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Discussion Starter #1
Hi again:

Chasing my tail on a 700R4 TV Cable set up. The trans was installed by the company that built it, and while it’s been OK, I’ve never been happy with the feel (under slow acceleration the 1-2 was firm and the rest felt soft), or the almost, but not quite WOT.

It’s behind a 455 Buick with a Holley HO carb. After messing with the Lokar universal cable for years, I thought it might be easier to start from scratch. I checked the pressures before taking it apart, and they were all in spec.

I ordered a new factory style TV Cable and Carb Linkage kit from Bowtie Overdrive Transmissions. When I pulled the pan, the fluid wasn’t super ugly, but it wasn’t super red either with some darker areas in the bottom of the pan. Something isn’t right.

So, I changed the TV spring with the one supplied in the kit, installed the lever on the carb, and installed the new cable adjusted for WOT as the instructions call for (push in the detent, let it ratchet to the right spot when moved to WOT).

The issue: I have a ton of space between the TV Lever and the TV Plunger (see pic) at idle. If I adjust the cable to touch at idle, the cable doesn’t have enough pull to get anywhere near WOT.

I must be missing something. Will the plunger move further out with transmission fluid pressure once it’s running (although it looks quite a bit extended already)? Did I install the new TV spring incorrectly? Screw up the linkage/lever somehow?

I am going to get back under the car tomorrow and recheck my work installing the TV spring, but would love to hear thoughts… I’ve searched YouTube and the rest of the web, but have found little other than the lever needs to be in contact with the plunger at idle (naturally).

FWIW, I did find that Sonnax makes a shorter Throttle Valve Link, but I really don’t want to start ordering and throwing parts at something I don’t feel like I fully understand (yet).

TIA!



92445
 

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There are a lot of things that come in the play to making this all work. If things are not in sync and not working together things aren’t happy .
Make sure that the spring you got from Bowtie Overdrives is at least 2.100-2.150 inches in length if it’s not you need to get some shims to space it so it is that long. The moment you touch the throttle the lever that pushes the TV plunger in should be pushing on the tv plunger and raising the pressure immediately. You also may have a bent lever assembly the piece that bolts to the valve body that depresses the TV plunger. By your description of what is in the pan it sounds like there are other things that are not correct and possibly other damage has happened in the transmission.
 

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Its all about combinations. Different motors and rear axle ratios VS carb linkage. Many times I have had to make custom fulcrum point carb linkages to make these work properly and for the most part they work well.


Hutch
 

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Discussion Starter #5
Thank you all - I've come to the conclusion you all did, and the issue is on top (carb linkage). Back to that today...

I measured the new TV spring from Bowtie Overdrives against the one that came in the trans from the builder (CK), and...

BTO: 2.050"
CK: 2.280"

All things being equal like the spring rate, is it true the longer the spring the firmer the shifts? Or, is the stiffness of the spring as important as the length? I can break out my valve spring tester if need be.

Oh, and if there is a good book or reference, feel free to point me in that direction too...

Thanks again.
 

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Spring rate is determined by the combination of wire diameter, number of active coils and installed height.
I have tested many small springs and you would be surprised at how different two identical looking springs can be.
The main thing is not to coil bind the spring under full travel, which is why you have different lengths and different wire diameters. If wire diameter is the same, the spring with the fewer coils would be the stiffer one. Think that the stiffest spring is a straight rod. As you add turns to it it lowers the rate.
 

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After messing with the Lokar universal cable for years, I thought it might be easier to start from scratch.
After years of this, damage is most likely done.


How do you have the TV cable mounted? Post a picture of bracket, carb, cable.
Are you getting WOT on your carb?

The issue: I have a ton of space between the TV Lever and the TV Plunger (see pic) at idle. If I adjust the cable to touch at idle, the cable doesn’t have enough pull to get anywhere near WOT.

With the cable hooked up at idle, that throttle lever should be resting on the TV plunger. That way the moment you push on the gas TV pressure is rising.
If that BTO spring is .230" shorter, you are going in the wrong direction. If the unit came from CK then his spring should be in the unit. Everyone does things differently, but his spring should work with how he built the unit.
 

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Length of the tv usually effects part throttle shift timing more than anything.
That will also require more pull by the geometry in the carb linkage.


Hutch
 

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Discussion Starter #9
Thank you both! So... posting photos of where I am now and the two carburetor leverage arms I have to choose from. The one on the carb came from Bowtie Overdrives along with their cable. I also have the Holley arm.

When I take up the slack in the cable (TV Lever just touching the TV Piston down below) and set the carb to idle, I am at the very end of the cable adjuster – actually past the serrated lines in the cable. I measured the cable while at idle (4.625” from bracket to carb attaching point) and to get to WOT, I am about 1.375” too short in cable length.

I am going to try the Holley Lever next, or do I need a different cable?

Feel like I making progress, maybe. :)

93544




93545




93543


93546
 

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Discussion Starter #10
After years of this, damage is most likely done.

Agree - not in place to pull the trans though... though I am adding a deeper pan with cooling fins, and a bigger stacked plate cooler in place of the average sized tube and fin that was there. Could be a moot point, but will be done for the future...


How do you have the TV cable mounted? Post a picture of bracket, carb, cable.
Are you getting WOT on your carb?

Photos posted above. And nope, was close but no WOT - that's part of what started this...


With the cable hooked up at idle, that throttle lever should be resting on the TV plunger. That way the moment you push on the gas TV pressure is rising.
If that BTO spring is .230" shorter, you are going in the wrong direction. If the unit came from CK then his spring should be in the unit. Everyone does things differently, but his spring should work with how he built the unit.

Thank you, put the CK spring back in...
 

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If memory serves me lol, I thought the BTO spring was longer than what you posted. I know people that swear by the BTO kit you purchased but have not used it myself. I'd call BTO and let them know what you've got and see if they can help you. Make sure the pan is off the trans.

Looking at your last set of pics, the second one specifically, if you were to loosen the allen bolt adjustment on the BTO piece where the cable end attaches and rotate it all the way clockwise looks like it might get you where you need to be? Where is the throttle lever in relation to the TV plunger on pick #2?
 

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Discussion Starter #12 (Edited)
If memory serves me lol, I thought the BTO spring was longer than what you posted. I know people that swear by the BTO kit you purchased but have not used it myself. I'd call BTO and let them know what you've got and see if they can help you. Make sure the pan is off the trans.

Looking at your last set of pics, the second one specifically, if you were to loosen the allen bolt adjustment on the BTO piece where the cable end attaches and rotate it all the way clockwise looks like it might get you where you need to be? Where is the throttle lever in relation to the TV plunger on pick #2?
I had the allen bolt adjtment all over trying... it was never enough.

A call to BTO will happen Monday…

After more trial and error tonight, it looks like I need 1.5” of stroke for my Holley from idle to WOT. And, it appears I only have about an inch of Cable to play with… I do have that gap which I first thought was my issue, between the TV Lever and Plunger: it measures about 0.470” of cable pull before they touch.

Oh, and yes – that’s the length of the BTO spring that came with their cable and bracketry…

Thanks again for the help – if nothing else, at least I know I am not crazy (and that’s not a little thing)!

*Edit: I did come across something from Sonnax Transmissions - a shorter TV Link that fits between the cable and TV Lever, but I haven't been able to find how much shorter it is. That would certainly move things closer in the trans...



93630
 

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For reference and to start with, check the inner cable travel from at rest to WOT. It should be 1.48" travel. There can be times to deviate from this but it is best to start here and see what result you get.

See method here. . .https://d2q1ebiag300ih.cloudfront.net/uploads/part/2766/AS4-04K-IN.pdf?v=1580160025784

Gregg Nader
Sonnax Tech
 

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Discussion Starter #14
For reference and to start with, check the inner cable travel from at rest to WOT. It should be 1.48" travel. There can be times to deviate from this but it is best to start here and see what result you get.

See method here. . .https://d2q1ebiag300ih.cloudfront.net/uploads/part/2766/AS4-04K-IN.pdf?v=1580160025784

Gregg Nader
Sonnax Tech
Thank you, Gregg - I read the Sonnax instructions and came up with the same measurements - about 1" of travel from the time the lever touches the plunger in the trans, to the point I can't pull the cable out any further. Definitely not 1.48"

Not sure if this is a cable issue or a trans issue. I understand that moving the cable stop point at the adjuster makes the cable seem shorter or longer, but the pull should remain the same - just the start and stop points change?
 

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By the look of your first picture, the TV sleeve is installed incorrectly. The outer edge of the sleeve should be visible and the control arm rests on it when the valve is pressed WOT.
 

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Discussion Starter #16
By the look of your first picture, the TV sleeve is installed incorrectly. The outer edge of the sleeve should be visible and the control arm rests on it when the valve is pressed WOT.
hmmmm - don’t doubt it. Thank you. I’ve been looking for photos of how that should be. Heading back to the garage...
 

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Discussion Starter #19
And, success! I have it set so the lever is touching the plunger at idle, and still get full WOT at the carb - what I didn't have before. I put the pressure gauge on it tonight, and once I finish plumbing the new cooler, I'll get the new pan on it and get it off the jack stands... Thank you all.
 

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It's been awhile- I use BTO on a TPI, they made a custom length cable for me and I got their latest generation spring.
 
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