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BBD Mods
https://slantsix.org/forum/viewtopic.php?t=22758		 Page 1 of 2
Author:  Rug_Trucker [ Mon Apr 16, 2007 10:43 pm ]
Post subject:  BBD Mods
One of the BBD's I have has .066 jets. I drilled it out to .078. That was the next biggest sized bit I had. I may drop those into the carb it is running tomorrow night.

Headers, ported and polsihed head with stock heads and valves.

I am running extremely lean on the highway. This is a BBD with the smaller rods with the tall looking jets. Not the short jets.
Author:  Rug_Trucker [ Tue Apr 17, 2007 5:54 pm ]
Post subject: 
58 views and no comments?

No old school BBD modifying guys here?
Author:  SlantSixDan [ Tue Apr 17, 2007 7:06 pm ]
Post subject: 
BBDs with stock, undrilled jets work well on slant-6s. I think there's something the matter with your carburetor, and drilling the jets didn't fix it, just masked it.
Author:  Daddiojoe [ Tue Apr 17, 2007 8:08 pm ]
Post subject: 
FWIW, the absolute biggest problem with BBD's is that they wear out around the throttle plate shaft. That might have caused your lean running--lots of air being sucked in through the wear areas around that shaft. Easy to check with 10w-40. Just spray some on the carb (externally) when the engine is running. If the idle speeds up, that is more than likely your problem.

Goodluck,


Joe
Author:  slantzilla [ Tue Apr 17, 2007 8:22 pm ]
Post subject: 
I know of a Slant race motor with a BBD on it that was dyno'd a few weeks ago. The stock jets were actually a little rich for it. :shock:
Author:  Rug_Trucker [ Tue Apr 17, 2007 8:47 pm ]
Post subject: 
Well, I checked the drill bit I used. It wasn't .078 it was .070. I smaller step up.

All I know is this thing is burning white plugs and it is pinging on premium.

I got agrivated with the choke and fast idle cam linkage and am done for the night.

I guess a test drive tomorrow. I do have the stock jets to put back in. Both BBD's I have are the same in jetting. I checked the rods with a micrometer and the others were bigger in diameter so they are leaner.
Author:  Rug_Trucker [ Tue Apr 17, 2007 8:48 pm ]
Post subject: 
Quote:
I know of a Slant race motor with a BBD on it that was dyno'd a few weeks ago. The stock jets were actually a little rich for it. :shock:
What year BBD?
Author:  61 V200 [ Tue Apr 17, 2007 8:49 pm ]
Post subject: 
I'm getting ready to modify a BBD throttle plate shaft to put on my custom 2 bbl intake manifold. I'd hate to do the mods only to find that the shaft is worn and leaking. I picked up the BBD from a person on .com and have no idea how it runs.

So my question is:
What kind of shaft/bushing clearance would you
expect to find on an " un-worn" BBD?

Thanks
Author:  slantzilla [ Tue Apr 17, 2007 9:03 pm ]
Post subject: 
Quote:

What year BBD?
'80
Author:  supton [ Wed Apr 18, 2007 3:51 am ]
Post subject: 
It's running lean on the highway? No chance it's running hot on the highway instead? Can you put a vaccum gauge on it? See what you are pulling at idle/cruise/WOT? Temp gauge?

Was it running good, and now not so good? Or always that way? I see your sig shows an et, so I'm wondering if it used to run good, or if it's never liked the highway.

I forget--wouldn't pinging tend to clean off plugs?
Author:  Rug_Trucker [ Wed Apr 18, 2007 5:39 am ]
Post subject: 
Insulator is white. Set the idle with a vac gauge. Rock steady@ 19" It will run 80 mph with the gears it has all day long. It has been to Florida and back many times.

It runs great.

This is a $10 carb I bought and disassembled and checked. It had been "proffessionally" rebuilt and never used.

I've had a problem with pinging ever since I put this head on.

Temp won't go beyond 175* This engine just rolled 60K on the factory build. I pulled it @ 32K and regasketed it. It was new inside.

Valves are set at .008 intake and exhaust. Not that that mattered before when I had them set to the stock specs. This was done buy the guy that ported the head.

After setting the valves on Monday this thing has lots of power as long as you easy into it slowly. If you mat the pedal you can lift and it will speed up faster. To me that says more fuel needed. Low end sucks too!

I just need to fix the durned linkage and drive it to Bowling Green for the Chrysler Classic. I
Author:  SlantSixDan [ Wed Apr 18, 2007 6:22 am ]
Post subject: 
Quote:
What kind of shaft/bushing clearance would you
expect to find on an " un-worn" BBD?
Essentially none. If there's perceptible side-to-side wiggle of the shaft within its bushings, there's wear, and you'll want to have the throttle body bushed.
Author:  Rug_Trucker [ Thu Apr 19, 2007 4:31 pm ]
Post subject: 
Well it is pulling harder. I am going to drill the others out to .078 either drop them in tomorrow or late tonight. See what happens!

Haven't pulled a plug yet.

Less pinging, more OOOOMPH!

There is no adjustment on the metering rod tree like a Thermoquad :cry:
Author:  mopardemon71 [ Thu Apr 19, 2007 8:25 pm ]
Post subject: 
I'm in the same boat I got no bottom end on my power band but it pulls good on the highway. The 1 bbl always tried to pull the front end up and this bbd is very lack luster. Oh Dan we typed about my carb issues a while back and the reason my other carb dumped fuel every where the air horn body (the top piece) is warpped. What is the stock metering rod/jet numbers for a /s bbd? Someone used a 318 one and said it worked great are they the same??
Author:  Rug_Trucker [ Thu Apr 19, 2007 11:21 pm ]
Post subject: 
I have 3. 2 are alike. They both had .066 jets. The rods mic'ed different. I put the smaller diameter of the 2 back in the carb. Those are the richer ones.

I drilled the other set of jets to .078. I am going to take those with me to Bowling Green.

I am going to check my gas mileage. I ordered a set of Autolights that are 2 heat ranges cooler than normal. That might help with the preignition. I will take them with me.
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