Re: Thermoquad secondary tuning?
[Re: ragtop]
#1100965
03/01/12 04:58 PM
03/01/12 04:58 PM
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Joined: Mar 2007
Posts: 9,336 South-Central (Sebring), FL
Commando1
master
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master
Joined: Mar 2007
Posts: 9,336
South-Central (Sebring), FL
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Quote:
...says that some bogs cannot be tuned away unless the air door is tight against stop. He was right.
I just installed a new TQ from Scott @ Harms on my bone stock '76 440 (GREAT job, Scott, BTW). The engine never ran smoother except for a slight bog upon stepping on the accelerator. Because of this thread, I went to check on the secondary air door gap. It was dead on according to what you guys described. Frustrated, I noticed something. The bowl vent lever arm.
Picture no. 1 shows the position as it was on the new carb. Picture no. 2 shows it as it was on my old carb. I repositioned the lever on the new carb to the same position as the old carb and the bog went totally away.
I'm no genius on this stuff and I have no idea what I did and why it worked but I had to throw this out there to you guys.
Pic #1 (lever position similar to the new TQ):
Pic #2 (lever position that is on old TQ):
but it cured the problem.
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Re: Thermoquad secondary tuning?
[Re: Dave Watt]
#1100966
03/01/12 06:45 PM
03/01/12 06:45 PM
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Joined: Jan 2003
Posts: 3,704 MICHIGAN
DynoDave
master
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master
Joined: Jan 2003
Posts: 3,704
MICHIGAN
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Quote:
Quote:
How does one determine this orifice size? Photo?
I have a tiny drill bit set that is #60 (.039") through #80 (.0115"). Some hobby shops have them. Just keep inserting a drill in the orifice hole until you get to a drill big enough that it won't go in anymore. No photo, sorry. I'll try the next time I work on it.
Quote:
Did you make this restrictor? Picture?
I found a 3/16" diameter plastic rod, drilled a .013" hole in the middle, then inserted it in the vacuum line.
Awesome. Thanks Dave. I was thinking maybe it was stamped somewhere or something.
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Re: Thermoquad secondary tuning?
[Re: DynoDave]
#1100969
03/03/12 10:20 AM
03/03/12 10:20 AM
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Joined: Feb 2003
Posts: 609 NY
old340dog
mopar
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mopar
Joined: Feb 2003
Posts: 609
NY
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Thanks for the great information and tips. This will be a great aid to me and others.
old340dog
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Re: Thermoquad secondary tuning?
[Re: Dave Watt]
#1100976
10/28/13 04:27 PM
10/28/13 04:27 PM
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Joined: Nov 2003
Posts: 5,048 Atlanta Indiana
Dave Watt
master
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master
Joined: Nov 2003
Posts: 5,048
Atlanta Indiana
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I wanted to bring this thread back up. There are a few things that might help guys out. Some of the carbs I've bought were completely stuck. A propane torch and PB Blaster can help remove some really stubborn screws, idle mixture screws, and loosen the throttle shafts. Heat the area around the stuck screw or shaft, then shoot the area with the Blaster. Apply more heat until the area is smoking again, you might see the Blaster bubbling up which is great, shoot it with more Blaster. It may take 5 or 6 tries but eventually you should be able to remove anything. Be patient, don't force the screw or it will just break off. The Blaster will flame up but nothing scary. Work in a well ventilated, open area away from things that can burn.
Finally worked with the choke pull-off adjustment enough at the track that the carb doesn't bog anymore. The car has run 13.90 @ 101MPH at our local track, and 14.12 @ 99MPH during the Pure Stock Muscle Car Drags.
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Re: Thermoquad secondary tuning?
[Re: Dave Watt]
#1100977
10/28/13 10:27 PM
10/28/13 10:27 PM
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Joined: Jan 2006
Posts: 419 NY
F1Scamp
mopar
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mopar
Joined: Jan 2006
Posts: 419
NY
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Good tips Dave. Sometimes it doesn't seem to matter how much you want them to come apart, they still don't want too. I experienced the dredded bog for the first time with the Duster at MIR. One pump shot adjustment and the next pass it was blowing the tires off again.
Work In Progress- 71' Duster F.A.S.T.- 10.36@130 Smallblock Record Holder.
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