TheSamba.com :: View topic - Need help with a 40 DCNF laying around, and numbered drill bits

Thu Oct 13, 2022 9:49 pm

Brent wrote: I measured (two 42's), both are the same and fit a #56 drill snug.

Edit: Hopefully you didn't drill anything.

I measured two of each.

40's, #50
42's, #56
44's, #54, almost a #53, but not quite

Interesting that 42's are the smallest, which also seem to be the most common Berg 'Special'. I wonder if they drilled that out as part of the special process.

I have 36's on my Fastback, I should measure those just for reference.

I'll dig out my good calipers and measure the bits just to be sure and send an update.

If you do start drilling them, maybe start with a #54, then #52 to #50? See how it changes things.

Thanks Brent,

This has confirmed my suspicions that there are different versions of these carbs out there, so nothing is "standard". Before I start drilling, I'm going to try some of the suggestions (solder closed some idles, and check for seating). Then if I do drill, I will do it in stages.

We'll never know what Berg was thinking when he was using these carbs. Maybe he thought that the 40s and under were too small to mess with. I have heard from old timers that for best running there is a relationship between the carb's throat and venturi size: "Its better to run a small venturi in a large carb, the run a large venturi in a small carb". However, I don't know if there is truth to this, or if it is just an old time myth.

Anyone ever do a test?

volksworld, my floats are brass, but they can still leak. I have done the shake test on them and no fuel inside.

Sun Oct 23, 2022 12:53 am

Finally got a little time to get back on my car. Dug out my Kester eutectic solder and soldered up a set of extra idle jets.

Sure enough, the engine will not stay running. I can keep it running by pumping the accelerator, but as soon as I stop, the engine dies immediately. I was going to check for jet sealing with layout dye, but I believe that the solder test covers two birds with one stone. I'm not really looking forward to it, but since Brent confirmed that his 40s have a larger air correction, and it seems that the ideas have dried up, I will start drilling tomorrow. I guess in the worst case scenario, if I'm wrong, I should be able to pull the original "air correctors" out of the body and make new ones and press them back in.

I plan on starting the drilling small and in stages. My main concern is keeping the cuttings out of the idle circuit, so I whipped up this little device.

For lack of a better term I am calling it a jet blow pipe. I took an extra idle jet holder and chucked it in my lathe. I faced off the screwdriver slot, then drilled a snug fit hole for the copper tube, and soldered it together. When I soldered the idle jets, I only closed up the center fuel passage, and left the two mixing passages in the middle of the jets open. Before I start drilling, I will close the mixture needle, and cover the progression ports with Gorilla tape. Next, install the blow pipe and a soldered idle jet into the carb, and connect the blow pipe to constant air from my air compressor. Then the only way for the air to go will be out the air corrector bushes. This "should" keep the cuttings out of the idle circuit as I drill. However, I won't be able to get on this until about 1:00pm (pacific time) tomorrow (church in the morning). So if anyone sees a problem before then, or something else to check, let me know.

Sun Nov 13, 2022 10:16 pm

Well I went ahead and drilled the "calibrated bushes" out to a larger size. I'm glad that I went at it in stages, because even though I was very careful, and used a mill instead of a drill press, the hole diameter came out larger then the size of the drill bit. The original hole was the diameter of a #56 drill bit, so with the first cut, I went with a #54 bit. I then checked the hole size, and a #52 bit fit, so it was a little larger then what I wanted to start with. I drilled the other three holes, and they all came out the same. I decided that I would stop here no matter the results. So did it help, Yes. Did it fix the problem, No. Would I recommend this procedure to someone else, No. The problem seems like the mains are coming into play too soon. However, once again life is putting a hold on this project.

Recently I had to put my dad in an assisted living home, and I am scheduled for back surgery early December. So I have to get his "machine shop" moved into my garage before my surgery so his house can be sold. Basically, every moment that I am not working is spent boxing up everything and moving it to my house. Basically its 50 years of stuff that he has accumulated, with a lot of it all VW related. mcmscott is supposed to come by and pick up some boxes of transmission parts. Plus there are cranks, rods, heads hubcaps you name it, that I have boxed up. However, the main concern is getting all of the tools before my surgery. This is just a portion of what needs to be moved in less then a month. I'll be very busy.

Mon Nov 14, 2022 7:35 am

Dag,
Was wondering how this came out…

Sweet little mill and lathe.
I dream of having a setup like that one day at home.

Spend time with your Dad while you can.
Dads don’t live forever. :(

Mon Nov 14, 2022 7:45 am

Clatter wrote: Spend time with your Dad while you can.
Dads don’t live forever. :(
Absolutely! There is a lot of experience, wisdom and history under that gray hair. Glean as much as you can while you can. I missed out on too much of that (too busy with work and life) with my Dad, especially on the family history side!

Mon Nov 14, 2022 5:53 pm

oprn wrote: Clatter wrote: Spend time with your Dad while you can.
Dads don’t live forever. :(
Absolutely! There is a lot of experience, wisdom and history under that gray hair. Glean as much as you can while you can. I missed out on too much of that (too busy with work and life) with my Dad, especially on the family history side!

Since he is still able to get around, I kidnap him and take him out to eat and to visit with his friends, or sometimes we just sit outside and talk about the old days.

Tue Jan 24, 2023 2:16 pm

Weber 40 dcnf

Hi the mesured jet is 1,8mm

have u found some more?

Tue Jan 24, 2023 8:21 pm

Drilling jets is a joke. It’s not the proper way period. The only way to measure a jet is to put it on a flow meter. I flow jets every day for customers and have found that even new jets don’t flow correctly. I returned over 30 new jet last month to the manufacturers.
I have found that it doesn’t mater the manufacturer, do it correctly or your wasting money and time.

Thu Jan 26, 2023 12:07 pm

Vespist, thanks for the info. Everything is still on hold due to taking care of my dad.

Nightshift, true drilling jets in not the "proper" way to do it, but when things don't go right sometimes you have to go outside the box.