timgunn1962 Posted May 2, 2018 Share Posted May 2, 2018 Unless you do something really outlandish, pretty much any NA burner can be tuned for air:fuel ratio by changing the jet size and leaving everything else fixed (IME). The other way is to leave the jet size fixed and to play around with the bits that affect the inlet air flow. First thing I'd try is changing the 0.8mm mig tips for 0.6mm mig tips (.032" and .024" approx.). The actual holes tend to be "about" 0.15mm bigger than the nominal wire size (.006"). This will lean off the mixture by *very roughly* 35% and should get you a noticeably hotter flame. The smaller jet will mean that there is also about 35% less gas flowing at any given pressure, so you may need to run at a higher pressure to compensate. How much you need to increase pressure by will depend on how the balance between the higher temperature and the lower pressure pans out in your setup: to get the same gas flow through the smaller jet would take *about* 2 1/2 times the pressure if my mental arithmetic is up to scratch. If you then have a hot enough forge and still have enough Dragons Breath to indicate a rich mixture (enough excess gas to ensure a reducing atmosphere), you are sorted. If not, you have the option of playing with the inlet air flow to try to increase it and lean off the mixture further (smaller mig tips than 0.6mm are not available), or to enlarge the holes in the small mig tips to richen the mixture. Link to comment Share on other sites More sharing options...
Frosty Posted May 3, 2018 Share Posted May 3, 2018 I'd like a look at the jet position before I recommended a jet change. 0.035 mig tips run just a hair rich in my 3/4" Ts. Not taking issue Tim, both approaches work, just a little different is all. I tend to look at changing jets as a couple options down the list. Frosty The Lucky. Link to comment Share on other sites More sharing options...
timgunn1962 Posted May 3, 2018 Share Posted May 3, 2018 It's nominally a T-burner Frosty. Normally, I'd have left it to you. In this case though, he's in the UK and parts availability will be different to whatever your plans show. I don't know what he'll actually have in there: I'm guessing that tip trimming is possible, but there's probably not going to be any easy way to get any additional insertion depth. Reference to a "cap" in the OP may mean there's a big obstruction to airflow. Whilst it may look like a T-burner from a distance, I'd be prepared to place a small wager that it doesn't took much like one close up. Simon, any chance of some pics of the Tee end of the burner? Alec uses Gameco burners from Australia AFAIK. It might be worth checking out Amal Atmospheric Injectors from Burlen Fuel Systems in the UK. Link to comment Share on other sites More sharing options...
Simon_Dubman Posted May 3, 2018 Author Share Posted May 3, 2018 Images of the T Burners Link to comment Share on other sites More sharing options...
Latticino Posted May 3, 2018 Share Posted May 3, 2018 3 hours ago, timgunn1962 said: big obstruction to airflow Wow, you sure called it. Any chance I can get you to predict the next lottery numbers... Link to comment Share on other sites More sharing options...
Frosty Posted May 3, 2018 Share Posted May 3, 2018 BINGO Tim, right in one! That's why I asked to see a pic from this angle before making suggestions, I'm not familiar with available parts your side of the pond. If smaller shorter fittings aren't available I second changing to a smaller mig tip. Tune on Simon. Frosty The Lucky. Link to comment Share on other sites More sharing options...
Simon_Dubman Posted May 3, 2018 Author Share Posted May 3, 2018 If i move the Cap to the top of the T and hve the tip in the T, i guess this would help the situation? Easy enough to cut out and weld up. Link to comment Share on other sites More sharing options...
Frosty Posted May 3, 2018 Share Posted May 3, 2018 It would help a lot, the fitting is blocking a LOT of intake air. Frosty The Lucky. Link to comment Share on other sites More sharing options...
Latticino Posted May 3, 2018 Share Posted May 3, 2018 26 minutes ago, Simon_Dubman said: If i move the Cap to the top of the T and hve the tip in the T, i guess this would help the situation? Easy enough to cut out and weld up. Just remember that the alignment and location of the orifice is one of the critical parameters in getting your NA burner to work well. I would strongly recommend some kind of jig when welding. Link to comment Share on other sites More sharing options...
Simon_Dubman Posted May 3, 2018 Author Share Posted May 3, 2018 Seems better. How does this look? Link to comment Share on other sites More sharing options...
Frosty Posted May 3, 2018 Share Posted May 3, 2018 Is the front burner the one you adjusted? It looks much better still a bit rich but getting there. Alignment IS critical. Frosty The Lucky. Link to comment Share on other sites More sharing options...
Simon_Dubman Posted May 3, 2018 Author Share Posted May 3, 2018 Adjusted both.. The one furthest away has a 1.0 mm Tip and the one closest has 0.8 mm Tip. It may be i order some from either Gameco or look at the Amal ones. Or hook up some blower for some forced air. Open to ideas Simon Link to comment Share on other sites More sharing options...
Frosty Posted May 3, 2018 Share Posted May 3, 2018 1.0 mm is too large for sure the 0.8 looks well within easy tuning range. Looking good it'll be a high performance forge in no time. Frosty The Lucky. Link to comment Share on other sites More sharing options...
Simon_Dubman Posted May 8, 2018 Author Share Posted May 8, 2018 Placed 0.8mm tips in both burners. Now the one at the rear is struggling to keep lit. Would this be pressure too high? Or Not high ebough? Thanks Link to comment Share on other sites More sharing options...
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