Jump to content
HybridZ
Heroez

Dellorto DHLA and Triple Talk

Recommended Posts

I picked up a set of 3 Dellorto DHLA 40 carburetors. They came with an inlet manifold, linkage for, and air filters. It was a package deal that also included an extra intake manifold with linkage that is for another type of carburetor I think. I have always liked the way they look, and they add performance. Outdated compared to ITBs and EFI, yet I still like the mechanical carburetors. I chose to buy the Dellorto DHLA because of old research I did at the interest phase. Much like a person that would choose Mikuni, I was not looking for a race dedicated part such as Weber DCOE. I wanted to use something for a car driven on the street. When I finally saw the Dellorto set for sale at a good price, I could not pass it up. I found part suppliers, some diagrams and basic info that is helpful. Unfortunately, searches here and from Google do not give information in depth in how to tune triple Dellortos. I have found guides to tune dual Dellortos. Many of the same tips apply such as to balance them by finding the weakest barrel and reduce the others to match it and so forth. I have seen a book about how to tune them and I will likely get that book soon. There is just not much information available for DHLA Dellorto triples on a Z car. I would like to invite people out there to share information on Dellorto DHLA carburetors if they have experience with them, or any other factual information to share. If you have advice, tips, or info for me or others who are starting an adventure with triples, it would also help. Next time someone searches, maybe there will be some helpful information here to read. I will post in this thread from time to time as more information arises.

Edited by Heroez

Share this post


Link to post
Share on other sites

Here is a photo of them with the inlet manifold, Z car linkage, and some air cleaners. The manifold manufacturer is unknown to me at this time. The air cleaners have Bap Geon, Warneford Design on the sticker. A fitting for the PCV system is attached to the middle air cleaner. Photo518.jpgIn this photo you can see a rigid copper wire connecting each carburetor. The wire connects their choke mechanism. These are DHLA 40, not 40E or later versions. If the air cleaner is removed you can look down into the front and see the main venturi. It will have a number engraved which is the size of the choke. Mine say 30. Never look into the front of the carburetor while the engine is running. If you have to, use a mirror and keep yourself at an angle. At the top front of the carburetor there is a plate with a number, just to the left of center. Mine says, R5232 on each. On the left rear, near where they attach to the Inlet manifold you will find the model number. Mine says, DHLA 40. These are considered perfectly matched. Because several versions were made, you want to make sure your carburetors are all the same type. I have read that the same model with close number plates are a good match. You want to avoid mixing DHLA 40 with DHLA 40E, and such.

Edited by Heroez

Share this post


Link to post
Share on other sites

As I said in your other thread, the DCOE is not a "race dedicated" carb, at least no more than a DHLA is. The biggest difference between the two are the DHLA's external adjustments for float levels and accel pump shot. The DHLA shares jets with the DCOE and is no different in function. Most info for DCOEs is either directly or analogously linked to the DHLA.

 

EDIT: I should clarify. Whether they can share jets or not, physically, their operation is the same.

Edited by Leon

Share this post


Link to post
Share on other sites

"Race dedicated" is poor wording choice on my part. Lets just say the Weber DCOE was designed for race application. Dellorto and Mikuni of similar type are a better choice for vehicles driven around town and on the street as well as the track. That is if you consider greater gas mileage without a compromise in power "better." The point of this thread is informational, not confrontational. Not to defend one over another or insult those who chose Webers. So if you are looking for an arguement, you are barking up the wrong tree.

Edited by Heroez

Share this post


Link to post
Share on other sites

I recently sold my DHLA setup on ebay and it was a very bitter-sweet goodbye, they were so darn pretty. After 10 years of working with them, I could not get them to make as much power/speed as the SUs on my stock L24 (using 1/8-mile drag times as my dyno), and my fuel consumption was terrible. Once you get these carbs running, don't let the car sit, you gotta drive it almost daily to keep them from plugging passages. The first few winters, the chokes worked well, but that eventually stopped and the car became a warm weather only car. Even though these carbs have about a zillion parts to clean and a ton of o-rings (must be nitrile), and jets to figure out, the thing I hated most about them was the vent location of the float bowls - they puked on my polished cam cover and ruined the clear coat, and fuel like to drip down the back of the bowls onto the accellerator pumps then drip onto the header heat shield. I used CBPerformance.com for aircleaners and velocity stacks. PM me if interested and I'll see if I can find the spec sheet from my final venturi/jet combination. They drove well at full throttle (and sounded incredible), but I never could get away from an intermittent lean backfire on low-power part throttle driving. I may have sold all the jets and paperwork with the carbs...

Share this post


Link to post
Share on other sites

I recently sold my DHLA setup on ebay and it was a very bitter-sweet goodbye, they were so darn pretty. After 10 years of working with them, I could not get them to make as much power/speed as the SUs on my stock L24 (using 1/8-mile drag times as my dyno), and my fuel consumption was terrible. Once you get these carbs running, don't let the car sit, you gotta drive it almost daily to keep them from plugging passages. The first few winters, the chokes worked well, but that eventually stopped and the car became a warm weather only car. Even though these carbs have about a zillion parts to clean and a ton of o-rings (must be nitrile), and jets to figure out, the thing I hated most about them was the vent location of the float bowls - they puked on my polished cam cover and ruined the clear coat, and fuel like to drip down the back of the bowls onto the accellerator pumps then drip onto the header heat shield. I used CBPerformance.com for aircleaners and velocity stacks. PM me if interested and I'll see if I can find the spec sheet from my final venturi/jet combination. They drove well at full throttle (and sounded incredible), but I never could get away from an intermittent lean backfire on low-power part throttle driving. I may have sold all the jets and paperwork with the carbs...

That is unfortunate. Thank you for adding your experiences. Any additional info would be very welcome.

Edited by Heroez

Share this post


Link to post
Share on other sites

Webers were the racing alternative to the Solex...

Solexes were an OEM offering, the Webers with drastically smaller acceleration pumps were the "racing alternative" as for some reason Solexes got a bad rap (likely because they were the OEM offering, nothing more.)

Share this post


Link to post
Share on other sites

Thank you for the clarification Tony. This information will allow others to follow the reasoning I have put forth. Leon, I agree that there is bad information to be found. There is also good information. We have to examine credibility to determine which is which. I did not want to digress to confrontational dialogue. I do not want to lose your input. Just because some information is not usual does not make it incorrect. No matter how much we think we know, there is always room to learn. While I gather and organize information for my next post. Would anyone like to talk about the issue of timing, timing advance, or recurved distributors? This is an important aspect of using the triple carburetors. What is the best solution? What have you found to give the best results?

Edited by Heroez

Share this post


Link to post
Share on other sites

Thank you for the clarification Tony. This information will allow others to follow the reasoning I have put forth. Leon, I agree that there is bad information to be found. There is also good information. We have to examine credibility to determine which is which. I did not want to digress to confrontational dialogue. I do not want to lose your input. Just because some information is not usual does not make it incorrect. No matter how much we think we know, there is always room to learn. While I gather and organize information for my next post. Would anyone like to talk about the issue of timing, timing advance, or recurved distributors? This is an important aspect of using the triple carburetors. What is the best solution? What have you found to give the best results?

No one is being confrontational (or I wasn't trying to be), I was just attempting to provide some factual feedback on your topic. In fact, I praise the DHLA for having external float and pump adjustability...

 

I don't consider the DCOE to be "race dedicated" as it was the OEM carburettor on many European cars of the time.

 

As for timing, well first of all, there is no "best" on HybridZ. There can be a best option for your situation, though. Want a serious ignition system? Get a programmable, crank-trigger, wasted-spark standalone ignition setup. Otherwise, look around for used/rebuilt distributors that either have a decent curve, or get one recurved.

 

I use Megajolt + EDIS on my triple DCOE Z. It's money well-spent in the long run, at least for me. I can tap on my laptop's keyboard and set a 3D ignition map from the driver's seat. Beats the heck out of pulling apart distributors and playing with tiny slots and springs...

 

BTW, the crank-triggered setup ran about $400 and can be had for cheaper, a bargain if you ask me.

Edited by Leon

Share this post


Link to post
Share on other sites

I can't tell you how to tune but I can share this diagram with you that may be helpful to you?? I was going to run turbo Dellortos and I picked up a set, I even purchased a couple of books on Amazon about them.

 

From what I have read and also hearing the experience of those who run Dellortos it's a very capable carb and one that is highly respected by those that know their carbs.

post-989-0-15107900-1352820311_thumb.jpg

Share this post


Link to post
Share on other sites

No problem Leon, I must have misunderstood your intention. I did see your additions to the information here, and thanks for your thoughts on ignition. When we comment, lets try, as you did to give examples of inexpensive, expensive, and middle alternatives. If we cover many choices, the pros and cons, it will give the diverse readers more information to use. Whenever possible, give information towards a stock type motor, a modified street, and race type build. That way many can find information that more or less applies to them. For example a fuel rail. There is the Nissan rail from Japan at a high cost, TWM rail, Datsun Spirit rail for $125, and something people have built themselves. Fuel return line is not used by a lot of people. What type of fuel rail have you folks built or used? How was it attached? What size fuel line? Lets add detailed information for others.

Share this post


Link to post
Share on other sites

I want to join in on this thread, i have some .pdf files for these carbs, how can i upload them here?

 

I am running dhla40 with the largest chokes available. 36mm??? My car is otherwise as described in the signature ;)

The car has a rough idle and is difficult to coldstart, once its hot it idles rough. It somties just dies out, but start right up.

I have the Crane firball xr700 ignition setup.

It somtimes bakfires through the carbs at low to mid range rpm. The exhaust ignites on the overrun. Between 4500 to 7500 it screams like mad, and runs REALLY WELL. when hot the throttle respons is just rediculous to me, i think it is super fast compared to my old Audi S4 V8 which isn't slow either.

It seems to me like the DHLA40s supplies to much "soup" for the L24 i am using right now. I hope it will sort itself out after the L28 swap, of cours with a full service of the carbs as well.

 

i have tuned them so they suck in the same amount of air.

 

-Arnulf

Share this post


Link to post
Share on other sites

I want to join in on this thread, i have some .pdf files for these carbs, how can i upload them here?

 

I am running dhla40 with the largest chokes available. 36mm??? My car is otherwise as described in the signature ;)

The car has a rough idle and is difficult to coldstart, once its hot it idles rough. It somties just dies out, but start right up.

I have the Crane firball xr700 ignition setup.

It somtimes bakfires through the carbs at low to mid range rpm. The exhaust ignites on the overrun. Between 4500 to 7500 it screams like mad, and runs REALLY WELL. when hot the throttle respons is just rediculous to me, i think it is super fast compared to my old Audi S4 V8 which isn't slow either.

It seems to me like the DHLA40s supplies to much "soup" for the L24 i am using right now. I hope it will sort itself out after the L28 swap, of cours with a full service of the carbs as well.

 

i have tuned them so they suck in the same amount of air.

 

-Arnulf

Arnulf, I am glad that this thread is gaining interest and people are making contributions. As with an earlier poster, I think the poor performance is coming from bad equipment, unbalanced build for the application, being out of tune. or a combination. Im no expert, just a student at this point. I could be wrong, but running the largest choke possible could be part of your troubles. A friend was telling me he had a problem in the lower RPM range that went away when he went with a smaller choke. He sacrificed a bit of top end but gained smooth transitions. As for your PDF files, maybe upload them to a site and post a link to them? If you are unable to do that, I will send you a message so that I can also try to get your files up. They would be a good contribution to this thread. Tonight I am going to try and post some information I found about balance and tune of Dellortos.

Share this post


Link to post
Share on other sites

Here are some links I found interesting for setting up and balancing Dellortos. Notice the examples of how unbalanced or improperly adjusted carburetors effects their performance, and how it relates to some symptoms of problems already posted. They are highly tunable, a blessing or curse depending on how well you know them. These links are not about Z engines or Triple Dellortos, but its better than anything anyone has posted about Dellortos on Hybridz.org so far. Let me know what you think of the links! http://espritfactfil...bbalancing.html

Edited by Heroez

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...