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| Dellorto 40DHLA-F or G on Mini https://www.ausmini.com/forums/viewtopic.php?f=2&t=96401 |
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| Author: | drmini in aust [ Sun Dec 03, 2017 6:37 am ] |
| Post subject: | Dellorto 40DHLA-F or G on Mini |
The Dellorto/Weber book by Des Hammill suggests these emission carbys ex Alfa should be avoided. However after setting up a couple recently I find they work great on a 1275 or bigger modified street motors, with 36 chokes in. 1. Fit 36 chokes or bore the 32s out. (Edit) For a stock 1275, make them 34. For a 998 or 1098, leave the 32s in. 2. Idle jets 0.65 or 0.70. 3. Air corrector jets 180. 4. Main jets 200. 5. Pump jets drill to 0.5mm. 6. Use #6 emulsion tubes. Edit: Note the above settings are for the 40DHLA-G ones, an -F one needed smaller jets- 55 idle, 180 mains. Otherwise same. On a 1310. Compared the 40-G to my 45DHLA with 36 chokes, found the low and midrange torque is better, the 45 is only slightly better above 5500 RPM. |
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| Author: | Goldbrocade_62 [ Sun Dec 03, 2017 10:29 am ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Is there a plastic part in a Dellorto that's gets brittle with age |
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| Author: | drmini in aust [ Sun Dec 03, 2017 12:15 pm ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Only the float, but I've never seen one cracked. Even some Webers have plastic floats now. Edit: The accelerator pump diaphragm will go hard if carby is unused for 20 years, as will most carbs. To rebuild, strip and clean it out then fit a service kit. I did my 45 about 25 years ago and it's been fine since. 
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| Author: | Goldbrocade_62 [ Sun Dec 03, 2017 7:10 pm ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Was looking at the ones on eBay i noticed a white plastic part externally that covers the main jets does that ever give problems |
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| Author: | timmy201 [ Sun Dec 03, 2017 7:13 pm ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Heres one with the white plastic cover. https://www.ebay.com.au/itm/DELLORTO-45 ... 3010682899 |
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| Author: | drmini in aust [ Sun Dec 03, 2017 9:58 pm ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
That is just a splash cover, with a gasket under. I leave it off for a drive whilst testing jetting. It also is the air intake for the choke circuit. No, they are pretty robust. The screws can bend but I've not seen one break. Unlike on a Weber DCOE, it doesn't help hold the lid down. |
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| Author: | Ian_B [ Mon Dec 04, 2017 7:10 pm ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
I am looking at a pair of Gs for my Elder crossflow.Any ideas Doc appreciated Apparantly there is a model with fine thread idle screws that can seize in the carb body and be a bitch.Thanks mate PM soon.Looking at 32 chokes Not sure on emulsion tubes but F16 with webers is fine.The more I think about it an emission carb would be to do with more refined idle and progression.It cant affect mid and top end much as these are governed by main jet choke emulsion tube combo.Ive played with a mates DCOE42 Weber and we could never get the progression right and I had heaps of jets at the time I also understand the fuel droplet size or mist is finer with a Dellorto Im thinking less bore wash of oil.Very interesting topic.Maybe the guy didnt recommend them is they werent for siamesed engines where idle and progression would be much different like more demand than one carb per cylinder.And yes my life has got better and so has my own head lol 
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| Author: | drmini in aust [ Tue Dec 05, 2017 5:37 am ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Twin 40 Dellorto work fine on a crossflow head, leave the Alfa jetting and chokes in it to start with. I can repair the fine thread in the body if it strips or gets damaged. I make a bronze bush with M7x0.5 thread and press it in. Have done one already. New mixture screws and other parts are available from eurocarb in UK. Supercooper runs a pair of these on his S, PM him. |
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| Author: | Ian_B [ Tue Dec 05, 2017 7:04 am ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Excellent news thank you. Found this info hunting around Its a long post but..... Type 3 DHLA40F-G-H-N-R-S models. These are called emission completely different to the DCOE science, but noone really understands them and tries always to tune them like the early models. These differ because they have more progression holes and use the*idle jet*to feed most of the cruise phase and low rpm/low TP area of the engine AT ALL TIMES when the main jet isn’t in operation completely automatically no jetting needed. The*idle jet has a very large fixed 2.2mm air feed, you cannot tune this phase of the carburetor for length like the others, but here lays the secrets…. The*idle jet*doesn’t feed from the*float*bowl, it feeds directly from the main jet stack, what happens after this is what gives these Dell’Ortos the sweetest road behaviour (what 25years of research came up with and not just for emissions) and dead easy tuning, you see when the main jet starts to emulsify fuel in the tube, the*idle jet*is feeding from it, so the gassy airy fuel shuts down the*idle jet*and sucks backwards yes BACKWARDS through the idle!! using every drip of fuel efficiently without ANY waste in circuit cross over where one is going after the other…this happens the moment the main jet fires, so there is NO need at all to tune the length of the progression and idle phase. This is pure magic they are automatically calibrated, you simply keep the*idle jet*above 59 up to 62 and not make the mistake of fitting numbers suited to the early DHLA or DCOE - with this simple technique you can tune anything from a 1300 to a 2000cc without really doing anything. The emulsion tubes in these carbs are always 8-10-11 and have to stay that way - which are really rich and have a hole straight down with loads of air holes, these atomise the fuel to an massive degree, also they have to be used cause the*idle jet*will not run correctly using the DHLA40-E type tubes (1-6-7-5) as the*idle jet*needs these airy tubes to function and cut out as designed…Usually people ram the DHLA40 idle holders with air holes in these carbs add the 1-6-5-7 style tubes and wonder why its a massive lean spot off idle, cause they missed the point completely!…These carbs use a .3 vent which has a very small*signal*tube*to the main jet stack, this is because the holey tubes are basically ready to go from about 1250rpm (on my car using an 8tube 1 vent it was on the mains at 1250rpm!) so the holey tubes need holding back with a signal killing venturi…These carbs are wicked if you want bolt on power, they tune themselves! The early types are better in respect of punch and tuneability on odd applications but dont’ really do anything these late types won’t on all but the best engines…I have run em all! These carbs will give the maximum power available on any engine if you take time to tune them right, but they are a bit more suited to standard motors over 1500cc, motors with mild cams or standard cams and they operate best if you are using 30-33 chokes, they hate race engines, mad cams and mad chokes cause they they are designed mainly for hot production engines with a clear pulse strength to suit the retarded venturi and tubes - great where silk town driving and alike is paramount and you do commuting or just sunday driving, they also give superior economy to the early types. |
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| Author: | drmini in aust [ Tue Dec 05, 2017 1:33 pm ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Thanks Ian. I think the comments above are for 1 choke per cylinder?? I will try a single 40-G carby with the Alfa emulsion tubes, as I have a bunch. But I couldn't get them to work in my 45DHLA at all on a Mini. |
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| Author: | Ian_B [ Tue Dec 05, 2017 2:12 pm ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Yes its definitely for one choke per cylinder but verifies the better low and mid range that you encountered Im at a bit of a loss on emulsion tube choice I know F16 are advised for DCOE Cheers and thanks for the help |
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| Author: | drmini in aust [ Tue Dec 05, 2017 3:17 pm ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Generally on a Mini with a 5 port head either a #5 or#6 will work fine. But for a crossflow head I would run Alfa ones. Don't know the number but will look at my spare ones. Ian can you please reply to my PM re clutch plunger. 
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| Author: | Ian_B [ Tue Dec 05, 2017 5:42 pm ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Done ! The DHLA 40Gs will be here soon. One number different in serials A matched pair .Ripper
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| Author: | awdmoke [ Tue Dec 05, 2017 11:24 pm ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
I'm not sure on the spacing between ports on the Elder crossflow, but on my Pearce 7 port it is the same as the Alfa 40 dhlas I've bought. |
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| Author: | Ian_B [ Wed Dec 06, 2017 6:53 am ] |
| Post subject: | Re: Dellorto 40DHLA-F or G on Mini |
Hi mate Spacings same as dcoe weber so straight on they go What type were yours and how did you go with jetting etc Have you had the porting mods done to the Pearce. Aparrantly can be improved much by the right person More and more searching on this reveals the emission ones cover the idle to main circuit smoothly. It seems if its a race car the non emission or DCOE weber are the way to go. Doc has done well getting an emission carb working on siamesed ports . All the good info on one choke per cylinder is put aside with what he has achieved five port |
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