Holly ultra issues

I experienced similar issues with a single plane but I was having cooling issues as well so the engine would get very heatsoaked and fuel was probably boiling over the vents. I would also experience a dieseling effect occasionally after I switched from a Holley 750 to a bigger carb. I was able to adjust that out.

My theory is the direct shot to the intake with the single plane causes more pronounced flooding. When the engine is cold the fuel does not vaporize as efficiently as it does when the engine is warm or even heatsoaked after running. So inherently you toss a bunch of fuel into the car when cold and then when its hot its just too much fuel vaporizing. One method is to just hold the accelerator pedal 1/3 of the way down, just enough to not engage the accelerator pump in the carb which will prevent flooding the chambers further. It takes a little practice but you will find the sweet spot. Another possible fix is to adjust the float/fuel level to reduce boilover.

http://forums.holley.com/entry...r-Barrel-Carburetors

As far as the slugginess at low rpm, part of that is the lower velocity created for the air now having a shorter/larger path to the intake valve, so atomization of fuel is decreased and can drop out of suspension. A carburetor with annular boosters (Holley HP) vs the (Holley Ultra) which has downleg boosters would improve atomization coming from the carburetor. This would improve low rpm throttle response, especially if you are experiencing hesitation on abrupt throttle changes.

I ran a Race Demon with annular boosters vs my Holley 750 and was pleased with the 4 corner idle adjust-ability as well. I later sold it to a member here after I switched to EFI. I'm a little more versed in EFI and you have more control over hot/cold starting fuel depending on the system. Hopefully someone else can chime in who can provide some other carburetor tweaks.

Push, once you get tired of the high rpm power from your current setup, or especially if you drive in city traffic, you can put the same carb on a small-port 2V intake WITHOUT PORT-MATCHING or changing the cam. You will be astounded at the increase in low end acceleration and throttle response.

Of course the engine will fall flat on its face at 5500 rpms & above, but you may find with your style of driving, you really don't spend much time up there anyway. The port mismatch acts like an intake restrictor plate and also often results in noticable fuel mileage increases.

quote:

Originally posted by Push1267:


However, I have one issue with hot starts that I didn’t have with the dualplane and the 770 avenger. When the motor is warm it needs maybe 3-5 seconds on the starter and half throttle before it starts. Starter turns fine. I’ve leaned it out as much as possible, played around with secondary idle throttleblade opening to prevent too much exposure of transfer slots and even put in a phenolic spacer for heat insulation but I still can’t seem to solve the problem. Looking down the carb after I have shut it down the throttle blades are slightly wet of fuel and it smells a little from fumes standing next to the car.

Any suggestions to what the "problem" could be? 

Kristian

Have a look at your accelerator pump check valves. Sometimes during a hot soak fuel can drip out of the accelerator pump discharge nozzles, wetting the throttle blades and dumping a load of gasoline into the manifold making it flooded on a hot start up.

Check the float level also.

How many turns out are the idle screws ?

What size are the idle jets and idle air bleeds ?

I run the floats low and adjusted the idle screws lean using a vacuum gauge - they are 3/4 to 1 turn out.

I've also added a Holley heat shield with a 1/4 inch plastic spacer AND insulated the fuellines.

I also tried to run the fuel bowls almost empty before shutting the motor down (I have a switch for the Electric pump) thinking that the fuel pressure is too high leading to fuel being pressed through the needle and seats(pressure gauge reads 3-4 psi with the engine running, but maybe reading incorrect as the pump is internally regulated for 6.5 psi).
I will add a regulator.

None of these mods has solved the hotstart problem.

The carb is brand new but it's possible that the acc. pumps need to be checked? As Hustler mention, it may also be a single plane thing I have to live with.

I'm adding a pantera Electronics engine controller which run the fuel pump at 50% reduced speed which should reduce pressure as well. It also generates more spark compared to my current MSD set-up so maybe that will help.

Kristian, maybe first determine if the hard start is due to too much or too little fuel.
1. pump accelerator 4-5 times, try to start. If better, was too lean
2. push acc to the floor, wait 10 seconds, try to start (like fixing a drowned carb). If better, was too rich

I assume starter runs fast, it's not figthing a too early ignition/less than optimal battery connections issue and turning slow when hot?

I've tried both. It's clearly too much fuel. Maybe not a lot but still enough to inhibit start-up. Starter spins fine cold or hot.

The engine actually runs real well and responds readyly to adjustments. It's when I shut it down it seems to continue to dump excess fuel into the manifold.

Kristian some thoughts, in random order (like most of my thoughts):
-Can you move your fuel line away from headders/heads/intake, so it doesn't boil?
-When Hustler suggest pedal 1/3 down so acc pumps don't come into play, they do, acc pumps work immediately, so when clearing up a rich condition by opening to reduce vacuum, wait patiently for fuel to evaporate, keep foot still
-Sometimes a hard starting car when hot has timing wrong, one of Erik Bossing's friends in a Mustang came by me, had tried everything, adjusted idle timing, no more starting problems
-Should you be happy that the engine comes on so strong at a high rpm? Probably not. My Pantera was like that when I first got it, very entertaining, but allow me to quote from my book:
"One comment on how a car feels: A car with too much carb and camshaft may feel very powerful the first time you try it, because the power comes in when you reach 4000-5000 rpm. Suddenly you get a kick in the back. It can be a lot of fun; it feels like you suddenly have two engines. But that’s actually a bad sign; it means that the car has too little power below the rpm where the power finally kicks in. An engine is an air pump that, based on parts choice, has a certain max HP. As I’ve stated before, the best (i.e. fastest and most fun to live with) car will have that power at all rpms. The car in this example has lost that below 4500 rpm, and it does not have extra power above 4500 rpm, it just has the type of power it should have had all throughout the rev band. Engines’ power does vary with rpm, that’s unavoidable, but if power comes on very suddenly at a certain rpm, the engine is not well-tuned and is losing potential power below that rpm."
-Float level OK?
-I doubt clearing slots would do a difference

Here's what I would do. I would start all over adjusting everything, ignition and then carb. And I would play with the timing curve so I got power at low and middle rpm as well.

You're welcome to come over one day if it doesn't get you the result you need...

quote:

Originally posted by Push1267:
I run the floats low and adjusted the idle screws lean using a vacuum gauge - they are 3/4 to 1 turn out.

I've also added a Holley heat shield with a 1/4 inch plastic spacer AND insulated the fuellines.

I also tried to run the fuel bowls almost empty before shutting the motor down (I have a switch for the Electric pump) thinking that the fuel pressure is too high leading to fuel being pressed through the needle and seats(pressure gauge reads 3-4 psi with the engine running, but maybe reading incorrect as the pump is internally regulated for 6.5 psi).
I will add a regulator.

None of these mods has solved the hotstart problem.

The carb is brand new but it's possible that the acc. pumps need to be checked? As Hustler mention, it may also be a single plane thing I have to live with.

I'm adding a pantera Electronics engine controller which run the fuel pump at 50% reduced speed which should reduce pressure as well. It also generates more spark compared to my current MSD set-up so maybe that will help.

I agree with No Quarter in that timing issues may be influencing hot starting, it's worth a look and the effects of the Pantera Electronics ignition controller when you get to fit it may also help the problem.

But at the moment i might also suggest that you drive the car, get it nice and hot, then shut it down and immediately remove the air cleaner and get into a position where you can watch (and listen) down the throats of the carb. Use a flashlight, it may be a bit dark to see small amounts of fuel otherwise.

See if you can observe fuel spilling out into the throttle bores from anywhere eg: accelerator pump discharge nozzles, idle transfer slots, idle holes if you can see them and the boosters. If there is fuel going in you should be able to observe it and then you can focus on the carb system that is causing the problem.

Remember if you move the throttle shaft the accelerator pump will spray fuel in !

Also sometimes new carbs are worse than old ones. Sometimes old carbs are good because they have proven themslves and new ones are a unknown until they are fully sorted out.

I once had a new Holley 650 that would empty it's primary float bowl into the engine every time the engine was shut down. It had a passageway that was not drilled properly allowing fuel to siphon from the fuel bowl.I don't think that is your problem because in this case the flooding was severe and your flooding sounds mild (just enough to be annoying).

Someone should have an answer for this. There are plenty of guys running air gap single plane manifolds on both windsors and clevelands especially the folks running aluminum heads. can't imagine everyone deals with this.

OK, I had a chance to work on the car.

I had a look into the carb. after shutting it down. Surely, fuel is leaking from the secondary fuel bowl leaving a pool of fuel on top of the throttleblades. This continues untill the fuel bowl is pretty much empty I think.

This is primarily from the drivers side of the carb.

I was kind of shocked to find that one of the pressed in airbleeds are pressed in sideways !!! , and thus it appears that one airbleed is totally blocked . This is how the carb came from Holley.

Would this cause the flooding?? I would think so.

Question is what to do?? Can I break it free and put it in right??

Although the carburator is brand new there is no warranty as it is a long time ago I bought it and I'm in europe and Holley is in the US complicating things.

I'll try and post a picture

Air bleeds

Push, from your photo, that carb body was smashed or badly made when Holley did the assembly. Zinc castings cannot practically be welded (zinc catches fire if welded in air). It may be that Ultras use an aluminum body. Some but not all cast aluminum can be welded. Aluminum carb bodies are relatively recent and I don't know what alloy is commonly being used.

If it was me, I'd fire that chunk back to Holley ASAP, but given your location, I suspect the car will not be driveable this year even if it gets fixed free. Shipping 9 lbs of metal across the pond- twice- is not cheap, either. Probably your best alternative is to take the damaged carb to a local machinist and ask him to pull the air bleed out and make a pressed-in aluminum bushing that can then take your stock jet in the std. manner.

I realize this is a lot of trouble, including clean-up afterward, and not your fault, but it seems like the quickest, cheapest overall solution for you. Of course, buying a new carb and contacting Holley for a refund will also work if you have the extra cash and the patience to follow up. If you do this, be SURE to mention that you belong to a large car club with an Internet site, and photos of the badly made carb are already posted showing their quality.... And other members are watching for their response.

I think the fix for now is to buy one of Holleys ultra HP main bodies and transfer the parts over. It's without the choke tower, but I never use the choke anyways.

http://www.summitracing.com/in...y-134-300c/overview/

I'll take the battle with Holley, but for now I'm in a hurry, as I'm leaving for Le mans in a little over two weeks.

quote:

Originally posted by Push1267:


I was kind of shocked to find that one of the pressed in airbleeds are pressed in sideways !!! , and thus it appears that one airbleed is totally blocked . This is how the carb came from Holley.

Would this cause the flooding?? I would think so.

Yes that's it !!

I agree with Bosswrench on this. Disassemble the carb, go to a local machine shop to remove the damaged air bleed, if you are lucky the hole in the carb body may not be too badly damaged and then get them to make a new air bleed jet the same as the one on the other side but to fit the damaged hole.

I think they will have to make the jet as i don"t think press in air bleed jets are available.
But that should be no problem for them. The size of the hole in the jet is critical to .001"

Also make sure the passageway in the main body has been drilled properly (again check it against the corresponding passageway on the other side).

I Wonder if the screw-in airbleeds that are available for the HP ultras would screw in the press-in airbleed bosses if they are tapped for it?

They might, it's worth looking into. Make sure you can get the correct tap !

Problem solved so far. Bought a Holley HP main body and transferred all parts from the Ultra over.

Starts right up now when hot and no fuel leaking into the intake. Had to richen the carb up quite a bit, so surely it was dumping fuel into the intake while running too.

Holley have acknowledged the problem and will repair or replace the carburator.
Will have to wait though as I need most of it for this years long trip Ddwn to Le Mans Classic.

Thanks for everybodys help to identify the problem.