[Bantam Altered]

OK I use two AFB's on my Pontiac powered altered and they work great. Now on to my problem. I just installed a Edelbrock dual quad air gap manifold on my 1960 Ford Falcon and I am using 2 3895s AFB's the same that I use on my Pontiac 400. I can tune them in great at idle and it snaps the throttle nice and crisp. When I do a burn out everything seems good, but when I launch the car it takes off good on the accerlerator pump / squirt and then falls on it face and I have to let off and roll back in to the gas but I can never go all the way into it or it starts breaking up. My fuel presure never drop below 4.5 and I have a brand new Holley blue pump installed with -8 line running from my tank to the pump to the regulator where I go to -6 off the regulator and go to the carbs. I have the regulator set at 6.5 psi at idle. The plugs look lean and I have been all over the place with rods and jets. I thought the floats were set to low but they are fine. I know this is a Ford but alot of Pontiac guys use AFB's and I am in need of some help. I am sure I have left something out so please let me know if there is any other information that could help. Thanks for any help.

Jon Tomkins

[rompn63]

Are the secondary air valves still in the carbs?

[60man]

Ditto...my thoughts too Joe...
What about carb mounting angle....??
Max was given to me as 11 degrees...mines borderline but it still responds great !!

[Tom Vaught]

First off I would get rid of that lousy Holley Blue Pump. A terrible pump for a drag race application and this is coming from a former Holley Employee. (30 years ago).

The pump cannot keep up under acceleration. Same deal for the little blue regulator.

Get a proper fuel pump like a Mallory 140 or similar and then buy the large Holley regulator that has the 7/16" diameter orifice ball in the regulator.

If you have a old Fram Canister fuel filter between the tank and the pump get rid of that deal too. Buy a 20 micron screen pancake type fuel filter from Holley (The large one - They make two sizes) and use that. It comes threaded with both AN or pipe threads in the screen filter housing.

Tom V.

[Bantam Altered]

Originally Posted by rompn63

Are the secondary air valves still in the carbs?

We did pull them out for a run and it made no difference, we thought it might have stumble to it with them gone and then it would pick it up but there was no change.

thanks for the thought

Jon

[BruceWilkie]

Agree with Tom. However, try the carbs off your altered just to see if the problem isnt in the carbs. I had a sticking air valve(not fully opening) on the front carb on my wifes car when I was first sorting the dual quad setup. It would go very rich and breakup badly. Stuck open or missing would be a bog.

A few months ago Mike Davis had a metering rod piston stuck in the down position causing it to run too lean.

Some needle seat assemblies have a very small opening that could possibly lean you out.

Last thought, while your float height may be fine, if your float doesnt drop the needle sufficiently (float drop setting) you can starve for fuel.(I've been there once) Too much drop can cause flooding from needle binding and not seating.(been there too)

FWIW, I've been using Edelbrock "off road" spring loaded needle and seat assemblies for a while now and havent had any float related issues since. I have installed them in several other peoples carbs with no more float issues for them either. Just be sure float height and drop are correct.

[Bantam Altered]

Originally Posted by BruceWilkie

Agree with Tom. However, try the carbs off your altered just to see if the problem isnt in the carbs. I had a sticking air valve(not fully opening) on the front carb on my wifes car when I was first sorting the dual quad setup. It would go very rich and breakup badly. Stuck open or missing would be a bog.

A few months ago Mike Davis had a metering rod piston stuck in the down position causing it to run too lean.

Some needle seat assemblies have a very small opening that could possibly lean you out.

Last thought, while your float height may be fine, if your float doesnt drop the needle sufficiently (float drop setting) you can starve for fuel.(I've been there once) Too much drop can cause flooding from needle binding and not seating.(been there too)

FWIW, I've been using Edelbrock "off road" spring loaded needle and seat assemblies for a while now and havent had any float related issues since. I have installed them in several other peoples carbs with no more float issues for them either. Just be sure float height and drop are correct.

I am going to try the altereds carbs, maybe on Sunday it looks like I will be able to fit it in and I am only 4 miles from the track. As far as the fuel pump I have never had a issue with the Holleys, I use a red unit on my Bantam with dual quads and never had a issue. I also use two of them on my SCCA GT-1 road race car and it make about 600 h.p. and never had a issue, but this also does not mean that something else might be better, and Tom seems to know his stuff so his input is really great but this does not seem to be the issue that I having. This car is a high 11 second type car. I am going to check the angle of the carbs in the mornig to make sure this is not an issue.

Thanks for the info everyone.

Jon

[TIN TIGR]

tom is correct, run the biggest pumps and lines you can afford..no such animal as "too much fuel to the regulators"..does anyone else modify their afb style carbs for dual feed anymore?..my mentor use to port his fuel bowls also, saying every bit helps..and in my experience, getting the pump shot right is the biggest problem..

i bet 2 really nice q-jets would kick the afbs butt..

[440GP69]

Bantam, some very smart guys in here giving the answere's ! take note, I agree with Tom, under acceleration is where you have the problem, sounds like fuel delivery issues to me too

[Bantam Altered]

Originally Posted by 440GP69

Bantam, some very smart guys in here giving the answere's ! take note, I agree with Tom, under acceleration is where you have the problem, sounds like fuel delivery issues to me too

I have to agree on the people and how smart they are here, and I think it is a fuel delivery issue, But I just cant go out and spend money on a new pump and put bigger lines on and find out it might be something I have overlooked ( I.E. float issue or carbs on to much of an angle or something else ) I have to think -8 line from the tank up is good for the amount of volume needed. I guess what bothers me is that this same set up on my Altered works great, never had a fuel problem one and never lays over and pulls hard right to the end. If it comes down to different pump i will do it I just want to make sure I check everything else. The people here are great so I am hearing and I taking notes and thats why I posted it here was for the great information that is out in this forum, I guess the other problem is somtimes you like to think you set up everything correct and you cant believe you did not do it right. thanks everyone for all the great help and ideas, this is where you wish everybody was able to meet at a track and bring all there problems and have people like that are posting here with ideas and solve the issues.

thanks agian
Jon

[60man]

Agree with Tom on the Black Holly 140 pump and large regulator...
Have you tried moving the pump rod location to some different holes in the link ??
I would at least try the larger regulator if you don't want to spring for pump now..
I had a high speed lay down on my car at 1,000' and going to a black pump & large regulator cured it..however it did launch OK..I ran a Perma-cool filter set up as it way out flows the junk Fram set up ....IMO...think they are made for lawn mowers.. Fram rated at 1.5gpm and the Perma-cool is 25gpm....no brainer..
I just moved the fuel system from under car to inside trunk now to make room for coilovers...I went with a 40 MC inline filter over the Perma-cool....guess I should heed Tom V.'s advice....He's the one with the Engineer degree....and head to use it !
CYA at Norwalk Tom..
BTW: As per class rules I run dual AFB Comp.series 750's with the choke horns removed on mine

You didn't say what size your Ford engine is ??

Good luck..

[60man]

Whoops..Forgot to mention. Check all the linkage screws on pass.side of carbs. I had one back out enough that secondary did not open on front carb....!!!!

Just for kicks here's a pic

[Tom Vaught]

Quote:

"I use a red unit on my Bantam with dual quads and never had a issue. I also use two of them on my SCCA GT-1 road race car and it make about 600 h.p. and never had a issue,"

I did the Tech Inspector deal/Corner worked deal for SCCA for 13 years. A lot of TRANS AM and GT-1 background. have seen a LOT of GT-1 cars built with a pair of Holley BLUE pumps (sometimes the 2nd one was a back-up) that would run well on the track at over 600 hp. Deal was the engines are on and off the gas which allows the pump(s) to catch up. Drag racing is a different deal with a severe high demand load on the pump immediately, no chance to recover from a weak pump rate. Why the carb basically runs out of fuel in third gear under load.

Quote:"Agree with Tom on the Black Holly 140 pump and large regulator..."

I was recommending the MALLORY 140 pump, not the Holley Black pump. I would not put a Holley pump on my car.

Tom V.

[Skip Fix]

Another thing to look at as you sort through these deals if the secondary is OK do you have too soft a power piston spring not allowing it to pull the metering rod out to enrich it.

[60man]

Tom V. quote: I was recommending the MALLORY 140 pump, not the Holley Black pump. I would not put a Holley pump on my car

Sorry 'bout that Tom...I screwed that up !!
So far Holley Black "seems" to be OK but I'm looking to upgrade this winter,to something with more capicity/flow......
May I ask about your poor assesment of Holley pumps...what should I be on the look out for ??

[440GP69]

Originally Posted by Bantam Altered

I have to agree on the people and how smart they are here, and I think it is a fuel delivery issue, But I just cant go out and spend money on a new pump and put bigger lines on and find out it might be something I have overlooked ( I.E. float issue or carbs on to much of an angle or something else ) I have to think -8 line from the tank up is good for the amount of volume needed. I guess what bothers me is that this same set up on my Altered works great, never had a fuel problem one and never lays over and pulls hard right to the end. If it comes down to different pump i will do it I just want to make sure I check everything else. The people here are great so I am hearing and I taking notes and thats why I posted it here was for the great information that is out in this forum, I guess the other problem is somtimes you like to think you set up everything correct and you cant believe you did not do it right. thanks everyone for all the great help and ideas, this is where you wish everybody was able to meet at a track and bring all there problems and have people like that are posting here with ideas and solve the issues.

thanks agian
Jon

I hear you, look at it like you never touched it like its someone elses car what would you do first to find the problem? and don't cancel anything out you can't think well it couldn't be the pump i run that on my altered, just an example be open minded because something isn't right,jm2

[Tom Vaught]

Quote: "May I ask about your poor assesment of Holley pumps...what should I be on the look out for ??"

The pumps (red and blue) were from the old days 40+ years ago. Bill Jenkins and a lot of racers QUICKLY figured out that they needed at least two blue pumps and maybe three to get the job done. Same deal for the little blue regulator. Look at any of the jenkins pictures and you will see that they are feeding two regulators with two fuel lines and then putting a pipe coupling between the regulators to balance the flow. Regulators were too small. Holley fixed the regulator issue with the large ball regulator.

I like the Mallory 140 and 2X0 (240 or 250, I forget) because as soon as we put one on Jim Brady's 64 GTO Steel car we picked up 3 tenths. Obviously a lot better than his dual Blue Pump deal.

I would not mess with the BG pumps either. Aeromotive, Magnaflow,
Mallory, all make quality pumps.

JMO

Tom V.

[60man]

Thanks Tom...3 tenths is a lot of ponies......

[straycat]

alot of knowledge here. listen to what these guys say. but i would swap the other carbs too.