Holley 950 Ultra HP Carb

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HQM383
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Re: Holley 950 Ultra HP Carb

Post by HQM383 »

USMC_Spike wrote: Tue Mar 07, 2023 3:09 pm Here are pics of the actual carb.

Note on the downleg boosters, the dark spots are not junk, but eroded away from
too much cleaner and too long a time ultrasonic cleaning 45 minutes. Sadly.

The unit is a lab grade Bronson, 4500. holds about 1.5 gallons.
I also have a larger Bronson that hold about 5 gallons.

- Thx Spike
From the pics the body looks zinc. Is it?

If it is it has stripped the chromate conversion and must be redone. Same with all the parts on the body that have the finish affected by the ultrasonic.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
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Re: Holley 950 Ultra HP Carb

Post by USMC_Spike »

@ Tuner, everything is apart right now.
Carb is made, set up, it was symmetrical front & rear.
When trying to get it idling only the primary side was set to increase idle;
the way we used to do it with the non-ultra XP carbs. Live and learn.

No, I have not replaced inlet o-rings. They are original. That is on the list of things to do.
I do have two tuning kits, I'll attach pics of them.

The new Holley tuning guide, (-1) says to set the primary and secondary the same amount
when adjusting the idle (after setting the the center flow through).
https://documents.holley.com/199r10565-1rev.pdf
My carb part number is 80805-1.
Current part number is 80805HBX.
I don't know what the difference is.

When I pulled the carb and removed the throttle plate,
I noticed throttle blades had about 1/8 inch clearance between them
and the bore. I if I recall, the t-slot was fully exposed--Yes, I know,
I didn't think to check them.

When I reassemble the throttle plate, etc, I will measure them.
and post the results.

I did find a site that showed how to set up the primary and secondary
pump squinter linkage, but I can't find it any longer. I do recall it showed
using a feeler gauge to set the clearance for primary and secondary linkage.
This was shown on the carb, not the acceleration cable.

Next steps, finish cleaning, find parts from kits, then begin reassembling.
At this point in the process I won't make any additional changes to carb
until I get it up and running on Chevelle (spell check want chenille, go figure).

If I'm missing anything please advise.

Please note I intend to do this in a process, Starting with the Holley carb at baseline.
From there, I'll make one change at a time, then documenting it.

I've done this process once before with my old BBC. Before I pulled it, the guy I had install the
new BBC told me it was the best BBC that he has ever ridden in, and why would I want to change it.
My response was that I wanted more of everything. Then we pulled and replaced it with the new improved
BBC that TW/DV sold me. It had to be towed from the installation shop. The engine has never run correctly.

With that, If I haven't said so, I appreciate everyone's thoughts and advise to help me get this
engine up and running in my Chevelle. I need to drive it again, and enjoy it while I can.
It will be a gift to my little girl when I've passed--She loves this vehicle.

Final thoughts:
The process needs to be as controlled at I can make it. Gong back to baseline,
and starting from there.

Keeping my assistant busy and out of trouble.
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Re: Holley 950 Ultra HP Carb

Post by USMC_Spike »

@HQM383,

I thought the carb was supposed to be anodized. Now sure which parts are zinc,
accept the downleg boosters. Not sure what else is.

I need to identify the proper o-rings for the two fuel inlets,
then start rebuilding the carb.

Who does the re-zinc of carb parts?
Sounds expensive.

-thx Spike
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Re: Holley 950 Ultra HP Carb

Post by USMC_Spike »

@ClassAct,

Well annular boosters would be nice, but it didn't come with them. If used, I suspect I would want to
cut a step in them, they way Vizard recommend for better bootee atomization. Wondering what that would cost.

Recall this is a Holley 950 Ultra XP carb, with Holley base plate.
How is T-slot re-stricter accomplished? Would that involve tapping it,
then installing something like a jet in the thread above the slot?

Or, is this better accomplished by tapping the Holley main body at the
appropriate place, then installing the restrictions there?
If you know, it would be appreciated if you could point it out on the
pics that I've posted here.

-thx Spike
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Re: Holley 950 Ultra HP Carb

Post by 1980RS »

Monza355 wrote: Tue Mar 07, 2023 5:40 am
1980RS wrote: Mon Mar 06, 2023 11:45 pm I have one of the early 950hp Holley's with the non-replaceable air bleeds and it works great, as a matter of fact perfect. Everyone I have let try it wants to buy it but I am hanging on to that one. I had a chance to test a newer one this past year, ran like crap, was out of the box settings. Hesitated like a mo-fo. Put mine back on and the car ran great again.
What’s the part number on that carburetor ? And do you have a picture of the main body ?
I can get them when I go out to the shop sometime this week.
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Re: Holley 950 Ultra HP Carb

Post by USMC_Spike »

@1980RS,

Holley P/N: 80805-1. If I go and look it will delete everything here again.

Pics are on page 2, post #28 I think. They don't seem to have post numbers, here
so it makes things difficult to say where. Here is a link:
viewtopic.php?p=939045#p939045


GENERAL QUESTION:
@Everyman

I've not gotten into carbs this deep before and have a question.
When I reassemble some parts I want to put a drop of oil on the threads.

On the 4 corner idle screws, on the two carb gas bowl feeds when I reinstall,
with the adjust nut and locking screw.

Also thinking on the 4 bolts holding the bowls on. Putting new o-rings and gaskets on
so everything should hold fine.

Also still finding sand like crap in the needles and other places so I am re sonic cleaning
the bowls and metering blocks.

I need to make some e-holes at .029" same as originals but without the shoulders.
Because I have plenty of 6-32 set screws I was thinking of makes full sets for all the
e-holes. But then I realize they female part for the e-holes were machined with shoulder provisions.
Those new set screws will have loctite blue applied to them so why won't vibrate out.

The new UltraSonic sauce is about 1 cup LA Awesome to 5 gals water.
For smaller parts I place in a glass jar with the same sauce to clean them.
The holes in the screen in the unit are too large for small parts. The ultra sonic
vibrations will penetrate glass jar and work on the sauce to clean small parts.

First batch out parts are cleaned and dried.
Second batch is on the way.
Time to go

-thx Spike
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Re: Holley 950 Ultra HP Carb

Post by HQM383 »

USMC_Spike wrote: Tue Mar 07, 2023 5:54 pm @HQM383,

I thought the carb was supposed to be anodized. Now sure which parts are zinc,
accept the downleg boosters. Not sure what else is.

I need to identify the proper o-rings for the two fuel inlets,
then start rebuilding the carb.

Who does the re-zinc of carb parts?
Sounds expensive.

-thx Spike
The pics do look like dull zinc after ultrasonic but aluminum can go all freaky like that from excess time in the ultrasonic as well. It was the side on pic with the part number that had me thinking zinc main body but apparently all those models are aluminum. Still, it will need some kind of surface treatment in that environment or will look funky in no time. The plating on the squirter screws and vent tubes has come off and as you have already pointed out the boosters. Boosters will end up looking aged but the others may develop rust.

USMC_Spike wrote: Tue Mar 07, 2023 5:54 pmPlease note I intend to do this in a process, Starting with the Holley carb at baseline. From there, I'll make one change at a time, then documenting it.
Best way to do it. Do you have an AFR gauge in the car? I assume so if you say you have done it before. Put the original IFR in the bottom location. It will be rich but take note of afr at several steady speeds. Then when you drop down a few sizes to lean you will get a better understanding of how far into the throttle the ifr/iab is having an effect. Very helpful to know when you move on to dialing in the mains. Main jets at 92 does seem excessive. I'd be willing to go down to at least 85's to test first up.

Leave the boosters alone, they are as per factory with the step.

Dont be concerned with the PV rating being near the idle vacuum, PV has no influence on idle. Later down the track when the calibration is sorted you can trial different rated power valves.

Accelerator arm adjustment is hold at WOT and there should be around .015" clearance between the adjusting screw head and pump diaphram lever.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
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Re: Holley 950 Ultra HP Carb

Post by Tom68 »

HQM383 wrote: Wed Mar 08, 2023 1:23 am

Dont be concerned with the PV rating being near the idle vacuum, PV has no influence on idle.
Hmmm, good point, no significant air flow through the venturi, so no fuel flow at idle even if the PV is wide open.

And it's not the Mark Campbell accelerator pump circuit metering block leak because that wouldn't spill out around the throttle shafts.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
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Re: Holley 950 Ultra HP Carb

Post by Tuner »

Tom68 wrote: Wed Mar 08, 2023 2:53 am And it's not the Mark Campbell accelerator pump circuit metering block leak because that wouldn't spill out around the throttle shafts.
It leaks out the throttle shafts when the motor is not running because there is no vacuum to cause air to suck in through the throttle shafts.
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Re: Holley 950 Ultra HP Carb

Post by Tuner »

USMC_Spike wrote: Wed Mar 08, 2023 12:59 am
If I go and look it will delete everything here again.
Open another tab in the browser and open the thread in it, then you can browse in one and post in the other, copy from one tab and drop in the other to post the copy in your reply. Pay attention in editing to who the quote belongs to so no confusion starts.
The new UltraSonic sauce is about 1 cup LA Awesome to 5 gals water.
For smaller parts I place in a glass jar with the same sauce to clean them.
The holes in the screen in the unit are too large for small parts. The ultra sonic
vibrations will penetrate glass jar and work on the sauce to clean small parts.

First batch out parts are cleaned and dried.
Second batch is on the way.
Time to go

-thx Spike
Zip lock bags and plastic food containers are good to do small batches. Some food containers will seal waterproof so you can use them for different cleaning solutions in just a plain water bath. Small batch uses less cleaner.

Rinsing in hot water is necessary and blow dry.
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Re: Holley 950 Ultra HP Carb

Post by Tom68 »

Tuner wrote: Wed Mar 08, 2023 3:20 pm
Tom68 wrote: Wed Mar 08, 2023 2:53 am And it's not the Mark Campbell accelerator pump circuit metering block leak because that wouldn't spill out around the throttle shafts.
It leaks out the throttle shafts when the motor is not running because there is no vacuum to cause air to suck in through the throttle shafts.
That's ported below the shafts.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
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Re: Holley 950 Ultra HP Carb

Post by Tuner »

Tom68 wrote: Wed Mar 08, 2023 4:33 pm
Tuner wrote: Wed Mar 08, 2023 3:20 pm
Tom68 wrote: Wed Mar 08, 2023 2:53 am And it's not the Mark Campbell accelerator pump circuit metering block leak because that wouldn't spill out around the throttle shafts.
It leaks out the throttle shafts when the motor is not running because there is no vacuum to cause air to suck in through the throttle shafts.
That's ported below the shafts.
I don't know what you mean unless it is a reference to the passages some people add for a blow through carb. If the engine is running vacuum keeps the fuel inside the base plate.
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Re: Holley 950 Ultra HP Carb

Post by HQM383 »

Tom is assuming the throttle shaft leak is occurring when the engine is running and Tuner is assuming the leak is occurring without the engine running.

O/P to clarify
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
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Re: Holley 950 Ultra HP Carb

Post by Tom68 »

Tuner wrote: Wed Mar 08, 2023 4:35 pm

I don't know what you mean unless it is a reference to the passages some people add for a blow through carb. If the engine is running vacuum keeps the fuel inside the base plate.
I was ruling out the accel pump metering block port leaking into the power valve vacuum cavity and discharging under the base plate.

I've had it happen with a spreadbore with the o-ringed brass transfer tube. O-rings broke down.

Mark Campbell points out that the zinc bodies suffer from heat flow and allow leakage on the gasketed connections.

The pictured carby may have its own issues in that area.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
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Re: Holley 950 Ultra HP Carb

Post by USMC_Spike »

@ Tom68, "Carby?" Really? You're starting to sound like
my little girl talking about something Sponge Bob square pants would say
or maybe Patrick the starfish.

I was thining (Now I'm sounding like Desi Arnez) the primary throttle shaft might have been
a different Aluminum mixture and expands/contracts at a different rate then the throttle plate.
After the engine get to temperature, the fountain of fuel stops.

That is all for the moment if you think of anything or I find out something, I'll post.

--thx Spike
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