Holley Tuning Tips for Frustrated Idiot!?!

[71383bee]

Well darn it... I just left the garage swearing to never go back until the car wakes up and learns to behave!!!

I am trying to tune a new Holley 770 Street Avenger on my built 383. The car starts on the first crank and idles excellent and it drives good, but I noticed a hesitation when gassing it from a stop. Figuring it was rich, I looked at the see-thru sight plugs and I gotta shake the car to see the fuel sloshing at the top of the sights. For further confirmation I pulled 1 plug from each side and both were brown and sooty with a tingle of deep tan to them. Yep rich. Now mind you, I have never tuned a carburator of any kind in my life. I got the Street Avenger because of it's excellent reviews and ease of tuning. I know I got a size too large only because I will be adding an RPM intake and 1.6 roller rockers in the future so the motor will be upgraded and I also convinced myself that this is an excellent way for me to learn how to tune carbs by downtuning to present performance and uptuning to future performance. So tonight I got out the Holley book and did a little research and warmed the car up tonight and atached my tach/dwell and laid out my tools and attempted to tune my carb. Well nothing prepared me for the geiser of gasoline shooting out of the float adjustment nut onto the coil! This happened instantly as I slightly unscrewed the lock screw! Is this what is supposed to happen?!? To top it off I tightened the screw again and it would not stop dribbling gas down the side of the carb until I backed the float adjusting nut back to it's original setting. I just about threw that 5/8 wrench through the windshield! Damn am I pissed! Can someone explain to me why I am doing this?

But seriously, too make a long story short can someone please give me a checklist or breakdown about how to tune your Holley? I know there are dozens of posts like this all of the time, but I really need some good advice from the Pros. Also please don't scimp on the details like gas spraying on coils or anything and I also would like to hear about setting the correct mixture with a vacum gauge.

Thanks to all who help... I really need a beer!!!

[blackcuda]

Do you still need help?

If so e-mail me blackcuda@hotmail.com

I tried to post a reply but was timed out...

[mauve66]

WELL, I'm glad to know that I'm not the ONLY one..............
I love my Charger but as soon as I can produce a vision of the next group of lottery numbers I'm going buy lots of old cars and retrofit them all with EFI to make the rest of the people like us happy...... or at least sane and retaining our eye brows......
I found a site that looks pretty good but I haven't had the chance to test it out yet....... yes the car was running but now its up in the air to switch out the old, tired, leaking,.... well you get the idea, tranny for the new one with the GearVendor OD on it, which doesn't look like it will fit in that tiny tunnel.... but that's another post..... here it is
http://www.mortec.com/carbtip1.htm

[71383bee]

Anybody else...Doug, cuda66, rumblefish360, Dart, PRO? I can really use a bit of advice. I'll email you too black cuda.

Mauve,

Yeah I just would like something to work just the way it's supposed to for once. I am very nervous beacause this is my first total restification and it is almost upsetting me that I aint even on the road yet. Oh well whoever said it was going to be easy right...

[sam spade]

Check out this site: http://www.bob2000.com/carb.htm
That should answer a lot of your carb questions.

[pishta]

Well, let me try and calm you down. Try adjusting the the floats with the motor not running. Not a big deal, just turn the nut 1/4 turn and start the car, let idle for a minute and take a new reading. Keep doing this until the level is just visible, right at the base of the plug. Ok, so it is still leaking..you have 2 fiber gaskets and an Oring to check. The gasket is under the set screw and nut, might have torn either. No telling how long that thing was on the shelf. The O ring is down around the brass inlet valve, It could have failed. These are the only things between the gas and the freshly painted manifold. My Oring was damaged when I put it in. The carb shaved off a slice of it and it got hung in the needle seat, flooding the car at idle, easy fix though. If the plugs are rich, I would get the fuel level down to a manageable level and give it a few passes. Next check the idle setting and make sure it is in the idle circuit (if it idles good it probably is) next check the power valve, the have blow out protection on those carbs, but it is worth a check. Are your eyes watering at idle, how about black smoke on acceleration? Too rich on acceleration means jetting, go a little leaner. Too rich on idle means the plate may need replacing with a leaner plate. just read the book again, not too complex. Good luck.

[rumblefish360]

sam spade, mauve66

Nice sites. Good work fella's!


71383bee;

Sorry I didn't jump in sooner. Those sites should really help you out. For the most part, I must confess, I'm not to great on tuning carbs. I can get them in the ball park. Perfection is out.
I went through the same things you are going through to. Best thing is take your time, stay calm and keep on it. Remember it is just a part that requires methodical thinking and patience.
pishta Gave you a good start.
The float level isn't critical on start up if you can shake the car a little and see it. You can adjust it later. I had the same problem with my Holley. Drove me nuts. I took the whole damn thing apart to mess with it.
Your brown plugs are a sign of being rich. Try 2 jet sizes smaller. This may not cure the problem, but it's a step in the right direction. Continue till the plugs clear up.
The problem on acceleration is a adjustment on pump shot.
You'll have to decide if it's lean or rich for the engine. Go a step in the opposite direction. If shes rich, try a step leaner and try it out.

Let us know how you make out with those sites and your carb tuning. I think you did the right thing in trying this yourself as a learning experance. Things like this allways hand out fits of fustration.
DON'T LET A PEICE OF METAL BEAT YOU!!!
YOU CAN DO IT!!!

[451Mopar]

Here is the deal on the fuel inlet, Needle/seat setup on a Holley.

The fuel comes into the top of the fuel bowl housing, and the needle/seat assembly drops in from the top, with the outlet of the needle/seat flowing into the bowl area. The "O" ring on the needle/seat just seperates the inlet fuel from the bowl area so all the fuel has to go through the needle/seat. If the "O" ring is bad and leaking the fuel will flow around the needle/seat and FLOOD the carburator.
Because the needle/seat assembly is installed through the top of the bowl housing, it needs to be sealed at the top to keep the fuel from the fuel pump from leaking out the top of the fuel bowl, but Holley also designed the needle/seat to be adjusted so you can adjust the float level without removing the fuel bowl. That is why there is the adjusting nut. The screw on top is used to seal the assembly (along with the two gaskets) and to hold the float level adjustment from moving once set.

Before tring to adjust the float level, with the engine off (no fuel pressure), remove the set screw on top of the adjusting nut and remove the adjusting nut to make sure the gaskets do not stick. If they stick while adjusting the float level you may tear the gasket and it will leak untill you replace it.

To adjust the float level you need to loosen the set screw slightly and turn the nut counter clockwise to raise the fuel level, or clockwise to lower the float level. You should start with the fuel level lower than needed as only using the fuel from the fuel bowl will lower the level when going from high to low fuel level.
When you go from a lower fuel level to a higher fuel level (adjusting counterclockwise) the responds is immedate (if the fuel pump is running.)
When adjusting the float level with the engine running it is normal to have some fuel seepage, but if you carefully control the set screw while adjusting the float level it should not be too bad. The real trick is to make sure the gaskets are not stivking before starting the adjustment process. Some people even remove the gaskets and put petrolum jelly or chap stick on them so they do not stick, making the adjustments easier.
This is also true (coating the gaskets) with the metering block and fuel bowl gaskets to keep them from sticking (when changing jets or power valves), but now there are teflon type replacement gaskets so solve that problem.

[71383bee]

Thankyou everyone you have all been very help full the sites you all listed are very helpfull. I'll try another crack at it tonight or maybe tomorrow. The car idles at about 750 to 800 RPM in park and it is a nice smooth idle so I don't think I have a vacum leak...(Been there before ) I just was a bit worried that with the slightest loosening of the lock screw gas was leaking out and it seemed that I really had to crank on it too stop it from leaking. 451 may be right in that the gaskets in the inlet are trashed. Either way i'll try it while it is not running.

The hesitation is not really noticeable because I am easy on the throttle...which brings me to another question. What is the best way to break in the first 200+ miles on a rebuilt motor? Keep the revs below 3500 or drive it like you stole it?

[RB74DART]

Hey 71383bee that is a question we get all the time at the shop,
my car hesitates off idle what can you do?
Most of the time it's as simple as changing the accellerater pump cam timing, or change the cam itself. Holley sells a kit with a few different cams for very little money. Also do have ported vacum or manifold vacum? As far as tuning with a vacum gauge that won't help because when you break the throttle the idle circuit is not working anymore.
451, you nailed the needle/seat setup, we see so many people try to adjust them and end up tearing up something that it's not even funny.



P.S. Most new Holleys we install come out of the box with the floats right on the money


Later

[blackcuda]

Looks like your heaeded in the right direction, the pump should cure your hesitation problem. As far as the break in goes that would depend on the type of ring you installed. If you went with a rough bore/ stock ring I would toke it easy on the motor the first few hundered miles. If you went with a smooth bore/ moly ring then drive it any way you like they seat pretty quick.
I think the Mopar engines book had a break in procedure for a race motor. It went like make a few passes half throttle, then a few more a little more throttle and by like the seventh or eight pass go for it... But this was with the moly rings I think. I'm at work now so I don't have the book in front of me.
If you need more help I'll be glad to help any I can...
Good Luck!

[rumblefish360]

RB74DART

Most of the time there good to go is right. I had one give me fits. My first one no less. Lots of tinkering, didnt know any better. Finally got it. I remember I felt like 71383bee does.

[John Kunkel]

A hesitation just off idle is caused by a lean condition, not rich. As the throttle is opened, more air is introduced and more fuel is needed. If the idle mixture is overlean to begin with, there will be a hesitation as the mixture leans further. Trying to read the idle mixture by looking at the plugs won't tell much, it takes a while for a change in mixture to effect the plug coloring.
Playing with the accelerator pump might help but simply richening the idle mixture might cure the hesitation.

[71383bee]

Ahh now that is better. With your help I tried it again with a cooler head. I was able to lower my floats with out staring any fires and i noticed an instant improvement. It still is a little hard to read the level because the glass sites are fogged in, but I definately got it closer to where it should be. I adjusted the mixture to optimum vacum too. I am running about 14" at 750-800 RPM now. That seems to be the best I could get during idle. Actually I had to lean out the mixture to get a smother idle started at 1.5 turns out. The car did seem to run better and I did not get the typical hesitation. I did notice a slight flutter though as I laid into it. Any thoughts on that?

Again kudos to everyone!