The Ford Barn

cuzncletus · 04-07-2015, 09:14 AM

My recently completed 39 Tudor is great.....except for the fact that it's hard to start, fouls plugs, and runs extremely rich. Here's the combo: 274 inch 8ba, Bubba's Chevy conversion ignition, Edelbrock heads, Sig Erson cam (very similar specs to L100), Eddie Meyer hi-rise manifold with dual 94's, Edmunds air filters. The carbs are linked, not progressive. The engine was professionally built (ported, flowed, cc matched) and broken in on a dyno. The builder set the first set of carbs on the dyno with the instructions to not touch them. Of course, the first mechanic to set hands on the car pronounced them wrong and immediately went to dialing on them. It's been downhill since.

When the car starts, it runs extremely rich. It often fouls plugs instead of starting. It had a set of rebuilt 94's that ran rough after they were tweaked by a self-acknowledged expert. The carbs on it now were good running 94's when they were a pair on a basically stock 239 dressed with a dual intake and aluminum heads. Choke plates are in the carbs but the choke isn't hooked up. I don't know about power valves or jets in these carbs.

What power valve and jet sized is a good place to start with this combo. To my knowledge they are now stock Ford specs. I'm not averse to replacing the old leakers with new Edelbrock 94's or the English 97's. I don't want to go to a single 4 bbl. but if that's what it takes to get this car on the road reliably, then that's a last option.

.

trainguy · 04-07-2015, 09:31 AM

Dual carbs look cool but are a PIA.i have a similar engine in my hi boy but have a Holley 390 it works great,have not needed to adjust it in 3 years.I had dual 97s on my 36,nothing but problems took it off and replaced it with a single 97.no problems since.Phil

Bruce Lancaster · 04-07-2015, 09:42 AM

Before messing around further, give it a test run without the air cleaners. MANY hotrod air cleaners are actually chokes.

flathead4rd · 04-07-2015, 09:54 AM

Quote:

Originally Posted by Bruce Lancaster

Before messing around further, give it a test run without the air cleaners. MANY hotrod air cleaners are actually chokes.

I agree with Bruce. Had the same problem with my trip 97's, straight linkage on a 286 CI engine. Took the filters out of the air cleaners and big difference. Incidentally they were K&N filters which are very good but just didn't work out for my setup. If your jets and powervalves are right you shouldn't have a problem with dual 94's.

sidevalve8ba · 04-07-2015, 10:28 AM

Bruce is correct about the air cleaners and I've found a Uni-Syn carb synchronizing tool helped a ton.

Fred A · 04-07-2015, 10:35 AM

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What's goin-on out there? Millions on Millions of the 94s made and can't find a nice pair of stockers to start out with? Starting with apparent defectives is a tough one cause there can be some changes that may not be obvious. Vac power valves are the usual suspects where rich slobbering conditions are observed. The old 7.5 that still in rebuild kits comes out of an era when the Corn Belt had not yet jammed us with their ethanol blend. Here in CA where the fuel may be the worst in the country, my old Fords run a bit better with a lower number power valve. Good Luck: Fred A

Willit Stop · 04-07-2015, 11:26 AM

Are you using a fuel pressure regulator? By the way...I was told that just one backfire through the carb will blow out the power valve.

PeterC · 04-07-2015, 12:00 PM

Quote:

Originally Posted by trainguy

Dual carbs look cool but are a PIA.i have a similar engine in my hi boy but have a Holley 390 it works great,have not needed to adjust it in 3 years.I had dual 97s on my 36,nothing but problems took it off and replaced it with a single 97.no problems since.Phil

Not doubting at all your experience but just wanted to add that my experiences with my former 1939 Coupe 296cu dual 97s 59L and current 1935 Coupe 284 supercharged dual 48's 59AB - both operate flawlessly – carbs matching the specific requirements of the build - each component i.e. intake type and flow, head type, cc's, compression, cam, timing, plugs, exhaust, gearing, tire size, driving style were all factored to the jetting, tuning and sync of the carbs – also air cleaner flow was considered as well … just suggesting here that as we all know ... carburation takes much thought and consideration when dropping on the top of our beloved flatheads.

cuzncletus · 04-07-2015, 12:26 PM

1. Running without air cleaners was tried with no noticeable difference.

2. Fuel pressure regulator is in place and indicating 2.5-3 lbs.

3. Uni-Syn has hot been used. Will look at ordering one today. This may be my first flathead but there's two more waiting in the wings; one running and one being built.

4. Many thanks to a Ford Barn pariah who took the time to call and talk with me personally.

Bruce_MO · 04-07-2015, 01:28 PM

On the advice of others long ago, I switched to .049 jets from the stock .051's, and I changed the power valves to 4.5's... at least those are the numbers that I recall- may be off a little. It made a big difference in rich running and fouled plugs. I think I've seen others here on FB recommend the same thing.

Bruce Lancaster · 04-07-2015, 02:24 PM

If air cleaners work, onward...
Float level...low side of spec or a little bit below that, which is biggest number as usually measured
If your pressure reading is from one of those little Mr. Gasket regulators with gauge, re-check with a respectable gauge.
Jets, start around stock or a bit lower. If you have to go very far lower something else is wrong. The .049 above is a reasonable lowering here.
Power valve...if it is not leaking at its gasket, it is irrelevant at cruise, part throttle, and idle and can be dealt with later. If gasket leaks (common if PV's are 4150 type, seating is different from Ford 94) you have a random joker in your deck. Go in there and verify that it is sealed.
PV numbers relate to tip in time, NOT amount of enrichment, and usually need considerably lower vac number than the stock 7 or so. Should be relevant only at high throttle settings, but if they open too soon will greatly over enrich normal main operation. The 4.5 noted above is a reasonable beginning setting.

Charlie ny · 04-07-2015, 02:29 PM

CUZ,
If I built those carbs let me know PRONTO, right here on the Barn is fine
with me. We can pick up the conversation at that time. If you have a problem,
I have a problem.
Gracias,
Charlie ny

my4dv8 · 04-07-2015, 02:36 PM

What a load of nonsense about two carbs being a pain, so decades of hot rodders were wrong.a little patience will get them running sweet.
Our 3 runs a very similar set al be it a 260 motor , Eddie Meyer, L 100 cam , Chevy dist. Converted, navarro heads, but two 97s on top . The Edmunds air cleaners should flow enough( probably)
We experienced starting problems on occasions , more often than not, if not fired straight away it would foul a plug or two and be a problem to start , when started a mile or so down the road it would clear. The plugs looked a great colour when hot and doing a road side read. We changed from B6L plugs to B4L and after 2000 miles the past two months all seems to be good.

Mart · 04-07-2015, 04:14 PM

I have twin holley 2100s (later versions derived from 94s) on my 270 inch flatty.
I run 51 jets and stock power valves in both carbs. Now here's the thing: If you have plug fouling problems it isn't due to jets and power valves. What I am trying to say is plug fouling would be caused by things like faulty needle valve, porous float, too much fuel pressure, warped housings, faulty power valves, incorrect power valve gaskets etc etc.

If you make sure everything is correct, you will not have plug fouling problems, even with 51s and stock power valves. Once all is well, then fine tuning can take place. Using leaner jets and lower number power valves to try and off set an over rich condition caused by an actual fault is futile.

Here endeth the sermon.

Mart.

zzlegend · 04-07-2015, 04:40 PM

59AB here. Running an Isky Max 1 cam and two 94's. Jetting is 48's and 4.5 power valves. Was running 49's but was a hair on the rich side so went to 48's. Starts to easy and responds perfect. On a side note, I have another 59AB running in another car. Used it to run each of these carbs separate and tune them one at a time and then did the other. Then installed them on my good motor. Did that help? I think so. Mark.

cuzncletus · 04-07-2015, 04:49 PM

1. I see lower # power valves (4.5, 3.5) advertised at Summit et al. I also looked them up on EBay. Are the power valves from Summit not compatible with old 94's? There's a vendor in Fla. who claims his are US built and correct for the 94. It also looks to me like a Holley jet is a Holley jet; 94's are no different from 4150's?

2. Charlie, you did not build the first set of carbs. However, you may be on deck if I can't get this second set going satisfactorily. Contact me.

3. my4dv8; The engine on my stand is a 258 w/L100 cam and Chevy dist., work in progress as the money permits. That aside, I'll try some B4L's as the engine runs better after it's warm and has gone a mile or two. The more it runs the better it seems to run. It's the start/warm up that's the problem. It still runs very rich from the smell when warm. I don't have any kind of O2 sensor to see what the mixture is.

Charlie ny · 04-07-2015, 06:23 PM

cuz,
Here is my opinion for what ever it is worth. If not related to air cleaners
I'd be shocked if your problem is not related to the power valves.
If you find the PV's in your carbs have 2 square shaped 'windows' to allow fuel
passage there is at least a 50% chance that these PV's will not perform reliably.
I used to use these PV's and had excellent results during my test proceedure in my shop. However shortly after delivery some of my carbs began to misbehave...run
rich and stumble. For a couple months I didn't make a lot of $$$$$ and depended on
the patience of my customers while I changed offending PV's. By far not all the
window style PV's were bad actors, but plenty were.
I absolutely agree the PV's that are sold by DAYTONA PARTS in Florida
are the best at least from my experience. DP sells 5.5 and 7.5 PV's I use 5.5's and
I'm happy to say the least. Daytonas PV's are HIGH quality and feature 3 small round
fuel escape holes typical of the original style from back in the day. There
is a correctable problem with the Daytona PVs and that is the gasket face is not
always square with the threads and this requires a bit of lathe work to true things up,
not a big deal. I will caution anyone taking the time to read this
that there is another supplier that does chase the gasket face of the PVs sold by
him, my caution is 2 fold....these PVs are the window style and the machining is
extremely marginal.
These are my opinions only and I certainly respect everyone's opinion.
Charlie ny

uncle max · 04-07-2015, 06:40 PM

If Gina was a man, she'd be The Man!

Quote:

Originally Posted by Charlie ny

cuz,
Here is my opinion for what ever it is worth. If not related to air cleaners
I'd be shocked if your problem is not related to the power valves.
If you find the PV's in your carbs have 2 square shaped 'windows' to allow fuel
passage there is at least a 50% chance that these PV's will not perform reliably.
I used to use these PV's and had excellent results during my test proceedure in my shop. However shortly after delivery some of my carbs began to misbehave...run
rich and stumble. For a couple months I didn't make a lot of $$$$$ and depended on
the patience of my customers while I changed offending PV's. By far not all the
window style PV's were bad actors, but plenty were.
I absolutely agree the PV's that are sold by DAYTONA PARTS in Florida
are the best at least from my experience. DP sells 5.5 and 7.5 PV's I use 5.5's and
I'm happy to say the least. Daytonas PV's are HIGH quality and feature 3 small round
fuel escape holes typical of the original style from back in the day. There
is a correctable problem with the Daytona PVs and that is the gasket face is not
always square with the threads and this requires a bit of lathe work to true things up,
not a big deal. I will caution anyone taking the time to read this
that there is another supplier that does chase the gasket face of the PVs sold by
him, my caution is 2 fold....these PVs are the window style and the machining is
extremely marginal.
These are my opinions only and I certainly respect everyone's opinion.
Charlie ny

Binx · 04-07-2015, 06:46 PM

If you want to test for blown or verify the accuracy of a power valve, this tester is super handy...

http://www.summitracing.com/parts/mor-62295

Lonnie

JonC · 04-07-2015, 08:56 PM

I ran dual 94's on a 36 worked great I think the progressive linkage I made was the answer, I tried without and it always dumped too much fuel. If you try it make sure the second carb throttle plate shut completely and I never opened the idle mixture screws on that carb as well. Maybe I was just lucky but it worked well for me.

04-07-2015, 09:14 AM	#1
cuzncletus Senior Member Join Date: Aug 2010 Location: Sevierville, Tenn. Posts: 391	Old story: Dual 94 problems My recently completed 39 Tudor is great.....except for the fact that it's hard to start, fouls plugs, and runs extremely rich. Here's the combo: 274 inch 8ba, Bubba's Chevy conversion ignition, Edelbrock heads, Sig Erson cam (very similar specs to L100), Eddie Meyer hi-rise manifold with dual 94's, Edmunds air filters. The carbs are linked, not progressive. The engine was professionally built (ported, flowed, cc matched) and broken in on a dyno. The builder set the first set of carbs on the dyno with the instructions to not touch them. Of course, the first mechanic to set hands on the car pronounced them wrong and immediately went to dialing on them. It's been downhill since. When the car starts, it runs extremely rich. It often fouls plugs instead of starting. It had a set of rebuilt 94's that ran rough after they were tweaked by a self-acknowledged expert. The carbs on it now were good running 94's when they were a pair on a basically stock 239 dressed with a dual intake and aluminum heads. Choke plates are in the carbs but the choke isn't hooked up. I don't know about power valves or jets in these carbs. What power valve and jet sized is a good place to start with this combo. To my knowledge they are now stock Ford specs. I'm not averse to replacing the old leakers with new Edelbrock 94's or the English 97's. I don't want to go to a single 4 bbl. but if that's what it takes to get this car on the road reliably, then that's a last option. .

04-07-2015, 09:31 AM	#2
trainguy Senior Member Join Date: May 2010 Location: Lehighton Pa Posts: 1,085	Re: Old story: Dual 94 problems Dual carbs look cool but are a PIA.i have a similar engine in my hi boy but have a Holley 390 it works great,have not needed to adjust it in 3 years.I had dual 97s on my 36,nothing but problems took it off and replaced it with a single 97.no problems since.Phil

04-07-2015, 09:42 AM	#3
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: Old story: Dual 94 problems Before messing around further, give it a test run without the air cleaners. MANY hotrod air cleaners are actually chokes.

04-07-2015, 10:28 AM	#5
sidevalve8ba Senior Member Join Date: May 2013 Location: Harrisonburg, VA Posts: 842	Re: Old story: Dual 94 problems Bruce is correct about the air cleaners and I've found a Uni-Syn carb synchronizing tool helped a ton. __________________ The more I learn about new automobiles, the more I value my old ones.

04-07-2015, 10:35 AM	#6
Fred A Senior Member Join Date: May 2010 Location: Encino California, near Burbank Posts: 935	Re: Old story: Dual 94 problems Sponsored Links (Register now to hide all advertisements) What's goin-on out there? Millions on Millions of the 94s made and can't find a nice pair of stockers to start out with? Starting with apparent defectives is a tough one cause there can be some changes that may not be obvious. Vac power valves are the usual suspects where rich slobbering conditions are observed. The old 7.5 that still in rebuild kits comes out of an era when the Corn Belt had not yet jammed us with their ethanol blend. Here in CA where the fuel may be the worst in the country, my old Fords run a bit better with a lower number power valve. Good Luck: Fred A

04-07-2015, 11:26 AM	#7
Willit Stop Senior Member Join Date: Feb 2013 Location: Eureka Calif. Posts: 969	Re: Old story: Dual 94 problems Are you using a fuel pressure regulator? By the way...I was told that just one backfire through the carb will blow out the power valve.

04-07-2015, 12:26 PM	#9
cuzncletus Senior Member Join Date: Aug 2010 Location: Sevierville, Tenn. Posts: 391	Re: Old story: Dual 94 problems 1. Running without air cleaners was tried with no noticeable difference. 2. Fuel pressure regulator is in place and indicating 2.5-3 lbs. 3. Uni-Syn has hot been used. Will look at ordering one today. This may be my first flathead but there's two more waiting in the wings; one running and one being built. 4. Many thanks to a Ford Barn pariah who took the time to call and talk with me personally.

04-07-2015, 01:28 PM	#10
Bruce_MO Senior Member Join Date: May 2010 Posts: 433	Re: Old story: Dual 94 problems On the advice of others long ago, I switched to .049 jets from the stock .051's, and I changed the power valves to 4.5's... at least those are the numbers that I recall- may be off a little. It made a big difference in rich running and fouled plugs. I think I've seen others here on FB recommend the same thing.

04-07-2015, 02:24 PM	#11
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: Old story: Dual 94 problems If air cleaners work, onward... Float level...low side of spec or a little bit below that, which is biggest number as usually measured If your pressure reading is from one of those little Mr. Gasket regulators with gauge, re-check with a respectable gauge. Jets, start around stock or a bit lower. If you have to go very far lower something else is wrong. The .049 above is a reasonable lowering here. Power valve...if it is not leaking at its gasket, it is irrelevant at cruise, part throttle, and idle and can be dealt with later. If gasket leaks (common if PV's are 4150 type, seating is different from Ford 94) you have a random joker in your deck. Go in there and verify that it is sealed. PV numbers relate to tip in time, NOT amount of enrichment, and usually need considerably lower vac number than the stock 7 or so. Should be relevant only at high throttle settings, but if they open too soon will greatly over enrich normal main operation. The 4.5 noted above is a reasonable beginning setting.

04-07-2015, 02:29 PM	#12
Charlie ny BANNED Join Date: May 2010 Posts: 3,019	Re: Old story: Dual 94 problems CUZ, If I built those carbs let me know PRONTO, right here on the Barn is fine with me. We can pick up the conversation at that time. If you have a problem, I have a problem. Gracias, Charlie ny

04-07-2015, 02:36 PM	#13
my4dv8 Senior Member Join Date: Aug 2010 Location: New Zealand Posts: 1,111	Re: Old story: Dual 94 problems What a load of nonsense about two carbs being a pain, so decades of hot rodders were wrong.a little patience will get them running sweet. Our 3 runs a very similar set al be it a 260 motor , Eddie Meyer, L 100 cam , Chevy dist. Converted, navarro heads, but two 97s on top . The Edmunds air cleaners should flow enough( probably) We experienced starting problems on occasions , more often than not, if not fired straight away it would foul a plug or two and be a problem to start , when started a mile or so down the road it would clear. The plugs looked a great colour when hot and doing a road side read. We changed from B6L plugs to B4L and after 2000 miles the past two months all seems to be good.

04-07-2015, 04:14 PM	#14
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,749	Re: Old story: Dual 94 problems I have twin holley 2100s (later versions derived from 94s) on my 270 inch flatty. I run 51 jets and stock power valves in both carbs. Now here's the thing: If you have plug fouling problems it isn't due to jets and power valves. What I am trying to say is plug fouling would be caused by things like faulty needle valve, porous float, too much fuel pressure, warped housings, faulty power valves, incorrect power valve gaskets etc etc. If you make sure everything is correct, you will not have plug fouling problems, even with 51s and stock power valves. Once all is well, then fine tuning can take place. Using leaner jets and lower number power valves to try and off set an over rich condition caused by an actual fault is futile. Here endeth the sermon. Mart.

04-07-2015, 04:40 PM	#15
zzlegend Senior Member Join Date: May 2010 Location: Reseda, Calif. Posts: 2,188	Re: Old story: Dual 94 problems 59AB here. Running an Isky Max 1 cam and two 94's. Jetting is 48's and 4.5 power valves. Was running 49's but was a hair on the rich side so went to 48's. Starts to easy and responds perfect. On a side note, I have another 59AB running in another car. Used it to run each of these carbs separate and tune them one at a time and then did the other. Then installed them on my good motor. Did that help? I think so. Mark.

04-07-2015, 04:49 PM	#16
cuzncletus Senior Member Join Date: Aug 2010 Location: Sevierville, Tenn. Posts: 391	Re: Old story: Dual 94 problems 1. I see lower # power valves (4.5, 3.5) advertised at Summit et al. I also looked them up on EBay. Are the power valves from Summit not compatible with old 94's? There's a vendor in Fla. who claims his are US built and correct for the 94. It also looks to me like a Holley jet is a Holley jet; 94's are no different from 4150's? 2. Charlie, you did not build the first set of carbs. However, you may be on deck if I can't get this second set going satisfactorily. Contact me. 3. my4dv8; The engine on my stand is a 258 w/L100 cam and Chevy dist., work in progress as the money permits. That aside, I'll try some B4L's as the engine runs better after it's warm and has gone a mile or two. The more it runs the better it seems to run. It's the start/warm up that's the problem. It still runs very rich from the smell when warm. I don't have any kind of O2 sensor to see what the mixture is.

04-07-2015, 06:23 PM	#17
Charlie ny BANNED Join Date: May 2010 Posts: 3,019	Re: Old story: Dual 94 problems cuz, Here is my opinion for what ever it is worth. If not related to air cleaners I'd be shocked if your problem is not related to the power valves. If you find the PV's in your carbs have 2 square shaped 'windows' to allow fuel passage there is at least a 50% chance that these PV's will not perform reliably. I used to use these PV's and had excellent results during my test proceedure in my shop. However shortly after delivery some of my carbs began to misbehave...run rich and stumble. For a couple months I didn't make a lot of $$$$$ and depended on the patience of my customers while I changed offending PV's. By far not all the window style PV's were bad actors, but plenty were. I absolutely agree the PV's that are sold by DAYTONA PARTS in Florida are the best at least from my experience. DP sells 5.5 and 7.5 PV's I use 5.5's and I'm happy to say the least. Daytonas PV's are HIGH quality and feature 3 small round fuel escape holes typical of the original style from back in the day. There is a correctable problem with the Daytona PVs and that is the gasket face is not always square with the threads and this requires a bit of lathe work to true things up, not a big deal. I will caution anyone taking the time to read this that there is another supplier that does chase the gasket face of the PVs sold by him, my caution is 2 fold....these PVs are the window style and the machining is extremely marginal. These are my opinions only and I certainly respect everyone's opinion. Charlie ny

04-07-2015, 06:46 PM	#19
Binx Senior Member Join Date: Oct 2011 Location: Gloucester VA Posts: 1,042	Re: Old story: Dual 94 problems If you want to test for blown or verify the accuracy of a power valve, this tester is super handy... http://www.summitracing.com/parts/mor-62295 Lonnie

04-07-2015, 08:56 PM	#20
JonC Senior Member Join Date: Oct 2011 Location: Central NY Posts: 629	Re: Old story: Dual 94 problems I ran dual 94's on a 36 worked great I think the progressive linkage I made was the answer, I tried without and it always dumped too much fuel. If you try it make sure the second carb throttle plate shut completely and I never opened the idle mixture screws on that carb as well. Maybe I was just lucky but it worked well for me.