Im helping my friend try and get his coupe to run...its a 327 that was rebuilt just before he bought it, but the guy who did it has no idea about mechanics...his brother is a mechanic, but who knows of what caliber? Thats the problem with buying something you dont know about. It seems to run OK, although very very rich, above 1500 RPM or so, but it just will not idle below that. We had 3 different carbs on it (all were known to be good) removed the intake (Holley Commander i think) checked it for cracks, and replaced it with new gaskets. Set the timing...its a new HEI dist. Wires are good. Lots of fuel. The only other thing I can figure is, if these other guys installed the cam quite a bit off, would this do it? I mean, would it still run at all, or run at higher speeds but not idle? We're both at a loss at this point. There is about 18" vacuum at this high idle speed. Thanks, John

John, there comes a time when you should pay a visit to your friendly local mechanic of good reputation. That time comes when you are dealing with something of questionable background and your ministrations are going nowhere.

Well, three known good carbs should eliminate that tack - actually one known good carb would have been sufficient.

I do however have a hunch on what ails this 327. I'll bet that timing is the issue, plain and simple (you did check the distributor for proper operation?). Perhaps even to the point that the non-mechanic engine rebuider didn't properly position the balancer (left out the woodruff key), or that it has the wrong timing tab or dampener for that engine. Here's what I want you to do before you cart it off to a shop: loosen up the distributor clamp, twist the distributor in the direction that increases engine speed with nothing else being changed, tighten dist clamp back down, now see if you can reduce the idle speed successfully.

Thomas

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"Bomber" '67 El Camino, Beater comes back to life.
Was 350/TH350 14.90 @ 93mph, 360,000+ miles on car.
Now 406 roller, 340rwhp, more hp coming, 3.08 gears.
Street radials, left in drive, 13.20 e.t.@108.35 mph.
8/1/01 added Plum Mist '67 to collection
ProCharger D-2R 468 under construction.

Thomas, thanks for the reply...I guess I didnt mention this..the car came with a dual point type dist....which we tried the timing and dwell on first. When my friend replaced the intake and gaskets, thats when he went with the HEI...it does exactly the same thing with either one..I tried retarding the timing while it was running, but as soon as you hit about 1200 RPM it starts to stumble and stalls. When you set the timing to where it should be (I agree, the tab could be off, or the balancer, but wnen it starts good and runs) and you just back off on the idle speed screw, it does the same thing. He's ready to yank it out adn pull the engine apart, but Im just trying to cover the bases first. But it looks like we did. Thanks again. J

Johnny, does he know if its a mechanical or hydraulic cam? Last base I would cover is the valve adjustment. When I was a kid and only had mice, I torch cut the center out of a valve cover which made valve adjsutments ( hyd) a 10 minute job at best. Heck you can tin snip it out.

Just a few thoughts, in order from easiest to hardest to check --

You've got a vacuum gage -- how much vacuum at lower idle speeds, before it stalls?

Any unplugged holes in the intake, creating vacuum leaks?

The "very, very rich" part of your post concerns me -- you said these are "known good" carbs? How do your plugs look? Maybe float level is off? Are the carbs Edelbrock? They don't like much inlet pressure; do you have a regulator to go with the brand new fuel pump on that rebuilt motor? Easy test -- get the motor running (at your fast idle). Pinch off the fuel supply line. Now adjust the idle speed down -- does it still stall; or run OK until the bowls run dry?

Easy enough to check cam timing. Put a magnetic base dial indicator on the #1 cylinder, and rotate the crank through TDC by hand.

Remember, this is FUN. Right?

Cheers,
mark.
'71 Fodor
"Soon to be... 383"

Thanks for the replys guys...Gene, thats a good point...dont know what type of cam, Im guessing hyd, but it wouldnt hurt to pull the valve covers and just watch the rockers to see if they're all doing the same thing!! Then we can check the lash.

Mark, the lowest we can get it to idle is where the 18" is...cant go any lower or it stalls. There are no uncovered vacuum ports or holes, we check very many times. The plugs are wet and black, smell like gas. The carbs were #1, 600 Edelbrock, brand new, came on engine. #2, 750 Edelbrock, mine, just to see if it made a difference. #3, 600 Holley, and it ran just the same with all three. However, the fuel pressure might be a problem. He's gonna check the pressure at the inlet to the carb. There is no regulator, but the fuel pump is a little tiny square box, cant see a name of any kind on it. Its noisier than a Holley!! But then, they mounted it right on the metal, no rubber bushings. So that will be the next check. Yeah, this is so much fun. The only consolation to me is that it's not MINE!!! Of course, I have my own issues too!! Thanks again to everyone so far. We'll see how it goes. John

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Eat dessert first, cause life is uncertain.

John's ride 1 (http://www.chevelles.com/showroom/johnnyosride1.jpg)

Interior (http://www.chevelles.com/showroom/ncinterior.jpg)

I think that a vacuum leak is your most likely cause of difficulty. I've seen this
problem several times and had much difficulty
finding the cause.
Once it was a rusted power brake
cannister which wasn't too visible but caused
a major vacuum leak. The other was a busted vacuum advance diaphram. Might be worth checking ???

Ron, I agree, it sounds too much like a vaccum leak...but we checked and checked...good point on the brake booster though, I'll pass it on...John