I have a Dellorto that I had running some time ago on one of my long gone 1st gens... Prob 15+ years already has past since I pulled her off where she has sat on a shelf clean and indoors. A buddy of mine (whom I no longer have contact with) helped me dial her in and she ran beautifully before being pulled.

Fast forward to today... I now have her sitting on another set-up and I was hoping that I would be able to just start and go. Not the case.

The problem I'm having is as soon as I give it gas anywhere above 2k rpms (I'd like to guess, tach is not hooked up yet) it falls flat on it's face if I'm under load / driving.

I've been doing some reading using the search and figured I'd post before pulling her to give a once over / cleaning in case it could be something simple.

The set-up has changed. It came off a S4 na block w/stock lower n/a manifold, RB upper and a header... The new set-up is a S4 TII block w/stock TII lower manifold, same RB upper and stock 13B n/a exhaust manifold.

The cat is also glowing red after I limp back in the driveway and pop the hood.

There were a couple of older threads with the same symptoms but no follow up to what actully worked to fix the problem. Thanks in advance.

 

Exhaust glowing red is an indication of running extremely lean to my knowledge. Sounds like the main fuel circuit is possibly a bit clogged up with crud from sitting for so long. When the carb was pulled, was it absolutely fully drained of all the fuel? If not, its possible it has turned into a sludge like substance in some of the internal passages. This will definitely clog it up pretty good. Generally, if a carb has had gas in it at one time and then sat for a long time afterward, its best to just do a rebuild. Its not expensive, and if your careful about your workspace and how you organize parts, its really not all that hard to do. IMO, a carb rebuild is just about the best $40 you can put into an older car.

On another note, your new engine should run relatively well on the same jets and air bleeds as your old engine ran on. The air flow would be similar if porting is stock for both, but it will likely need a bit of tuning to get it really dialed in to run perfect.

 

first lets talk about how the dell works. It is running on the low speed jets until around 2500 rpm, it transitions to the main jets after that. so you may have a combination of problems addind to the running issue.

My suggestion is to pull the jet cover off and pull all four jets out and inspect them. Make sure you pull the jets out of the bottom of the e tubes and check ALL of the air bleed holes for obstruction. spray carb cleaner in the carb where the jets fit, this can be done on the car with out issues. Take note of the jet size, e tube number, and air corrector size this will be of help later.

While you have the jets out pull the float cover off and make sure the fuel ports to the jet well is clear and no junk in the bottom of the carb. reassenble and drive again. if there is no change then you know you have a tuning issue. Fuel pressure needs to be 2.5 to 3 psi and will need a large volume to keep up with the dell, I know from my tuning issues this is very important.

If the cat is still glowing red you are very lean, this is where the jet numbers from earlier will come into play. go to www.gruntled.com and read the info from me on the jetting and set up for the 6 port 13b with info from racing beat on the mods needed for the dellarto to work on the rotary. Using to t2 block with lower compression will mean the jetting I used will be on the rich side for your engine and exhaust set up, so 1 or 2 jet sizes smaller will get you close.

The most important thing to remember with the dell on an n/a engine is the air corrector(top jet in e tube) must be larger that the jet in the botton of the e tube, if not then the tip in transition is very poor and will cause stumble or bog.

Also make sure the air corrector in the top of the low speed jets are drilled and not solid. Hole size is posted at gruntled in the write up. The other issue I see is the exhaust being stock, the carb will work but not be optimal.

Hope this helps you as I have spent a lot of $ to make mine run really well and dellarto parts have to come from the uk and are not cheap.

good luck and pm me if you need more help.

Joe

 

+1 to that.

 

joe said what I was gonna say..

 

to be even more basic...disconnect exhaust before the cat and then see if you can rev above 2k under load...might just be a plugged converter

 

So it turned out to be a EASY fix... Took me the better portion of the day to figure out but still an easy fix.

My buddy had another Dellorto he picked up off eBay that I stole the fuel bowl cover off of when I was having problems getting the fuel pressure from the stock TII fuel pump down into the 3'ish area. I thought maybe I messed up the needle and seat w/the much higher efi pressures....??? Wasn't the case, both needle and seats are still fine. However, the one fuel cover off of the eBay carb the previous owner put a simple little gasket under the black breather totally choke'ing the carb out anytime it I got into the pedal.

Took me so long to figure out bc I thought I was missing a gasket on mine, not that it shouldn't of been there. Anyways, at least everything's now clean. Thanks much for the help.

 

Cool Jimmy! Glad to hear it is sorted. The turboII is up and running already?? Man you've been busy!

 

Yes sir...