# Oh my - bye bye bog



## BearGFR (Aug 25, 2008)

Been struggling for awhile now trying to get a bog out of the Beast. I've had the carb apart more times than I can count, read and re-read everything I could get my hands on from Lars, Cliff Ruggles, Doug Roe --- talked to a guy in the local Pontiac club who's really supposed to know his stuff. Nothing seemed to work. Air valve tension loose, air valve tension way past tight, play with accelerator pump, play with rods, hangers, jets.... no matter what I did, not only would it not go away and act right, but nothing seemed to change it.

Know what it took to fix it? A one-inch long strip of electrical tape.

I just got back from a little test.
Hold the brakes, tach to 2000 rpm, off the brakes and hit it. No bog, no stumble, no nothing --- just power and two VERY unhappy drag radials.

Oh yeah.... :cheers

Bear


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## geeteeohguy (Feb 2, 2008)

Great! So what _WAS_ IT??? You're killin' me!


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## AlaGreyGoat (Jul 6, 2006)

OK, I'll bite....
Where did you put this one-inch long strip of electrical tape???

Larry


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## lars (Sep 28, 2004)

OK... I'll be the first to guess:

He taped the notches in the secondary airvalves to eliminate the air bleed through the valves...

Lars


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## BearGFR (Aug 25, 2008)

Lars is close - my carb actually has two sets of secondary air bleeds. Tubes, and then there are a couple holes in the top of the air horn right next to the tubes. The holes I've already epoxied shut, and the tubes have been replaced with smaller orifices (orifi?).

The tape went over the two holes immediately beneath the secondary rods. It turns out that this car launches hard enough so that fuel sloshes out of the bowl, up through the holes where the metering rods insert, and over into the secondaries creating a momentary rich condition. By putting tape over the holes in the gasket, reassembling the carb, putting a dab of lubricant on the rods then punching them through the tape, I now have a seal around the rods that prevents the fuel from sloshing out. I was truly amazed.

I wish I could take credit for coming up with it, but the credit goes to Cliff Ruggles. He suggested that might be the problem during an email exchange where I was trying to describe in great detail how it was acting. The key clue I think was that the car would behave exactly the same way if I'd hold it with the brake, take it up to around 2000 rpm, then just release the brake without moving the throttle at all. It would make an initial move, then stumble, then recover.

Bear


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## geeteeohguy (Feb 2, 2008)

That's an impressive bit of diagnosis, in my experience. Not an easy one at all. Very advanced troubleshooting...color me IMPRESSED!!


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## facn8me (Jul 30, 2011)

Agreed. tracking down the small things are a killer


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## BearGFR (Aug 25, 2008)

Well, alrighty then.  I just got back from the Motorplex. My first ever pass, through the mufflers was a 12.72 at 109.85 with a 2.025 60 ft. On the run I heard a few sputters like it was maybe going lean. My second pass, with the dumps open, started off with a 1.98 60 ft, then about half track it ran plumb out of gas like I'd shut the ignition off. It recovered from that after a bit and still went 13.9 at 101. The other day I dialed the pressure back on the pump thinking that would tend to "save" the diaphragm in the regulator. Looks like I went too far with it and I got it down to where it couldn't keep up. On that run the a/c compressor belt rolled (no, I wasn't running the a/c at the time  ) and also took out the power steering pump cap --- just gone. So considering I still had an hour's drive to get back home I decided to pack it in after getting the belts straightened out and improvising a p/s pump cover with a rag and some duct tape.

All in all, I'm reasonably satisfied with this as a first outing considering how nervous I was 

Bear


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## ppurfield001 (Jan 21, 2008)

BearGFR said:


> Well, alrighty then.  I just got back from the Motorplex. My first ever pass, through the mufflers was a 12.72 at 109.85 with a 2.025 60 ft. On the run I heard a few sputters like it was maybe going lean. My second pass, with the dumps open, started off with a 1.98 60 ft, then about half track it ran plumb out of gas like I'd shut the ignition off. It recovered from that after a bit and still went 13.9 at 101. The other day I dialed the pressure back on the pump thinking that would tend to "save" the diaphragm in the regulator. Looks like I went too far with it and I got it down to where it couldn't keep up. On that run the a/c compressor belt rolled (no, I wasn't running the a/c at the time  ) and also took out the power steering pump cap --- just gone. So considering I still had an hour's drive to get back home I decided to pack it in after getting the belts straightened out and improvising a p/s pump cover with a rag and some duct tape.
> 
> All in all, I'm reasonably satisfied with this as a first outing considering how nervous I was
> 
> Bear


Congrats. Your posts raise some very interesting issues.


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## geeteeohguy (Feb 2, 2008)

Congrats, Bear. I predict that with practice and dialing in the car, you will be in the low to mid 11's. Back in the day, a friend of mine had a '66 GTO that he put a budget built but mostly stock 455 in with a TH400 and 3.73 gears....and I watched him run 12.00. His car was nowhere NEAR the level yours is, but he had racing experience. Personally, I have never owned even a 12 second GTO...strictly a 13+ second and up guy! Again, congrats!


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## BearGFR (Aug 25, 2008)

Got a couple videos. The first one is of the very first pass, ever --- this is the 12.723 @ 109.85, through the mufflers.






Second one was with the exhaust dumps open. It has a 1.987 60-foot time, but sucked the carb dry about half track  it still went 13.9 @ 101 after taking a brief siesta.






Bear


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## FlambeauHO (Nov 24, 2011)

Sweet !


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## geeteeohguy (Feb 2, 2008)

The launch on the second run was excellent...you can see how well the suspension is working as the weight transfers....it almost pulls the L/F wheel clear of the track. If not for the mid-track bog, that would have been a heck of a run. Car looks absolutely wicked with the color and the tire/wheel combo. Sounds wicked, too! Congrats....you are going out there and "doing it"!!


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## ALKYGTO (Mar 29, 2010)

Nice! I agree, nothing better than enjoying the fruits of your labor.

Way to go Bear! arty:


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