Orange cam #2 hole

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

I based my settings on what is specified in the slant six racing manual - it might help to extrapolate from that - since you have a bigger carb

I have a 390 4150/60 (converted) and no funnies or lean spots - my engine is also less highly tuned than yours

When I was using the 465 I used to run into mixture problems

FanieG

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Regards,
Fanie Gerber
It's never junk, it's just a part you're not currently using

http://www.valiant50.co.za
Just say I own a few Mopars

Try screw hole #1. It should make the pump shot hit sooner IIRC.

CJ

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Part of Tyrde-Browne Racing

Well I am heading to the track in 30 mins. if it doesn't rain. I am somewhat happy with the primary bog as it is minimal. The secondary bog is still pretty bad and not sure what to do about it.
Which is better in terms of track time.
A. Install a heavy secondary spring to postpone the bog untill further down the track, but not pull as hard in the begining.
or
B. Install a lighter spring and get the bog over with and pull hard most of the way down the track.

I am pretty sure I can hold it at the line and get the secondaries open some before leaving the line. If I can't which one of the about should yeild a faster time?

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

You never checked for the secondary check ball did you?

You're going to have to run the car both ways (light and heavy secondary springs) and tell us which was faster. My guess is the lighter spring will be faster, but again, that's my guess. With too heavy a secondary spring you might not get the secondaries to open at all.

BTW, I used to run a stock calibrated Holley 3310-2 (750 vacuum secondary) on a 318 that was bored to 325ci on an old Edelbrock LD4B dual plane and it worked great. I bet if you divided your intake 123/456 the carb would work better. I'd build a spacer with a divided to fit down into the manifold and a sideways mounted carb.

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Joshua

A bog on secondaries..........

Vacuum: they're opening too quick, need more spring
Mechanical: need more gas with secondary accelerator pump

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Yes checked and the ball is there. With the heavest spring I will still bog, just waits longer to do it.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

OK, then there is either a problem in the secondary transition circuit or the carb is just too big.

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Joshua

Can having the secondaries throttle screw set to far open cause the transition circuit problem?

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Its to lean still, this may need the air bleeds dealt with as I meantioned before. Going to a 50cc accel pump can help cover the lean spot up, if you set it agressive and have the secondaries come in quick enough to make use of the extra pump shot.


I would try going bigger on secondary jets first though. It may require going bigger on the secondary, but lower on the primary to keep the A/F right. Then if cruize and idle are to lean that circuit will need addressing.


But this carb has no rear PV, its calibration in the metering blocks/plates needs a bigger spread than you have in the S/P jets. If you are still running the 57 pri jets then you need around 68 sec jet. I would try going to a 55 pri, and 66 sec jets. The primary idle and cruize will lean down, but the secondary has idle circuit also even though it doesnt have seconday idle screws. When you jet the secondays up it will make up for some of the primary idle and cruize. The factory jets for this carb are 54/65 and that spread in the jets need to be maintained atleast close. If I am remebering right you where running 57/60, with no PV in the rear this leaves the rear to lean and it will bog unless you make up for it with a hugh accel pump. Even then I would think its going to lean down three of your cylinders at WOT.


Jess

At this very moment I running:
P= 54
S= 60
PV 8.5
Blue cam
35 nozzle
Purple spring
Primary float 1/4" below window.
Secondary float at window bottom edge. (couple days ago found it the same as the front)


I am getting a lean surge at highway cruise (14.9 -15.1).

At idle I am running 12.0-12.3 at 950rpm and 13.8-14.1) at 750rpm. I starts very hard if I raise the idle AFR at the needles. The last time I was at the dyno the Carb guy played with it and in the end he said "well I guess this one just likes being a little rich"

WOT yeilds 12.7 - 13.2 after it stablizes.

I have yet been able to get it to spike rich with any accelerator cam or nozzle combination.

I have the purple spring in today for the track to see if I could power brake through the lean spikes at the line, but the track was rained out.

The purple spring is to light with the way things are set now. The silver spring or maybe the brown one is likely the correct spring. The purple and lighter springs I am able to power brake the secondaries open a bit. (used video camera to watch the linkage)

I am taking a step back from it for a day or two. I don't know for sure but these bogs are costing me at least .5 to a full second. I have been thinging about the 50cc pump and doing as you say with basicly flood the primary shot over into the secondary with a huge shot and lite spring. Use a little smaller nozzle to extend the shot time into the secondary.
Thanks for the help guys.

PS I need to do some reading on air bleeds. I really don't understand their function that much. I have been told not to touch them until all other options have been exhausted.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Here's a thought (to complicate things)

Is it possible you're too rich?

I know the AFR meter says lean; but if it temporarily goes so rich that there's a misfire, the AFR will read lean because there was no combustion (plenty of O2 left over giving lean reading)

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Spark knock or missfire would show as lean that is true and sometimes it doesnt take much to cause this.


I dont expect this to be the problem though, when you run a stiff seconday spring I would think it would help take the load off and not missfire,ect,ect,ect because of it taking longer to open secondary. You stated it only delayed the lean spot when you used a stiff spring if I am remembering right. But even with no missing/spark knocking to much timing can cause leaness and uneven A/F.


I dissagree with not touching the air bleeds until everything else is right. But jumping into tuning like this is not easy, but I expect it will cure your problems. But still it pays to run through other test before going down that road so there is some truth to what is said. But to get everything else right, requires the air bleed system to be right ( I am not helping there am I )

A quick & dirty description of air bleed tuning would be a Smaller bleed will make the circuit richer and most of the time make the circuit come in quicker (like with the mains). It really can effect how responsive, and steady each circuit is. But it can get really hard to work things out sometimes. The idle/cruize circuit is the hardest, and it will effect the main circuit when changes are made to it.


I really believe it would pay to atleast try and do the quick little air bleed test I meantioned about using wire with. Try it in the secondary circuit. Just take some multi stran wire and peel the insulation off of it
( something with course strans). Wrap it around the secondary vent tube ( this will hold it in place for you) then stick each end down in the secodary main air bleeds. ( this is just like having a metering rod in a jet). This will make the secondary main circuit come in & flow quicker, plus richen it up some. Raising that rear float may just help this also, put it about half way up the hole. This will effect how quick the main starts when the throttle pops open, plus richen things up again, its worth a try.


The best place to learn about air bleeds is the Innovate site, but there is a lot to it and it takes a lot of time reading. Then after you read start all over and read again because your hole understanding of things will have changed and stuff will make more & more sense as you keep learning.

I know what you mean about taking a few days and backing up to just think & review things and clear your mind. Sometimes things just get all cluttlered and you have to sort them out. The big jigsaw puzzle that tuning is can be real trying at times because there can be many way to achive the same thing. That mix of cruize,economy and power is the hardest thing. To cruize & idle lean, but then still have a good punch with no bog is a hard one. One thing is for sure, sometimes you just have to give the car what it wants, instead of what you think it should need.

No matter how hard you try, or how good you get it, its still is a big collection of overlaping comprimizes. It just takes time, and testing. Keeping good ducmentation of effects from changes can really help to put the big picture into focus after you gather mounds of info and start looking back at them.

I am getting 25/18mph out of mine right now and it leaves the line like it is ready to race, it also cruizes as lean as 16.5 at times with no hesitation/surge. But it took me two months of tuning to get it there and I backed away from it several times and let it just set until I could get my composer back and not go crazy.


Timing now can really change things also, I would think it would want maybe a little more timing on the cruize and bottom than before, but want less timing in the upper RPM than before ( just guesses though, the main thing is try differnt stuff, even if you think it may be wrong).
Oh well, here I am piling more on top of that jigsaw puzzle, not the think you need when a breaks is in order .


Jess

There are two things that control vac sec opening, the afore mentioned spring and the kill bleed. Of the two, the kill bleed has the greatest effect. The kill bleed is NOT the port that supplies vac to the sec vac housing, it's a port that bleeds off vac so the sec doesn't start to open to soon.
Although they influence each other, basically the kill bleed starts the opening point, the spring allows the open rate.
Example;
Baseline, sec opening starts at 2000, full open at 5000
Drill the kill bleed larger, starts at 3000, full open at 6000
Install a weaker spring, starts at 3000, full open at 5000
Drilling the bleed larger is easy. A smaller bleed needs to be epoxied and redrilled; or drill, tap, insert set screws with vcarious size holes.


A 30cc pump does not neccessarilly mean 30cc of fuel. Cams control how much volume and the rate. To get full 30cc, use the #330 pink cam in hole #1, or if a different rate is needed along with 30cc use the #290 green cam in hole #2. The #466 orange gives 19 in #1 and 24.5 in #2.
The #330 in hole #2 and the #366 shouldn't be used as they produce enough lift to supply more than 30cc, meaning they are to be used on a 50cc pump.

A larger discharge nozzle gives more fuel, up to a certain size. The slots on either side of the nozzle screw threads restict how much fuel can be delivered. The fix is a hollow screw. Holley sells them, or drill your own with a pin drill and some time.
TIP; DON'T over tighten the nozzle screw. The feed slots reduce the amount of threads making it easy to pull the rest out if overtightened.

Other things to give better response, lower hg PV and different boosters. The PV is easily changed but makes minimal difference. The booster type makes a noticable difference. Dog leg is one of the most responsive, annular the slowest. Problem is they are not easily changed on the 2300/4150/4160 carbs like they are on the 4500 series.

You may never get rid a acc pump lean spike. It takes a few microseconds for the pump shot to make it to the cylinder. If you do, it will be over-rich elsewhere. Mech fuel injection doesn't have a acc pump and the throttle response is instant. They do it with an over-rich idle so when the throttle is opened, it actually goes from rich to correct A/F ratio, instead of correct A/F to lean like on a carb.

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Slant Cecil