Dellorto Carb Flooding

Hmmmmm... any ideas?

I have pulled all main and idle jets/emulsion tubes and turned the engine back over and the carb flooded just the same.

Floats out of adjustment?

Also check for dirt in the needle valve....

Brass float????? Remove it and shake it......Something may be sloshing around inside, thanks to a leak....

Like was said, most likely bad float or valve. The flood seemed to surge in time with the fuel pump pulsing. Get a Dell book from CB or Peek may have one. Peek should have or be able to get a rebuild kit to freshen it up. Mostly changing out o-rings and gaskets. If I can do it you surely can. Just do it on a clean work bench.
As far as the gas coming from the exhaust, you likely have gas in the bores and crankcase. I'd pull the plugs and drain the oil.

~WB

This should be good, ive never torn into these Dell's.

It's easy, Paul. Take the screws out of the top and lift up carefully. The floats come out with the top.

You've either got bad floats, a piece of crud in your needle valve, a bad needle valve, or misadjusted floats. Proper adjustment ("drop") effects a lot of things- transition from idle to main jet circuits, etc. For a pretty clear explanation of how to do it- run a search on "Dellorto float adjustment" over on the Samba.

Fuel pressure too high???? That will definitely do it. 2.5 - 3.5 psi max.

Don't forget, depending on your pressure regulator set up, reducing pressure also reduces flow. So if you reduce pressure make sure you have enough flow to maintain fuel supply at wide open throttle.

Should Be able to rule certain things out by giving some history. My speedster has teeth rattling wheel hop when I get on it hard off the line. Friday night, I got on it hard off the line. At the next light I could smell gas and it sounded and felt like I had dropped two cylinders. After reading previous responses I'm pretty sure I broke something, knocked something loose, bent something, or freed up some dirt intern clogging something.

Good to know I can pull the float out with pulling the entire carb from the manifold.

Just don't drop anything down a bore..... Stuff the bores before loosening the screws..... I learned this lesson in 1958......

Wheel hop would cause a float to stick..... That would keep the fill valve open, and would cause your carb to blow fuel out of it.. Exactly like it is doing.

Mike

Thanks Mike. I pulled the float out tonight. Float distance measured at full drop was right around 18.6mm, my book says it should be 12-13mm. Adjusted it to 12.5, reinstalled and car is back to normal. It did push out plenty of white smoke initially. I will change oil over the weekend.

Im beginning to wonder if i have gas in the exhaust. I jacked the front end of the car up to work on the steering column Satuday. I did notice the smell of gas got much heavier. Was probably siphoning from the elevated tank into the carb and out of the open valve into the exhaust?

Paul-

While you are doing the oil change, check the float drop on the other carb. You're going to become a Dellorto pro.

We need arm patches for that available at Carlisle:

"I'm a Dellorto Pro!"

Then other people will wonder what the hell THAT means!!!!

Can I get one that says "I'm a Webber Wacko"?

I think it's "Weber weenie" --- the grille don't ya know!

I have this book - welcome to borrow it (at least til mine is running)!

http://www.amazon.com/Dellorto-Tech-Superformance-Calibration-guide/dp/B0013I6YG2

Not sure release of mine but from early '90's.

I had a float fill with gas and gave me the same problem. Took it to a radiator shop and had it re-sodered. Perfect after that.
p.s. carbs were less than 6 mths. old Tom

Paul says: "I pulled the float out tonight. Float distance measured at full drop was right around 18.6mm, my book says it should be 12-13mm. Adjusted it to 12.5, reinstalled and car is back to normal."

Seems to me that a "deep" float would cause early needle valve closure -- exactly the opposite effect of the overflowing float bowl that Paul had.

Paul, when you bent the float level adjustment tab did you notice that it is not that easy to bend? Did you wonder at that time how the tab could all of the sudden somehow manage to get bent by itself and cause this problem you had? I don't think there is a probable likelihood that it bent by itself.

My guess: Maybe the float was out of adjustment, but it was in the same adjustment it had been in for a long time -- long before the sudden appearance of the problem. And as mentioned before, a deep float should relate to a low float bowl, not an overflowing one.
Since things are OK now and fuel pressure hasn't been changed since then and now, I'd say there was an issue with the needle valve or some sand / grit was stuck in the needle valve jet preventing the valve from closing. All of the shaking around while working on it freed-up the obstruction. Since you did blow out all of the jets and channels thoroughly with carb cleaner while the carb was disassembled (you did that, didn't you?), then hopefully whatever was in there is gone now.

Last, as previously mentioned, check the float adjustment on the other carb. If one carb was maladjusted there is no reason to believe the other one isn't.

Mark,

I was assuming the same thing, either the float ended up stuck, or i knocked something loose and ended up somewhere it should'nt be. The tab did not seem hard to bend in order to makke the adjustment. I will pull the other side this week and see where it is, make adjustments if necessary. I did my best to blow everything out using carb cleaner. In all honestly I cant say its back to normal. I should have said its idling, reving with no problems. I have not and most likely will not have it on the road for another week. These carbs are old, Italian DRLA's. I nicked them from my fathers 2 liter motor.

Paul -- you are quickly becoming "Dellorto Pro" (much more respected than "Weber weenie").

You MUST get the book Wolfgang suggested: http://www.amazon.com/Dellorto-Tech-Superformance-Calibration-guide/dp/B0013I6YG2

Get it soon! You can get it also at CB Performance. Order it at the same time as a "balancing snail" if you don't already have one. The book and the snail are REQUIRED for dual Dellorto ownership.
http://www.cbperformance.com/catalog.asp?ProductID=2
http://www.cbperformance.com/catalog.asp?ProductID=572

What Mark said x2! Worked for me.

~WB

I've had the CB book for years. Aside from the exploded views and a few good points, I can't recommend it. It's a book that would have made a great pamphlet.

The Samba has provided a wealth of information- some of it good, other- not so much. Reading enough over there will leave you with a decent understanding of the idle, progression, and main jet circuits. The air jet will still be iffy, but what comes stock usually works really pretty well.

A good flow meter for balance, and a LM1 Lamba meter are invaluable (you'll need an O2 sensor bung in your exhaust for this). That, and about $500 worth of jets, and you'll be all set....

Honestly, I have a snail air-flow meter and seldom use it, but I've been setting up dual and multi-carbs for decades and can get them pretty close by ear. If you don't have the ear for that, then the snail-meter works just fine. Avoid a "Uni-Syn" Pitot-tube meter, as the amount of air flow at idle in these carbs is pretty low for a UniSyn to show anything useful (or repeat-able, for that matter).

What I HAVE found, however, for both Dells and Webers, is that, right-out-of-the-box they are almost never close to being set up right. I always take them apart and check float levels (almost always re-setting them to the correct heights) and then go through them to make sure everything is what I want and reference the settings in Bob Tomlinson's book (or pamphlet, if you're a mid-westerner) to get them in the ballpark before I install them. I also check the fuel pressure from the pump and either dial that in or compensate elsewhere. Then, it's just a simple matter to dial them in once the engine is running.

BTW: My vote would be that your axle hop (most likely caused by a mis-adjusted Bowden tube) caused some grit to loosen and lodge in the pilot valve and hold it open, thus, flooding that side. An oil change is DEFINITELY in order, very soon.

mis-adjusted Bowden tube? where is the adjustment? I have replaced the Bowden tube... no difference. So, how do you adjust the Bowden Tube? My car has jumped around from day one. One day i hope to be able to smoothly lay out two lines of rubber.

Paul-

I agree 100% with Gordon on "the snail" v the "unisyn"- the unisyn is junk, the snail is a real tool.

I'm no "pin-ball wizard" tuner- I can't tune by sense of smell, I need tools to get the job done. This deaf, dumb, and blind kid needs tools to play a mean pin-ball. I haven't been tuning duals for years, as I'm a midwestern boy who cut my teeth on American V8s- which had no duals at my teenaged price point. If you missed the whole "bug-era", you'll need a tool. The snail is the tool you want.

Old timers "read the plugs" as well to get their jetting right. I have always found this to be like trying to read a micrometer through the bottom of a Coke bottle- it measures something very fine with something very crude. Guys that can do it, do it well. The rest of us.... get a lamba meter. A lamba meter reads an displays the a:f ratio in real-time- so you know what is wrong right away, rather than guessing if you were rich or lean, on the idles jets or in progression, and what (exactly) was going on when the car stated "running cruddy".

I also monitor all 4 cylinders head temperatures in the car. Among other things, this is invaluable in knowing exactly which cylinder has an idle jet issue (it's the cold one).

In other news- the wheel hop is from the frame horns flexing, I'd bet a donut. I'd try an inexpensive "traction bar" (really just a support for the engine further back) first, then a CSP Kaefer bar to tie the frame horns to the shock mounts after that.

As for the 2 strips of rubber... save your pennies. I got an original ZF LSD on the Samba. Expect to pay at least $1000 and wait until they come up (they're a rare-ish 40 year old part). A Quaife TBD is about $1400 new, but isn't a true LSD.

Maybe Gordon'll buy you a t-shirt. ;)

I purchased the Dellorto book some time ago. Pulled it out to reference where the floats should be set. only other time ive looked at it was to find the baseline for the mixture screws. I also have a snail. Its actually my brothers, but he claims his Zeniths on his Porsche 356 dont need to be touched. Whatever the case its mine now.

I agree, and have always thought i needed a torque bar. I was looking at the one from Eyeball Engineering. When changing the oil ill take some measurements and see if it will fit. I spoke with someone at Aircooled and was told the transmission mount should be all I really need. I guess the idea is if you can keep the transmission from rotating up it will keep the engine from flexing down. Aircooled had zero in stock at the time. Too bad, there design was far superior to the one I purchased. You can actually adjust theirs to pull the transmission snug against the frame horns.

As for the Bowden tube... the car drives great at any other time. I think if the tube were mis-adjusted id be feeling it in day to day driving. please correct me if I am wrong. All I have researched says if there isnt enough of a dip to add washers. I have a solid 2+ inches in dip. The car only starts jumping up and down when I brake the rear tires loose from a stand still start. Around corners I can easily spin the inner tire, get the back loose and drive on through.

As for jetting. I have a plastic baggy with a good $100 worth of jets. Tried them all only to realize the ones I was running were the best for the motor. It was worth a shot. I should try and sell the jets to offset the cost of the torque bar.

Ill wait on the limited slip until i build a new transmission for a new motor. My father has a type IV just sitting around. I was several 356's go at it around a course a couple years ago. there was one in particular that looked sooo smooth and carried so much speed through the corners. I spoke with him after the race (he won) and he told me he was running a limited slip diff.

anyone know if the engine has to come all the way out to install the bar?

http://www.eyeball-engineering.net/TorqueBar.html

If there's not enough slack in the bowden tube, your clutch can slip or even disengage every time the engine/trans rocks. Something you would definitely notice during regular driving. Granted, if it was just on the edge of being too straight, a hard launch would cause it, but pretty much guaranteed that it's wheel hop from the frame horns flexing.

If you support the engine/trans well, you should be able to. You'll have to loosen all the trans mounting bolts because you'll need to slide it back by the thickness of the new tabs for the frame horns. Take 1 frame horn bolt out at a time to put the tab in. You'll have to adjust your shifter after you bolt the trans back in. The tricky part might be bolting the 2 halves of the crossmember together if you can't put it in place as 1 piece. I'm not sure how much room you have to move it around under there if you want to move it to a more favorable position to bolt the halves together. Make sure you won't have any clearance issues with rear body subframe inboard of the shock towers.

Paul- I like the design of the CSP bar a LOT more, as it ties the shock mounts to the frame horns, instead of relying on the strength of the horizontal bar.

However, it still might not be enough. I've got no frame horns (it's a tube frame IM, but still had wheel hop until I re-did the entire engine/transaxle mounting system. I use 911 mounts on a mid-mount on the transaxle, and fabbed a 911/Type 3 mount that attaches to the bosses on the non-flywheel end of the case and hangs the rear of the engine on another set of 911 mounts. This supports the rear of the engine, rather than cantilevering it out on the transaxle mounts.

If I had a pan-based car- I'd do a CSP bar, and build my own "traction bar" out of 1" box section steel, and 1/2" all-thread to support the rear of the engine. Tie the transaxle down with some rubber cushioned straps, and you'll not have wheel-hop.

Yup, Stan pretty much said it, even if he thinks I'm maybe an "old timer" (friggin kid, anyway.....)

The CSP bar, while more expensive than some others out there, ties in the shock mounts and makes everything back there WAY more solid. And, Yes, a mal-adjusted Bowden tube (which it sounds like you do not have) would chatter off the line almost every time - warm, cold, whatever - while it sounds like you've got classic, post-engaged axle hop (what size engine is that, anyway????) and the cure for THAT is what Stan described. He may be a friggin kid, but he does a lot of homework.

And Stan! Try settin' up one of these:

http://www.britishv8.org/Other/SteveSanett/SteveSanett-B.jpg

Gordon- you've forgotten more about more stuff than most of the rest of us will ever learn. You sir, are the man.

This is what I fabbed for a rear mount on my car. It locates everything pretty well, without resorting to solidly mounting stuff. I've got some preload adjustment (with washers), but not as much as I'd have with a Kaefer bar and a decent traction bar on a pan-based car.

Eric- do a websearch on "pinion angle" and you'll find that the height of the rear of the engine (in relation to the front of the transaxle) will determine a lot about how the car "hooks up", even if everything is nice and stiff.

Everything is back together. Turns out the other carb float was 18+ mm... pretty much the same as the one i was having problems with. Like i said, these came off a hopped up 2 liter. Would there be a reason to set the float with more drop when tuning on a bigger motor?

Jumped in for a test drive and got the car about 8 blocks away and it died on me. After about 5 minutes of sitting in the car, angry, and thinking I realized i had zero gas in the tank. An easy enough fix.

The car is pulling pretty hard :) The note from the exhaust sounds different. Not sure if adjusting the floats would have anything to do with that...

I also noticed the car does not smell of gas when idling. A problem i tried to correct in the past by switching to smaller jets. Th ejets did more to rob performance so i ended up back with what i was running, and a slightly smelly exhaust.

Will put a timing light on it this weekend and dial in the cross bar linkage.

Eventually getting dialed-in, Paul! But I'm sure it will be worth all the effort you're putting in.

"Would there be a reason to set the float with more drop when tuning on a bigger motor?"

Maybe, depending on what they were running for idle and main jets. Still, 18mm is one hell of a drop, making it run super-rich (upside-down drop = higher fuel level in the bowls and richer mix).

Jumped in for a test drive and got the car about 8 blocks away and it died on me. After about 5 minutes of sitting in the car, angry, and thinking I realized i had zero gas in the tank. An easy enough fix.

DUH.........."Hey, why's the gas gauge way down there on 'Empty'??"

The car is pulling pretty hard :) The note from the exhaust sounds different. Not sure if adjusting the floats would have anything to do with that...

Yup....It's running right, now! It's also not running rich, which will give it a sharper "bark".

I also noticed the car does not smell of gas when idling. A problem i tried to correct in the past by switching to smaller jets. The jets did more to rob performance so i ended up back with what i was running, and a slightly smelly exhaust.

And now you've finally arrived at something much closer to air/fuel mix "Nirvana". Pop a wide band gauge on it this weekend and dial her in!

Enjoy the ride!!

gn

You know- when you actually figure out what is happening inside the carbs, it's pretty close to magic. Dellorto DLRAs are pretty much the high-water mark of what is possible without resorting to EFI.

When I was a kid, and learned how an internal combustion engine worked, I was amazed the thing even worked at all- let alone ran reliably for tens of thousands of miles. Considering the duty cycles of a lot of stuff- the fact that pistons go up and down in cylinders 3000 times (or more) every minute, for thousands and thousands of hours, it's amazing engines last even 10K mi.

We live in an amazing world.

A lengthy but valuable read recommended by John at Aircooled:
"The only

Still have some tweaking to do. At some point im going to pull the carbs and make sure everything is set to spec. If ive learned one thing in 3.5 years of ownership its that you can throw a lot of money and time at something trying to do a 'quick fix' only to end up doing it right anyway. typing that out... makes me feel a little dumber. DUH!

So, I tuned up the carbs with some seafoam additive in the petrol. When i filled back up i did not put any seafoam in the tank. the car was hesitating while accelerating hard... puffing from the exhaust like it wasnt getting enough gas. I bought some seafoam and poured it into the tank and everything seemed to go back to pretty darn good.

Im guessing I should be doing the tuning with zero additives in the fuel?

Well....yeah.

Unless you just want to run the additives all the time.

It's kinda like tuning up a Fiat Abarth: Tune it in the conditions you want to drive it in (rain, snow, clear, whatever) and it'll run well only in those conditions and be lousy in all others.

Looking back at your video, though, it looks like a pilot valve stuck wide open by crud stuck in the valve. It doesn't take much...

went for a drive tonight, car is running hot. wish i knew how hot, 3/4 way up the gauge doesnt tell me much. The fan shroud, even my aluminum fresh air tubes were very very hot. will adjust valves, timing, and do another tune on carbs tomorrow night. it strange, as i accelerated the temp needle would react immediatley and rotate in the direction of hot, as i backed off the gas it would go toward cool.

Last night I could not get the temp needle close to the middle of the gauge. ran nice and cool.

Sounds like A) slipping belt, B) lean mixture or C) timing too advanced, in that order.