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Old 05-25-2002, 01:40 PM
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Red face Rough Idle

OK here it is I just installed a comp 292 cam with anti pump up lifters, 289 heads with the works chevy valves (194) trick flow springs for the cam, ported and polished (heads)a tunnel ram intake with a single barry grant 650 carb. on my ford 289, the car idles really rough and throws out white smoke out the exhaust. which pushed me to the head gaskets but, i checked everything i could think of , the oil has no antifreeze in it the antifreeze has no oil in it, the compression checks out ok, a vacuum gauge tells me 5lbs with a little jumping around. I realize the cam is going to give me a rough idle and low vacuum readings, but something is just not right. the timing is right on the money ,the carb floats are adjusted just right i have 6psi pounds of fuel pressure going through a holley black electric pump regulated by a barry grant unit. If the valves are adjust wrong will it cause this? the car fires right up and will hold an idle at 900rpm roughly, and runs cools. Any suggestions I am puzzled I do not no where to look next

[ May 25, 2002: Message edited by: Stevestang1966 ]I also tries antoher carb hoping that maybe it was a vacuum leak and no luck same problem.

[ May 25, 2002: Message edited by: Stevestang1966 ]</p>

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Old 05-25-2002, 01:54 PM
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[quote]...a vacuum gauge tells me 5lbs with a little jumping around.<hr></blockquote>

A reading like this indicates a leak in the air intake somewheres.
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Old 05-25-2002, 02:22 PM
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Are you sure the intake is sealing to the heads. Your vacume is low and the smoke is an indication of antifreeze burning. Was the blocck decked, heads milled, if so the intake may not match -up any longer without machining.
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Old 05-25-2002, 11:25 PM
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The huge cam and the tunnel ram would explain the rough idle. Comp cams website even said "very rough idle" I would think that the vaccum is low because of the tunnel ram. Somebody posted a topic a while ago about the plusses and minuses of tunnel rams. That was one of the minuses, the vaccum is low at low rpms because there is such a strait shot to the intake ports. Also, about the white smoke, is it like pure fog machine type white smoke or just a little bit? Cuz i noticed after i changed the jets on my carberator it was running so rich that i had some white smoke coming out of my exaust when the secondaries opened. Just a thought.
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Old 05-26-2002, 03:26 AM
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Thanks for all the suggestions, I will try to answer everything, the car seems to produce the white smoke a little bit at idle when i give it a good rev it shoots out more not alot like a fog machine, it does have a rich smell to it which led me to the carb, i leaned it out and still no luck i even turned down the fuel pressure thinking it was flooding a bit, but i will change the jets and see what happens.... I ruled out antifreeze because i am not losing any of it and the compression is good, i thought maybe condensation because the car sat for about 4 years without running but it has not stopped smoking yet after about 2 hours run time. the bottom end is stock and never touched (No machine work) heads have not been milled either. As i rev the motor up i get 17Psi of vacuum and then it drops down to about 5Psi if i turn the idle up the car produces more vacuum and i get about 10psi.

[ May 26, 2002: Message edited by: Stevestang1966 ]</p>
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Old 05-26-2002, 03:53 AM
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a higher idle RPM might help because your car is a racecar wich is set up for high rpm
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Old 05-26-2002, 05:40 AM
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idle or no idle, you still hav ea problem of burning antifreeze, it might show up with a coolant system pressure test, and it might not. just because there is no mixing of oil and antifreeze doesnt mean that your headgasket is sealing properly.

here in europe uou can get a test strip to determine wether there is exhaust cases in the cooling sysstem, try that and if that doesnt work.. it athe hard way,

Yank both heads, check and recheck block and heads for straightness. and re-seal the engine, my bet is that your smoke problem will go away.
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Old 05-26-2002, 08:08 PM
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If your running a automatic trans.Check your trans. vacuum modulator valve sounds like your sucking tranmission fluid in your carb.or intake which causes white smoke and probably rough idle (wrenchturner) good luck

[ May 27, 2002: Message edited by: wrenchturner ]</p>
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