Setting up the throttle/trans linkages on my Hilborn EFI setup. I need to know the angle of the trans control lever at the carb (for carb setups the cable is horizontal as it goes to the carb making it easier to measure) when at idle. I know it angles back some, but need a good measurement of the angle between the throttle shaft (rotation point) and the trans linkage connection.

Thanks - Greg

 

Not sure I have an angle for you but the T.V. cable needs a total of 1 1/8" of movement to accurately operate the trans PSI. I put a 200-R4 in a '70 Cutlass Conv a few years ago that didn't have the correct spacing from the center line of the throttle shaft for the T.V. adjustment. Laid it out so when at full throttle the pin for the T.V. only moved 1 1/8".

 

I have (from earlier info) that the working radius of the TV arm is 1.25". That will give 1.96" of cable pull for 90* of throttle blade movement. I'll re-check the info I had, but your throw would require a 0.716" arm radius.

-Greg

 

http://purplesagetradingpost.com/sum...o/700R4p1.html Though not really technical, this site does have similar info with some of the illustrations that are copied from other sites. Along with one showing the pin layout for the T.V. cable. Somewhere I have this same info from one of the Hiperf Trans companies, but this may help for now.

 

This diagram was created by redwingvette.
Let us know what your final measurements are for future reference.

 

Thanks. The geometry picture is just what I need.

-Greg

 

Is this for just the throttle cable?

 

Interesting. The two sets of figures differ, and the 1.25" radius I had from earlier is exactly in the middle. I'll probably give that radius a try first since that is what the throttle shaft arm I have is, and see if it meets the travel reqmts at the trans.

 

Are using the stock Accel Pedal? Or a Pro-style with your tubbed ride? I don't believe the above diagram will be as usefull if you aren't using the stock pedal.

 

The pedal and throttle linkage shouldn't matter, as the throttle shaft must still turn 90* from closed to full open (minus the small initial angle when the butterflies are closed).

-Greg

 

Ok, now I'm really confused. I've been looking over the chart above and I have no idea how with a 1.37 radius, he gets 1.610" distance across. Laying it out in AutoCad I get 1.572" @ 70° with an Arc length of 1.6738".

At R1.25" I do calc your 1.9635 of Arc Length with a distance across of 1.768". Not sure how you figured the .716" arm radius.

"Pedal vs Linkage" shouldn't matter? If your "Loud" pedal is going to open to WOT they better be "matched". There's a "rod" ratio for the Pedal and one for the Throttle arm on the shaft. Adjust the engine side after you get the comfort fit inside @ your foot.

Ithought, based on your original post, that you were looking for the ratio for the 200R-4 T.V. cable to match up to your Vette's stock linkage. But now if your talking about Hilborn's "bank-to-bank" linkage that's different. Doesn't your EFT have but one shaft vs the dual shaft on a typical Hilborn?

Regardless, if you pull that T.V. cable out more than 1 1/8" your asking for trouble. First time is the only chance you get, then the PSI spikes and burns up the trans.

Good Luck,

I'm out.

 

That drawing had a few errors in it. I replaced it some time back: Trans install
I came up with the 1.610 from the idle position to the full throttle position needed for the valve travel. Creating a right triangle I calculated the distance of the side C being half of that (.805). The Angle C should be half of the 70* I got by measureing the travel of the throttle plate from idle to full open. The 1.37 came from using my calculater as being side b. That gave me the radius that would give me the correct amount of travel to reach the 1.610 needed. The angle of the TV cable is created by the plane of Side c. If my math is wrong then I am sorry but it got me close enough to do what worked for me.

 

redwingvette,
This is just one of those cool puzzles to prove we know things. Or at least can fake it. Similar to the mutiple ways to get that Speedometer to work no matter what gear or tire we throw at it. Just one question, is the 1.610 for the "cable ball throw"? Because the T.V. arc is much less than the throttle.

Would you do us a favor and measure from the center of the throttle shaft to the center of the T.V. pin. With your angle measurement I think I calc'd about .910" C/C earlier today. Maybe you could also measure the throttle cable pin to the throttle shaft center. And then what is the measured stroke of the pins. This would be measured with a ruler, (etc) parallel to the throttle lever, and measure the amount each pin moves (C/C) as they move to WOT from idle. I'd measure it myself but I sold the Cutlass Conv. with the 200R-4 to a friend and it's not close by.

TCI and a few others have been selling a carb bracket that works pretty good for most applications. I still couldn't use one though, figures!

During the drive home tonight I was thinking that the arc travel length is not important. Because if your using a ball mount for the cable it's going to travel in almost a straight line. But if your using a lever similar to a new O.E.throttle body, they use a curved holder and then the arc traveled would be more critical.

Sorry rambling,
Thanks.

 

From C/L of throttle plate shaft to the C/L of the throttle cable attachment is 1.315".
From C/L of throttle plate shaft to the C/L of the TV cable attachment ball is 1.360" (the 0.010" difference here is because of the slot that I made to allow some adjustment).
The travel of the Throttle ball is about 1.150".
The travel of the TV cable is about 1.550" (the 0.060" difference suggest that I am a little heavy on the idle position, which is safer then being light. This is also seen as a slight increase in pressure when the TV cable is attached to the linkage of about 2psi. This condition guarantees instant pressure increase the second the throttle moves with no lag).

 

Thanks for getting that so quick. Here's a link from TCI about T.V.. cable adjustments. Not sure why your measured lengths are longer, but hey it works! Interesting that they're Q-Jet bracket looks the same as GM's only plate different.
http://www.tciauto.com/instructions/...ble_adjust.htm

Later

 

Not sure on how the math works out but their are calling for a 78* arc. That would cause an increase in travel over my 70* arc. That would mean a shoter distance from the C/L odf the throttle plate to the C/L of the TV cable. Keep in mind that any adjustment in the idle screw changes the amount of the travel arc. My engine runs best where I have mine adjusted to 800rpm's at idle. If it ran better at 600rpm's my travel arc would be longer. Maybe closer to the 78* they callout. Also, the spring in the trans valve can a count for slight differences in the pressure circut so some adjustment room is needed for your setup. Unlike a engine with fuel injection computer control systems that adjust for the differences.