1394Cc N/a Setup Single Dhla 40 H

[CodeXS]

Hello,

 

I joined this forum because i seen many of you have success in using dellorto carbs and i have some problems with my setup which i cannot figgure out. Engine is a 1394cc with rmp range up to 6000, i use a single dellorto 40H with jettings i think factory from a giulietta :

 

58 idle

130 main

180 air corr

7772.11 emulsion tube

 

The troubles which i'm having are: hard starting and lumpy idle (progression phase seems ok) and i assume after progression (i have no rpm counter) if i accelerate hard (more or less) the engine makes a low noise and instead of accelerating it even slows then suddenly it "wakes up" and accelerate quite well.(the hole in acceleration phase is quite big i have to press clutch to rev it up faster then let it go...)

 

I've tried to mod the advance, changed the sparkplugs, plug wires, opened more the idle mixture screw...nothing.

 

Any ideeas please? (excuse my english, it's not my native language)

[CodeXS]

I forgot to mention choke is 30mm. I'll check the lvl setting today maybe i get lucky and it's incorrect.

[Nick Jones]

Is this the Peugeot 205 1.4 XS?

 

Sounds like it is either going lean (not enough fuel) when you accelerate, or maybe (perhaps more likely) too rich - do you get black smoke and a petrol smell when you press the accelerator fast?

 

I don't know much about carbs myself, but hopefully you'll get an answer from someone who does.

 

Cheers

 

Nick

[CodeXS]

It's a renault 12 with a renault 5 engine, i was thinking the same about lean between progression and main... still jets are from giulietta so it should be fine. (no there is no black smoke when i accelerate)

 

Carb it's emmision type i think not too many people can say for sure what's the proper manner to jet it but i will take any hint and test it

[Gerard]

Pics! Ihaven't seen a 12 for years!

[DaveNotSoSideways]

Single????

 

It's REALLY LEAN!!

 

That's a REALLY MAD IDEA!

 

You need HELP and not cause you are insane.

 

You need a bag of jets, lots of jets and to experiment.

 

I suggest atleast 160 main jet

 

Tuning this will be VERY HARD without Co2 meter or gas analysis and many jets.

 

Don't even have any idea what to say, sorry!!

[CodeXS]

 

Hopefully i've atached the images correctly, so you can see my setup (messy) and the looks (ugly) of that family car

Unfortunatelly arround here there are no rolling roads and co2 analisers nor i can get diff sizes jets but we'll manage somehow to do it right?

 

I have a couple of questions:

 

- if it's single why does it need main jet even bigger and since only one cilinder is filled at the time from one barrel?

- if i use a 160 main (which i don't have but i might be able to bore to size...) what should be main air correction?

 

As i said before idle is at least lumpy....but as soon as i barely touch throttle (get into progression circuit) engine spring to life...

I cannot close throttle to cover first progression hole completely as engine will die...(lean? 58 idle jet is big enough for the 220 fixed idle air?)

 

Thanks for helping, i need all the help i can get!

[CodeXS]

I forgot to add ... this setup of carb will be used in the next engine i have outside waiting for rebuild.

The engine outside is a 1289cc will get 282/282 degree camshaft, high comp 10.2:1 and maybe a diy programable CDI.

 

So far i use this as daily driver and it's a lot of fun, i love old cars.

[Nick Jones]

Interesting pics. I can't remember when I last saw a Renault 12 in UK. Saw lots in Baku (actually Dacias) as few years back. Why are you warming your petrol before it goes in the carb? I would think this is a bad thing and will cause vapourisation....?

 

Have you thought about buying a wideband lamba sensor (O2 sensor) like Innovate LC1 (LM1 with display I think) or Techedge? Then you can see what is happening at least. Not crazy expensive and can save you a lot of time and fuel.

 

If you can't get jets then you need some solder and a set of jeweller drills.

 

Cheers

 

Nick

 

Edit: in the pics it looks like the carb is VERY close to the inner wing

[CodeXS]

Dacia manufactured it yes, but since it's a 1973 car it's mostly a R12

Distance from inner wing is 10-12cm, perhaps not enough for a decent airbox but ok for a simple filtering element.

Gasoline heater it's yet another crazy ideea perhaps will be there no more when i'll change the engine.(no noticeable results neither in economy nor smoothness or bad things)

 

As for the wide lambda yes i would like to have one, but since it's a hobby and i got plenty of chassy work and paint and so on i try to keep it as low as i can with the costs i am sure you understand...

 

So guys do you think if i just start with making main jet 160 without modifying main air corrector things will improve?

[CodeXS]

Got drillbits, wore pretty hard to find in this city and got not a full range just: 0.6,0.7,0.9,1.0,1.2,1.3,1.5,2.0.

 

I'll try today to drill main jet to 150 (nearest to value sugested by davesideways) should i leave air corr at 180, or use the rule of thumb +50 and drill to 200?

[CodeXS]

Drilled main jet to 160 from 130...on sudden throttle engine dies.(which didn't happen so far)

Now i got the itch to modiy air corr to 200...i'll be back after with the miracle i hope

[CodeXS]

Ok, so what i ended up with last evening is:

 

choke: 30mm

main jet: 160 (drilled from 130)

main air corr: 200 (drilled from 180)

idle jet : 60 (drilled from 58)

 

It's not a miracle but the car moves better, the "hole" in acceleration is barely noticeable...i suspect i am verry close to a good setting of jets...

 

I would try to make sleeves for the idle air corr to make it smaller but that if i find a guy to make them on a small lathe.

[spitNL]

You could try soldering or epoxy and re-drill the air bleed.

 

Just don't drill to the final size on the first go, drill at least one size smaller and "ream" to size with the "right" drill bit.

[CodeXS]

Thanks for the ideea, still soldering those jets would be impossible without overheating rest of the upper cap. I'm still considering epoxying it with something like J-B Weld or sleeving them. (sleeving can solve even soldering and removal/interchange sleevs)

 

I'll see how i'll kill the time this saturday with yet another trial-error

[CodeXS]

So far setup is:

 

30mm choke

70 idle jet

140 main jet (on 150 i got black sparkplugs)

200 air corr

 

after looking today at plugs with this setup they look light-brown, i would say pretty good looking

 

still fuel consumption is not what i had with initial setup, grew with 1-2 liter /100km but i suspect it's the heavy foot i'm experiencing since carb goes well.

 

One issue still i have that is near 60km/h in 4'th gear - maybe 2000-2500rpm (no rev counter) i hear it knocking...above that less and less, could it be main jet insuficient or airr corr too large (so it becomes to lean)

 

Hopefully next week i'll be able to check it on a gas analiser, so i'll know for sure what is all about....(no rolling road just a gas analiser one that is used for MOT)