holley setup

[spdcrazy]

That's true, people give up too early.

The biggest stumbling block is the accelerator pump. The squirters and coloured cam are there for delivery adjustment, but people still don't realize that the total VOLUME of fuel delivered for our little engines is too much. You can easily drown the engine by just blipping the throttle, to the point where it actually stalls. I've done it. As you've stated, its a carb that's used on a wide variety of engines. That's why the pump is so big and without tuning this properly, people just say...."Them too big those Holeezzz" Easy trap and most of the write ups often fail to address this situation properly, if at all. I know how to do it, simple really but someone needs to start a new thread for this kind of discussion! :bulb:

The size of the primaries, both the venturi and the throttle plate are not too large at all for our engines (List 7002 390 cfm 4 barrel) and the secondaries are progressive (Vacuum operated) so that's appropriate in terms of airflow.

The 390 is an excellent carb IMO if done right!

new thread it is!

i had a buddy come down and wrench on my Z a bit, and he knows holley's so he could give me some insight. guess i have the quick change vaccuum secondary's. so we popped the cap and found the diaphram torn in a few places. swapped that, and it ran soo much better. still a bit of stumbling, but we didn't check float levels or anything of that sort since we were at 3k above sea level, and the Z's new home is about 6k.

need to sort out the new leaking brake master and my clutch leak as well. then the carb gets rebuilt and tuned. so far i am happy with it tho. its such a great feeling when the secondary's open up!

[ozconnection]

Good to hear that there are some people who don't mind playing with a Holley.

Theoretically, you shouldn't feel the secondaries kick in. But some people like the feeling but it means that either the primary jetting is too rich/lean and the secondaries are too rich lean as well as the secondary spring is too light. There is a momentary bog followed by a surge of power as the fuel flow in the secondaries catches up with the airflow through that side of the carb.

On another point, you would be really surprised by how far open the primaries have to be tied with how many revs are on board before the mains take over from the transition slots!

In my auto trans L28 with a 2.5K high stall converter fitted, I tune in drive. I jam on the handbrake, put the drive into '2nd' so its actually second and not first gear (good old Jatco box) and chock every wheel with a big housebrick, I have my own dyno to the stall speed! Since most cruising is done at or below this rpm, I can tune the carb on the spot under load at home! Really really dangerous....sure.....but I'm ready to pull the coil HT lead and only stand to the side of the car, never in front of it!! You could do this against a tree or something too but I don't have one at my place. Brick wall might be ok too. I'd still use the handbrake and 4 wheel chocks. I must also add, I do this by screwing in the idle speed screw, not winging the throttle by hand. I have my timing light attached with the tach feature on so I can see the revs rise as I tune the transition screws on the primaries. I also have an Innovate Wide Band O2 sensor telling me my mixtures.

When you look down the primary barrels at the point of mains activation, fuel gushes out of the carb in spurts, hardly what you'd call 'nice atomisation' at all. Still, my car doesn't surge on the street as you'd expect it to with this happening. I guess the transition slot fuel feed is still dominant at that point and as more main fuel comes into it, there is a tapering off of the transition mixtures.

Ya gotta tune your car in drive or with as many accessories on as possible, (A/C on, lights on) so there is a representative situation you will find at some point on the street. Tuning the idle without them on means that the car will not have the correct AFR when they are used and the thing may tend to die or run roughly or inconsistantly after a minute or so at the lights.

The accelerator pump is where the work is needed. The setup procedure Holley use suggests there is some gap between the spring loaded nut/bolt thing and the diaphragm pivot arm when at WOT. This setup will use the whole pump capacity and is too much fuel delivery for the little L series. I actually do what Holley don't want too and unwind the bolt so that the diaphragm arm is preloaded and the arms movement pushes the diaphragm up to about halfway of its total movement. (You can put a flat metal washer or two under the spring to restore some tension to the spring so that the acc. shot doesn't become laggy.) The accel pump shot volume is reduced because you're using only half its capacity approximately. You'll notice the change off the line especially when you floor it as there won't be the massive dumping of accelerator fuel into the engine (which takes time for the engine to clean up) before the car starts to accelerate properly. You'll need to play around with this one, it can take some time to get right, but it's time well spent IMHO.

Intake manifold design will affect all this. The Clifford is very different to the Arizona in this respect and I've mentioned this in other posts on the subject. You cannot grab a carb tuned on a Clifford and put it on an Arizona and expect all to be sweet as it won't be. I have two distinct Tune calibrations that I use (and recorded) whenever I decide I need/want to do some manifold swapping for R and D or tuning etc. I like having two separate carbs for this really. The Arizona suffers from massive induction pulsing and so reversion of the AF mixture happens strongly as the engine revs rise and the jetting has to be dropped heaps or a filthy rich mixture will be given to the engine. This is with a stock cam. I'm sure many aren't aware of this and why few make good power because they're running about 10.5 to one mixtures at WOT. "Holleeezzz don't give good power mate" Yeah right.

Float levels are critical and largely decide how responsive your fuel delivery will be. BUT the levels change every time you pull apart the carb for a jet change etc so what I have done is using a sharp scribe, mark a horizontal line across the main body, metering block and fuel bowl on both sides for the mains and secondaries. Every re-assembly I do I can ensure that the carb goes back together exactly the way it came apart and this saves heaps of time having to worry about float levels. Yes I do check them, but only sometimes not everytime! :bulb:

The other issue that's really dumb with a Holley is the power valve channel restriction (PVCR) is not easily adjustable. Problem is it's too friggin big. I'm currently using some fine fuse wire to reduce the size of the hole on both sides and that works. Some aftermarket metering blocks have this feature and use air bleed jets in them. Using a drill shank from a small drill set, you can see how big the original PVCR is so that can give you a starting point for how much smaller you may need it to be.

Two stage Power valves are often cited as crap and there is little info on them. I find that they are progressive in their delivery rather than the 'all or nothing' standard power valves. If you must use a standard valve, I use a very late opening one, about 3.5 inches. My car idles at 17 inches in gear when warm so you can see the 'rule of thumb' Holley suggest just overfuels our little engines if it were to open at 8.5 or 9.5 inches!! The two stage opens a bit at 12 inches and the rest at about 5.5 so its acceptabe with a slightly leaner jet on the mains.

That's enough. My brain hurts now.

Edited March 5, 2011 by ozconnection

[Zedrally]

Good to hear that there are some people who don't mind playing with a Holley.

big snip...

That's enough. My brain hurts now.

Of course it hurts, it's thinking Hollies...

[spdcrazy]

just skimmed through this tonite but WOW. thanks for spending so much time to explain things to me.

so far i am impressed with the setup. i had my buddy come back over and tune it further, and of course it need more. but its getting there. it seems to rev fine with no load on it, but when driving still boggs when you smash the gas under about 3k. i'm sure if i read you post carefully i'll figure it out. thinking the accelerator pump.

we also timed the engine today. as far as i know we did it right, and i hear no pinging but to double check this is what we did.

found #1 plug wire and hooked up timing light to it.

then unhooked and pluged the vaccuum line that goes to the dist.

timed the engine at OP temp to 10. was far below 20 before.

only other thing i'm kinda sketchy on is the denso plugs, they are all even in color and a light grey, but i've always been a NGK guy. thoughts?

[ozconnection]

just skimmed through this tonite but WOW. thanks for spending so much time to explain things to me.

so far i am impressed with the setup. i had my buddy come back over and tune it further, and of course it need more. but its getting there. it seems to rev fine with no load on it, but when driving still boggs when you smash the gas under about 3k. i'm sure if i read you post carefully i'll figure it out. thinking the accelerator pump.

we also timed the engine today. as far as i know we did it right, and i hear no pinging but to double check this is what we did.

found #1 plug wire and hooked up timing light to it.

then unhooked and pluged the vaccuum line that goes to the dist.

timed the engine at OP temp to 10. was far below 20 before.

only other thing i'm kinda sketchy on is the denso plugs, they are all even in color and a light grey, but i've always been a NGK guy. thoughts?

The info is to help all Holley owners with just a different perspective, but you're welcome! :classic:

The Clifford is a good manifold! But it can be difficult to work with because of that huge open plenum that sits under the carb. It will give you the most power (as tested by me) but it can be a pain to try and tune out that flat spot you mention. It's that big open plenum thats the culprit for both!!

The accelerator pump can only go so far with the design of this manifold...thats a big plenum under there and opening the throttle wide quickly drops vacuum to zero really quickly. All fuel drops out of suspension and the gas velocity through the carb and intake manifold is low, especially at lower than 3k rpm, like you've noticed. To cover it up, use more pump capacity by putting in a bigger accel pump cam and use a bigger bore squirter like a #31 BUT, part throttle response goes out the window because ya dumping in too much fuel now. Solution, design your own pump cam profile but this isn't as easy as it sounds and can take TIME to get right. I didn't bother and just pressed the throttle with some respect.....not to encounter this situation. For a saloon car, that's a reasonable thing........

but for a sports car that's not right, is it?

I overcame the situation by making the plenum smaller. I made up a plenum divider out of sheets of aluminium that divided the plenum in half, changing what was a single plane manifold to a dual plane manifold. (Google these and see what I'm talking about..typically V8 terms but still applicable to our engines.) It worked, and my low speed torque was up noticeably! Top end was down even after tuning. To give you an idea, I was pulling 105kw@ wheels with the single plane, down to 90kw's after putting the divider in.

More torque and less power. Depends what floats your boat. Power with concessions or torque with abandon.....

10 degrees isn't much. You could try a bit more say 12 or 13 degrees.

The plugs colour sounds fine...means the carb tune is pretty good jet wise.

If you start pulling things apart...get an exercise book to record everything you change or adjust mate. Gotta do it. Don't try and commit all this tuning data to memory. You'll thank me later.

cheers.

[spdcrazy]

we did not tune my carb while in first, or even under a load, makes sense that we should however.

i was wondering about how the clifford was setup, as far as a single plane style or dual. tho i'm not sure enough on how a single plane is designed vs a dual plane. might look into it a bit.

i am also not familar enough with the accel pump, so i will start looking into it as well. we (my holley guy, and myself) both thought this might be the culprit, but didn't make too much adjustments as we ran out of time.

i won't be back home till tues, but when i am, i'll play around with some things and see how it goes.

ohh and FYI, my vacuum was at 15 3/4 at idle without a load, and timing ended up being about 12-13ish. timing mark is kind of wide to get a precise number with the timing gun we were using. i'll throw mine on it next week and get a better number.

[spdcrazy]

i'm researching into converting my clifford into a dual plane, tho its far down on my list of things to do, maybe i need to understand and tune my carb first, finish the interior, and the pcv and other things that haven't been finished.

but i do enjoy doing something different than usual, and fabbing things such as what i have in my mind for a dual plane clifford.

here is a link i found to a guy building his own dual plane intake. now i don't exactly like his setup, as it is not very effecient, but that wasn't his objective.

http://www.jalopyjournal.com/forum/showthread.php?t=323149&page=4

so the other thing i wonder about, is this "divider" would have to take the space of the area under the 4bbl and divide it into six ports, three on the primary's, evenly, and three on the secondary's, evenly. and it would need to be every other correct? i.e.

P=primary's

S=secondary's

1,2,3,4,5,6=cylinder's

1P 2S 3P 4S 5P 6S?

or

1P 2S 3S 4P 5P 6S?

either way it shouldn't be

1P 2P 3P 4S 5S 6S correct?

[ozconnection]

Here are some of those pictures I promised.

Enjoy!

[ozconnection]

I read what you had written and had a look at that forum thread.

We don't have to go so complicated, all I did was to divide the engine into two firing groups.The twin su setup is already designed along these lines.

Firing order is 1 5 3 6 2 4 and if you take every second cylinder, separated by 240 degrees (a six like ours fires ever 120 degrees, thus 240 deg. for every second plug fire), you have 1,3,2 and 5,6,4.

Think twin carb setup again and the numbers just cited fit nicely into these two groups.....presto, dual plane setup. The pulses in the manifold are not soup like a single plane but separated by even 240 degrees, enhancing the wave action and resonance in the manifold, improving torque.

By placing the divider in the plenum, you can create the same thing! Presto, dual plane manifold from a single plane manifold...talk about parts tuning! I got a mate of mine to make this...about 20 minutes and a few coldies

[spdcrazy]

wow. talk about over thinking something!

how did you decided on the holes from one plane to the other? they look kinda random.

also on a different note, the rubber hoses i see on your pics, the furthest one forward in the engine bay goes to the pcv tube i pointed at? with a pcv valve i assume?

[ozconnection]

wow. talk about over thinking something!

how did you decided on the holes from one plane to the other? they look kinda random.

also on a different note, the rubber hoses i see on your pics, the furthest one forward in the engine bay goes to the pcv tube i pointed at? with a pcv valve i assume?

Those little holes are random. And not really needed....I just wanted to see what would happen.

Yeah, the big mutha hose goes to the metal breather tube you were pointing to in the other thread. There is a PCV valve at the manifold end of the hose...look closely and you'll see the hex part of the valve!

[spdcrazy]

Those little holes are random. And not really needed....I just wanted to see what would happen.

Yeah, the big mutha hose goes to the metal breather tube you were pointing to in the other thread. There is a PCV valve at the manifold end of the hose...look closely and you'll see the hex part of the valve!

perfect! now i can put that hose back together!

i think i need to start asking around for someone to weld some aluminum for me!

being thats its not nearr as difficult as i expected, i should be able to move this up on the list and mesh it in with tuning the holley as well.

i am sure i will have more questions when it comes time, but so far so good, thanks for spending the time to, hopefully, show what potential the holley has in the Z cars!