Newly installed six pack questions

So I have a new six pack setup on the car. It's new from Holley, so the later carbs, not original ones.

I have the idle set reasonably well, still need to play with it but it does idle fine. Front carb is set, need to swap it with the rear one and set that one.

Took it for a quick run, and it felt good. When I went for about 1/2 or more throttle, there was a big hesitation, and then the secondaries kicked in.

I did replace the main jets with 66's, came with 62's. It idles with 10-11 inches of vacuum, and I have a 4.5 power valve in it.

Is the hesitation just the springs in the secondary diaphragms? I was told by Mike Goyette to put the white springs in, the lightest ones, but I don't have them yet.

Just want to get an understanding of how the system works.

I had same thing on my 6 bbl on my old 440. I put lighter springs in and problem seemed worse. I went with heavier spring and cleared up. If I recall what I read, is that the hesitation is perceived to be leaning out, so everyone says go lighter to get the outboards to open sooner. But in reality, its a rich bog, and a slight delay on outboards clears it up. I bought a kit that had something 5 or 6 different springs in it.

I have no data from A/F ratio to verify, only seat of the pants work. This was several years ago too. YMMV

It's amazing the varieties of experience out there!

I assume the springs that are in there now are mid range. I'll give one a try, and then the other, and see what I get.

I hope you mean one set at a time.

well, I thought that if I put the full light one in the front, and the full heavy one in the rear, then if under full throttle the front of the car lifts, then I'll know the front one is correct, and if the rear of the car lifts, then I'll know the rear one is correct. Right? if the front is running correct, that should give the front cylinders power right away, so that will lift the front end, as that is where the power is coming from, and if the rear one is correct, the rear of the car will lift, as all the power is coming from the rear cylinders.

Should be a simple test, no?

I use the lightest spring I can use but I have a small SS fish tank valve to regulate the vac. (more or less its just bleeding some off, but its adjustable) so if im hooking good on the street or track or spinning a bit it takes no more then one or two adjustments to be where I want to be for those conditions to keep the bog away and the transition smooth or violent.

The same valve also works on vac. turbo wastegates.

But with the ss fish tank valve I could adjust to race on wet pavement or a preped track.

Do not mix and match springs, use the same color springs matched if your going that way.

6 pack on a 340, 440, or Hemi?

Try the purple springs.

Hemi.

So I'm new to Holley's. I think I understand the basic principles of the various circuits, but probably not as well as I think.

The power valve starts to open at it's vacuum rating, to richen the mixture when coming off of cruise to a more open throttle. Correct? General rule of thumb is the PV should be rated at 1/2 your idle vacuum. Mine fluctuates between 10-11, but was told to use a 4.5 PV. So vacuum has to get pretty low before it kicks in.

Could this be part of my hesitation as well?

And yes, I would use the same spring on both carbs!

Mick,


usually most of the Holley re-issue carbs come with the black or brown springs, replace both springs at the same time, don't stagger their rating, IMHO if your experiencing a "hesitation" during the out board carbs coming on line it's because of the slow opening rate of the heavier springs, if you were experiencing a bog/break down during the transition then I'd say your opening too rapidly and need a heavier spring

Put the WHITE springs in and go up the color scale if you need more delay, and or higher RPM tip in, you need to know what's in your carbs before even operating them, I hope you put new plugs in the motor?, HEMI's run a bit lean on cylinders 5 and 6 running the six pack, your jet change may be for the good? but I'd read the cylinders after a few good runs on fresh plugs

Normally I'd recommend the clear sight plugs on the carbs fuel bowls, but the plugs are really sucking with today's plastics and today's gas, but I would buy a set and install them just to establish exactly were the running/idle fuel level is, generally I like to set the float level on all 3 carbs at the halfway point on the clear plastic float, then re-install the brass screws, don't leave the clear plugs in too long as they will soften/break off, when installing them, just finger tight

What have you done for a choke?

Mike

Mike,

I have 2 sets of springs on order, should be here soon. Just wanted to get it up and running, and see where it's at. Did the idle adjustment as you suggested, front is done, will switch it with the rear next. It needs it, idle speeds up on both sides when blocking the air bleeds on the rear carb.

I'll start with the white as you suggest. And have heard the same about the sight plugs, so I'll do that.

So what do you think of the 4.5 PV? Any chance that is part of my issue?

Haven't done anything with the choke. It's wired open for the moment. I'll either remove it, or install a cable as you suggested. You have a spare one?

Another issue I noticed is that when it is cold, it doesn't like to stay running, even when I"m giving it enough gas to keep above 1500rpm. I need to pump the pedal to keep it running for the first minute or two.

Is that just because it wants the choke on?

Well the 4.5 PV should be OK, the stock set up would be the 6.5, But I understand the 4.5 based on your vacuum manifold baseline reading

But do get the fuel/air mixture ratios set up on all 3 carbs, fuel level, make sure your fuel pump is up to the task psi wise, double check the mechanical operation is 100%, then start playing/tuning the system out to what your motor needs, and you desire performance wise

I do have a spare cable for the choke set up, but you'll need to fabricate some linkage/bracketry unless you'd like me to do that for you?, just let me know

But I would recommend a functioning choke, up to you if you want a hand choke (that I can provide)or if you want to tinker with an electric set up of some kind

Mike

Speaking of PSI, what do Holley's like? I have the carter pump on there now with a pressure regulator set at 5.5-6psi.

Mick, I usually run the Carter pump as well the 6903 model, it's good for 6-7 PSI and the GPH is 120, you'll find that Holley needle seats don't like/handle high pressure, keep a good filter on it as well, as 3 seats multiplies any issues from particles in the fuel causing the seat(s) to leak (flood) or stick closed resulting in no fuel

Mike

I too live in Calyfornua where it seldom gets down to 40 degrees. Run no choke and when engine starts, has no tendency to stall out. Runs a Comp Cam roller, idle speed set about 800 rpm. If been parked a few days, hit the foot feed a couple of whacks before turning key. Always fires right off and settles right down. Car is factory V code, however running later Holly carbs as OP.

No hesitation when I floor it,,,just hang on and go. Love it. Hemi what?!!!

I got you on this one MikeM since I just went through my 440 six pack set up (for the umptienth time) and now I think I've got a good handle on it....thanks to guys here and over at FBBO.

Anway....

1. Your power valve is correct for your vacuum. I'm also running a 4.5 with 12" vacuum (I could go to a 5.5 since there's a teeny-tiny hesitation just off idle during acceleration).

2. Front/Rear springs should be the same.... the front/rear carbs are connected via the mechanical linkage anyway.

3. A "bog" is because the front/rear are opening too fast vs. the accelerator pump squirt in the center carb. Either put in stiffer/slower springs or increase the center carb accelerator pump squirt with a bigger pump cam, larger squirter + bigger pump cam, or change the existing white pump cam between "hole #1" and "hole #2". I can't remember which hole gives a bigger squirt.

4. Many people tell you to increase the center carb's jets & do a bunch of modifications to idle circuits, air bleeds, etc. I STRONGLY suggest that you start with the carbs completely stock & work from there. I un-did a bunch of these modifications I'd done in the past on my six pack and the car is MUCH faster with the carbs almost bone stock. I'm running #61 main jets at the suggestion of "Six Packs to Go" (I think that's their name) out in Albequerque, New Mexico. He's raced six packs for MANY years and knows his stuff. The only REAL way to be sure is to use oxygen sensors or get the car tuned on a dyno where they can measure your fuel mixture.... or track time.

5. Your cold stalling issue is definitely because you're not running the choke.

540 Hemi.

Good to know. thanks for the response. I'm staying stock and working from there. I hope to modify things as little as possible. I'm not into getting every ounce of performance out of them, just a good running setup.

Install a wideband sensor and gauge on your car and check out whats actually happening with the air/fuel ratio. its the cheaper route

Or get an innovate LM2 from INNOVATE. get the dual sensor unit.

Anything else is guesswork....you are playing with a HEMI I think it would be a good thing to have...mistakes on air fuel ratio can be expensive on that engine!

got one.

Dear OP
I am always amazed at six pak threads.
Some bad advice and no one discusses how to baseline a six pak.
It is a fundamental procedure that is well documented and tested.
It is stickied on the lift off hood playground forum and has been posted here many times.
It works, I do not know why no one suggests the proper info.
You have to baseline the set up!

In the working world I provide technical support on very complex technology so I might have a clue about troubleshooting complex systems, writing procedures and testing them.

PM sogtx if you want offline help. He is very six pak literate.

Just a few more comments and I will leave you in the hands of the experts...

I do not understand why people will not give you the proper help when they have the same information as many others.

If you read the guide you will learn:
A properly tuned six pak starts easily hot or cold.
The transition to the secondaries should be seamless.
If there is a bog - the bog is a LEAN bog.
The fuel levels are different that what has been suggested.
Use the carter street pump and 195 degree thermostat.

Good luck

Well then it should not be too hard!

Have u got metering plates with removeable jets on the outboards? if not get some from Pro form.

Then after that is not much different that adjusting a Holley 4160 really. At least I have been able to tune mine pretty easy....but they all have been on stock displacement engines and witht the stock intake manifolds.

You can also get some idle needles that you can adjust at an angle with a special tool (better and cheaper solutiuon that the Pro Form Baseplates with the angled needles).

Scott Smith at HARMS can probably tell u where to get them.

Goodbye to removing carbs. you can set your idle while the engine is running.

Oh and get this.

http://www.ebay.com/itm/Holley-Carburetors-Manifolds-Fuel-Injection-HP1052-/311807898351?hash=item489932f2ef:g:t0wAAOSw5ZBWIOY-

Did you type that with a straight face ...

Also getting the front and rear carbs set up with the adjustable idle screws is the proper way to set them up but the signal to the carbs, and how the engine reacts to the adjustment, is not going to be the same front to rear, how the engine runs with the carb on the front and then switched to the rear is not going to be the same.

Also suggesting what jets and PV works best on a 440 is not going to be the same because he has an engine that is 100 cubic inches BIGGER .... (not directed at you D)

Put the white springs in, gave it about 1/2 throttle. Very slight hesitation, nothing like with the yellow springs in, then broke the rear tires loose.

Something felt odd though, took it home and discovered the broken motor mount.

So, tuning on hold for the moment...

One thing I didn't see mentioned in this thread is float level. If the float level on all three carbs is not correct, the tuning you do will be in vein. Set the float levels first (with the car running). I set mine so the fuel runs out of the sight gauge with a slight bump of the fender. Then set the air fuel mixture on all three carbs, starting with the center carb. If you purchased two sets of springs from Holley, read the instructions before changing the springs. I agree that the looser (yellow) springs will typically show a bog due to too much fuel at one time. I started with the yellows and was rewarded with a zoooo-whhaaaa. That is not good and as mentioned earlier, the transition from idle to secondary should be "seamless". You can test this by taking the car for a ride. Get it into high gear at around 50 mph. Floor the throttle and note the smoothness of the transition from 2bbl to 6bbl. I run the purple or brown springs (I currently have one of each) in the outboard carbs. They are mechanically connected by the driver's side linkage. In order for them to open, the center carb must be at wide open throttle (WOT). Once in that position, the vacuum will be allowed overcome the springs to open the outboard carbs. The road test mentioned above is easier if you have a manual valve body, or a 4-speed. Automatics with kick-down linkage will want to down shift. I believe you have a 4-speed, so no issues. Good luck. Nice car. You'll love the 6bbl once sorted out. Good gas mileage and great performance.

John, I was wondering if anyone was going to comment on that! No, I was laughing the whole time I was typing!

One thing I did do on my new Six Pack carbs is change out the main jet as it was a #62 , A bit on the lean side for my 500 cube sixpack. I stepped up to a 65 main jet and it run so much better.

Yes, I put 66's in, and at cruise it seems to do well. Have only had it out on short sprints though, need to get it out and go through the whole range.

I do not understand why people will not give you the proper help when they have the same information as many others.

If you read the guide you will learn:
A properly tuned six pak starts easily hot or cold.
The transition to the secondaries should be seamless.
If there is a bog - the bog is a LEAN bog.
The fuel levels are different that what has been suggested.
Use the carter street pump and 195 degree thermostat.


These do not apply to every build and maybe thats why its not so popular, might be good for a 275hp 340 or a 390 440 but all that crap dont apply to most situations.

Simple things like, not everyone runs a choke, a heat crossover, some cars never get over 180 degrees. Some run modified intakes, camshaft, rear gear, converter, personal driving habbits, already made modifications, compression,some run spacers...

Maybe in the all stock world those are things to live by but hardly in modified setting.

Well, it's getting there. EV2, you are correct. When the bog hit, the 02 sensor went off the scale lean.

So I put the purple spring in, bog almost gone. Put the clear spring in, bog completely gone, at least at 1/2 throttle. Haven't tested full throttle yet, as I have a little issue where the reproduction return spring isn't strong enough to close the throttle under WOT, and it hangs for a couple of seconds, not a nice feeling. So need to fix that before I want to lay into it.

So far:

- 4.5 PV
- 66 jets
- starts immediately hot or cold
- bog gone, at least on 1/2 throttle
- my one WOT run A/F was steady at 12.6
- cruise is around 14 or so
- idle seems to bounce around, sometimes it's 14-15 and sometimes 15-17
- it's lean off idle into the main circuit, and I can feel it as a slight stumble
- also, not using the idle solenoid

Getting close!

I've set the fuel level to be in the middle of the sight glass on the outer carbs, per Mike Goyette's suggestion. Am using the carter street pump with a regulator, which should be set to around 6lbs, I'll have to double check that.

Why the 195 thermostat? I have a 160 in there now, and it likes to hover at 170 or so.

EV2, sorry, I just realized that you didn't write that middle section.

In my case the bog did turn out to be lean. As far as everything else, I agree with you, each according to his build.

well it seams like everyone has there 2 cents BUT that bog/hesitation you get when you start laying on the throttle and the seconardies are opening is a LEAN BOG, the secondary carbs have no accelerator pumps so when those 2x500cfm carbs open up at the same time, that engine is getting a lot of extra air and it takes a bit for the fuel to catch up(the reason your primary has an accelerator pump). putting heavier springs in the seconardies will slow them and make the transition smoother. I have an LM2 in my car to watch the Air/Fuel and you can watch it go lean for a slit second

Well, things are good, but the DOH! factor did slip in.

The bog was completely gone, and I finally got a chance to get it out and put my foot to the floor. Disappointing, and didn't feel like the first few times I took it out. Well, ~935CFM on a dual plane is not going to perform like 1350CFM on a single plane, but I still wasn't at all happy.

Went at it again the next day, and the vacuum line to the rear carb was off! Which I assume means it probably wasn't even bringing the front one in very much!

Ok, so I'm now sitting with the clear spring in, and have to start trying different springs again. It still has a bog, but is less than what it previously was, and it's back to being an animal!

Onwards...

Mick - what are the results with the vacuum line hooked back up?

So are you liking the LM-2? Are you using the rpm module also? I am messing with the six bbl on a 512 wedge and have realized I need a wide band gauge. I have posted questions about wide bands on 2 different websites. The guys on here like the LM-2 but on the other forum nothing but bad reviews and they recommend the Daytona WEGO. How has your experience been?

You still haven't answered the question unless I missed it,did you do anything with the jetting in the end carbs ? I would "assume" that if you have anything more than a cam with specs close to a sixpack cam,you would be lean as soon as you got into the throttle especially with a 540 cu in motor,you will have to change the end carb jetting.

There is still a bog, not nearly as bad, but does need to be addressed. But when they kick in, it's a beast!

I'm going to work with more springs tomorrow, and see if that solves it. hopefully it's as easy as that.

It's interesting, I expected it to be lean as well.

I have 66 jets in the center carb, have not touched a thing on the outboard carbs.

Reading about 12.6:1 at WOT. If thats the case, I actually need to lean it out a bit.

I have an AEM wide band gauge in the car. I don't remember which model it is, would have to look it up. I do believe it has a USB port on it, so I may look into playing with that.

Read this.

http://www.innovatemotorsports.com/resources/carb-tuning-hero.php

I agree. If you have a stumble/bog/hesitation and you change the vacum pod springs and it gets better then I agree slowing them up will not let them slam open to fast before the circuits in the end carbs start to work and deliver fuel. If you made no fuel changes but stop a lean bog you are just slowing up the end carbs. Course it sounds like the end carbs may be to lean for your combo and need more jet and so on. Good luck with it as adding the 02 is a good help and you are learning more about the setup as you go along. When you get into 540 Hemi's and add a six pack normal 440 six pack jetting wont work. Ron

Mick,


Whats the timing your set at, initial and total?, vacuum or mechanical?, I see vac in your pics, don't know if you changed out? points?, electronic/aftermarket


Mike

18 initial, 32 total. Vacuum advance hooked up. MSD box on a mopar electronic distributor.