The Ford Barn

JBD · 03-09-2011, 03:23 PM

Building a Model A with dual carbs on a 4 banger Model A engine. Have two Ford Holley 94's 8BA on an aluminun "equalizer intake" manifold. Starts and runs fine but runs rich. Any advice on fine tuning this setup or changing out the jets - what jets to get. I unhooked the back carb's acelerator pump and starts fine. Just runs rich, as I expected. Thanks JBD.

Chris Haynes · 03-09-2011, 03:44 PM

Smaller jets are a must.

Vanspeed · 03-09-2011, 08:35 PM

Check the Hamb, the guys over there can really help when it comes to speed secrets for bangers. They have a monthly banger thread that is very informative. In my opinion, you are never going to get it to run less rich, two Holleys are alot of carb for a banger.

George Miller · 03-09-2011, 09:19 PM

Quote:

Originally Posted by JBD

Building a Model A ratrod with dual carbs on a 4 banger Model A engine. Have two Ford Holley 94's 8BA on an aluminun "equalizer intake" manifold. Starts and runs fine but runs rich. Any advice on fine tuning this setup or changing out the jets - what jets to get. I unhooked the back carb's acelerator pump and starts fine. Just runs rich, as I expected. Thanks JBD.

You are going to have to keep changing jets until you get it right. There are a lot of things that determine what jet size to use. Also you might not want the power valves. Manifold design, cam shaft, compression, exhaust, all come into play.

Two 94's will work well on a Model A engine if you get every thing right. Not sure about those manifolds though. If think they need a bigger area for the fuel and air to mix.

AstroZombie · 03-09-2011, 11:18 PM

I agree on smaller jets, what size are you running right now?

Also, for the love of god, DON'T use the rat rod word on the HAMB.

PC/SR · 03-10-2011, 01:47 AM

Sponsored Links (Register now to hide all advertisements)

Check the power valves for leakage. They may be blown out, or they may not be sealed after all these years. Half fill the bowl with gas, let it sit overnight, then check to see if there is any gas in the power valve chamber. The stock power valves will open to soon, causing it to run richer.The new power valves do not seal correctly without modification.

fordcragar · 03-10-2011, 02:56 AM

Quote:

Originally Posted by Vanspeed

Check the Hamb, the guys over there can really help when it comes to speed secrets for bangers. They have a monthly banger thread that is very informative. In my opinion, you are never going to get it to run less rich, two Holleys are alot of carb for a banger.

And mention that you are building a "Rat Rod" for special treatment.

Bassman/NZ · 03-10-2011, 04:38 AM

Quote:

Originally Posted by Vanspeed

Check the Hamb, the guys over there can really help when it comes to speed secrets for bangers. They have a monthly banger thread that is very informative. In my opinion, you are never going to get it to run less rich, two Holleys are alot of carb for a banger.

We're not very partial to rat rods on the Hamb, but there's a wealth of knowledge there, so I wouldn't mention the rat word there. That way you'll get lots of info. Rat will get you flamed.

V4F · 03-10-2011, 11:11 AM

ive been told on 94's , that the trick is to block off the power valve & all will be good . if you want some work , i have a pair of 97's ! .................. steve

1931 flamingo · 03-10-2011, 11:41 AM

Ck on the EV8 board, there are several carb guru's there that should be able to offer some suggestions.
Paul in CT

Jason in TX · 03-10-2011, 12:08 PM

People in the "know" really don't like the word Rat Rod. Cars purposely built to look junky don't have a lot of good things said about them behind the owners back.

The holley 94-8BA is rated at 162 cfm Doubling that is 324 cfm!!

Stromberg 97s were rated at 155 cfm Two would be 310 cfm.

Stromberg 81s flow at 125 cfm, or doubled up make 250 cfm.
This is why the 81s are the hot ticket for the banger and v860 crowd.

The stock Model A engine with it's 201 cu/in displacement runs most efficiently when not going over the 290 cfm range, so you are going to be really fighting with those Holley 94s when you try to jet them down, but throw the air to fuel mixture out of whack.

You may want to consider finding some 97s and jetting those down a little bit.

Sparky · 03-10-2011, 12:18 PM

Just curious, how much does a stock Zenith flow?

Jason in TX · 03-10-2011, 12:28 PM

I've been trying to locate what the cfm is of the Zenith carbs, but can't seem to find that info. I've also been curious to know what the cfm is of the weber downdrafts is as well.

BC Texas · 03-12-2011, 11:44 PM

Hello Jason. Bud Calicutt just SE of Tyler and member of the Tyler Model A club. JBD was asking questions for me because my puter has been acting up. Need a new one. I Have a B motor, bored 100 over, Brumfield 5.9 head, Winfield race cam,counterweighted, balanced, lightened flywheel, early v/8 clutch and fsI electronic dist. I put a scaulded dog equalizer dual downdraft intake, with 2 94's 8bas,with progressive linkage. Primary and secondary has stock jets. Secondary has plugged idle jets. secondary butterflys, choke assy removed and is set to come in at about 3/4 throttle. When I first gas it, it stalls for just a second then hauls a--. Looking down into the primary when you accelerate I only get a dribble of gas from the accelerator pump jets. When the secondary opens it gives a good squirt. Should I remove the accelerator pump from the secondary or leave it in? Also should I remove the primary accelerator pump jets and double check gaskets and make sure it is not partually pllugged up or maybe replace the accelerator pump parts? They are new. What does removing the power valve and plugging it do? Thanks

Mike V. Florida · 03-12-2011, 11:48 PM

Quote:

Originally Posted by AstroZombie

Also, for the love of god, DON'T use the rat rod word on the HAMB.

There are times that using modified, rod, etc. here is not so safe either!

Milton · 03-13-2011, 12:20 AM

"When I first gas it, it stalls for just a second then hauls a--."

BC,
Don't forget the power valves. Our engines are close to identical with the exception that mine is an A, you have a 100 over versus my standard bore, a 5.9 head vs my 5.5 Snyder head. I'm running two 94's model 51's with straight linkage stock main jets middle position on the pumps. I divided the power valve vacuum in half and am using 3.5 inHg instead of the stock 7 inHg. Does not hesitate on acceleration at all. I would not recommend removing the valves as they allow the fuel to richen under varying load conditions i.e. acceleration. Also there are check balls under the pump nozzles, the dribbler my be missing the little bb sized ball.

BC Texas · 03-13-2011, 12:47 AM

Thanks for the info. Will check it out

James Rogers · 03-13-2011, 07:40 AM

Bud, I find most times when a carb stumbles on acceleration, it is because the accelerator pump is not working to put that squirt of gas the motor needs to increase RPM's. This may be the problem with yours since you only get a dribble when you punch the throttle. I would make sure the accelerator pump is working properly before moving on to the overloading problem.

BC Texas · 03-13-2011, 06:43 PM

I'm running progressive linkage. I run on one carb up to about 3/4 throttle, and i have new pumps in them . Went back today and rechecked them.

James Rogers · 03-13-2011, 08:35 PM

Quote:

Originally Posted by BC Texas

I'm running progressive linkage. I run on one carb up to about 3/4 throttle, and i have new pumps in them . Went back today and rechecked them.

Regardless, nyou should have a good squirt when you stab the throttle on the primary carb. Something is amiss. Maybe the jets are stopped up or the acc pump channels are stopped up.

03-09-2011, 03:23 PM	#1
JBD Senior Member Join Date: May 2010 Location: Arp, Texas Posts: 123	Installing dual 94 carbs on a Model A ratrod Building a Model A with dual carbs on a 4 banger Model A engine. Have two Ford Holley 94's 8BA on an aluminun "equalizer intake" manifold. Starts and runs fine but runs rich. Any advice on fine tuning this setup or changing out the jets - what jets to get. I unhooked the back carb's acelerator pump and starts fine. Just runs rich, as I expected. Thanks JBD. Last edited by JBD; 03-10-2011 at 08:23 AM.

03-09-2011, 03:44 PM	#2
Chris Haynes Senior Member Join Date: May 2010 Location: Camarillo, CA and Pine Grove, CA Posts: 2,832	Re: Installing dual 94 carbs on a Model A ratrod Smaller jets are a must. __________________ 1921 Runabout 1930 Tudor Early 1930 AA Speed costs money. How fast do you want to go?

03-09-2011, 08:35 PM	#3
Vanspeed Senior Member Join Date: May 2010 Location: Suttons Bay, Mich. Posts: 3,384	Re: Installing dual 94 carbs on a Model A ratrod Check the Hamb, the guys over there can really help when it comes to speed secrets for bangers. They have a monthly banger thread that is very informative. In my opinion, you are never going to get it to run less rich, two Holleys are alot of carb for a banger. __________________ *Respecting and Resurrecting Ford Model A's.*

03-09-2011, 11:18 PM	#5
AstroZombie Member Join Date: Mar 2011 Location: Armona, CA Posts: 61	Re: Installing dual 94 carbs on a Model A ratrod I agree on smaller jets, what size are you running right now? Also, for the love of god, DON'T use the rat rod word on the HAMB.

03-10-2011, 01:47 AM	#6
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,279	Re: Installing dual 94 carbs on a Model A ratrod Sponsored Links (Register now to hide all advertisements) Check the power valves for leakage. They may be blown out, or they may not be sealed after all these years. Half fill the bowl with gas, let it sit overnight, then check to see if there is any gas in the power valve chamber. The stock power valves will open to soon, causing it to run richer.The new power valves do not seal correctly without modification.

03-10-2011, 11:11 AM	#9
V4F Senior Member Join Date: May 2010 Location: ca. Posts: 2,522	Re: Installing dual 94 carbs on a Model A ratrod ive been told on 94's , that the trick is to block off the power valve & all will be good . if you want some work , i have a pair of 97's ! .................. steve __________________ V4f

03-10-2011, 11:41 AM	#10
1931 flamingo Senior Member Join Date: May 2010 Location: new britain,ct 06052 Posts: 9,390	Re: Installing dual 94 carbs on a Model A ratrod Ck on the EV8 board, there are several carb guru's there that should be able to offer some suggestions. Paul in CT

03-10-2011, 12:08 PM	#11
Jason in TX Senior Member Join Date: May 2010 Location: ⓉⒺXⒶⓈ Posts: 2,047	Re: Installing dual 94 carbs on a Model A ratrod People in the "know" really don't like the word Rat Rod. Cars purposely built to look junky don't have a lot of good things said about them behind the owners back. The holley 94-8BA is rated at 162 cfm Doubling that is 324 cfm!! Stromberg 97s were rated at 155 cfm Two would be 310 cfm. Stromberg 81s flow at 125 cfm, or doubled up make 250 cfm. This is why the 81s are the hot ticket for the banger and v860 crowd. The stock Model A engine with it's 201 cu/in displacement runs most efficiently when not going over the 290 cfm range, so you are going to be really fighting with those Holley 94s when you try to jet them down, but throw the air to fuel mixture out of whack. You may want to consider finding some 97s and jetting those down a little bit. __________________ -------------- Drive it like you know how to fix it! DMAFC / OILERS CC-MC Last edited by Jason in TX; 03-10-2011 at 12:28 PM.

03-10-2011, 12:18 PM	#12
Sparky Senior Member Join Date: May 2010 Location: Rhode Island Posts: 649	Re: Installing dual 94 carbs on a Model A ratrod Just curious, how much does a stock Zenith flow?

03-10-2011, 12:28 PM	#13
Jason in TX Senior Member Join Date: May 2010 Location: ⓉⒺXⒶⓈ Posts: 2,047	Re: Installing dual 94 carbs on a Model A ratrod I've been trying to locate what the cfm is of the Zenith carbs, but can't seem to find that info. I've also been curious to know what the cfm is of the weber downdrafts is as well. __________________ -------------- Drive it like you know how to fix it! DMAFC / OILERS CC-MC

03-12-2011, 11:44 PM	#14
BC Texas Senior Member Join Date: May 2010 Location: East Texas Posts: 146	Re: Installing dual 94 carbs on a Model A ratrod Hello Jason. Bud Calicutt just SE of Tyler and member of the Tyler Model A club. JBD was asking questions for me because my puter has been acting up. Need a new one. I Have a B motor, bored 100 over, Brumfield 5.9 head, Winfield race cam,counterweighted, balanced, lightened flywheel, early v/8 clutch and fsI electronic dist. I put a scaulded dog equalizer dual downdraft intake, with 2 94's 8bas,with progressive linkage. Primary and secondary has stock jets. Secondary has plugged idle jets. secondary butterflys, choke assy removed and is set to come in at about 3/4 throttle. When I first gas it, it stalls for just a second then hauls a--. Looking down into the primary when you accelerate I only get a dribble of gas from the accelerator pump jets. When the secondary opens it gives a good squirt. Should I remove the accelerator pump from the secondary or leave it in? Also should I remove the primary accelerator pump jets and double check gaskets and make sure it is not partually pllugged up or maybe replace the accelerator pump parts? They are new. What does removing the power valve and plugging it do? Thanks

03-13-2011, 12:20 AM	#16
Milton Senior Member Join Date: Oct 2010 Posts: 837	Re: Installing dual 94 carbs on a Model A ratrod "When I first gas it, it stalls for just a second then hauls a--." BC, Don't forget the power valves. Our engines are close to identical with the exception that mine is an A, you have a 100 over versus my standard bore, a 5.9 head vs my 5.5 Snyder head. I'm running two 94's model 51's with straight linkage stock main jets middle position on the pumps. I divided the power valve vacuum in half and am using 3.5 inHg instead of the stock 7 inHg. Does not hesitate on acceleration at all. I would not recommend removing the valves as they allow the fuel to richen under varying load conditions i.e. acceleration. Also there are check balls under the pump nozzles, the dribbler my be missing the little bb sized ball.

03-13-2011, 12:47 AM	#17
BC Texas Senior Member Join Date: May 2010 Location: East Texas Posts: 146	Re: Installing dual 94 carbs on a Model A ratrod Thanks for the info. Will check it out

03-13-2011, 07:40 AM	#18
James Rogers Senior Member Join Date: May 2010 Location: Asheville,NC Posts: 3,104	Re: Installing dual 94 carbs on a Model A ratrod Bud, I find most times when a carb stumbles on acceleration, it is because the accelerator pump is not working to put that squirt of gas the motor needs to increase RPM's. This may be the problem with yours since you only get a dribble when you punch the throttle. I would make sure the accelerator pump is working properly before moving on to the overloading problem.

03-13-2011, 06:43 PM	#19
BC Texas Senior Member Join Date: May 2010 Location: East Texas Posts: 146	Re: Installing dual 94 carbs on a Model A ratrod I'm running progressive linkage. I run on one carb up to about 3/4 throttle, and i have new pumps in them . Went back today and rechecked them.