Another 6bbl Question

Posted By: RoadRunner

Another 6bbl Question - 06/30/13 05:56 PM

I have followed many of the postings on advice on how to set up a 6bbl, especially the one posted by Tom Quad. So I decided to go through my carbs again to inspect and replace. I never adjusted the idle circuits on the outboards. What I noticed on the front carb was that one of the little idle needles is sticking into the air stream much more than the other. On one barrel it sticks out about 3/32", the other about 1/32". So I pop out the lead plug and the holes are full of some corrosion, or brown hardened sealant. After trying to scrape it all out, I tried to gently turn the needles. The tanks snapped right off.

So what is the fix? Replace base plate? Drill out the bras needle? Though it looks pretty small drill bit will be necessary. The car seemed to run fine before, though I did have issues trying to get idle set.

I am trying to get the car out of hibernation, as we already have seen a third of the summer go by.

Posted By: mikemee1331

Re: Another 6bbl Question - 06/30/13 06:07 PM

if i had done that on mine i would look at it as an opportunity to upgrade to these - http://www.promaxcarbs.com/ (look under 'our products' to the left). pricey but what would new stock bases be?

Posted By: Cab_Burge

Re: Another 6bbl Question - 06/30/13 06:12 PM

If you have a big cam the outboards seem to like from 1/4 to 3/4 turn out from fully closed, if a stock cam one full turn will work usually. Make sure the power valve is not opening when idling in gear

as far as fixing the broken off tangs on the idle mixture screw you may need to replace the baseplate. I would have heated he base plate up with a hair dryers first to loosen the corosion up between the brass screw and the aluminum

You may still be able to do that with a very small EZ out and the proper drill bit

Good luck

Posted By: 62maxwgn

Re: Another 6bbl Question - 07/01/13 12:33 AM

The biggest problem is that the old cork seal turns to cement over the years,very few will come out without breaking.Get the cork out first,heat the base,a little PB Blaster and most will come out.I made a jig to remove them if necessary,if it doesn't work I drill the opening and have made inserts to repair then,don't throw away any bases,they can be fixed.

Attached picture 7760580-PA310551.JPG

Posted By: rbstroker

Re: Another 6bbl Question - 07/01/13 01:02 AM

I have never tried this, but saved the article. Look at the bottom right of the attached page. If anyone has tried this method, please chime in.

Attached picture 7760618-carbs6.jpg

Posted By: 70sixpkrt

Re: Another 6bbl Question - 07/01/13 01:55 AM

That happened to me when I was rebuilding my buddies carbs about 6 months ago. My local machine shop drilled it out for me.

Posted By: RoadRunner

Re: Another 6bbl Question - 07/01/13 01:57 AM

Looks like i'll try a little heat tomorrow night. If that fails, then the drill press gets exercised. Thanks.

Posted By: 62maxwgn

Re: Another 6bbl Question - 07/01/13 02:55 AM

Quote:

I have never tried this, but saved the article. Look at the bottom right of the attached page. If anyone has tried this method, please chime in.

All that does is cut off the end of the needle,once the head of the screw are broken off that does nothing,that didn't work 30yrs ago !

Posted By: RoadRunner

Re: Another 6bbl Question - 07/02/13 06:50 PM

OK, a little heat and some PB blaster softened up the old cork. I used a small pick to get the material out. I got my dremel tool out with a very small ball burr and cut new slots into the needles and tried again. They just broke further down into the hole. The two machine shops I stopped by today wouldn't touch them. Time to dust off the home drill press.

Here is another question. What would happen if I drill out the broken needle then plug complete idle circuit so that the fuel cannot get to the slot or the hole where the needle jet was?

In theory, the center carb should have all the idle circuitry. I can see the outbords providing some idle mixture to avoid leaning out the cylinders furthest from the center carb. But having center carb doing full idle duty wouldn't be any different than having a 383 or 440 with a 2 bbl on it. Though the manifild desing on a dedicated 2bbl engine would be better suited for distribution.

Anyway. While we ponder that question, I will drill out and see if I can get a helicoil or keensert installed. I'll do it myself I guess.

Posted By: rbstroker

Re: Another 6bbl Question - 07/02/13 07:42 PM

If you are going to try it yourself, why not try the instructions in the old Chrysler Power article above. What have you got to lose?

Posted By: 62maxwgn

Re: Another 6bbl Question - 07/02/13 08:38 PM

The instructions still lets part of the threaded needle in the base.

Posted By: 62maxwgn

Re: Another 6bbl Question - 07/02/13 08:44 PM

Quote:

OK, a little heat and some PB blaster softened up the old cork. I used a small pick to get the material out. I got my dremel tool out with a very small ball burr and cut new slots into the needles and tried again. They just broke further down into the hole. The two machine shops I stopped by today wouldn't touch them. Time to dust off the home drill press.

Here is another question. What would happen if I drill out the broken needle then plug complete idle circuit so that the fuel cannot get to the slot or the hole where the needle jet was?

In theory, the center carb should have all the idle circuitry. I can see the outbords providing some idle mixture to avoid leaning out the cylinders furthest from the center carb. But having center carb doing full idle duty wouldn't be any different than having a 383 or 440 with a 2 bbl on it. Though the manifild desing on a dedicated 2bbl engine would be better suited for distribution.

Anyway. While we ponder that question, I will drill out and see if I can get a helicoil or keensert installed. I'll do it myself I guess.

If you drill it,get a few pieces of smaller diameter tubing to use as a pilot.You need to use a drill the diameter of the screw less the threads and it must be centered,if you drill it off center you're done unless you make an insert as I do.
Good luck !

Posted By: RoadRunner

Re: Another 6bbl Question - 07/02/13 10:20 PM

Centering it is a concern. I was thinking of using a collar of some type to center the drill. I'll also be using a vise thats bolted to my drill press table so I should be able to get it pretty close. I'll know more tomorrow.

Posted By: b54406barrel

Re: Another 6bbl Question - 07/02/13 11:02 PM

Quote:

Here is another question. What would happen if I drill out the broken needle then plug complete idle circuit so that the fuel cannot get to the slot or the hole where the needle jet was?

In theory, the center carb should have all the idle circuitry. I can see the outbords providing some idle mixture to avoid leaning out the cylinders furthest from the center carb. But having center carb doing full idle duty wouldn't be any different than having a 383 or 440 with a 2 bbl on it. Though the manifild desing on a dedicated 2bbl engine would be better suited for distribution.

You don't want to do that. The idle circuit on the end carbs is needed. The transition from closed to opening without the idle circuit in them will definitely cause a stumble unless your center carb is way rich. Idle quality is actually better anyway, using all 6 screws to set it.

Posted By: 62maxwgn

Re: Another 6bbl Question - 07/03/13 01:11 AM

Quote:

Centering it is a concern. I was thinking of using a collar of some type to center the drill. I'll also be using a vise thats bolted to my drill press table so I should be able to get it pretty close. I'll know more tomorrow.

If you mess it up,I'll fix it for you,all it will cost you is the shipping !!

Posted By: lokalik

Re: Another 6bbl Question - 07/03/13 03:04 PM

save yourself the headach, get the promax kit.

Posted By: 62maxwgn

Re: Another 6bbl Question - 07/03/13 03:58 PM

Quote:

save yourself the headach, get the promax kit.

Only if you have $$$ you don't need,Promax needs to be a little better on their pricing as far as I'm concerned,as an example a pair of jetable metering plates at $150 is a little out of line when you can buy the same billet plate from Quick Fuel for $35 each ! !!

Posted By: lokalik

Re: Another 6bbl Question - 07/04/13 04:09 AM

you get what you pay for

Posted By: 62maxwgn

Re: Another 6bbl Question - 07/04/13 05:19 AM

Quote:

you get what you pay for

And the difference other than $80 is ?

Posted By: jcastle1

Re: Another 6bbl Question - 07/04/13 05:24 AM

And the difference other than $80 is ?

I would also like to know??????

Posted By: 62maxwgn

Re: Another 6bbl Question - 07/04/13 05:28 AM

Other than one fancier than the other,they both fit and function the same,no more,no less,and I'd take Quick Fuel over Promax without even thinking twice..

Posted By: a12superbee

Re: Another 6bbl Question - 07/04/13 06:10 AM

Quote:

Other than one fancier than the other,they both fit and function the same,no more,no less,and I'd take Quick Fuel over Promax without even thinking twice..

Bill knows as much as anybody about how your carburetor works. Trust the man.