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post #11 of (permalink) Old 12-08-2001, 11:38 AM
 
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Re: Holley Carb problems

Want more?

Buy a large face vacuum gauge (Sears, Auto Zone) and get back to me.

So many cats, so few recipes...
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post #12 of (permalink) Old 12-08-2001, 11:59 AM
 
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Re: Holley Carb problems

Aaron,
Have you had any success getting a Holley to run well at severe angles? If so, I'd like to see how. My Q-jet is a PAIN to tune, but will run almost vertical.
Thanks.


BillR
'86 CJ-7, 360, 727, OEM Dana 44, locked and loaded!
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post #13 of (permalink) Old 12-08-2001, 02:26 PM Thread Starter
 
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Re: Holley Carb problems

List 9923
1707
Thanks for the encylopedia of info,I'll be printing it off and bringing it to my dads and go over it with him.
The small "leak" is on that thing I labeled number one in the pictures.
I don't know if its actually a leak but when I touch them there is always a bit of gas on them.
I checked the throttle blades and its working as you described.
Checked the pump's "shooting" and it didn't stutter.When I did it very slowly the "last part" of opening(from my butterflys 70-90 degrees) it didn't shoot out any fuel.
The float bowl was my only problem on the diagnosis team.Do you have a picture of where the bowl adjustment is on my carb?
I didn't see it in either places(side or front)
Thanks a bunch
that writeup is awesome.
Very easy to follow!


And sas,I figure if I have to spend 350-400 to buy a new carb(which I don't have)I might as well go buy some parts from a yard and try to get it injected.I was already thinking about it but I'm not sure if I am capable of the job.

78 CJ7
Spring over 33's
4.3L V6, TH350
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post #14 of (permalink) Old 12-08-2001, 03:05 PM
 
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Re: Holley Carb problems

To be truthful, I had never tuned a Holley for anything but street driven vehicles and race vehicles.
The only 'Severe Angle' application carb I have ever tuned was my own Jeep carb, and it runs farely well for me.

I think I need to do a little hair splitting here.
I've built for mudboggers, and for off-road racers, but not for low speed crawlers...

In most racing, you are at Idle or near WOT (Wide Open Throttle) most of the time.
At high RPM the carb has VERY different characteristics, and very different needs for desired output.
I mostly tune for high flow, high RPM racing, and if you are off camber at 'Severe Angles', you are probably at idle or just above idle.

Here is what I've done to mine to get the desired response... (In no particular order)

----------------
First off,
FUEL FILTERS, LOTS OF THEM, GOOD ONES, CHANGED OFTEN
No excuse for dirty fuel in the carb.
Every carb I have to tear down here is always full of crap.
The guys that don't have problems always have good fuel filters, and other than minor tuning, don't have problems...

I have three filters, One paper type canister filter at the pump, One paper type inline filter just before the regulator, and a brass 'Rock' type filter in the fuel bowl inlet.
----------------

1. Extended the float bowl vent tubes.
This helps keep the fuel from the bowls from flooding the carb by leaking out of the vent tubes when you go up/ down steep hills, or the needle and seat opens from severe angles or washboard bumps.

I've used rubber fuel line, old spark plug boots (Silicone type, NOT PLASTIC, they melt) and made metal ones out of brake tubing and aluminum tubing. Copper line is particularly easy to work with, but looks like crap after a little while.

2. Lowered the fuel level by appx. 1/16".
This gives you a little buffer zone before fuel in the tilted fuel bowl opens the needle and seat.

3. I have 'Nitrile' floats, (Black Plastic Foam Filled Floats, available from Holley) and cut the ends off.
(I run center pivot float bowls, so the float is long and rectangle, I reshaped the foam floats to be short, centered and almost rounded on the ends)
Now, when you lean the vehicle, the fuel climbing the side of the float bowl doesn't open the needle and seat right away.

NOTE.
You can also accomplish this using side pivot float bowls that have rounded floats already...

4. Used Holley Jet Extensions to get the jets into the center of the fuel bowl area, so it's harder for fuel to get away from the primary jets no matter what angle you are at.

5. Used 'Off-Road' needle and seat assemblies (Holley factory stock parts).
These needle and seats have a dampening spring that keeps the floats from 'bouncing' or having the needle and seat opened from fuel trying to climb the sides of the fuel bowl.

6. Raised my power valve rating to 2-3/4 below the normal cruse vacuum reading.
That way the power valve doesn't open too soon and flood the engine at low RPM when it's in distress already....
(Some people will need as much as 5 or 6 below the normal cruse vacuum)

7. Used an electric fuel pump and proper regulator. (Holley blue pump and regulator kit)
With out proper regulation you will blow the needle off the seat, and flood the vehicle. There is only one way to do that as far as I'm concerned, and that is with a Good Quality Fuel Pressure Regulator.
Run between 5 and 7 pounds of fuel pressure. Lower it a little when you get into severe angles, and that will help keep your fuel control problems down...
Most Holleys will run well with as little as 4 pounds of fuel pressure to the needle and seat inlet.

NOTE:
Ever need gas for someone that ran out, or need gas for cleaning parts on the trail? An electric pump with manual over ride switch and a fuel safe tap valve in the fuel line is just dandy for things like that...

8. Used a Moroso fuel return valve and fuel manifold.
This little jewel keeps fuel from sitting (and heating up) in the fuel line during low consumption rates (like idling along on a tight spot on the trail or stopped talking to some one) and boiling the fuel.
(I have headers, so I'm particularly hard on fuel temperature...)
It also relieves excess pressure against the pump by returning excess fuel back to the tank.
Usually set 1/2 to 1-1/2 pounds higher pressure than the regulator/ carb inlet pressure.

9. Keep the main and idle well bleed vents CLEAN!
Any crap at all collects on these air bleed orifices, and they will cause Rich/ Lean conditions, and sometime draw raw fuel right into the carb throat.
Look just inside the choke horn, (and if you have a 4 barrel, in the back too) and you will see a row of four small holes.
Clean these with carb cleaner REGULARLY.
DO NOT ATTEMPT TO STICK ANYTHING DOWN THESE HOLES TO CLEAN THEM!
Even tiny size increases or particles from your cleaning instrument will dramatically affect the fuel mixtures in the emulsion tubes...

10. NICE BIG AIR CLEANER!
Small or dirty air cleaners will raise the vacuum level inside the carb throat, and give false vacuum (and flow signals) to the internal workings of the carb and ignition.
A 'Normally' dirty air cleaner can make your engine run up to three jet sizes rich from the start...
(Really dirty air cleaners can make the engine 10 jet sizes too rich)
Large (wide and tall) will allow some of the spilled fuel to vaporize in the air cleaner, instead of running down the carb throat as raw fuel and flooding the engine.
The average engine requires a lot more free air flow that most people have air cleaner to support.
(This includes all factory air cleaners other than the 'Muscle Car' arrangements... Hemi Scoop, Delta 'Tri Power' filter, Cobra Oval filters, ect.)

Stacking 'Normal' air filters IS an option! (Old Racers Trick.)
Stack them up, glue them together!
You are looking for Square Inches of filter, and Form will follow Function here...
Use as much filter as you can get under the hood.
My old CJ-7 will support a 14" X 6" filter under the hood, so there is really no excuse...
------------------

Is that sort of what you wanted to know?



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post #15 of (permalink) Old 12-08-2001, 04:32 PM
 
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Re: Holley Carb problems

Holley Reference Book 36-51-7
List 9923
650 CFM, 4175
1975-78 Chev/GMC, All 3/4 & 1Ton Truck, 350 4-barrel W/AC
----------------

Holley Carb Usage From .pdf file on Holley Tech Website.

Holley 4 barrel, Vacuum Secondary
Spread Bore (Preformance Quadrajet Replacment)
List 9923
Type 4175 (Spread Bore)
CFM (Cubic Feet Per Minute) 650
Renew Kit 37-1537
Trick Kit 37-933
Primary & Secondary Needle & Seat (16-17)
Primary Main Jet Size 122-542
Secondary Main Jet or Plate N/S
Primary Metering Block N/S
Secondary Metering Block N/S
Primary Power Valve 125-211
Primary Discharge Nozzle Size .025
Secondary Spring Color. Black
Primary Bowl Gasket 108-92-2
Primary Metering Block Gasket 108-91-2
Seconddary Bowl Gasket 108-90-2
Secondary Metering Block Gasket 108-90-2
Secondary Metering Plate Gasket 108-27-2
Primary Fuel Bowl N/S
Secondary Fuel Bowl N/S
Throttle Body & Shaft N/S
Primary Venturi Dia.1-13/64"
Secondary Venturi Dia. 1-13/32"
Primary Throttle Bore Dia. 1-3/8"
Secondary Throttle Bore Dia. 2"
----------------

Don't sweat the fuel 'Seep' around the throttle shafts, all Holleys do it, and especially the older ones...
Spray a little 'Carb Cleaner' around the shafts, and see if the idle goes up.
If it does, you may have enough leakage we'll have to install bushings in the shafts.
If the idle doesn't go up, don't worry about the leakage, it's just ugly at this point...
-----------------

As far as fuel level adjustment goes, you have the third type of common float bowl...
The one I didn't cover....

You actually have to take the float bowls off to adjust this type, and they are a pain in the butt of beginners.
(In fact, I don't even recommend beginners do the adjustment, have a pro rebuild the carb, and set the float level.)

You have to take the fuel bowl off, turn it upside down, measure the distance from the float to the bowl, and adjust the float level that way. (A rebuild kit has a gauge included, or you will have to buy gaskets and a gauge)
Be VERY careful of the fuel transfer tube to the back float bowls, that tube gets bent, or it's 'O' rings chewed up, you will NEVER stop the leak, and finding replacement parts for these carbs is getting harder all the time.
(The good news is, if you rebuild the carb, it should be good for another 20 Years!)

Auto shop teachers are a good place to start looking for someone competent that will work for cheap...
And a carb rebuild is pretty basic, so most good mechanics can do them in short order,
BUT...
This is pretty delicate, so don't let just any 'Joe Blow' have the job...

If you don't have an Auto Shop (God Forbid!) teacher handy, try any of the local Auto Mechanic trade schools.
Most teachers are grossly under paid, and will 'Moonlight' for cash... Also, be generous when you pay him...
This would be a good friend to have...

Rebuild kit should be under $60. Most are around $40. A gallon of carb cleaner is around $10.
(Gunk brand Part Number CC3K works well, can be purchased at most auto parts stores, and has a small parts basket included in the can.)
Expect $20 to $40 in total labor from an individual, and $35 to $45 AN HOUR from most shops.
-----------------

I can almost tell you what has happened here now...
This carb is old enough that it doesn't have the Power Valve saving anti back fire valve, and the thing is probably just filthy inside... (haven't made these sense about '79 or '80. Newer made carbs externally adjustable needle and seat float bowls)

I'd pay the extra money and have the anti-backfire valve installed (we do it for under $10 here, parts and all, during rebuild).

Here is a little tip, if you open the rebuild kit, and the carb turns out to be junk, you can not return the kit...
Have the guy tear down, and clean the carb, then go buy the rebuild kit when you are sure this carb is repairable.
------------------

On the up side...
I have used TONS of these carbs down through the years, and I like them!
(Everybody else thinks they are a pain in the butt!)
If you change the float bowls to ones that are externally adjustable, you can use the spring loaded needle and seat. (Off Road Needle & Seat...) AND you get the side pivot, round floats.

I have great luck with this spread bore arrangement.
You can really get great bottom end throttle response with those small primary venturis, and the secondaries are large enough to feed almost any small block!
-----------------

There was one stupid version of this carb made that had backwards idle mixture adjustment screws...
I can't see the screws in your picture... and the book guys didn't see fit to include it in the mechanical drawings...
Get me a picture of the idle mixture adjustment screw from the drivers side... I can tell in short order from that ...

-----------------

In the mean time,

1. Just inside the choke horn there will be four little air bleed holes (not the 'shooter' nozzles).
Take a can of carb cleaner, and let those suckers have it!! Get the kind with the little red tube so you can get right down in there on them! Shoot straight down in them, really give them a good cleaning, with the engine stopped, and with the engine running...
See if that smooths your idle out...

You will find 2 to 4 more in the back of the secondaries, clean them too.

2. Screw the idle mixture screws all the way in LIGHTLY! Don't crank down on these, and immediately turn them out 1-1/2 turns.
You must move these screws together at all times.

Hook up your vacuum gauge (The one I told you to get...) to the carb base plate, (or manifold vacuum if you can't get to a base plate port, but base plate is better).

Screw in the idle screws 1/4 turn TOGETHER (always one side then the other) until you get lean misfire.
You can't miss lean misfire. You will know it when you hear it...

Back the screws out TOGETHER until you get the highest vacuum reading.

Make a note of how many turns (IE: 3/4 or 1-1/3 turns out, but both EVEN) out the screws are.

Have a beer, you have just set the idle mixture the correct way.
(The only way you can do it any better is with a real time exhaust gas analyzer or dyno, and not everyone has $10 grand to blow on one...)
----------------

REMEMBER, this is not a substitute for getting the float level checked, which is almost always wrong...




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post #16 of (permalink) Old 12-08-2001, 05:10 PM
 
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Re: Holley Carb problems

Corrected pic...

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post #17 of (permalink) Old 12-08-2001, 08:02 PM Thread Starter
 
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Re: Holley Carb problems

I think I'll bring it to a shop or have to get it rebuilt,or have one of my dad's friends look at it.
You said 35-40 and hour for labor..
How much do you think it would cost in all to get it rebuilt?
I'll take pics of my screws tomorrow.
I've learned a hell of a lot from this post
Thanks!

78 CJ7
Spring over 33's
4.3L V6, TH350
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post #18 of (permalink) Old 12-08-2001, 09:04 PM
 
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Re: Holley Carb problems

I'm only about half way through a proper tune up for the Holley carb...
Where you going???

Seriously, glad I could help...
Couldn't help those guys that wanted to drill out jets or use a vacuum gauge to set timing, but you I could help...

Even after the rebuild, you are going to have to tune the carb, so keep that in mind...
It would be a good idea to try to tune it before you have it rebuilt, then drive around with a vacuum gauge hooked up, noting the vacuum readings when you are at idle, cruising down the highway, trying to pass someone, ect., so you know what power valve to put in...
Without those vacuum readings you are guessing at the power valve size.

----------------

Maybe that one guy can figure out what power valve you are supposed to use with a timing light, sense he uses a vacuum gauge to time the vehicle...[img]/wwwthreads_images/icons/wink.gif[/img].
Or the kid that tells guys to drill jets with out telling him how to tell when something is rich or lean...
Maybe he can figure out what jets you should be using without looking at any of the indicators...[img]/wwwthreads_images/icons/crazy.gif[/img]
----------------

Have a good night one and all!!
Aaron.

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post #19 of (permalink) Old 12-09-2001, 04:43 PM
 
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Re: Holley Carb problems

There's a LOT of good info there. Thanks, Aaron!

BillR
'86 CJ-7, 360, 727, OEM Dana 44, locked and loaded!
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post #20 of (permalink) Old 12-09-2001, 05:24 PM
 
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Re: Holley Carb problems

Haven't you been keeping up on the hate mail?
I'm not helping anyone anymore, and everybody hates me! [angry]

Are you like me and just can't seem to get with a mandated 'Program'?....
------------------

JoeyCJ55,
To your last question of how much, I'd say under $100 unless you run in to real problems somewhere.
I just looked, and the anti-backfire valve is included in the new Trick Kits I have here. It's a worthy upgrade, and takes all of 5 minutes to do.
-------------------

Seriously, glad I could help guys!
It's easy to teach someone that is ready to learn!!

(but the armchair 'experts' already know everything, and you can't do any thing
for them... they won't learn even when you explain what's going on, and how to correct it...)

Hope everything goes well for you guys, this has been a good thread to work with.
(We sure went over a lot of information fast here! Bright crowd on this thread!)

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