Anybody got experience with plugging jets with solder so they can be re-drilled with a smaller jet size? Is it just a case of heating up the jet and blobbing it with solder. Is it normal electrical solder? Any problems with it coming loose? I know the jets should be drilled and reamed but I'm looking to do some experimentation and this is a lot easier and cheaper than buying bucket fulls of jets. If I get it right I'd change back to a reamed set of jets. Thanks
in general, jets aren't just holes drilled. they are flared and rounded on either end. plus, if you get close with a drilled jet, when you change it to a "reamed" jet it won't flow the same. you actually are better off getting the bucket full of jets.
If the jet is brass should be no issue. I have done it on my Indian chief with no problems, I used 50-50 solder plumbers grade, but I guess that stuff is outlawed now, good thing I still have a bunch of it. Does not fall off any more than copper pumbing comes apart.
it'll be hit or miss. you could make a mini "flow bench" to test the flow before installation, but it'd probably be hard to measure small changes in flow. even better would be a wideband o2 meter to tune with, but that would defeat the whole money saving aspect of drilling jets. i've done is succesfully. the big issue with drilling, is say you have a stock size jet in the car, you decide to drill it for more fuel, if you increase by only one or two drill sizes, that may very well decrease flow depending on the chamfer, relative to what it was to start. now if you are soldering them up completely, and starting from scratch and do a variety of sizes, all with identical chamfers, your results would be more consistent comparing drilled jet to drilled jet than comparing drilled jet to stock jet.
I've done that before, and it worked well... http://www.jalopyjournal.com/forum/showthread.php?t=103301&highlight=raffle+webers
ive never done this with jets but something that may help if you dont have a small lathe put the jet in a drill and hold the bit in a pin-vice you can feel when it gets centered as theres no more wobble, they just lightly let it go through i used to do this making small brass worm gears and such good luck
for what it's worth, i've rebuilt quite a few carbs where that had been done and they were having some driveability problems...replaced them with real jets, usually a touch smaller than the drilled size and they worked smashingly afterwards.
Google "jet reamers" for a closer to correct way. Jet flow benches are thoroughly described with easy Home-Depot type materials in any of the Model A carburetor books; Model A people like to discard good Zenith jets and replace them with randomly made repro jets that have to be flowed and then shimmed to correct height...you don't need any standard on the flowbench except repeatability so you can compsre. But...what are you up to? Aren't you just after a minor top end leaning problem in Strombergs?? Likely you just need stock jets or within a step or two and minor enlargement of power valve holes...or maybe even just attention to fuel level rather than trying to reinvent the thing.
Although it is not the preferred method, it would be good for trial and error testing to find the ideal size range. I would use the lead-free solder instead of the 50Pb-50Sn stuff. Not that the engine's health could suffer from eating lead chips, but seriously the lead-free stuff around here is slightly harder and melts at a slightly higher temp. Keep the chamfers the same as OEM, and make sure the orifice length does not get changed. Carb jets are simply metering orifices, and orifice length is one of the factors that affects the flow rate.
Another method I've used is steel guitar stings. Guitar strings are very precise and corrosion resistant. I've used small pieces to restrict the jets sticking it in the jet and making a loop over the end of the jet to keep it from falling out. It was definitely a trial and error process since I didn't have any way of determining exactly how much restriction I was adding. When I was finished, the engine was tuned to an "A".
I have a set of Reamers, but I sill like to start with a small pilot hole ( done on the Lathe, so its exactly Centered and Even ) A Flow Bench seems like a really good idea. ( maybe a TECH Article for the HAMB? ) So you can make the Jets Flow exactly the same. For the Mixture I have a Innovate Air/Fuel Meter. Great Machine... That sure speeds things up, when Tuning a Carb...
How do jet sizes compare to # drills? The jet reamers I found with a google search are metric and you would have to approximate fractional sizes . Is the shape of the metric reamers compatable with say rochester jets? Thanks for your help.
I have read of others having erosion and enlargement of soldered jets after a period of time, so I elected to solder in a piece of 3/32 brass rod and then drilling for the new size.
I just reamed some jets today. I bought "chucking reamers" from Mc Master Carr. They are available in .0005" increments. When you order you specify the diameter you want. I built a little fixture to hold the jet in the lathe chuck and held the reamer in the tail stock. The reamer hole ends up looking like a tubular mirror. Hope this helps DAVE
the chances of you being able to make 2 jets flow the same is very slim. a jet is not just about the hole size, if your only going for a small change then you dont need to solder it, take a couple pieces of round stock and match the tapers on the inlet and outlet of your jet, now clamp one of the tapered round stock piece in a vice and use the other to cruch the jet closed a little, then use your drill, only make one pass through as every pass will remove more materal.
Silver Solder is commonly available in 'good' hardware stores. You'll need a bottle of flux and a solder brush. It's harder than other solders and stronger as well. Lessee, knock something out that would hold the jet and adapt to an air hose chuck. Set up a regulated air supply. Fill a small portable air tank with the regulated - for pressure - air. Time how long it takes to bleed down the portable air tank from say 20# to 10# or so. A touch crude, but repeated several times on the "standard" jet you'd get a feel for it and then be able to tell if a particular jet flowed the same or different from the "test" jet. Nothing wrong with using water in a container and draining it through the jet and timing it. Probably more accurate than air flow. Especially if you used a graduated glass tube.
GOOD GOD PEOPLE!!!! i'm laffing so damn hard this ain't easy to type! a carb is a semi-calibrated fuel leak anyway PLUS the re-jet is only good for the air you've got at the time and at the altitude you're at WHEN you do the rejet! i'm sure enbloc would like to actually drive the damn thing in his lifetime,too! C9, i'd worry more about the silver solder thing IF it has needles in the jets, otherwise rosen core works just fine. why do i know this shit? the county where i work has emissions tests....
Use the rosin core and run water thru the jets. Buy yourself a couple of cheap measuring cups at the dollar store, hook a hose up to a faucet, stick a plasic Y fitting into the hose. Hook another hose to each end of the Y fitting then stick the jets you want to use in each hose, placing each one in a separate measuring cup. Now turn on the facet[very low] and you can compare one jet to another and by comparing the amount of liquid in each cup, You can also calculate the percentage of flow difference between 2 jets or more if you use a manifold with more hoses. Believe me this works fine. Up until a few years ago I was racing a formula 1 V-8 2 stoke outboard which had 8- 2 barrel carbs, each carb had a low, medium, and high speed jet in each barrel[6 jets each]. Just make sure your measuring cups are in the same horizontal plane;so pressure is equal, and you can also drill a hole in the hose which is hooked to the faucet so the pressure stays low. This also works excellent for building a rod type nitous system.
You guys don't need to make this more complicated than it has to be. I did the center two 97's on my 2x4 setup by soldering (resin core) and drilling. No fancy reamers or testing equipment. I did use a fuel/air guage in the car to test. If it was lean I'd take them out and drill a bit more. If it got to rich I'd solder up and drill with the previous lean drill and wollow it out a bit. Sounds crude but it worked well. I will admit the process is a bit tedius
It's OK to solder and drill a jet. I think the other important part is to match the power valve to the jets..Drill # 56 is the .045 jet size..If you really want to get bold, try drilling out the emulsion tubes also..For best performance it should all compliment each other.. Who ever said, all it is, is a contolled gas leak..GREAT, I like it.. Duane.
Use silver solder and if you know of a plumbers supply place,ask for a gas jet drill kit.they are ALL hand drills ,and EXPENSIVE but the kits normally have around 100 drills . Gas fitters all have them to set up burners etc . This's a cheap set you can get from summit,but not really accurate enough for perfomance engine tuning .http://store.summitracing.com/partdetail.asp?part=nos-15992nos
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