Pablo Posted December 20, 2011 Share Posted December 20, 2011 Hello, what a fantastic Forum here ! So i hope to find out which Carb to use with a reliable jetting. I got a pair of DHLA L Carbs and a pair of DHLA E. So what i can read the recommendation will be to use DHLA E. Unfortunately are the E Carbs in bad condition.Nevertheless are recommendations for both types welcome.The Car is a Alfetta GTV 2,0 with ported Cylinderhead, 304 ° Cams with 10.5 lift, Comp. Ratio 10:1, and a sports exhaust with bigger diameter. At the moment are mounted DHLA L - jetted with Venturi 34mm - Tube .10 - Idle 62 with original holder- Air 180 - Pump 42- Main 140. and Aux Vent. .1 Is this right when mount the Aux Vent. 1 in a emission Carb the Main Jet have to be smaller in different to the Aux. Vent .3 Available are Tubes .11 - .5- .7 Idle Jet holder .1 - .2 Aux Vent. .1 - .2- .3 Pump vertical 38 / 40 Pump horizontal 33 / 35 / 42 / 45 also different Main, Air, and Idle Jets Also the right Float Level is a theme for me. 8,5 grams have to be set at 15mm and 25mm and 10 grams will be set 16.5mm and 25mm shut off- is this correct ? Can i also mount the 10grams float at the emission Carbs ? A Million of questions but ...... thanks ! Cheers Pablo Link to comment Share on other sites More sharing options...
DaveNotSoSideways Posted December 21, 2011 Share Posted December 21, 2011 Hi. http://sideways-technologies.co.uk/forums/index.php/topic/1048-setting-dhla-dellorto-dellorto-float-fuel-level/ Set the fuel level within the fuel chamber as ^^ above. This removes doubt about the actual fuel level. Floats can appear set correctly but this often doesn't translate into a correct fuel level in the carburettor. 1 Venturi is operating earlier in rpm range / lower vacuum / rpm when it starts to operate. So yes, it needs a leaner tube and main jet. 3 venturi is lazy and has higher operating rpm's / vacuum requirements. So needs a larger main jet and a richer tube. "Also the right Float Level is a theme for me. 8,5 grams have to be set at 15mm and 25mm and 10 grams will be set 16.5mm and 25mm shut off- is this correct ?" That will be ok. More important is the fuel level in chamber. You can use 10gram float in the emission carbs but it is heavier, so a fuel level reset will be required. 10grams may be more stable and less prone to cornering issues. I see no reason to use the E model carbs, your engine is mildly tuned, no problem there. I imagine a good result can be obtained with the L models. Link to comment Share on other sites More sharing options...
Pablo Posted December 21, 2011 Author Share Posted December 21, 2011 Hi. http://sideways-technologies.co.uk/forums/index.php/topic/1048-setting-dhla-dellorto-dellorto-float-fuel-level/ Set the fuel level within the fuel chamber as ^^ above. This removes doubt about the actual fuel level. Floats can appear set correctly but this often doesn't translate into a correct fuel level in the carburettor. 1 Venturi is operating earlier in rpm range / lower vacuum / rpm when it starts to operate. So yes, it needs a leaner tube and main jet. 3 venturi is lazy and has higher operating rpm's / vacuum requirements. So needs a larger main jet and a richer tube. "Also the right Float Level is a theme for me. 8,5 grams have to be set at 15mm and 25mm and 10 grams will be set 16.5mm and 25mm shut off- is this correct ?" That will be ok. More important is the fuel level in chamber. You can use 10gram float in the emission carbs but it is heavier, so a fuel level reset will be required. 10grams may be more stable and less prone to cornering issues. I see no reason to use the E model carbs, your engine is mildly tuned, no problem there. I imagine a good result can be obtained with the L models. Hi Dave, thank you for the answer! What will be a good starting point of jetting ? Does It means the shut off set 27 mm? Great Website, once more. Admiration value how you do ! Best Regards Link to comment Share on other sites More sharing options...
DaveNotSoSideways Posted December 26, 2011 Share Posted December 26, 2011 Hmm. You have to follow and understand the exact proceedure for the fuel level check. English translation will not be much good. Do not proceed if you cannot understand the document. Setup on the 8 gram floats at 14.5mm is the factory setting. 14.5mm and 25mm droop. Jetting. DHLAL40. 62idle OK Original Idle Holder OK 160 main jet 200 air jet 11 tube 3 venturi 40pump. Forget the 1 venturi and 5-7 tubes in my opinion. Carb should run good on 3 venturi and original idle holder and 10 or 11 tubes. The emission carb has different internal design, it uses the unmarked idle holder and 3 venturi. The main and idle jet fuel wells are connected in emission carbs and unconnected in non-emission. Using non-emission tubes (1-6-7-5) and marked idle holders in emission carbs ruins the functional operation of the carburettors design. The emission has it's own idle holder for a reason and uses 9-10-11 and 12 tubes. You may have to play around with the air-corrector to sort any flat spots in the mid-range. Link to comment Share on other sites More sharing options...
Pablo Posted December 27, 2011 Author Share Posted December 27, 2011 Hi Dave, i have understand your Float level advice. my short summary 1. First set the float level like the recomending hight of the different weight of the Floats (for 7gr. or 8,5gr. or 10 gr.) 2. fill up the Carbs with the fuel pump, ( disconect the ignition ) 3. wait some seconds and lift the top cover quickly 4. check the fuel level in the bowl of the Carbs ( it have to be 27mm, measured with the caliper. 5. if the level is deeper for maybe 2 mm so set the float for the difference to 27mm higher, or otherwise lower. My question is, what is the right Float level in the lower position, Factory setting of 25mm or 27mm ? With jetting i have trouble shooting. Tested .10 & .11 with Mains from 150 to 162, without results. So i have thought to change the AUX venturi from .3 to .1. Have you any Idea for this case ? Best Regards Link to comment Share on other sites More sharing options...
DaveNotSoSideways Posted December 27, 2011 Share Posted December 27, 2011 Good. 25mm will be fine for float droop. The float will never fully lower during use, it's not a critical measurement. It saves the needle valve from risk of falling out/jamming if the carbs empty of fuel. What air corrector are you using? 1 vent will make it much richer in early main jet phase/actuation period. What engine running issues are you presented with? Describe. Link to comment Share on other sites More sharing options...
Pablo Posted December 28, 2011 Author Share Posted December 28, 2011 Hello Dave, i have tested Air corrector 170 /180 / 190 / 200 / 210. Jetted the Carbs from 155 up to 162 with different Air Jets. No real power with the .3 Aux. As example - Idle Jet 62- Tube 11 - Main 162 with 190 - 180 - 170 Airs, The Plugs are white like snow . ( But the Engine not stumble or hesitat ) Flat spot in the mid-range and no power in the End. Only the throttle is like a melody. CO 3,2 % ( Idle screw at cyl. 1 & 3- 3,5 Turns out, at cyl. 4 - 4,5 turns and cyl. 2 - 2,25 turns out ? ) If I need a bigger needle Valve like 170 maybe ? With Aux .1 i have tested Idle 62 - tube .11 - with 150 Main ( maybe the Main need too be smaller) and 190 Air. The Plug will be near brown at higher RPM ( 4500 ), but once more the response is flat. Best Regards Link to comment Share on other sites More sharing options...
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