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Sun Dec 04, 2011 9:13 pm

awright
The trip from Italy has got to be rough you know........

Mon Dec 05, 2011 10:10 am

Good job getting it running right!

Some notes:

Dellorto mixture screws tend to screw out more than Webers with the jets are right, significantly more, like out 5 or 6 turns. One jet size can make a turn or two difference. But since they are finer threaded screws with more precision taper, they DO tend to screw out more to get the same results. The ones on my 48 DRLAs on my 2332 are out about 5 turns, give or take a turn variance between them. If you have big variance, you need to check the plate staging, and the flow numbers on each barrel at idle.

Float settings of 5 or 6 work best on an engine that will not see a lot of bumps.. 6-7 is a little more tolerant of that.

9164.2 tubes are the way to go on our engines. Nothing else works as well.

GENUINE Dellorto jets measure about a half size smaller than the number stamped on them. Just the way it is. Aftermarket jets tend to be the same size as the measure, but I have gotten some sets from a particular supplier that were way off, several times. MEASURE them.

Half size measuring pins can be bought from McMaster carr. They are long, and you just need to keep them marked with a piece of tape or something, and store them.. you can then measure things like 47, 52, 57, 62, etc. Alternatively you can approximate with a reamer by finding the points where your 55 and your 60 measure, for instance, and mark half way between to get a 57, and ream to that point.

Jets do not "wear" from use.

Dripping from the auxiliary vents means that the needle is not controlling the fuel - float hanging up, dirt in needle and seat, misalignment of the tab on the float causing side loading of the needle pin, excessive fuel pressure, leaking needle gasket, float adjustment, etc., will cause that. It tends to happen on one of the two barrels only, unless the control issure is severe. One tends to be slightly lower than the other due to orientation of the carbs.. The are rarely perfectly level enough to cause a slow leak to drip from both aux vents.

Dell drip comes from the progression ports and will pool on the plate if there is any fuel in the bowl, running or not, until it basically empties the bowl. Lead plugs are one way to fix it. I use brass plugs and screws on the access holes when I put them back together. Brass plugs can be drilled and pulled easier if you ever have to, but they tend to stay. You will find that many lead plugged carbs need new plugs to stop leaks. Brass and aluminum plugs tend to stay in place because you can achieve a tighter fit.

Ethanol supplemented fuels need bigger jets to achieve the same AFR readings. Fuels that are primarily ethanol have stoich numbers and power numbers at much lower values. Eric can comment on his experience with this on E85, I am sure.

Your mileage may vary. Don't eat yellow snow.. unless you KNOW it is lemon.

Mon Dec 05, 2011 10:50 am

Mark, thanks for your insight....I am definitely a student of yours and have learned so much from your articles and posts. Or should I say what I have learned is from your articles and posts....

here is where I am now. With the 60 idles it will idle fairly well, and I can adjust the mixture screws.......BUT no matter what I do this baby wants to run LEAN!!!! at 2000 rpm with 60's I am at 16.5 ish AFR......no power. (even if I adjust idle AFR to 12.5) At WOT and steady rpm......17.5-18ish....blahhhhhhhhh no power.

floats set
60, 122, 180, 50 pump...

Just for kicks I installed some 70 idles to see what she would do......in the high 13's......blah...no power.

Now remember we are working on 36 dells with 30 VENTS!!! does not make sense!!!!!!

I think I am done!!!! pack it up!!

Mon Dec 05, 2011 11:14 am

That suggests that a 135 would give you WOT AFR numbers you want. Keep the 60's that are in there. The most PROFOUND effect on transition would be changing the air jets, but you are already at the upper boundary of what I would recommend, and 135 mains might get there for you.

Also, realize that at cruise, you may be getting contamination of fresh air if you have a big muffler, and / or exhaust leaks. if it runs ok there, albeit showing lean, you WANT that at cruise.

Mon Dec 05, 2011 11:16 am

BTW.. when you adjust the floats, you are not letting the little nail (pin) on the end of the needle compress are you? That'll give this kinda result too.

Mon Dec 05, 2011 11:22 am

mharney wrote: BTW.. when you adjust the floats, you are not letting the little nail (pin) on the end of the needle compress are you? That'll give this kinda result too.

No....what I did was use a 5.5mm allen wrench.....carb top laying on its side and float swinging like a door. Pin not compressed. This basically puts the float parallel with the carb top.

Back to the main jets......Does a 135 main seem right with a 30 vent??? crazy huh?? That would put me at 4.5 times vent....

And idles....70 idles in a 30 vent? John Connolly preaches from the roof tops that 36 Dells absolutely run on 50 idles at sea level........not in these babies.

Nothing makes sense....but the lack of power and high AFR's tell no lies...

Mon Dec 05, 2011 11:35 am

You just jet for what works. Strange things happen.. I do find that the Euro ones jet out a little different, and fuels/engine combos can cause some variability.

Mystery motor could mean a high overlap cam, which will sure change things.

Mon Dec 05, 2011 4:30 pm

Ok installed 70 idles, and 162 mains.......runs great!!! Except real fat 10.2 on idle circuit driving and 10.5 on mains. Engine has power now though. Next step 65 idles as 60s fart and protest and 145-150 mains. Crazy.

Mon Dec 05, 2011 5:04 pm

I only tend to recommend one change at a time. I think that its weird too, the jets you are having to use. Seems like something is not right to me, like low compression and high overlap. The fact that it is across the board makes me wonder about what's in the engine.

Mon Dec 05, 2011 5:11 pm

Engine, cant be much, had a 34 pict 3 on it before. Valve lift is .325-.330....

It is no where near the power of my 1835, but does pull strong now with the larger jets.

These carbs may just be a little different. A couple factors that might be pushing this fat jetting... I am right at sea level, 70 degrees, 80% humidity.

Mon Dec 05, 2011 6:06 pm

Derluftwagen and Mark Harney mentioned this earlier and I thought I'd repeat it, are you sure your jets are what they are? Check with jet gauges to make sure.

One other thing crossed my mind, and it's a long shot I believe. If the carbs were rebuilt by Alfa1750 he might have used the wrong gaskets between carb top and body??? That might block or partially block some air access holes. Mark H. would know this better than I. I'm not sure if the rebuild gaskets for 36's vs. 40 Dells are different.

Mon Dec 05, 2011 6:08 pm

I hate to be the "are you sure" guy

But are you sure it's put together right?
It is possible to put the vents and aug-vent/nozzle parts in upside down, also possible to have the passage to the aug.vent not line up correctly.

If it requires a 140 main, then so be it, can't agrue with the engine......... but you have to wonder why.....
Did somebody drill out the air jets?

It's just odd

Mon Dec 05, 2011 6:56 pm

DEWWWDS.... I am sure. Why do you think I tried something like a 162 main in a 30 vent. I wanted to see that 17-18AFR.....DROP. It did...big time and the car runs like it should... a bit rich...but it drives like I have an engine back there now. Yea, I am freaking too.

Its like the worst "mechanics exam". The flowchart from hell. Nothing makes sense other than if I keep throwing gas at it the AFR's come down and the car runs better. I believe if i had a tackle box full of jets, like I have for my webers, I would have been done long time ago.

funny thing is, using the math and calculating percentages...it looks like in the end this mother is gonna want 155 mains for a 12.8-13.0 AFR. 155 mains on a 30 vent....ARE YOU KIDDING ME???? 65 idles on a 30 vent..ARE YOU KIDDING ME???? NOPE!!!!!

I have never seen anything like this in my life. I pride myself on being informed and being the go to guy, but this setup has eaten my lunch.

I wish I had my wideband hooked to the computer to data log this junk so you guys would believe this. Heck week before last, I tuned a 2017, FK10, street elimator'd BEAST with 44 webers. You know where we wound up? 36 vents, 50 idles, 155 mains, 200 airs. Idles were way low and mains kinda BIG(by internet standards :roll: )......but the car runs like a dream with them. Follow the wideband.....

Hell I don't know it may the gas down here in Louisiana.......peppered with hot sauce :lol: :lol: :lol:

I DO appreciate the help, suggestions, and mind sharing...as it keeps me from going INSANE :shock: :shock: :lol:

Mon Dec 05, 2011 7:08 pm

30mm vent x 4.1 = 162 mains ................it's The New Math! :lol:

What the hey, whatever works with the Tabasco Premium down there!

Mon Dec 05, 2011 7:13 pm

CHOOOOOT EM, CHOOOOOT EM!!! :lol: :lol: :lol: :lol:

Mon Dec 05, 2011 7:14 pm

Hello.
A couple of things to bear in mind. Harney has menthioned most already, but the Dells off the Alfa 1750 are 40 mm DHLA, NOT DRLA. The ones you have is from an Alfasud Ti or Sprint. That doesnt make them bad. but things to consider is that they most likely came off a 95 hp 1,5 l. engine, at best a 105 hp 1,5 engine.
36 Dells usually require relatively large idle jets due to the idle air bled is relatively large.
Pump jets in the 36 are 0,33. 50% of the time type 1 engines up to 1800 cc. WILL LIVE on that. But 0,45 are more like it in general. No need for more. It just pollutes the enviroment.
The 122 main jets are definitely too small, as you also have found out. I´m not sure how much the ethanol affect it, but I would say 0,10 over the chart to start with. That means about 135. You may have to go to 140. But only trial & error can tell you that.

You CAN NOT rely on the AFR at idle. When its good the meter will most likely show somewhere between 19 & 24 - 1. The VW engine has much air in the idle mix. You have to check how it runs at "upper part load" (50 - 65 mph) and see how the AFR reads. Then you back down or increase the idle jets and adjust the mixture screws for idle afterwards.

Hope this helps.

T

Mon Dec 05, 2011 7:15 pm

Them carbs must be junk.... you should remove them.........and mail them to me

:P

Mon Dec 05, 2011 7:29 pm

Alstrup wrote: Hello.
A couple of things to bear in mind. Harney has menthioned most already, but the Dells off the Alfa 1750 are 40 mm DHLA, NOT DRLA. The ones you have is from an Alfasud Ti or Sprint. That doesnt make them bad. but things to consider is that they most likely came off a 95 hp 1,5 l. engine, at best a 105 hp 1,5 engine.
36 Dells usually require relatively large idle jets due to the idle air bled is relatively large.
Pump jets in the 36 are 0,33. 50% of the time type 1 engines up to 1800 cc. WILL LIVE on that. But 0,45 are more like it in general. No need for more. It just pollutes the enviroment.
The 122 main jets are definitely too small, as you also have found out. I´m not sure how much the ethanol affect it, but I would say 0,10 over the chart to start with. That means about 135. You may have to go to 140. But only trial & error can tell you that.

You CAN NOT rely on the AFR at idle. When its good the meter will most likely show somewhere between 19 & 24 - 1. The VW engine has much air in the idle mix. You have to check how it runs at "upper part load" (50 - 65 mph) and see how the AFR reads. Then you back down or increase the idle jets and adjust the mixture screws for idle afterwards.

Hope this helps.

T

The carbs are casted with DRLA 36 on the carb body....but do come from ALFA1750 of ebay fame.

Here is the deal with AFR at Idle......anything more than say 12.5 AFR at idle, this thing farts, pops, sniffs, and poots. What I did was installed 55's..did best lean idle, came out a turn and drove it....18-19 AFR. NOPE.
I then backed the mixture screws out even further about 5 turns out...still sky high AFR.

Installed 60's...again poot and poop, adjust mixture screws....said heck with BLI and just started twisting them out....drove it with 60's at about 4-5 turns out....still SKY HIGH AFR....no power.

Then I installed 70's....knowing they would be pig rich...and they were...like 10.5 AFR driving it...but the power came back and the engine came alive. My hope is 65's will do it.

I have tried driving it and adjusting mixtures screws,(monitor, adjust, repeat) to richen it 1/2 turn at a time, but even with a 60 idle I could not get it down in the 12.8-13.5 range. 15-16's with popping and farting at idle was the best....with the idle mixture screws just hanging in there by a thread.

The car has a SVDA so you would think it could handle the higher AFR's with additional timing......NOPE.

Mon Dec 05, 2011 7:44 pm

Alstrup wrote: the Dells off the Alfa 1750 are 40 mm DHLA, NOT DRLA.

Just so you know, Alfa1750 is a seller on E-Bay who supplies many Weber and Dellorto carbs and parts to the VW community. DHLA's won't fit on an air cooled VW engine in a dual carb application. Manifolds don't exist as far as I know.

Mon Dec 05, 2011 11:01 pm

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