000rpm. We idle our mod at 1500. Remember that the only oil the cylinder walls and cam gets is from splash thrown off the crank. If you idle is too slow you wont get as much oil splashed around. On the other hand dont go overboard either. i would say 1200-1500 is about right.

If you have trouble with it idling you might need to adjust mixtures and idle speed screws, but it is not uncommon to have to bump up the ildle ***** while the engine warms up. Give the ***** a 1/2 turn or so then turn it back before racing. Or i will stick the end of a zip tie or a few feeler guages in between the ***** and stop, then just pull them out when she gets warm and your back to normal.

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