I'm thinking of having my 330 GTC (US version) carbs totally rebuilt after approximately 165,000 miles. They are the original carbs on my car, from 1967. The only thing that's been done is new float valves and accelerator diaphragms. Any recommendations for this type of service here in the US? Bob Z.
Pierce Manifolds did mine, and I have been very happy with the results. I think they are the go-to guys for Weber work in the US.
there isn't much reason to rebuild any carb until it stops performng well or parts are worn... some which have already been done... the carbs from "back in the day" are not sensitive as those from recent times that need to meet very strict emission requirements... the new alcohol based / blended fuels create problems even for a newly rebuilt carb, my preference would be to wait until something goes wrong
Yes Pierce is the way to go, I had them rebuild my BB512 carbs. Mike even check the flow of each and ensured that they were performing to the best of there design. East to speak to, lots of knowledge, highly recomended.
If the diaphragms are just leaking, change them out. It's just 4 screw. So easy David http://www.512bbi.com http://www.gtb4.com http://www.250gtl.com
Other than the acc pump, Weber's are very trouble free if not mechanically damaged. Base warp and shaft wear are sometimes noted, but otherwise best carb made! Jim
Pierce is great, and another great option is Gron Perry +1 408-781-3770 (number posted with Gron's permission). He does most Weber Carbs, and knows how to tune them on a car about as well as anyone I've ever met. IMHO, Gron has forgotten more about tuning Webers than most mechanics probably know. Whenever I've got him in the shop, I clear my schedule for the afternoon so I can watch him work, and ask many, many questions. He's delighted to share his knowledge about carburetors, and I always come away knowing a little more about the science.
I recently rebuilt the DCZs on my '66 GTC, and either I'm in a complete fog (probably) or I need to go back to the Holleys on my old 'Vettes. There is no accelerator pump diaphragm on these carbs of which I'm aware, as the pump is well fixed in the body and rarely needs to be serviced at all. If the pump gives a good "squirt" or "pump shot" when you hit the throttle arm, you needn't worry about pump. If it doesn't, and the nozzles are clean, it may need to go to Pierce. They're pretty easy to work on and usually only need the top cover gasket replaced. I took out all of the jets, etc and soaked the parts in carb cleaner, prior to which I gently sanded out the little warpage present. If you find a pump diaphragm in the exploded drawing, PLEASE show me the part number(s). More details if I'm correct and you want them. steve
Bob, As others have stated, Pierce Manifolds is the way to go. Mike usually doesn't do them though. Ralph does. Mike (usally) checks them over though. I recommend them and bring all the Weber carburetors to them, from the usual 36/40 DCLs, DCZs, DCSs, 40 DCN, 38 DCN, etc. to the ultra-rare 42IF2Cs. And, yes, the last one is on a Ferrari. I'm more amazed you got 165K miles on yours. My webers on a 16K mile Daytona Spyder already had the bases warped. (Whatever you do, don't machine a carburetor flat, you have to press them flat. If the person working on your carburetor doesn't understand why, find a new mechanic.) This was common because people would over tighten the screws instead of replacing the gaskets. So, as you tighten a sand cast carb down over the crushed gasket, they warp, you suck in air and the car doesn't run right. Also, I would have thought your throttle shafts would be worn by now. But, you might be a lot luckier than me. Regardless, Pierce Manifolds will make them right. Steve
"Whatever you do, don't machine a carburetor flat, you have to press them flat. If the person working on your carburetor doesn't understand why, find a new mechanic.) This was common because people would over tighten the screws instead of replacing the gaskets" I am learning everyday, Explain me how to press them flat please. I am glad my carburetor cars are maintained by myself. Cornelis
Mike has "pucks' that are machined to the correct thickness. He inserts them under the base of the carburetor at each corner as necessary and then slowly presses the carburetor body into the correct base configuration. He also freezes the carburetor body before doing this, not sure why. He told me it sometimes takes 2-3 cycles to get the required result. This is done slowly because the material is not very elastic. In my case the #1 carb body was too warped, so it would not come back into the correct configuration. Mike sourced a used carb body from England which did the trick. Now, I have a $700 paper weight. The procedure that Mike uses is important in 2 ways. When the carb body is warped it creates distortion in the throttle bodies, and the alignment of the shafts become mis-aligned. Machining the bottom of the carb body reduces the vertical relationship of the idle jets and does not solve the alignment problem: Not recommended. It's impressive what Mike can do with a Weber Carburetor.
Well, I could be mistaken here but the procedure might actually call for heating, instead of freezing, of the carb bodies to assist straightening for which Mike/Pierce Manifolds have developed various adjustable "fixtures" to slowly and in multiple very carefully applied cycles can bring the warped bases, bodies and top covers back to their original shape. Machining or sanding the base of the carb will make it straight, but the rest of the body can still be warped. After possibly several "base machining/sanding" procedures over the years and decades, it will be close to impossible to bring warped bodies and possibly misaligned shaft and throttle plate bores back to original shape as material has been lost.
I can follow these thoughts, But my old man in Turin( ex - worker of Weber) starts with a flat machined bases. then he makes new guides for the new shafts and new valves with the basis as reference. the new valve needs a bigger opening that makes the carbs a bit larger. if you send 40 DCL -6 you get back let say 41 DCL- 6 CARB or smaller I think overhauling means really make them new again or better. C.
There’s no question that if your carbs are BADLY warped, have worn throttle shafts or damaged in some way, Mike Pierce is your guy. He’s excellent, really nice and has all the parts and expertise. In fact, the previous owner of my GTC had the DCZs rebuilt by him, in about ‘’99 or so. The invoice was for $750/carb, so it’s gotta be a grand a piece now, at least. However, I’ll bet Bob’s carbs are in need of minimal work. Perhaps a good cleaning and a check of all parts, but I’ll bet not much more. I especially doubt machining, freezing or heating cycles will be required. When there’s a vacuum leak from a warped base or worn throttle shaft, the car will usually idle erratically because of that leak. With the carbs now off the car, one can’t easily test their functionality for a vacuum leak, but here’s what I did, just a few months ago with both my DCZs and the DCNs from my Daytona. 1) Only do one carb at a time, just in case you get confused when putting it back together. 2) I know that the CW is not to let anyone but Mike Pierce touch these babies, but I was given the green light by one of the most highly respected Ferrari gurus out there and proceeded unafraid. 3) After disassembling the carb, including all jets, emulsion tubes, needle/seat, etc. I blew out all passages and parts with compressed air, soaked them in carb cleaner, rinsed them in water and blew them out again. Some folks like MEK better than carb cleaner, but I had 9 carbs to do, so I chose the 5 gallon size from my FLAPS. 4) Before soaking the body or top, I laid them on a piece of 1/4” glass to check for warpage. You can see gaps when the part is laying on the nice level glass, but you can also very gently sand the base (or whatever part you want true) against a piece of sandpaper laying on the glass. When you pick up the base (in this example) after a bit of sanding, you will see “high” and “low” spots. Once you’ve done a modest amount of sanding, the entire surface will be free of these variances and thus level. I’m confident that with measured, gentle sanding, you’re not going to ruin the carb. A belt sander would be faster, but I felt better going slowly and deliberately. I started with 80 grit, went to 120 or so, then to 240, but it didn't take much time, effort or paper. I used a piece of glass that was about 20”X 20”. 5) I would also check EVERY carb part for it’s spec and part number. Don’t trust that all of the little parts are correct. Case in point: my Daytona ran like stinko in the midrange, that’s kinda how I got to taking the carbs off the car. Anyhow, the previous owner had main jets that were 2 sizes too small! With the correct jets, the car ran great, as it should. 6) Before complete reassembly, check your needle/seat (I replaced all of mine, as they came in the Pierce rebuild kit.) and check your floats for both integrity and for the correct height. 7) The DCZ DOES NOT have an accelerator pump diaphragm, the DCN does. 8) When I put the carbs back on the intake, I gently sanded the phenolic blocks to be sure they were true. I took great care and time as I bolted down the carb bodies, working in a “cross pattern” to assure equal tightening and pressure on each of the carb “feet”. Lots of dancing aroud the car! 9) Bob Z. is obviously and accomplished mechanic and this project is easily within his grasp. If I can do it, anyone can. 10) I’m with Cornelis in that if I can keep the carbs under my tutelage, I’m much happier. There’s clearly a place for Mike Pierce, I’m just not convinced that every carb issue needs his blessing. steve
