Dual Quad 428 CJ

[Khobra]

Originally Posted by patrickt

OK, you know, "eye burning" in the garage is a sign of too lean a mixture, not too rich. In a lean idle condition you do not get a complete burn and raw gas heads out the exhaust. That's why your eyes burn. Just thought I'd pass that along....

Thanks Patrick,

By advancing the time there is more time to burn the fuel. Hence, a cleaner, sweeter smell. Assuming that the condition was rich, would you not agree?
Much has been written and posted about throttle plates exposing too much transfer port thereby causing a rich idle. The solution has always been to close the throttle plates a bit to limit fuel flow from the transfer ports at idle.
By advancing the timing I was able to close the throttle plates at bit and achieving my desired idle speed of approx 950 RPM in neutral and also giving the fuel more time to burn.

[DanEC]

Originally Posted by Khobra

Thanks Patrick,

By advancing the time there is more time to burn the fuel. Hence, a cleaner, sweeter smell. Assuming that the condition was rich, would you not agree?
Much has been written and posted about throttle plates exposing too much transfer port thereby causing a rich idle. The solution has always been to close the throttle plates a bit to limit fuel flow from the transfer ports at idle.
By advancing the timing I was able to close the throttle plates at bit and achieving my desired idle speed of approx 950 RPM in neutral and also giving the fuel more time to burn.

That sounds like a reasonable, thought-out approach to me. I've probably never had a car with a carburetor that idled lean so I wouldn't know if burning eyes is a sign of that or not. If it worked, it worked.

[patrickt]

Sounds good to me. After 40 years of adjusting carbs every which way you could think of, two years ago I tried a method recommended by an 80 year old ex-Ford mechanic and had used this method on my exact carb and my exact cam back in the early/mid 60's. The method sounds so goofy that I won't even bother to recite it here, but it absolutely worked better than my vacuum gauge or the "just guessing" method by backing the screws out the same amount.

[Khobra]

Originally Posted by patrickt

Sounds good to me. After 40 years of adjusting carbs every which way you could think of, two years ago I tried a method recommended by an 80 year old ex-Ford mechanic and had used this method on my exact carb and my exact cam back in the early/mid 60's. The method sounds so goofy that I won't even bother to recite it here, but it absolutely worked better than my vacuum gauge or the "just guessing" method by backing the screws out the same amount.

Patrick, I would love to hear about this method you speak of. Would you take the time to post please.

[patrickt]

Originally Posted by Khobra

Patrick, I would love to hear about this method you speak of. Would you take the time to post please.

He told me that at the Ford dealership where he worked for umpteen years, the way they adjusted the 427 engine with the high overlap 324 degree solid lifter cam with the single four barrel carb (my setup exactly) was this: Turn the idle screws all the way in, back them out an equal amount for both, say one and a half turns, keep the rubber cap on the manifold vacuum port. Start the car and get it to running temp. Then adjust the carb screws equally so that when you pull the rubber cap off the manifold port the idle neither increases nor decreases. It sounds too simple to work but, I have to say, I am a convert.

[Khobra]

Originally Posted by patrickt

He told me that at the Ford dealership where he worked for umpteen years, the way they adjusted the 427 engine with the high overlap 324 degree solid lifter cam with the single four barrel carb (my setup exactly) was this: Turn the idle screws all the way in, back them out an equal amount for both, say one and a half turns, keep the rubber cap on the manifold vacuum port. Start the car and get it to running temp. Then adjust the carb screws equally so that when you pull the rubber cap off the manifold port the idle neither increases nor decreases. It sounds too simple to work but, I have to say, I am a convert.

Well, as what was said previously, whatever works. Sometimes we just have to think outside the box.

[patrickt]

Originally Posted by Khobra

Well, as what was said previously, whatever works. Sometimes we just have to think outside the box.

Yep, I don't even bother mentioning it to others.