Accelerator Cable

[Anonymous]

Hi, was hoping to fit a 500 holley # 4412 over the hoildays but have just realize that the accelerator cable won't reach around to where it connects up, the throttle linkage faces the left shocker tower where on the webers linkage faces the firewall, do i need to get a longer cable or is there another way round this, its on an XE ute

Thanks Joip

 

[xctasy]

I used a costom made Isuzu/Toyota Dyna-type acclerator cable. This truck stuff is real smooth on the inside, and removes drag from the go-peddle. Use of Chryler cables wont work well, as the drag is too much. They have a spiral inner with too much friction inside. Especially after you put the proper Cortina TC-TF /Falcon XE spring loaded ball and coupling on the end.

From memory, about 1.43 meters long is plenty extra length to fit the cable behind the engine, against the firewall. Just replicate the stock set-up, and lengthen it. The Valiant used two upside down 'p' shaped rubber-lined holders to ensure it mounted against the fire wall. I just clamped these to the two bolts that hold the main wiring loom on my XE.

The most important thing is to mount the spring loaded plastic coupling at the carby end at least 36 or more mm from the centre of the throttle pivot. Stock XE's have about 25 mm of cable travel at the top of the accelerator peddle. The Weber carby turns through less than 60 degrees. The Holley turns through 80 degrees.

When doing any calcs, the total pull-out at the carb must equal the total degrees of turn (theta 0), times the total radius distance ( r) from the pivot point, in this case about 36mm. The S is the pull-out.

S= radius*theta, where r is in mm, and theta is degrees divided by 57.3.

S= 36mm* (80/57.3)

S= 50 mm. So this gives you more throttle travel, but a Holley needs it as it has no progreddive throttle. If you find it too much, the bring the 6.3 mm steel ball back in to 32 mm.

My first effort came up with a 28 mm pivot point, and the old hump was hpertensive like an Uzzi at an Italian wedding... pretty soon, it'd take a life. So go easy first!

My Holley needed an additional Valiant VG-VH return spring and cable bracket to get registered. Holleys can have issues with getting stuck at wide open throttle if punters dont use a smooth internal cable, and the old Val linkage is pretty good at stopping this ever happening. The NZ Hot Rod manual used for certifying our modified cars over here says it must have one extra spring. (It'll end up with 3 after you've finished, one on the carby spindle, one on the cable, and one on the front of the carb, Valiant style!)

I followed David Vizards Cortina / Pinto cable arrangement, with the stock Valiant copy linkage bolted up with a cut-off Cortina/Pinto steel cable mount which allows you to adjust the cable in and out by turning the plastic hexagonal nut.

Sounds involved, but really a piece of weeeeze.

Have fun, and Merry Xmas!

 

[Anonymous]

I already made a bracket a couple of weeks back to attach the the cable to the linkage throttle but I will have to check its length , thanks for the help excute you have a good one as well

Joip

 

[xctasy]

Check these two from http://fordsix.com/forum/viewtopic.php?t=10733

These are 350 and 500 Holley 2-bbl linkages. I realise you are looking at cables, but this may help too

 

[Anonymous]

Thanks excute, I used a cable of an au, I just had to change over the plastic bracket at the peddle end and its was long enough, and made another bracket at the holley end and one for the kickdown for the C4, actually it came up pretty good, not long took it for a drive, abit of flooding on take off once it got pass that it when well, I was just going to have a look at pass posts about the carby flooding, I know the holley came of a cortina

Thanks Joip

 

[xctasy]

I'm delighted. AU Falc bits, eh. Wow!

The peak fuel pressure on a formerly Webered Falcon is an issue for me. Did you have any hassle with the fuel return line, or what? Normally, the return line bleeds of excess pressure. The earlier XD pump only has two fuel lines.


Check jimbo65 and tim for details on float levels and jetting. Use the site glass, and ensure the fuel system is clean, with a new line filter. Holleys hate sh1+ in the float bowl. If you get the float level in spec, and fuel clean, and are running 68 jets as an absolute minimum, you'll be in ball-park.


I've done my soap box rant to those guys. I have seen Valiants with 500 Holleys, and the 250 is similar in needs. I doubt you'll have any issues as long as you sustain a constant float level. I think 12.7mm was the spec. If its out 1mm, it will make a huge difference, so set it in spec.

 

[Anonymous]

Some time back I put the fuel pump on that had the return fuel line with it and just block off the carby where it was attached, not long before I change over to the holley I was running very rich, I did blow air back up my return line as I thought it might have been block but was clear so I'am not sure

With the jets on a holley how can you tell what size you have, do you need a gauge or is there a number ??

Joip

 

[xctasy]

You have to risk a gasket change, drop the bowl, and see the stamped call numbers. In the smaller sizes, the jet is the same size as the call size. When it gets to a 100 jet, they are like 128 thou inside. (See below for sizes)

Barry Grant posted some cc per minute flow rates for jets from 60 to 100. These work in with the maximum power you can get. So you can jet the carb for maximum power by finding the call size, and reading off the cc/min flow. You add the total jets discahrge, and divide by 5 to get the total flywheel hp. Very jolly simple.

See this http://fordsix.com/forum/viewtopic.php?t=8106&start=0&postdays=0&postorder=asc&highlight=

• 285 cc/min or 60 thou nominal, 60 call size jet
  298 cc/min or 60 thou nominal, 61 call size jet
  311 cc/min or 61 thou nominal, 62 call size jet
  325 cc/min or 62 thou nominal, 63 call size jet
  341 cc/min or 64 thou nominal, 64 call size jet
  357 cc/min or 65 thou nominal, 65 call size jet
  374 cc/min or 66 thou nominal, 66 call size jet
  392 cc/min or 68 thou nominal, 67 call size jet
  411 cc/min or 69 thou nominal, 68 call size jet
  429 cc/min or 70 thou nominal, 69 call size jet
  448 cc/min or 73 thou nominal, 70 call size jet
  470 cc/min or 76 thou nominal, 71 call size jet
  492 cc/min or 79 thou nominal, 72 call size jet
  517 cc/min or 79 thou nominal, 73 call size jet
  542 cc/min or 81 thou nominal, 74 call size jet
  566 cc/min or 82 thou nominal, 75 call size jet
  587 cc/min or 84 thou nominal, 76 call size jet
  615 cc/min or 86 thou nominal, 77 call size jet
  645 cc/min or 89 thou nominal, 78 call size jet
  677 cc/min or 91 thou nominal, 79 call size jet
  703 cc/min or 93 thou nominal, 80 call size jet
  731 cc/min or 93 thou nominal, 81 call size jet
  765 cc/min or 93 thou nominal, 82 call size jet
  795 cc/min or 94 thou nominal, 83 call size jet
  824 cc/min or 99 thou nominal, 84 call size jet
  858 cc/min or 100 thou nominal, 85 call size jet
  890 cc/min or 101 thou nominal, 86 call size jet
  923 cc/min or 103 thou nominal, 87 call size jet
  952 cc/min or 104 thou nominal, 88 call size jet
  987 cc/min or 104 thou nominal, 89 call size jet
  1014 cc/min or 104 thou nominal, 90 call size jet
  1080 cc/min or 105 thou nominal, 91 call size jet
  1150 cc/min or 105 thou nominal, 92 call size jet
  1200 cc/min or 105 thou nominal, 93 call size jet
  1260 cc/min or 108 thou nominal, 94 call size jet
  1320 cc/min or 118 thou nominal, 95 call size jet
  1375 cc/min or 118 thou nominal, 96 call size jet
  1440 cc/min or 125 thou nominal, 97 call size jet
  1500 cc/min or 125 thou nominal, 98 call size jet
  1570 cc/min or 125 thou nominal, 99 call size jet
  1640 cc/min or 128 thou nominal, 100 call size jet

The 68 jets are quite conservative, and flow 392 cc/min. Add the total flow of two (784 cc/min), and divide by 5. Thats 156 hp.

If you think you've got 180 hp, multiply by 5, and divide by two to find a likely jet. Thats (180*5)/2 = 450 cc/min. Look for a jet size, and the 70 call size is you man.

Basically, each call size increase gives another 5 hp each per jet, or 10 hp per jet for a two barrels taken together. If everybody know what the engine combo was likely to generate power wise, then there wouldn't any problems with jetting.

Once thats sorted, you can concentrate on the other bits:-

Float level
Idel mixture
Power valve (4.5 for a heavy car or 6.5 for a light one. 5.5 if you can't decide).
Pump jets are okay as they come unless you have problems.
The 23 thou or so PowerValve Channel Restrictions around the power valve body only need changing on really small 200 cube sixes with 350 or 500's)

If there are problems with surging idle, look at changing the PCV valve.

 

[Anonymous]

That explains alot, so really i would have to find out how much hp i've got then, so does that mean a dyno ?? also is there anyway of telling the size of the jets that are already in there

Thanks Joip

 

[xctasy]

Not unless you have a wire gauge which won't score the jet. If you can find the quage sizes of fuse wire or soft copper wire, then you could crank some wires at 90 degrees, drop it down the carb, and measure. Only other way is by dropping the float bowl, and doing a check.

Dyno is the ideal, but people like MustangGeezer and others just try the Holley website, and then make a change to suit there recomendations. You've got to start with a goodfirst guess, and then go up or down in steps to get it running right. Last check is they engine dyno.

 

[MustangSix]

I've been thinking about your jet calculations and they are pretty much right on, give or take a few horses for varying Brake Specific Fuel Consumption figures, but I have a couple of observations.

On most carbs, the main jet only operates within a part throttle cruise scenario. Once the carb is tasked to provide more air, usually the vacuum drops and a power circuit opens to provide more fuel. In addition, on most carbs, the idle circuit never entirely quits passing fuel either.

If you were to block the power valve circuit on a holley, I think your figures would be correct. Of course, the carb would probably pass way more air that the main jets alone could handle.

So while your figures are correct, I think the maximum power figures available from a particular carb have to be based on more than just the main jet numbers. You'd have to look at fuel flow at the other circuits as well. For example, If you think you have 160 hp and used 68 jets, you would be rich becuase the 160 hp figure would be achieved at WOT, low vacuum, with the Power Valve also supplying fuel.

Another thing, it's possible to still miss on the jet sizing if the carb sizing is off. A carb is just a dumb fuel mixer that releases and atomizes fuel in relative proportion to the air passing thru, based mostly on velocity past the venturi. If carb sizing is significnatly off, the fuel delivery may occur on a different curve than expected. You could probably get a 200 cube six to idle with a 1000cfm dominator, but no amount of jetting would get it to run properly past that point. Imagine a 540 Ford V8 running on an Autolite 1100. Same deal. Idle could probably be achieved, but no kind of jetting would keep up with the tornado being sucked thru the carb!

 

[xctasy]

Thanks Jack.

I looked really hard at the 3310 750 cfm Holley 4-bbl when I first started the calculations. It had insufficent flow from the stock rear jets as it came from the factory for even 350 hp. I ran through all listed Holley carb combinations I could find on this forum, then over every one of the 44 Holley modles, with over 120 stock pre 1980 model year jetting combinations. Result was a 95% hit average, using my method. Where it didn't fit well was in situations where a big Holley 2-bbl was placed on a small 4-cyl engine. I'm privy to quite a bit of 350 Holley Holden/Falcon/Valiant data, and found its pretty much on the money. Same with the 500 cfm 2-bbl.

I've looked at the power valve actuation, sometimes enough to equal 8 call numbers up on a set ups with two jets, or a massive 40 hp in some cases.

I will have another look. The pre-qualifiaction for it to work is that there is no less than 1 sq inch or carb area per 255 cubes, and no more than 1 sq in per 38 cubes for a 1, 2 or 4-bbl Holley carb.

I think the best advise ever was that Holley and Weber jet carbs at 1/20 th of the venturi size, and then adjust the line selections of carbs to suit the old cubic inches per square inch of carb rules. In almost all cases, the best jet selection is at that level if the carb is to work properly. When the jet goes less than 1/17 of the venturi area, then the calibration of the carb goes wonky as the carb is abvously being subjected to airflow above the call of duty. This happens in draw-through turbos and big engines with a small carb.

The undercarb / over carb rules I posted elseware are totally emperical. With a 540 cube engine, the smallest carb could have a venturi area of 540 divided by 255, or a 1.640", venturi with a 2" throttle bore. My 200 cube engine has a 1" venturi with at 1.3125" throttle. The biggest carb is set only by a lack of common sense!