# Help with Dellorto Specs on healthy 1.8L 8V's



## doctor12valve (Jul 20, 2005)

I just picked up a set of used Dellorto DHLA 40mm Side Drafts (off of a Alfa Alfetta 2.0L) and have them installed and somewhat operating on my 1984 Rabbit JH Engine which is mostly stock. I just rebuilt them, set the float level, replaced the needle and seat, accel. pump diaphragm, etc - Master kits from JHPS (great guys to buy from btw). The "fueling" is somewhat experimental on VW's but seems to have great success on Porsche App's care of PMO. I speak of the PCU (pressure control unit) which retains the returnable CIS fuel system and cuts the pressure down that which carbs like ~ Mine is set to 3-4psi at this time and has a small in line filter after the PCU.

I know little of tuning these things but from what I understand there are not really any screws to turn other than the Idle air screws. That being said, she starts right up on a warm day with a few pumps of the throttle and no Choke. Idles great at 800 or so and takes throttle OK. The problem I am having is that it breaks up under any sustained throttle past 1/4 pedal depression. It bogs and appears to run very rich and miss consistently. When this happens, you can feather the throttle and regain throttle (eventually) after a few seconds - Get brave with the accel pedal and repeat the process all over again. It just isnt practical, safe, or enjoyable to drive in its current state.

I will post the exact Dellorto specs of all the jetting, chokes, and Venturis when i get home in a couple hours - I am sure that will help you carb experts -> help me.

A few pics of the setup as it is now:


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## doctor12valve (Jul 20, 2005)

Ok - here are the specs on the ancillaries:

*Emulsions = 142 

Idles = 58

Pump jets = 33

Venturis = 7848 .1

Chokes = 32mm*


Super - hope to hear yeas and neas soon :thumbup:


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## B4S (Apr 16, 2003)

Ha! Dells are my favorite, on my third set now. A few things:

1) on the top, where it says DHLA 40...is there a letter after the 40? It's important to know if they are emissions spec carbs or universals. 90% of the 40s on the market today were originally on 70's Alfas during the era of tightening emissions, and are a bit different to tune.

2) a breakdown of the idles, mains, airs, and emulsion tubes will help too.

On my 1.8 8v, here's my specs for my old emissions carbs:
-.11 emulsion tubes
- 130ish mains
- 200-210 airs
- 58 idles (all emissions specs will run between 58-60)
- 32mm chokes

Currently I'm running a set of non-emissions carbs, and while I haven't had a chance to tune them properly, here's my specs:
- .5 emulsion tubes
- 132 mains (too lean, that much I know)
- .1 idle holder
- 55 idles
- 180 airs
- 33mm chokes

The car fires up and cruises great, but drops to the 15's at WOT with the above jetting. I'm running a neuspeed 256* cam (very mild).


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## B4S (Apr 16, 2003)

doctor12valve said:


> Ok - here are the specs on the ancillaries:
> 
> *Emulsions = 142
> 
> ...


The main jets will press into the bottom of the emulsion tubes, and the airs will press onto the top. There should be a number on the long middle portion, that's the emulsion tube. 33 pump jets are fairly low, and the 58 idles make me think they're emissions carbs. The .1 venturies are NOT an emulsion spec part though...so I hope these carbs haven't had mismatched parts put in them .


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## doctor12valve (Jul 20, 2005)

B4S said:


> The main jets will press into the bottom of the emulsion tubes, and the airs will press onto the top. There should be a number on the long middle portion, that's the emulsion tube. 33 pump jets are fairly low, and the 58 idles make me think they're emissions carbs. The .1 venturies are NOT an emulsion spec part though...so I hope these carbs haven't had mismatched parts put in them .


Good good - I was also concerned about the venturis... they are the largest at *.1*, correct? If that is the case they definitely dont match (if my common sense is worth damn). 

I will have to pull the emulsions out again and get the #'s sorted.. did my best trying to ID this stuff upon rebuilding. Thanks for your help :thumbup:

Ever heard of anyone using the PMO PCU with any success - it seemed like such a cool thing in theory but I am wondering if there is not enough volume with it installed.. Should the in-line filter be full while the pump is active? Is that any sort of indicator of anything?


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## B4S (Apr 16, 2003)

The .1 vents are the earliest starters, which doesn't work very well in the emissions 40s, unless you're running a sub-1.3L engine. If they're universal performance carbs (non-emission), then the .1s are standard issue. Snap a pic of the top of the carbs with the jet cover off, I can see if they're emissions carbs from the way the idle air bleed holes are laid out. It's VERY important to know what spec they are before tuning, otherwise you'll end up with a huge headache...and a FS thread, lol.

IIRC, anitchristonwheels is running the PMO regulator with success. I've never worked with one, but it seems like it would work great.


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## doctor12valve (Jul 20, 2005)

B4S said:


> The .1 vents are the earliest starters, which doesn't work very well in the emissions 40s, unless you're running a sub-1.3L engine. If they're universal performance carbs (non-emission), then the .1s are standard issue. Snap a pic of the top of the carbs with the jet cover off, I can see if they're emissions carbs from the way the idle air bleed holes are laid out. It's VERY important to know what spec they are before tuning, otherwise you'll end up with a huge headache...and a FS thread, lol.
> 
> IIRC, anitchristonwheels is running the PMO regulator with success. I've never worked with one, but it seems like it would work great.


Cool deal - I will get a pic tomorrow with the jet covers off and the numbers on the little metal tags that they still have :thumbup: If the Rabbit wasnt at the shop I'd take pics now ... and Ive been trying to get the Mk2 back in order... These darn VW's


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## B4S (Apr 16, 2003)

Not the metal tags, just look for DHLA 40 on the top, there will be a letter beside the 40. Yours are definitely late model DHLAs from what I can tell, so it's not as easy to distinguish the universals from the emissions.

I'd say it's 50/50 right now. The emissions carbs are actually a better choice for a driver/weekend warrior setup, I was getting 31mpg with mine, and dynoed a nearly-stock RV code 8v at 105whp .


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## doctor12valve (Jul 20, 2005)

B4S said:


> Not the metal tags, just look for DHLA 40 on the top, there will be a letter beside the 40. Yours are definitely late model DHLAs from what I can tell, so it's not as easy to distinguish the universals from the emissions.
> 
> I'd say it's 50/50 right now. The emissions carbs are actually a better choice for a driver/weekend warrior setup, I was getting 31mpg with mine, and dynoed a nearly-stock RV code 8v at 105whp .


Well I have my hopes that they arent a mixed bag  Let you know tomorrow!


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## doctor12valve (Jul 20, 2005)

So when you say "_33 pump jets are fairly low_", do you mean they are too small for my application? What size were your emissions carb's pump jets?


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## B4S (Apr 16, 2003)

They were about the same, that's another thing that leads me to believe they're emissions carbs. My current pump jets are 42s (non-emission).


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## Svedka (Jul 4, 2008)

had to comment love the pics,:thumbup:

Like the BFI valve cover and the way you attached the throttle linkage, what oil catch can did you use and how do you like the BFI valve cover?

And what alt bracketry did you use?
:beer:


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## doctor12valve (Jul 20, 2005)

Svedka said:


> had to comment love the pics,:thumbup:
> 
> Like the BFI valve cover and the way you attached the throttle linkage, what oil catch can did you use and how do you like the BFI valve cover?
> 
> ...


The Catch can is SPA and has a nice little drain at the bottom for the bad stuff to come out. The Alt. bracket is from a non-turbo diesel Mk1. Thanks for the kind words!


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## doctor12valve (Jul 20, 2005)

B4S said:


> They were about the same, that's another thing that leads me to believe they're emissions carbs. My current pump jets are 42s (non-emission).


Ok, so they are Dellorto DHLA *C*'s - I took pics but forgot the camera at work so pics will be up soon.

As well, I ID'd the following:

*Emulsion tube: 7772.11

Air Corrector Jet: 230

Mains Jets: 142

Idle Jets: 58

Idle Jet holder/housing: 7850.9

Pump jets = 33

Venturis = 7848 .1

Chokes = 32mm*

Hopefully all of this is in enough order and will work sufficiently for ripping around town... Unfortunately, I also developed a fuel leak on the DRV side carb... At sustained RPM above 3K, fuel is vigorously coming out of the Cold Start/choke mechanism. I thought it might have been coming from the vent cover but it really looks to be spewing from the choke mech. So yah, I have a new problem as of today. 

Tag, you're it opcorn:


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## B4S (Apr 16, 2003)

Ok, you lucked out. Those are non-emissions .
The jetting seems good to me, except the .11 emulsion tubes won't work well in a non-emissions carb. You'd benefit greatly from getting a set of .5/.6/.7 tubes (although the .7s are long discontinued). That stumble you feel is due in part from the non-compatible emulsion tubes IMO.


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## doctor12valve (Jul 20, 2005)

B4S said:


> Ok, you lucked out. Those are non-emissions .
> The jetting seems good to me, except the .11 emulsion tubes won't work well in a non-emissions carb. You'd benefit greatly from getting a set of .5/.6/.7 tubes (although the .7s are long discontinued). That stumble you feel is due in part from the non-compatible emulsion tubes IMO.


Well that is good news! - Do you have any emulsion tubes by chance? I will be searching for some shortly - found a few but they are abroad, and no signs of the *.7's*.

Also, Is the Main jet # too much @ 142? It seems that they are a bit big according to this scale. Could that also contribute to the WOT and Sustained throttle bog?



ALFA1750'S CARBURETORS PARTS STORE said:


> *Dell'orto DHLA 40 carburetor settings
> 
> chokes;Main jet ;emulsion tube;air corrector;idle jet;pump jet;needle valve;
> 
> ...


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## doctor12valve (Jul 20, 2005)

Ok so Ebay will be my saving grace in terms of a la carte Dellorto parts for cheap - found a couple shops that sell exactly what it seems I need - They both have the *.7's* emulsion tubes in stock as well - Any reason to go with a *.7* tube over a *.5* or *.6*?

And is it even possible for fuel to be coming from the choke mechanism on the top of the float bowl cover? I read if the float isnt set right that the bowl will continue to fill causing fuel to come out of the vent.. though it doesnt seem to be coming from the vent, it is still hard to say. When it happens, the fuel is fast moving and comes out in that area briefly but with much vigor at higher sustained RPMs.

Learning a lot :beer:


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## B4S (Apr 16, 2003)

I don't have any etubes, I foolishly sold all my carb stuff a few years back when I decided to try something else...only to return to carbs. All I've got is what's in my current set. I wouldn't try to find the .7's tubes, .5s would be just as good. The only difference is the thickness of the tube itself, so if necessary, .5s can be turned into .7s on a lathe.

Alfa1750s scale is a good way to get a baseline, but it's not the bible by any means. The bog could very well be caused by the .11 tubes, they aerate the fuel in a massive way, which is what an emissions carb needs to function. Don't bash your head trying to tune these carbs until you get a proper set of tubes, it's pointless IMO. 

On my carbs right now, I am running 132 mains, which are much too lean for WOT. They came with 142 mains, which I haven't had a chance to try out yet.


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## doctor12valve (Jul 20, 2005)

B4S said:


> I don't have any etubes, I foolishly sold all my carb stuff a few years back when I decided to try something else...only to return to carbs. All I've got is what's in my current set. I wouldn't try to find the .7's tubes, .5s would be just as good. The only difference is the thickness of the tube itself, so if necessary, .5s can be turned into .7s on a lathe.
> 
> Alfa1750s scale is a good way to get a baseline, but it's not the bible by any means. The bog could very well be caused by the .11 tubes, they aerate the fuel in a massive way, which is what an emissions carb needs to function. Don't bash your head trying to tune these carbs until you get a proper set of tubes, it's pointless IMO.
> 
> On my carbs right now, I am running 132 mains, which are much too lean for WOT. They came with 142 mains, which I haven't had a chance to try out yet.


Very good sir! You have been very helpful - I will get some proper etubes and report back ASAP!


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## doctor12valve (Jul 20, 2005)

New .5 etubes, 2.25" velocity stacks, and some trick foam filters from Ramair UK should be here soon! Hopefully this Friday - I am ready to really drive this thing :beer:


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## B4S (Apr 16, 2003)

Nice!


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## doctor12valve (Jul 20, 2005)

B4S said:


> Nice!


 Okay, Installed the .5 etubes and the problem is still there. Not really any better or worse. 

I pulled the plugs and they are fresh-fuel-black and I have up-fire coming out of the both carbs but more so on the Driver's side carb. I am aware this could be a ignition timing issue but I am still skeptical about the jetting. The timing is at about 15* BTDC @ 2500 or so. A lot of the component examples for similar engines seem to show much smaller main jets but not by a huge margin. 

The car idles beautifully, and does take throttle decently but seems to break up under the progression stage and during sustained RPM over 2500 or so.


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## doctor12valve (Jul 20, 2005)

I also believe, after reading the **** out of my Dell-tuning manual, that the Idle Jet holders are far too aggressive and dont really even make sense to be in my C's. I have 7850.9's and every other application I have seen as an example are using 7850.1's, a holder that is on the other end of the scale from what I understand... 

 And now I eat a late dinner.


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## B4S (Apr 16, 2003)

Well, the .5s may not have cured the problem, but trust me...you'll be glad you have them . 

My idle holders are a .1 (or .2 can't remember offhand), but I have had zero time to experiment with different ones, so I can't say for sure if they're a better option or not. My car has been off the road all summer, with tentative zips up and down the road for ****s and giggles . 

How many turns out from seated are the idle screws?


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## doctor12valve (Jul 20, 2005)

B4S said:


> Well, the .5s may not have cured the problem, but trust me...you'll be glad you have them .
> 
> My idle holders are a .1 (or .2 can't remember offhand), but I have had zero time to experiment with different ones, so I can't say for sure if they're a better option or not. My car has been off the road all summer, with tentative zips up and down the road for ****s and giggles .
> 
> How many turns out from seated are the idle screws?


 I am definitely glad I ordered the .5 etubes and will be happy when I know I have the right idle jet holders. If even after swapping these parts, the carbs still dont run right, I will feel better knowing they have the right components in them and they can be eliminated from the problem list. 

I will keep plugging away and will post as soon as the Idle jet holders (7850.1's Ordered today!) show up. C'mon Royal Air Mail!


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## B4S (Apr 16, 2003)

I love Royal Mail . 
My idles are 58s, if it helps any. I recall getting 'decent' wideband readings with them, at cruise. Your 55s should be similar in fueling with the .1s in there.


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## doctor12valve (Jul 20, 2005)

B4S said:


> How many turns out from seated are the idle screws?


 I believe they are turned out either 1/2 or 1 complete turn from specified -> So 3 or 3.5 turns out.


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## doctor12valve (Jul 20, 2005)

B4S said:


> I love Royal Mail .
> My idles are 58s, if it helps any. I recall getting 'decent' wideband readings with them, at cruise. Your 55s should be similar in fueling with the .1s in there.


 Sounds great! I am Looking forward to my 3rd UK based order in a month to get here...


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## doctor12valve (Jul 20, 2005)

Some pics of the new toys I just installed... 

*RAMAIR Filters and EMPI 2.25" V-Stacks* 









*Stacks Installed* 



























*RAMAIR filters installed*


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## microdub98 (May 12, 2007)

I'm really glad this thread is here opcorn:, & thanks to my buddy Andy for informing me this thread was started . I will probably be chiming in w/ questions aswell once I get mine up & ready to sart running. G/L with yours Dr. 12v :thumbup::beer: 

How well is the PMO pressure control unit working for you??? It seems to be a more logical, asthetically pleasing, & better way of going about the fuel delivery/controlling since you're mainting most of the stock delivery system....which I like :thumbup:. I have a Carter 4070 pump I planned on usning in conjunction w/ some sort of FPR(haven't decided which one to use but I was recommended to set it at 3-4psi like your PMO unit is set at). I checked PMO's website but it seems to lack a lot of info & such on their products. Where did you order your PCU from???? 

Thanks, Jeremy


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## doctor12valve (Jul 20, 2005)

microdub98 said:


> I'm really glad this thread is here opcorn:, & thanks to my buddy Andy for informing me this thread was started . I will probably be chiming in w/ questions aswell once I get mine up & ready to sart running. G/L with yours Dr. 12v :thumbup::beer:
> 
> How well is the PMO pressure control unit working for you??? It seems to be a more logical, asthetically pleasing, & better way of going about the fuel delivery/controlling since you're mainting most of the stock delivery system....which I like :thumbup:. I have a Carter 4070 pump I planned on usning in conjunction w/ some sort of FPR(haven't decided which one to use but I was recommended to set it at 3-4psi like your PMO unit is set at). I checked PMO's website but it seems to lack a lot of info & such on their products. Where did you order your PCU from????
> 
> Thanks, Jeremy


 The PMO PCU is a very neat part and nice quality - It is working fine for now but as you can see the Rabbit is not really driveable - It has been back an forth from home to the shop once and thats it (15 miles total). I have never heard anything bad about the carters and everyone says that is the best pump for this sort of thing. However, if the PCU does turn out to be good at it's job, I will be happier with it due to its simplicity and how rad it looks. 

I bought it straight from PMO (which is no small task) - I had to track down Richard @ PMO by calling one of his dealers in order to get his phone #. I was not too keen on mailing PMO a letter (which is what they wish you to do) mainly because my generation just does not do that sort of thing  

I will post as soon as I receive my 7850.1 Idle Jet Holders... I really want the .9's to be the problem  ~ That will be a sweet fix if the .1's are all I need.


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## YJSAABMAN (Jun 28, 2006)

Your welcome for pointing you in this direction, Jeremy. :thumbup: 

I found the PMO on the Pelican parts website for $90. Seems a fitting place for it, as I believe it was designed by a Porsche enthusiast for CIS to Weber conversions.


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## doctor12valve (Jul 20, 2005)

YJSAABMAN said:


> Your welcome for pointing you in this direction, Jeremy. :thumbup:
> 
> I found the PMO on the Pelican parts website for $90. Seems a fitting place for it, as I believe it was designed by a Porsche enthusiast for CIS to Weber conversions.


 Correct sir :thumbup:


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## doctor12valve (Jul 20, 2005)

Well I received the 7850.1 idle jet holders today (Royal Mail is awesome by the way!) and installed them...

Relatively no change. I just dont know where to go at this point.

*B4S *- what are your plugs and what are they gapped at?

I think I am going with a friends suggestion to switch to the carter pump and a bucket of fuel and see if the problem replicates itself that way.

I ran it today after installing the new holders and cleaned the plugs before hand - after about 15 min of running and duplicating the same "loading up" issue I pulled the plugs to find they were wet and fresh-fuel-black. 

To reiterate, the car fires right up, idles great, takes throttle nicely both easing into it and also stabbing it - It just wont handle WOT or sustained higher RPM for any reasonable length of time.

Ideas ?


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## doctor12valve (Jul 20, 2005)

So Far the Dell's have the following specs:

*Emulsion tube: 7772.5

Air Corrector Jet: 230

Mains Jets: 142

Idle Jets: 58

Idle Jet holder/housing: 7850.1

Pump jets = 33

Venturis = 7848 .1

Chokes = 32mm*

And now on the ABA setup (EDIT 11/22/11)

*Emulsion tube: 7772.5

Air Corrector Jet: 202.5

Mains Jets: 146

Idle Jets: 58

Idle Jet holder/housing: 7850.1

Pump jets = 33

Venturis = 7848 .1

Chokes = 32mm*


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## B4S (Apr 16, 2003)

How horribly odd .
I'm using champion RNY9Cs, gapped to .045" (distributorless ignition, Megajolt).


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## doctor12valve (Jul 20, 2005)

B4S said:


> How horribly odd .
> I'm using champion RNY9Cs, gapped to .045" (distributorless ignition, Megajolt).


Yah It is odd and somewhat horrible - I want to get this thing running before winter if possible..

Open to ideas :beer:


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## Svedka (Jul 4, 2008)

is it in your timing?

get a AFR gauge:beer:


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## doctor12valve (Jul 20, 2005)

Svedka said:


> is it in your timing?
> 
> get a AFR gauge:beer:



The initial timing and advance are well within the range of what they should be (as far as I can tell).

I agree with you as far as the AFR goes.. I am going to run a Facet low PSI pump on it today to see if that makes any positive differences. 

If the pump does not change anything, I will install the Gunson Colortune tester and see if it is leaning out or loading up when the problem occurs.

:thumbup:


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## Svedka (Jul 4, 2008)

what distributor? verified the cam timing with the valve cover off?


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## doctor12valve (Jul 20, 2005)

Svedka said:


> what distributor? verified the cam timing with the valve cover off?


Stock JH distributor with vacuum advance hooked up to manifold source - this car ran great off of it before the carbs and I have modeled my setup after a good running Rabbit with the same component group so I know the distributor should be fine for this app.

Cam timing is 100% correct. 

The revs/power simply die after a short stint of wide open or sustained high RPM. I Drove it today and it runs great for a short bit of WOT and then it begins missing and falls on its face. I then have to feather the throttle to regain power and start over again.

I tested the Facet pump on the car today and the problem occurred just the same.

I tested a new coil on the car today and the problem occurred just the same.

It is not fuel supply related and it is not timing or spark related. It as though something within the carbs is not correct and causing the misfiring... The concern can be repeated during a road test or while free revving at a fixed high rev (3500-4000). When it happens, gargling sounds come from the carbs and there are sometimes upfires from the horns when feathering the throttle during the misfiring.


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## candm (Apr 27, 2003)

i have a dual weber setup on my rabbit that uses an electromotive distributorless ignition so i never went through the other ignition setups possible using a distributor. however, i always remember something i read about not hooking up your vacuum for your timing to the intake manifold as it will cause problems such as you describe ( with sidedraft carbs ). if you look at the carb facts at the top of the carb forum, the 12th post in there says exactly this. that info is also pulled from the redline site, www.topendperformance.com. after you get that sorted out, i would run about 12 initial timing and about 30 overall to start with and then see how its running.


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## doctor12valve (Jul 20, 2005)

candm said:


> i have a dual weber setup on my rabbit that uses an electromotive distributorless ignition so i never went through the other ignition setups possible using a distributor. however, i always remember something i read about not hooking up your vacuum for your timing to the intake manifold as it will cause problems such as you describe ( with sidedraft carbs ). if you look at the carb facts at the top of the carb forum, the 12th post in there says exactly this. that info is also pulled from the redline site, www.topendperformance.com. after you get that sorted out, i would run about 12 initial timing and about 30 overall to start with and then see how its running.


Thank you for the suggestion :thumbup: I will try it today!


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## doctor12valve (Jul 20, 2005)

_



DO NOT hookup the distributor vacuum advance to the intake Manifold. That does not work and is a common mistake we see. If you do that you will pull full advance at idle then as soon as you open the throttle it loose vacuum and the timing will retard quickly causing a big stumble or flat spot and very bad throttle response.

When running Sidedrafts you need to either get a centrifugal advance distributor or leave your vacuum advance disconnected and just run more initial timing. You usually need 12-14 degress advance at 1000 RPM and 36 degrees total by 3000 RPM for the carbs to react properly. These timing numbers are baseline estimates only and can vary from car to car. You have to make sure you do not have a detonation problem from too much advance.

footnotedhttp://www.racetep.com/webfuelspark.html#webspark

icandigit,
Thomas

Click to expand...

_:thumbup:


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## doctor12valve (Jul 20, 2005)

Okay,

I reset timing as per above recommendation with Vac-Adv. not hooked up. Engine ran exactly the same and repeated the same concern. 

Rev Rev Rev Rev Rev Rev Rev Rev Rev Rev.... BOGGGGGGGGGGGGGGGGGGGGGGGGGG.

I must drive the point home that it runs great for a short period and then falls on its face. 

I am just about ready to sell this ****.


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## candm (Apr 27, 2003)

did you move the distributor as mentioned, to gain more timing?


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## doctor12valve (Jul 20, 2005)

candm said:


> did you move the distributor as mentioned, to gain more timing?


Egg.. my Face... ...










I had the timing adjusted for when the vac.adv. was hooked up - after your post I thought about it and decided to screw around with the timing in general and moved the dist after the vac.adv. was removed, started it, and listened by ear for the bog and turned the dist. until the bog was gone.

DONE! She runs Great!

Though there is more dialing in to be done.. I am Extremely Happy right now. 

A few hours ago I was ready to give up and now it runs relatively good and it is fun to drive - 

*Thank you all very much for your help!* :beer::beer::beer::beer::beer:

I will update further as I progress :thumbup::beer:


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## Svedka (Jul 4, 2008)

Svedka said:


> is it in your timing?
> 
> get a AFR gauge:beer:


:beer::beer::beer:


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## candm (Apr 27, 2003)

glad to here it. im no mechanic but i have worked on motorcycles and cars thruout the years. i went thru all of this when i did my dual carb rabbit a few years ago. first i had a leak at the intake ( softmounts were not tight enough ). then fuel pump issue and finally jetting. looking back on it most of the problems were self generated. its best to be patient and take your time with each aspect of the conversion to carbs. very seldom is it a problem with the carbs. after this, when you are tuning the carbs, do one part at a time. idle, then sync the carbs. idle and progression to about 3000 which are your idle jets and i think on dells, idle jet holders, at the same time making sure your mixture screws are within proper setting. not sure, but i think dells are supposed to be 3-4 turns out. after it runs good there then work on your main jet, say 3000-5000, and finally your air corrector jet for top end. through all of this, if it bogs, it is typically rich. if it hesitates, stumbles or spits back out the front of the carbs, it is lean. good luck


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## beetlevdubn (Apr 25, 2005)

I actually think that your issue is fuel pressure related. The Dells are really picky about pressure, and its recommented that you run no more than 2 to 2.5 psi. Any more, and the fuel pressure pushes past the needle/seat, and you get fuel dribbling into the engine when you don't want it to. You'll get loading, running rich, etc. 

I have actually known a lot of people that run 1.5psi, but I personally run about 2 to 2.5. 

If you can dial back your pressure, I think you will see some positive results right away. 

Are you getting any popping at idle or decel? If so, that can be a plugged idle jet. Dell idle jets are very temperamental, they plug easily due to thier small orifices, so its necessary to have a good clean fuel filter and keep the work area clean when you are swapping jets, etc.


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## beetlevdubn (Apr 25, 2005)

Sorry, I just noticed some other posts had happened since I read yesterday, and I also need to point out that your top end issue is related to running out of fuel due to not having a pump that can flow enough volume (facet pump). I have no idea on the PMO thing, but what I have always used, is the Carter P4070 and a Holley Red Fuel Pressure Regulator. The carter will give you enough volume, at 6psi, and the Holley FRP will cut the pressure to the 2psi you need, without cutting the volume. 

If you are sure that the PMO is cutting pressure but not cutting volume, then keep it. If you are unsure, then run what I mentioned.... it works. I have been down the road with cheap and expensive regulators and fuel pumps, and that combination has worked well for me on multiple Dellorto setups. 

I think your jetting is close, but I think you are battling two issues. At idle, you have too much pressure, so its running rich. At WOT or high end, its running out of volume, and its starving/running lean. There is still fuel in your accelerator pump, so when you pump the throttle a couple times, it adds fuel to your starving engine. 

I hope that helps give you some place to start. If you can put a fuel pressure gauge inline to check the pressure, that will help a lot. If you can watch the fuel pressure at WOT (run the gauge inside), I am guessing you can see the pressure drop when you are at WOT... running out of fuel.


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## doctor12valve (Jul 20, 2005)

All points duly noted.. It will be a long road getting this thing tip~top but at least it is driveable now and I dont feel bad actually spending more money and time on it. That was tough to come to terms with when it didnt run well. 

Next thing is a full exhaust and then some further tuning with the current parts. 

Hopefully I will soon order a grown-up's throttle setup like this one: 

http://www.dellorto.co.uk/merchandi...p?PartNo=LP4301&CategoryID=8&PartsectionID=49


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## doctor12valve (Jul 20, 2005)

Tonight I attempted to ID the timing to which my new found running success is attributed to find that none of it made much sense. 

With the car running reasonably, the base timing at 1000RPM is 25* BTDC according to the very old MAC Timing Light I have been using. I then backed it down to 20 and then 15 to find that it completely hated those base advances. 

I then ran it back up to 25* and installed the *Gunson Colortune* in cyl #1. This quickly indicated a relatively rich idle and reasonably (healthy) rich WOT. Adjusted the Idle Mixture screws to attempt to correct Idle richness (somewhat successful) and moved the Dist. slightly to get optimum combustion color which by Gunson's recommendation is Orange. I never checked the final timing after this calibration - it was too dark and truly, I forgot to. I will get back to you all with that info. 

The Results were absolutely spectacular! That little car is a veritable Rocket and runs superb! Fast-as or faster than it was on CIS (It ran very strongly on CIS) + super crisp throttle response and amazing sound! *And I must mention that I test drove the car earlier today with the factory Vac-Adv unplugged and blocked, only to find it popped and gurgled during throttle lifts and had trouble with progression.... I put the Vac-Adv back on it's normal duty and the popping/gurgling ceased and throttle response came back - the car runs flawlessly.* I find no reason to unhook the Vac.Adv. on a factory JH 1.8L when using the existing ignition system and a set of appropriate side drafts. 

Hoofreakingrayyyyy :vampire: Happy Carboween umpkin:


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## microdub98 (May 12, 2007)

That linkage setup is pretty tasty lookin :thumbup:. Wouldn't mind having that myself.


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## doctor12valve (Jul 20, 2005)

microdub98 said:


> That linkage setup is pretty tasty lookin :thumbup:. Wouldn't mind having that myself.


 Eurocarb/DellortoUK has them and they are a pleasure to deal with :thumbup:


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## wut_cel (Nov 27, 2009)

What's that orange rubber on your manifold?


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## YJSAABMAN (Jun 28, 2006)

wut_cel said:


> What's that orange rubber on your manifold?


 Vibration/heat isolator carb to manifold gaskets. :thumbup:


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## wut_cel (Nov 27, 2009)

YJSAABMAN said:


> Vibration/heat isolator carb to manifold gaskets. :thumbup:


 And where could one acquire one if these?


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## doctor12valve (Jul 20, 2005)

wut_cel said:


> And where could one acquire one if these?


 Ask and you shall receive - definitely buy from these guys. They are great to deal with and very helpful via email, too! 










http://www.dellorto.co.uk/merchandi...p?PartNo=SPACER&CategoryID=8&PartsectionID=46 

Not cool and red but are the same deal!


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## VenaGTi (Mar 19, 2006)

> I find no reason to unhook the Vac.Adv. on a factory JH 1.8L when using the existing ignition system and a set of appropriate side drafts.


does the doctor know the difference between port and manifold vacuum?


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## doctor12valve (Jul 20, 2005)

VenaGTi said:


> does the doctor know the difference between port and manifold vacuum?


The doctor know his Carb'd Rabbit will outrun Vena's Carb'd Rabbit :laugh:


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## VenaGTi (Mar 19, 2006)

DAAAAYUM! How the hell can you see into my garage??? I thought I closed the door.....:sly:


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## doctor12valve (Jul 20, 2005)

VenaGTi said:


> DAAAAYUM! How the hell can you see into my garage??? I thought I closed the door.....:sly:


Good comeback :beer:


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