34datr carb jets- what are you using

Kevin Cozzo

Kevin Cozzo

True Classic
never have got this thing to really work right- was wondering what everybody else that uses on of these is using as in idle and main jets, and emulsion tubes. Nothing wild on the engine- 1500 with mild European cam and headers
Was also wondering- one of you guys had posted something-I believe it was Steve C about using aftermarket electric fuel pumps and hard warm engine starting, post also had some info on a fuel pump safety setup with a particular oil sender- need to do this, can't find the post, thanks in advance
 
Do you per chance mean 34 DMTR or 32 DATR? I"m maybe showing my ignorance of the existance of a 34 DATR

I guess jets should be about the same.

I'll check and get back to you
 
The 3_ D_TR carburetors are all the same basic series...

All use the same body and jetting parts. Lots of variations to suit different applications and markets.

Ciao,
 
The trouble is there are many variations of 34DATR, they come with many different choke sizes, which allows them to flow different volumes of air. To advise which jets etc to use would require that you let us know what variant of DATR (DMTR / DATRA etc) your using.

I can then look up the stock specs in my Weber bible, and at least you have baseline jetting numbers as well as knowing what vehicle (and engine capacity) the carb was fitted as original equipment to.

Stock electric fuel pumps on Fiats are always relayed (Normally closed from memory) and the relay earths thru the oil pressure light switch, which means that when the engine looses oil pressure the relay opens and stops the pump and the car will hopefully run out of fuel before it siezes....

SteveC
 
Quoting myself from here: http://xwebforums.org/showpost.php?p=13554&postcount=7

My jets are somewhat out of spec too. This is the original numbers according to Haynes with my jets in parenthesis:

main primary 1,07 (1,12)
main secondary 1,30 (1,35)
air correction pri 1,60 (1,90)
air correction sec 1,50 (1,70)
emulsion tube pri F30 (F30)
emulsion tube sec F30 (F30)
Click to expand...

edit: And that was supposed to answer Kevin's original question...

For what it's worth, the car runs fine with these jets. It's perhaps a bit thirsty though (around 1 liter/10km). No problems with emissions at the "Bilprovning" :) .
 
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I smell a dyno day coming on!

We did one last friday and it was one of the best things I"ve ever done with a car. It was a great learning experience and paid dividends. You just can't beat the wideband O2 sensor on a dyno.

I suggest you get some base numbers then make an appointment :)
 
easy there....

just trying to get the thing running again after sitting a year, but it never ran right in the first place after I put this thing on- now I can't get it to idle cold. last year before I started painting, it would have problems starting after warming up, and not like vapor lock- it wouldn't warm start unless I floored it, and this could be after a 10 minute trip up to the store. I know it is a 34 datr, says so on the base plate. I'll get all the numbers off the base and post em here. Before this carb i was running a stock 77 28/32 with mech secondaries and it ran fine after I stole the jets out of the 1500 carb that was on the engine I put in her, BUT it would have that hard warm starting issue, and I think the fuel pressure might be too high, and causing flooding issues. What I'd like to know first is what anyone else running a 34 type carb is using for jets, so I can get a baseline tuning
 
ok got some numbers

baseplate has numbers as follows: 34 DATR 2 250 6c. I measured the choke plate and got a measurement of 4.2 cm at it's widest point. Also wasn't there a chart of jet setting on the old forum (Jimbo HELP!) So if you could help me out Steve, be much appreciated there too
 
Here is AnthonyG's testing thread

Kevin Cozzo said:
baseplate has numbers as follows: 34 DATR 2 250 6c. I measured the choke plate and got a measurement of 4.2 cm at it's widest point. Also wasn't there a chart of jet setting on the old forum (Jimbo HELP!) So if you could help me out Steve, be much appreciated there too
Click to expand...

Start with this Kevin... I am still hunting.

http://www.network54.com/Forum/12159/message/1151954169

Update. I don't find a chart posted, but I Googled this page. Not exactly what you are looking for.
http://www.gracieland.org/cars/techtalk/weboem.html

Courtney's 128 page has some dual DCNF and DCOE info.
http://www.mirafiori.com/~courtney/128/tech/dual_carbs_config.html

Oh Kevin... you are going to like this one comrade!
000.jpg
 
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34DATR 2 /250 is originally from a Lancia Beta 2000, and is probably one of the better carbs to use as an upgrade. I've scanned the pages from my Weber bible for you, sorry about the size, but it's the only way to get the text clear and legible.






Most people forget that a carby controls the amount of AIR that an engine can breathe in, and then mixes a pre determined amount of fuel with that air. As the venturi sizes are quite large in cross section when compared to the 22/22 venturis the 1500sohc came with for the US market, you will need substantially larger jets than the stock 32 uses to mix the required amount of fuel for the engine to perform at it's best. Also simply comparing the 34DMTR jetting that the X19 was supplied with for the european market will again be too lean as the venturi sizes for the Euro 1500X are again considerably smaller.

My personal opinion is that the stock F30 emulsion tubes your using will be too lean in design to work well. E tubes are not linear in their nomeclature, so an F30 bears no linear resemblance to an F29 ....unlike jets which follow a linear format. I would try some F24's as these are much slimmer and displace less volume of fuel in the jetwell.

Also if your cam timing isn't spot on, the amount of manifold vacuum you have will be lower than optimal, this requires the use of a larger idle jet to compensate for the reduced vacuum signal.

SteveC
 
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