Have you bought a "Holley Carburettors and Manifolds" book yet ???
quote:Originally posted by Bumblebee13:
Yes sorry vacum. The carb is less than four months old. Got it from precision proformance. Any general guess why the bowl level would change?
How old is your fuel tank ?
How much shite is in your fuel tank ?
Do you have any fuel line filters ?
I read the tech info another member sent me on a carb guy. Maily the holley acc pump adj and the cam chart from holley and my manual
Fuel tank is oem. Been drained and flushed twice. I have a inline fuel filter. An aluminum one that has two filters in it and yes the flow is going in the corecy way
quote:Originally posted by Bumblebee13:
Fuel tank is oem. Been drained and flushed twice. I have a inline fuel filter. An aluminum one that has two filters in it and yes the flow is going in the corecy way
Is there any contaminants in the filter ?
Are there any contaminants in the small mesh screen in the inlet fitting on the carb ?
What fuel pump do you have ?
Is it functioning correctly ?
What is your fuel pressure now ?
No it all looks good. Ur probably gona get on to me lol. Its an oem fuel pump. Original for all i know
quote:Originally posted by Bumblebee13:
No it all looks good. Ur probably gona get on to me lol. Its an oem fuel pump. Original for all i know
Original ???
You mean it is 40 years old ???
Go buy a new one. Stock replacement will be fine.
Buy a "Holley Carburettors and Manifolds " book as well !!
Ill get one from oriellys tomorrow. Honestly that was my thought earlier. That it went out
The problem is not your fuel pump. The fuel dribbling out is indicative of a bad carb accel pump diaphram or clogged fuel passage between the pump and the shooter. Perhaps even the wrong or misaligned gasket on the fuel bowl or metering block blocking the passage had the carb been rebuilt. It is not difficult to check those possibilities.
No its a cherry carb. Just noticed the low bowl level and the dribbling out of the squiter
quote:Originally posted by JTpantera:
The problem is not your fuel pump. The fuel dribbling out is indicative of a bad carb accel pump diaphram or clogged fuel passage between the pump and the shooter. Perhaps even the wrong or misaligned gasket on the fuel bowl or metering block blocking the passage had the carb been rebuilt. It is not difficult to check those possibilities.
He has as unexplained drop in float bowl level and he has a 40 year old pump.
He needs to get that sorted out first or all the stuffing around with the carb will be a total waste of time.
You must start with the basics correct eg:
clean fuel
clean fuel tank
clean fuel filters
A fuel pump that is known to deliver reliable flow and pressure
as far as i know he cant test his in any way but it would be fair to assume that a 40 year old pump will be compromised.
They dont cost much, it's time for a new one.
Then he can check there is no crap inside the carb possibly blocking passage ways and adjust his float levels to spec with some reasonable expectation that the float levels wont mysteriously vary.
The the carb tuning fun and games can begin.
Yes sir when i get off today im gona go get a new pump
Could it be as simple as the acc pimp adjusted wrong?
Your accel pump may still be adjusted wrong, but that wont explain the variation in the float bowl fuel level.
Think about it !!
Swap out your 40 year old fuel pump so you know at least that part is ok and is not a issue.
As i said earlier use your biological computer. Think !
Think about it !!
Swap out your 40 year old fuel pump so you know at least that part is ok and is not a issue.
As i said earlier use your biological computer. Think !
Will do thank you. Ill keep you posted. It will probably be tomorrow when i install
Yes please keep us posted.
I think it will fix one of your problems at least, but i am sure you will have further work to do.
While you are at the parts store i think you should get some gaskets for your carb because after you replace your pump i'm going to tell you to remove the float bowls from your carb and see what debris is inside.
Be prepared to do some work.
I think it will fix one of your problems at least, but i am sure you will have further work to do.
While you are at the parts store i think you should get some gaskets for your carb because after you replace your pump i'm going to tell you to remove the float bowls from your carb and see what debris is inside.
Be prepared to do some work.
Im sure. Its just weird squited just fine then went to a little drivble. I guess the pump would explain tge stalling out at an incline? This is just my luck all was good except for the little hesitation. Then the shop i took it to for an alignment dropped the car off the lift and folded the rear passenger fender and i need to get it to the body shop. Thats another story all in its self that im being lied to about. No way in hell that whe my pk brake was set it had enough
Momentum in less than 5 feet that it could roll over two 8 inch chocks and tgrough a roll up glass door. But
Magically thats what they said. Owell they are paying to paint the whole car
Momentum in less than 5 feet that it could roll over two 8 inch chocks and tgrough a roll up glass door. But
Magically thats what they said. Owell they are paying to paint the whole car
I suspect your accel pump has got some debris stuck in either it's inlet valve or discharge valve or both (possibly debris from the old fuel pump that is likely to be failing)
But let us do one task at a time for now.
But let us do one task at a time for now.
In order for you to keep a consistent fuel level in the bowls, you need consistent fuel pressure.
The higher the pressure, the higher the fuel level will be.
I find that even though Holley says the fuel should trickle out of the sight hole at idle, that the level is too high for going up or down a steep incline and you will get spillage through the boosters under those conditions.
I run an electric Holley pump with a Holley mechanical fuel pump with a pressure regulator. That keeps the pressure the most consistent, yet it still does vary, especially at idle.
That seems to be exactly consistent with the nature of the the pressure regulators. All seem to have about a 2psi variation in normal operation.
On a Holley, I also keep the level just at the bottom of the sight hole so it just doesn't trickle out.
Everything on a Holley is a compromise. The fuel shifts so badly under racing conditions in the bowls, that under hard braking the engine will stall.
What happens there is the fuel will slosh away from the metering block AND CAN spill out of the vents.
They are not good carbs for those reasons.
The higher the pressure, the higher the fuel level will be.
I find that even though Holley says the fuel should trickle out of the sight hole at idle, that the level is too high for going up or down a steep incline and you will get spillage through the boosters under those conditions.
I run an electric Holley pump with a Holley mechanical fuel pump with a pressure regulator. That keeps the pressure the most consistent, yet it still does vary, especially at idle.
That seems to be exactly consistent with the nature of the the pressure regulators. All seem to have about a 2psi variation in normal operation.
On a Holley, I also keep the level just at the bottom of the sight hole so it just doesn't trickle out.
Everything on a Holley is a compromise. The fuel shifts so badly under racing conditions in the bowls, that under hard braking the engine will stall.
What happens there is the fuel will slosh away from the metering block AND CAN spill out of the vents.
They are not good carbs for those reasons.
Deep breath.....
Your fuel level has dropped, and your accelerator pump now just dribbles?
You did RUN the motor right? Fuel for the accelerator pump is taken from the fuel bowl - if you keep squirting it by moving the throttle without the motor actually running then your carb bowl fuel level will drop on the primary side, and given enough tries, will eventually run out of fuel and the accelerator pump will just dribble.
Just to echo the thoughts of Aus Ford; I think a few nights away from the car and studying the Holley book would be time well invested. If you don't have a very good idea how the various systems work, and how they interact with one another, then you'll have a very hard time making progress - with or without the nice folks on here.
Andy
If you have done this, then be aware that your intake manifold now has quite a bit of raw fuel in it!
Your fuel level has dropped, and your accelerator pump now just dribbles?
You did RUN the motor right? Fuel for the accelerator pump is taken from the fuel bowl - if you keep squirting it by moving the throttle without the motor actually running then your carb bowl fuel level will drop on the primary side, and given enough tries, will eventually run out of fuel and the accelerator pump will just dribble.
Just to echo the thoughts of Aus Ford; I think a few nights away from the car and studying the Holley book would be time well invested. If you don't have a very good idea how the various systems work, and how they interact with one another, then you'll have a very hard time making progress - with or without the nice folks on here.
Andy
If you have done this, then be aware that your intake manifold now has quite a bit of raw fuel in it!
Man that does make perfect freakin sense i was manualy opening the throttle cking the acc pump. And watching the fuel dribble out. Hell is the bowl is empty then it wont have any in it to squirt out right? Got my pump.
quote:Originally posted by Marlin Jack:
...don't want to complicate the issue here, but.
Fuel bowl levels must be adjusted with the carb Level!
All 'Mustang' manifolds tilt the carb Forward to compensate for the Engine being tilted BACK, to align with the differential.
In the Pantera the Engine sits LEVEL to the Chassis, tilting all carbs FORWARD.
That is why Most of us have installed a 'Wedge' Spacer, of 5-8 degrees, under the Holleys, to tilt the carb Back to LEVEL.
also about fuel splashing out of the vents upon severe deceleration/acceleration. The racers connect both vents with a hose, in a 'U' shape, and cut a little vent in the top-side at the center.
As far as the Jets getting uncovered...That is what 'Slosh Tubes' and 'Vent whistles' are for, look it up in the book.
Last, sloshing fuel in the carb bowls is a Major reason why most drivers prefer 'Fuel Injecton'!
Good point on the carb level/angle. Novices would probably not notice that.
Yes on the fuel sloshing on the Holleys. The Weber 48 IDA's don't noticibly. The floats are set transversely vs. the Holley which are front to back.
You can run as hard as you can handle with the 48ida's and not have fuel shifting issues.
They were designed as a "racing carb". The Holley was not and as a result has all sorts of fuel delivery issues in competition due to fuel shifting in the bowls.
The way the float and fuel bowl are designed in the ida, fuel can not be drawn away from the jets.
Mr.Weber was a very, very bright individual.
As far as the Holley "trick" jet and vent extensions go, the way we would verify the brakes being acceptable was to test them before a race and if the car didn't stall from the brake g-forces generated, they were not race ready?
They are just attempts to fix the unfixable with a Holley. They can somewhat help with reducing the problems but do not eliminate them.
You will have better results with a Holley at mounting it sideways like you do with dual Dominators on a "Tunnel Ram". I wonder if there are any of those on a Pantera? Marlin? What do you think? Maybe one or two?
5 degrees on this Moroso spacer.
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Well i guess you could call it ate up with the dumb a@@. Watching and reading some more i solved my fuel dribble problem. I had the squirter in upside down. I know i know been hard enough on my self haha. Replaced fuel pump and now both sight glasses are showing fuel. Rear one is a little higher guessing that y i need the angled spacer. Car is running now but it still has that slight suck hesitation. Tomorrow going to play with the cams a little. Timing now set at 12. Running smooth but still slight hesitation. Air fuel screws are 1.5 out
It had a .30 in it from holley
Or should i try a .25. If i ask to many auestions i appologize. Here in texas i have no outreach for help on panteras. Yall are a huge help
I have 2-1850's (600 cfm each) on my 68 GT350. It's a 347.
Marlin's 450's are 1848's. I believe he has them on 1" spacers to create plenums under each. A little unusual with 2 individual plenums and two individual primary carbs but it obviously works.
It's a little trick to make the TR work like a street manifold. Don't look up his sleeves. You don't want to know what else is up there?
The 2x4 is a nice set up. In all honesty, I spend most of my time just trying to hold on to the steering wheel and not fall out of the car when I hit the accelerator.
The carbs are mounted backwards on mine. Seems to help with the sloshing issue?
#25's are the right shooters with no tubes. 31's should work but you should be happier with the smaller ones.
Ford put 31's in the 428's. It's a bigger mass to get going off of the line.
You need a constant 6-7 psi. An electric fuel pump pressurizing the mechanical pump is what I do.
With that you can set a consistent float level.
You should have the vent extension whistles and jet extensions. Those will help on hard acceleration.
I wouldn't challenge Marlin to a grudge match race. Those setups boogie. It's probably an honest 12 second car?
I am wondering if you have the cable installed properly on the carb? Did you test it to make sure that you are getting full opening at full pedal travel?
Marlin's 450's are 1848's. I believe he has them on 1" spacers to create plenums under each. A little unusual with 2 individual plenums and two individual primary carbs but it obviously works.
It's a little trick to make the TR work like a street manifold. Don't look up his sleeves. You don't want to know what else is up there?
The 2x4 is a nice set up. In all honesty, I spend most of my time just trying to hold on to the steering wheel and not fall out of the car when I hit the accelerator.
The carbs are mounted backwards on mine. Seems to help with the sloshing issue?
#25's are the right shooters with no tubes. 31's should work but you should be happier with the smaller ones.
Ford put 31's in the 428's. It's a bigger mass to get going off of the line.
You need a constant 6-7 psi. An electric fuel pump pressurizing the mechanical pump is what I do.
With that you can set a consistent float level.
You should have the vent extension whistles and jet extensions. Those will help on hard acceleration.
I wouldn't challenge Marlin to a grudge match race. Those setups boogie. It's probably an honest 12 second car?
I am wondering if you have the cable installed properly on the carb? Did you test it to make sure that you are getting full opening at full pedal travel?
quote:Originally posted by Bumblebee13:
It had a .30 in it from holley
Any time you have a hesitation or a bog down it means you need more fuel not less.
Too much fuel almost never causes a hesitation. It takes a ton of excess fuel to cause that, so much you would notice a ton of black smoke out the exhaust and even liquid gasoline out the exhaust.
So you can be almost certain: a hesitation = a lack of fuel
So if you have a hesitation as you crack the throttle open you still need more accel pump shot.
Is the accel pump working now ? Is it shooting fuel out in a stream that hits the booster venturi ?
If it does: Have you adjusted the accel pump override spring so it is touching the small accel pump arm slightly depressing it and with no slack between the two (forget the feeler gauge routine) .
You want the pump to shoot with even the slightest movement.
Try a 35 shooter or even a 40 shooter. I used a 40 on a Holley when i was running one.
Holley carbs are made for Chevys by people with a Chevy mindset. Consequently their fuel curves are more suited to Chevs and not the more obscure (in the states) 351 Cleveland. So Holleys generally speaking don't shoot enough fuel in off the line for a 351c and so you have the off idle bog.
Ultimately i needed to make up a custom accel pump cam for the Holley i used.
Now its squirting out yes. Today im going to swap some cames. If i easy opening the throttle its all good only when i goose it she bogs
If you will give me your email i can send a video of what is doing while running
You didn't say if the engine was stock or not?
If it is stock, this may be too much carb for the engine.
Stock something like a 600 cfm would be better.
What you may be describing as bogging to us may be just the engines inability to use this carb?
If it is stock, this may be too much carb for the engine.
Stock something like a 600 cfm would be better.
What you may be describing as bogging to us may be just the engines inability to use this carb?
Yes stock motor
I've seen lots of stock 351c's with 750 carbs and they have worked fine.
It is a vac secondary, so even if the throttle is stood on the engine is only going to see half the carb until the airflow goes up.
1/2 of 750 is only 375 cfm. That should not cause the off idle bog that has been described.
Though if i was going out to buy a carb for a stock motor i agree a 600 is what i'd go for.
It is a vac secondary, so even if the throttle is stood on the engine is only going to see half the carb until the airflow goes up.
1/2 of 750 is only 375 cfm. That should not cause the off idle bog that has been described.
Though if i was going out to buy a carb for a stock motor i agree a 600 is what i'd go for.
quote:Originally posted by Aus Ford:
I've seen lots of stock 351c's with 750 carbs and they have worked fine.
It is a vac secondary, so even if the throttle is stood on the engine is only going to see half the carb until the airflow goes up.
1/2 of 750 is only 375 cfm. That should not cause the off idle bog that has been described.
Though if i was going out to buy a carb for a stock motor i agree a 600 is what i'd go for.
Sure. I used a 4779, 750 dp for quite a while BUT the engine could use it, the car needs to be geared for it and I have obviously a different definition of "stumble".
A 600 is definitely going to be "crisper" and the 750 definitely "lazier".
There is no telling what people "expect" the engines reaction to be?
I have run the Shelby 715cfm, Ford "Boss 302" carb and the 428cj 735 carbs on a 12.0:1 cr engine with 3.70 gears and 2.32 1st gear top loader.
They were all slugs.
The 600cfm vacuum secondary R-1850 was by far the most "responsive". That IS the carb you want for your lowest 0-60 times.
The 4779 worked best on the Edelbrock torker but the combination was very "flat" until about 4,200 rpm.
Again, what "stumble" means to one person is not what it may mean to another?
The carb in question here MAY in fact be acting/reacting exactly as it should and the driver not expecting this type of a reaction?
This is very difficult to decipher from afar?
That is so true.
You can only give so many hints/tips to solve a problem. At some point the guy that is there with the car has to take the initiative and get in there and do the hard work.
This is exactly why the medical profession wont make a diagnosis over the phone or on the internet.
You can only give so many hints/tips to solve a problem. At some point the guy that is there with the car has to take the initiative and get in there and do the hard work.
This is exactly why the medical profession wont make a diagnosis over the phone or on the internet.
Marlin,
I see your logic and i feel you are quite correct.
The shooter size has more effect over fuel delivery timing rather than the total volume of fuel delivered.
As you say the 25 shooter nozzle will deliver the pump shot over a longer period of time and the 40 will deliver the same amount of fuel over a shorter time. It is the pump cam that governs the amount of fuel.
Your description of the pump spring adjustment is spot on, exactly what i have been trying to get across.
I see your logic and i feel you are quite correct.
The shooter size has more effect over fuel delivery timing rather than the total volume of fuel delivered.
As you say the 25 shooter nozzle will deliver the pump shot over a longer period of time and the 40 will deliver the same amount of fuel over a shorter time. It is the pump cam that governs the amount of fuel.
Your description of the pump spring adjustment is spot on, exactly what i have been trying to get across.
So big news i put the 25 back in and noticed is wasnt squirting one of the holes was semi blocked by a piece of debris. Also swapped the green cam out with the pink one. Heaitation has got better. At high rpms and when i ease into the throttle its ok just when i stick it and at low rpms it tries to die. But when i stick it is cuts out that split second them will give it all shes got
put a 28 in & try it
Ill have to wait to go to the shop tomorrow. I was thinking about goi g smaller to try it
as mentioned up earlier, the immediate stumble is likely a sign of needing more fuel at that specific moment
I just saw a thing about accel pump adjusting, make 3-size steps in the shooter... so I'd say 28 would be the next step
believe it or not, the main jets can also cause the Bog From Hell
http://www.network54.com/Forum...--++HEEEEEELLLLLP%21
http://www.network54.com/Forum...19/thread/1250362268
I just saw a thing about accel pump adjusting, make 3-size steps in the shooter... so I'd say 28 would be the next step
believe it or not, the main jets can also cause the Bog From Hell
http://www.network54.com/Forum...--++HEEEEEELLLLLP%21
http://www.network54.com/Forum...19/thread/1250362268