Weber progression hole differences

[big deuce]

Lately I picked up a set of IDA's all have the made in "blank" casting. Assuming Spain, all have the 3 progression holes. Three of them match, the 4th is drilled differently, but with 3 holes. See pics. When the butterfly is closed on the 3 that match,it covers the bottom hole. On the 4th carb with the different pattern, the bottom two holes are covered. Am I screwed? Or can they be filled and correct pattern established?

[Gaz64]

You could fill them, but it would need to be something pretty hard since much of the parent metal will be missing once you redrill the correct pattern.

Somebody who is good with the alloy welding filler rod using a butane torch would be the first step. (Google "alloy welding rods").

Or find another carb.

[jhirasak]

A method to fill the extra progression hole that does not require heat would be to use some epoxy like JB Weld. Before you fill the hole that you want to eliminate, you should put a polyethylene liner inside the throat to keep the epoxy from leaking into the barrel. After the epoxy has hardened, check and make sure that the epoxy is level with the inside of the barrel and then you can have the carb drilled for the progression hole to match the three other carbs. I noticed another thread by Bill Culbertson that had some details on how the drilling could be accomplished.

[Eljaro]

Originally Posted by big deuce

Lately I picked up a set of IDA's all have the made in "blank" casting. Assuming Spain, all have the 3 progression holes. Three of them match, the 4th is drilled differently, but with 3 holes. See pics. When the butterfly is closed on the 3 that match,it covers the bottom hole. On the 4th carb with the different pattern, the bottom two holes are covered. Am I screwed? Or can they be filled and correct pattern established?

You can fix that and drill the hole in the correct spot.
Make or have someone make a 1mm slightly conical aluminum shaft (starting ata say 0.9mm and anding at 1.2mm) and stick it inside the wrong hole. Hammer it with a punch until it is stays blocked inside the hole, cut off the excess (if any) sticking out inside the throat bore and you have the wrong hole plugged.
Now drill a new hole. With a strong needle first slightly mark the place you want to make the new hole.If it is not correct mark again where it should be until you get the right spot (use a magnifying las to see what you are doing). Then tap the needle with a hammer to mark the spot and make it a guide for the 1mm hole you will be drilling with a dremel or similar handheld electric drill.

[big deuce]

Here is what I consider the BIG problem. To make this carb identical to the other three, all three holes would need to be plugged and redrilled. The pics is not to exact scale, but the proportions are right. I am afraid of drilling the new holes so close to the old holes, filled or not. I know pierce does this, maybe to drill the 3rd extra hole that most need. But they may not want to get involved in this one

[Eljaro]

that IS a big problem ! If you weld the holes shut, you will have to repair the throat bores and the may never be perfect. Drilling the holes on a flat surface is one thing , doing it on a welded uneven surface is another, your drill may wander inside and the hole may end up off its correct location.
You can try the epoxy way or plug all three holes with an aluminum shaft and then drill all three.
If all this does not help you will have to get a new carb.
Or return the bad one it to whomever you bought it from. If you can.

[big deuce]

Cleaning up the inside of the throttle bores, would be a chore in itself. As far as the inspection hole area, could the weld be faced with an end mill in a diameter that would create a flat spot for the new holes to be drilled?

[Tom Howland]

I have a similar alinement problem. I've talked to Mike Pierce and he has corrected a number of these carbs. He makes a rivet to fit the bad hole. The head prevents it from getting into the engine. Then he uses a (guide/bushing) to drill a new hole. It can be clocked to the correct position for drilling. I think you could leave one bottom hole. Plug the other bottom and top hole. Then drill new center and top holes away from the old holes. I would only be concerned about the horizontal lines of the holes, not the vertical lines.

[Rick Parker]

Obviously the locations of the holes from a standpoint of syncronization is absolutely critical. It would appear all 3 need to be relocated. You'll be best advised to have this done in a Vertical Mill where minute dimensions can be replicated, or better yet (and unfortunately) consider, replacing the carb.

[big deuce]

I couldn't ask a better informed group of people, I thank all who have chimed in. I thought of even using lead pellets to fill the holes. My biggest challenge would be the drilling of the holes correct. I will call Mike Pierce and see what he recommends. SO, is there any IDA bowl bases out there floating around?

[Curt Presley]

You should reach out to the folks at Pierce Manifolds in Gilroy. Here is the web address piercemanifolds.com (408) 842-6667 321 Kishimura Dr, Gilroy, CA. They are the simply the best from a customer support standpoint when it comes to webers. I have bought 2 sets of 48 IDAs from them.

[big deuce]

Spoke to pierce and Inglese, both suggested finding a core body that had the correct progression holes. Or at least the 2 hole style and adding the 3rd hole. Jim Inglese said he had never seen an IDA with that type of hole pattern. So, I am on the search for a body, with the made in (blank) casting, with the 3 progression holes. The numbers on the base of my 3 carbs are, 48 IDA 13 b 8. Also looking for 4 aux vents 4.5 and 4 trumpets. Thanks for any help.

[big deuce]

Well, I took the plunge and used Eljaro's advice on plugging the holes. Worked like a charm. I also made a tool to redrill the holes. Its made from clothes hanger, yes a clothes hanger. I started to make one in alum, by threading 1/4" rod with the 7mm x 1.0 die. But realized it would be difficult to drill lengthwise without breaking fragile bits, or it wandering off path. So, I got the idea to use a more workable material and the clothes hanger is a few thousandths over 1/4". I covered the end with black magic marker, and threaded it into the port. Then transfered the 3 holes from a good carb with a small needle marking the holes from the inside of the carb body. Clocked the outside, and removed. Drilled the 3 holes with a pin vise in a drill press, reinstall in the plugged carb. Dialed back in, and secured with a jam nut. Proceed to drill the new holes. The pics show the tools. For a one time use, the plastic worked perfect and was easy to machine on a small lathe.

[Tom Howland]

Good for you. I like the coat hanger idea. I was going to use brass but was worried about the same thing. How much depth is the aluminum plug you used?

[big deuce]

I never even tried drilling the alum rod, I was thinking about it while turning it on the lathe. A person can get a better quality plastic at the hobby store. I used a bit of sea foam lub while drilling on the slowest speed, going down about 1/8" at a time and cleaning out the flutes of the bit quite alot.

[Tom Howland]

Looks like you used two different sized drill bits? Or was that just for the picture? And the three holes were not in the same arch? I am hoping to drill one hole in the guide and clock it for the three holes.

[big deuce]

The bits were to help show the holes for the pic. I drilled the bottom hole first, and rotated the "plug" for lack of better words, 90 degrees for the second hole. In that position, I tried to slide a bit from the inside through into the tool and it would not line up. I strongly believe they are not in a "arch". I again rotated the fixture 180 degrees to look at the top hole, it did not match either. So, I figued if I can safely transfer directly from hole to plug for the bottom hole, I had better do the same for the other two.