holley tuning issue at cruise

brianj5600 · Jun 1, 2009

mrmustangman357 said:
to clarify, right now, the way it is set up, the primary idle speed adjustment is backed out, such that it does not raise the idle speed. I turned the secondary idle speed screw in to raise the idle speed to my liking (850 rpm in neutral).

BrianJ, you wrote:"Air coming through the cracked secondaries is not pulling fuel." The holley 4160 I have does meter fuel in the idle side of the secondaries. I don't see how this is contributing to the problem when my idle mixture screws work fine and my idle a/f is good (12:1)

The first thing I would do is get the primary blades where they need to be. Look at this picture and set the primary idle screw so the the T slots look like this http://www.competitionplus.com/07_15_2004/photos/carb_rebuild_07.jpg Then put it on the car and use the secondaries to set idle. Do not adjust the primary idle screw.

What I was saying is that with the primary idle blades completely closed too much air is going through the secondaries. All this air is like a vacuum leak since it does not cause the carb to flow fuel. The first part of moving the throttle does not start flowing fuel from the transfer slot and the carb can not catch up flowing fuel until the mains start flowing. Setting the primary blades like the picture will make the transfer circuit start to flow fuel as soon as the throttle is moved off the idle screw. The way you have described, the throttle moves from the set point to the point in the pic and no additional fuel is added. Once it is at the throttle position in the pic it starts adding fuel, but by then it is lean and can't catch up. Sorry for the ramble.

mrmustangman357 · Jun 1, 2009

56k beware:

Took the carb off and reset the primary throttle blades from:

To this (.020 on the transition slot):

put it on and took some fiddling to get it to idle correctly. Set the idle to 850 and took it for a drive, it still was surging and shuttering above 2200. I stuck wire in the LSABs on the primary and took it for a drive. My A/F was restored! But it still surged even with decent (12:1) A/F. So, on a hunch, I thought I may have had too much timing in it so I pulled the vacuum line to the vac advance, removed the wire from the LSAB, and drove it. It did not surge! vacuum at cruise jumped from 16 to 20. It was rich at cruise, but a def. step in the right direction.

My next step is to change the light springs in the dizzy for heavier ones and get my advance in later, then mess with my cruise AFR, which is set by idle mixture screws right?

D.Hearne · Jun 2, 2009

The idle mixture screws are just that, idle mixture screws. You had too much timing, therefore the reason you couldn't get it to idle down where it needed to be. So did you have the primary blades open too far or closed all the way. In the beginning of this thread, it sounded to me like you had the primarys open too far, exposing too much of the transfer slots, thus the reason the idle mixture screws didn't respond. In my opinion, it's still idled too high at 850. It should idle fine at 500-600.

D.Hearne · Jun 2, 2009

10secgoal said:
How do you figure ? If the t-slot is showing like it should be, and it doesn't idle high enough, you have to open the secondaries to get the correct idle speed. You don't just open the primaries farther. If it was something in the metering block clogged up, he would have idle problems, and stuttering long before 2200.

Based on what he posted, it's obvious to me the transfer slots were exposed too much, thus screwing with the idle and transition. And based on his last post, it turns out the carb wasn't the problem, but the ignition was. So although I suggested that the vacuum advance might not be working, it was partly to blame for his problem, rather than having too little timing, he had too much. Once again, what I preach many times about carb problems not being carb problems has come true. His build isn't radical enough to require changes in the carb's tuning setup told me that what you all were chasing with the air bleeds was the wrong direction. It seems to me he maybe was partially buying into the myth about Holley's needing more attention to tuning here.

10secgoal · Jun 2, 2009

D.Hearne said:
Based on what he posted, it's obvious to me the transfer slots were exposed too much, thus screwing with the idle and transition. And based on his last post, it turns out the carb wasn't the problem, but the ignition was. So although I suggested that the vacuum advance might not be working, it was partly to blame for his problem, rather than having too little timing, he had too much. Once again, what I preach many times about carb problems not being carb problems has come true. His build isn't radical enough to require changes in the carb's tuning setup told me that what you all were chasing with the air bleeds was the wrong direction. It seems to me he maybe was partially buying into the myth about Holley's needing more attention to tuning here.

Wow, wanna step down from your soap box ? Your guess was luck, in the wrong direction. Your recommendations were all over the place Low timing doesn't cause surging unless it under a load and it's 10 btdc. We have blo thru cars running around with locked out timing under 20 deg all day long. I gave him an educated diagnosis, and a simple TEST to see if his air bleeds needed to be smaller. Didn't tell him to go out and spend $100 modifying it. If it wasn't it, it was easy to move onto the next thing. Just a test, just like getting out a timing light and checking the timing. But I have to fight people here giving out incorrect information for 3 days to try and convince him to do a 10 min test. Come on guys, you really think changing the PV is going to make a difference in a no load cruise ? It'll make the same difference at jetting, none, if you have the primaries setup correctly.

I don't get the preaching about it not being the carb, yet only one of your recommendations was none car related ? You really want to go round and round again about how holleys can't get good gas mileage ? Come on man. Same team.

D.Hearne · Jun 2, 2009

10secgoal said:
Wow, wanna step down from your soap box ? Your guess was luck, in the wrong direction. Your recommendations were all over the place Low timing doesn't cause surging unless it under a load and it's 10 btdc. We have blo thru cars running around with locked out timing under 20 deg all day long. I gave him an educated diagnosis, and a simple TEST to see if his air bleeds needed to be smaller. Didn't tell him to go out and spend $100 modifying it. If it wasn't it, it was easy to move onto the next thing. Just a test, just like getting out a timing light and checking the timing. But I have to fight people here giving out incorrect information for 3 days to try and convince him to do a 10 min test. Come on guys, you really think changing the PV is going to make a difference in a no load cruise ? It'll make the same difference at jetting, none, if you have the primaries setup correctly.

I don't get the preaching about it not being the carb, yet only one of your recommendations was none car related ? You really want to go round and round again about how holleys can't get good gas mileage ? Come on man. Same team.

I'm not on a soap box. You suggested he had a problem with the carb itself. I was making suggestions as to the cause, one of which pointed in the right direction............ignition timing. With whatyou told him to try with the air bleeds and nothing about the cause being anything else, looke dto me like you commited him to thinking he had a carb problem. As far as the surging, not enough timing does the same thing as too much. Had the same thing happen with the timing on my 89 Ranger's 5.0 when the vacuum advance diaphram went south, it ran the same way, surging at mid thottle. What seemed to me at first was a carb problem, turned out to be ignition related. And where does Holleys not getting good mileage come into the picture ?

10secgoal · Jun 2, 2009

Didn't commit him to a carb problem. If he had tried the 10 min test and it helped/fixed it then yes, a carb problem. I didn't think timing because even a light load with too much will rattle, not surge. My commitment was no more than yours to check the timing. I assumed with all his knowledge, he may have checked the basics.His description was indicative of a lean cruise circuit. If a holley is setup correctly with the t-slot showing right, it will cruise perfectly lean. But sometime a little too lean. But most have it too far uncovered, and change jets to "fix" the problem. Hence the reason everyone is throwing around jet and PV changes. The wire is just another tuning tool, not a fix all. It's not everyone's problem. It's the fact that rather than make a recommendation, you'd rather step on a crank like I'm some F'n Noob and haven't a clue what I'm talking about. The Gas mileage had to do with the last time to swung your di ck at me about carbs and had to teach you something about them. Remember ? "I've been working on carbs for 30 years, and I've never heard of that."

mrmustangman357 · Jun 2, 2009

whoa guys go easy. This thread isn't worth getting into a tassle over. we were all a little right in what was going on.

-I was wrong in assuming it would rattle with too much timing, instead of surge
-The air bleeds did bring the wideband back into reading the AFR in range
-the timing needs to be looked at.

Lets not swing any di cks around okay?

D.Hearne · Jun 2, 2009

10secgoal said:
It's the fact that rather than make a recommendation, you'd rather step on a crank like I'm some F'n Noob and haven't a clue what I'm talking about. The Gas mileage had to do with the last time to swung your di ck at me about carbs and had to teach you something about them. Remember ? "I've been working on carbs for 30 years, and I've never heard of that."

Where'd you get this ****? You've got a chip on your shoulder obviously, but I haven't a clue as to what you're talking about here. And you've NEVER taught me anything about carbs that I could ever recall. Sounds to me like you're the only di ck here with an attitude.

brianj5600 · Jun 2, 2009

Was the vacuum advance connected to manifold vacuum? If so it may like ported vacuum.

10secgoal · Jun 2, 2009

D.Hearne said:
Where'd you get this ****? You've got a chip on your shoulder obviously, but I haven't a clue as to what you're talking about here. And you've NEVER taught me anything about carbs that I could ever recall. Sounds to me like you're the only di ck here with an attitude.

I'll let a sleeping dog lie. Go look through your posts. It's a called a PVCR. Sure Brian remembers it.

mrmustangman357 · Jun 2, 2009

brianj5600 said:
Was the vacuum advance connected to manifold vacuum? If so it may like ported vacuum.

It was/is connected to manifold vacuum. It likes a lot of advance at idle and really cleans up.

jlangholzj · Jun 2, 2009

10secgoal said:
I'll let a sleeping dog lie. Go look through your posts. It's a called a PVCR. Sure Brian remembers it.

not even gonna go there....just calm down here fella....if you've worked on these things, you'll know that they're a blessing and a curse. The key is start at square one otherwise your chasin a rainbow.

educated luck or not, it was right.

10secgoal · Jun 3, 2009

jlangholzj said:
educated luck or not, it was right.

Correct or incorrect was not my problem.

D.Hearne · Jun 3, 2009

10secgoal said:
I'll let a sleeping dog lie. Go look through your posts. It's a called a PVCR. Sure Brian remembers it.

Yea, I do recall, he or someone else called it a Power Valve Restrictios Channel. Not a PVCR

mrmustangman357 · Jun 3, 2009

update: So I played around a bit, messing with the idle mixture and total timing, and the springs in the distributor. My vacuum advance was adding 22 degrees at cruise! I read most SBF like about 10 degrees vac advance, so it needs adjustment. I am now running 35 total with the vac adv disconnected.

At cruise (4th gear, 30 mph, 18" vacuum, 2200 rpm-ish), it is running at about 12.5:1. Trying to turn in the idle mixture screws just makes the motor want to die at idle. Should I look at the LSAB's now? I won't change anything until I get the 10 deg vac advance back in and see what the AFR is doing then.

By the way, at WOT it reads dead on at 12.5:1 yea buddy

brianj5600 · Jun 3, 2009

D.Hearne said:
Yea, I do recall, he or someone else called it a Power Valve Restrictios Channel. Not a PVCR

If I called it that it was a dyslexic moment.

Power
Valve
Channel
Restrictor

PVCR

D.Hearne · Jun 4, 2009

brianj5600 said:
If I called it that it was a dyslexic moment.

Power
Valve
Channel
Restrictor

PVCR

You did, that's why I had questioned it then Didn't sound kosher.

D.Hearne · Jun 4, 2009

mrmustangman357 said:
It was/is connected to manifold vacuum. It likes a lot of advance at idle and really cleans up.

It needs to be connected to ported vacuum to work correctly. There's no point in using it connected to full manifold vacuum. Connect it to ported on the carb metering block, set the initial to abuot 10-14* BTDC and see how it runs then.

10secgoal · Jun 4, 2009

D.Hearne said:
Yea, I do recall, he or someone else called it a Power Valve Restrictios Channel. Not a PVCR

Yep, that was me, and you know it. Or you remembered exactly how I miss spelled, but don't remember the lesson ? Still bad with the spelling and no checking. But you still didn't know what I was talking about then when you called me something to the effects of a down south coon ass? Something like that right ? But I was explaining it to someone else, you questioned it. Hell, I know I even called it a PVCR before screwing up the spelling of what it was. If you had actually knew was I was talking about at the time, you'd have realized is was nothing more than piss poor spelling.

This was what you said after I mentioned the PVCR's.

you said:
The power valve does not have it's own set of jets. Period.

Then I said this

me said:
See now. dang it hearne you didn't read close enough. And a pv does have does have it's own "jetting". Period. Jets are the lamens terms I used. That's why the () with the pvcr was typed in them. If you open them up, it will run richer under a higher load. They are not removable, so you better get that junk right the first time.

Now here, "getting it right the first time", I was referring to so drilling out the PVCR's, but the chip on your shoulder rendered this comment

you said:
No, I did get it right, you said they had Jets. And as far as the PVCR, that sounds like a load of BS to me, I've been fooling with Holley carbs for 30 years and never have I heard that term used for any part of a Holley carb. I read your post two or three times and still was baffled by what you were referring to. And it's LAY MAN'S terms not lamens, so maybe you need to "get it right" the first time.

But at least you've been reading up. I'd hate to have 30 years of Holley experience and not know what it is.

Then there was some more spelling corrections in defense to a weak holley based knowledge on your part.

Then came this one

you said:
OK, Smart ass, how about telling us more about your secret equation, so we can all benefit by what you think you know? Or would you still prefer to keep this to yourself?

So now you call me the dick with an attitude, when you've been doing all the name calling ? Have a good one.

Mrmustangman, I'd even try 18-24 inital. Mine was a monster at 20 compared to 16 in in throttle response and everything in between. You'll need to limit the total timing mechanically though. If you add 10 more at cruise, it will lean out, so do wait. But you may be on the right track with the LASB's,........or Holleys don't need to be modified, but haven't figured that out yet. They are work perfect outta the box.

Sorry for the edit. Was at a concert last night. tired as hell and can't hear, was afraid I would be made fun of again if I miss spelled.

holley tuning issue at cruise

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