200-4R TV cable

[davepl]

So I've had little luck finding a TV cable adapter for my BBC that works with the linkage the big block trucks have (which is short to clear the intake or everyone I've had uses a manual trans carb or has been cut).

Anyway, just a random question: if the TV cable is set correctly so that it shifts at the right point, can it be wrong? I understand the pivot point may not be linear (might be progressive) but it feels like if it were too 'loose' it'd shift late and too 'tight' it'd shift early, since shift point is determined by TV pull, or it sure seem like it when you've got it wrong, anyway.

Do you think this theory holds? Or could you have it where it shifts at exactly the right RPM and load, but it's actually still wrong and your pressure is wrong and you're going to grenade it?

Thanks!
Dave

[jocko]

Dave, you've probably already seen this stuff, but bowtie overdrives is a good source for all things tv cable-related. http://www.tvmadeez.com/

[davepl]

Originally Posted by jocko

Dave, you've probably already seen this stuff, but bowtie overdrives is a good source for all things tv cable-related. http://www.tvmadeez.com/

Doesn't fit our big block linkage. That's what I found out, and that's what they confirmed to me. Now, it could be my carb is all wrong, but it's numbers-correct. And it's numbers-correct for an automatic (some have said the manual trans trucks had this linkage style since no kickdown was needed).

Their kit needs the Q-jet linkage that extends down more, and can't be used without it.

It makes sense to ME that we'd never have the extended linkage style because you either got a stick or a TH400. TH400 just has electric kickdown, right? No cable?

I can't think of any application for this truck where a kickdown CABLE was used, at least not offhand.

[davepl]

Here's the carb as I got it straight off the truck. Now it's possible the PO cut it, and it sure does look rough for a factory part, but that's where it ends on mine. If anyone can find a big-block auto to take a photo of, which shouldn't be too hard, that'd answer it for me.

Thanks!
Dave

[davischevy]

I am getting ready to take my big block 71, with 700R for its first drive this week, depending on the snow and ice..

I ended up using a small block carb, set up for turbo 350, and using the big block jets. (tagged the original carb and put it on the shelf)

I had to use a 3/4 inch spacer to get the mechanism to clear the intake.

My tranny guy ordered a bracket for the TV hookup to the accelerator bracket. I will try to get some pics and part number for the bracket for you this week.

Larry

[davischevy]

Originally Posted by davepl

Here's the carb as I got it straight off the truck. Now it's possible the PO cut it, and it sure does look rough for a factory part, but that's where it ends on mine. If anyone can find a big-block auto to take a photo of, which shouldn't be too hard, that'd answer it for me.

Thanks!
Dave

That looks like my big block carb. I think you have already figured out, GM cut that bottom part off to clear the intake.

[leadfoot067]

if the cable is too "tight" it will shift late and harder,too "loose" and it will shift early and softer..if you are happy with the RPMS and MPH your shifts are happening,and the shifts arent slipping or feeling mushy...than its all good...if you dont have enough TV pressure,it will be in 3rd gear before you get thru an intersection....the other part of the cable being "right"..is when your cruising at 50 in OD and lockup,does it kick down properly?

[mechanicalman]

Originally Posted by davepl

Doesn't fit our big block linkage. That's what I found out, and that's what they confirmed to me. Now, it could be my carb is all wrong, but it's numbers-correct. And it's numbers-correct for an automatic (some have said the manual trans trucks had this linkage style since no kickdown was needed).

Their kit needs the Q-jet linkage that extends down more, and can't be used without it.

It makes sense to ME that we'd never have the extended linkage style because you either got a stick or a TH400. TH400 just has electric kickdown, right? No cable?

I can't think of any application for this truck where a kickdown CABLE was used, at least not offhand.

T400 did have an electric kick-down and no detent cable, yes. I suppose the big block never came with a T350.

I think you are going to have to go with a different carb or a different primary throttle shaft with the hang down part for the detent cable for a T350. You could just go with the shaft if you want to keep your carb numbers correct. Good time to put in new throttle shaft bushings, but I expect you already did that knowing you. If you don't clear the intake, you will need a spacer. Or maybe you could just do some minor clearance on the new shaft/carb I don't know if it's possible but I'd try before I put on an unsightly spacer.

Do you have a "divorced" choke? That might put the kibosh on a spacer.

Maybe try a small block Quad for an automatic on first to see if it clears.

Maybe you could modify something like this and make it clear the intake on your present carb (I know the geometry is critical).
http://www.summitracing.com/parts/tc...FYOSfgod_wgAFA
Or this.
http://www.jegs.com/i/JEGS-Performan...57301/10002/-1

Also, the 2004R never came behind a 4bbl spread-bore carb, that I know of. The throttle valve spring in the valve-body may not be calibrated for the Quadrajet, it might be calibrated for a 2bbl throttle body.

I know on 700's they offer a different throttle valve spring for the Quadrajets vs the throttle bodies. What happens is the carb you have is still opening the primaries as the secondaries start opening, thus a non-linear throttle progression vs a linear throttle progression on the fuel injected engines.

Maybe your trans builder/supplier already compensated for this, just adding info.

[mechanicalman]

Originally Posted by davepl

So I've had little luck finding a TV cable adapter for my BBC that works with the linkage the big block trucks have (which is short to clear the intake or everyone I've had uses a manual trans carb or has been cut).

Anyway, just a random question: if the TV cable is set correctly so that it shifts at the right point, can it be wrong? I understand the pivot point may not be linear (might be progressive) but it feels like if it were too 'loose' it'd shift late and too 'tight' it'd shift early, since shift point is determined by TV pull, or it sure seem like it when you've got it wrong, anyway.

Do you think this theory holds? Or could you have it where it shifts at exactly the right RPM and load, but it's actually still wrong and your pressure is wrong and you're going to grenade it?

Thanks!
Dave

I don't think you can get it to shift at the exact right RPM and load in all gears and with proper shift feel if your geometry and pressures are wrong.

That being said, you had better try as hard as you can to duplicate factory geometry on the carb linkage.

And as I mentioned in the other response, you may have another calibration issue inside the trans.

Are you saying that right now you have it shifting right with the present set-up?

[68c10airstream]

As a suggestion if it was me i would get a tbi truck and rob the throttle body off of it and duplicate everything, cable angle, pivot location etc. This would require cutting off the linkage from the tbi and attaching it to your carb. About 10 years ago i stumbled on the best article to address this. It had to do with a plumb bob hanging down through the center of the throttle shaft. Your throttle should be 33% open when the center of the stud is down at the 6 oclock position, leaving 66% to be pulled forward till wide open throttle. It also stated that the tv cable didn't pull linearly, very sensitive the first 33%, less sensitive the last 66%. It also stated putting a pressure gauge into the trans body and at curb idle fully warmed up, throttle completely closed, i believe the ideal pressure was about 100 psi. I also believe this was throttle valve pressure. I'm only stating this as it was difficult to find that info before, so take this as a fill in guide until it gets straightened out. I went through all of this when i put a carbed 5.7 /700r4 in my 68 c10 years ago before the ls change. I went to the junkyard and found an 1981 qjet 700r4 combo and robbed the throttle shaft out of it and put that into my 70's vintage qjet. I remember the final frustration was the cable attachment bracket. Cable was perfectly horizontal and trans didn't shift right. It worked correctly when i robbed a tbi truck bracket, as the cable was slopped uphill. Easier to find 90's parts in the rusty north than trying to find 70's parts. Good luck Brian F.

[mechanicalman]

Originally Posted by 68c10airstream

As a suggestion if it was me i would get a tbi truck and rob the throttle body off of it and duplicate everything, cable angle, pivot location etc. This would require cutting off the linkage from the tbi and attaching it to your carb. About 10 years ago i stumbled on the best article to address this. It had to do with a plumb bob hanging down through the center of the throttle shaft. Your throttle should be 33% open when the center of the stud is down at the 6 oclock position, leaving 66% to be pulled forward till wide open throttle. It also stated that the tv cable didn't pull linearly, very sensitive the first 33%, less sensitive the last 66%. It also stated putting a pressure gauge into the trans body and at curb idle fully warmed up, throttle completely closed, i believe the ideal pressure was about 100 psi. I also believe this was throttle valve pressure. I'm only stating this as it was difficult to find that info before, so take this as a fill in guide until it gets straightened out. I went through all of this when i put a carbed 5.7 /700r4 in my 68 c10 years ago before the ls change. I went to the junkyard and found an 1981 qjet 700r4 combo and robbed the throttle shaft out of it and put that into my 70's vintage qjet. I remember the final frustration was the cable attachment bracket. Cable was perfectly horizontal and trans didn't shift right. It worked correctly when i robbed a tbi truck bracket, as the cable was slopped uphill. Easier to find 90's parts in the rusty north than trying to find 70's parts. Good luck Brian F.

I only recently started posting on the engine and drivetrain area. I see I was missing out on some very informative posts.

[mechanicalman]

Originally Posted by 68c10airstream

As a suggestion if it was me i would get a tbi truck and rob the throttle body off of it and duplicate everything, cable angle, pivot location etc. This would require cutting off the linkage from the tbi and attaching it to your carb. About 10 years ago i stumbled on the best article to address this. It had to do with a plumb bob hanging down through the center of the throttle shaft. Your throttle should be 33% open when the center of the stud is down at the 6 oclock position, leaving 66% to be pulled forward till wide open throttle. It also stated that the tv cable didn't pull linearly, very sensitive the first 33%, less sensitive the last 66%. It also stated putting a pressure gauge into the trans body and at curb idle fully warmed up, throttle completely closed, i believe the ideal pressure was about 100 psi. I also believe this was throttle valve pressure. I'm only stating this as it was difficult to find that info before, so take this as a fill in guide until it gets straightened out. I went through all of this when i put a carbed 5.7 /700r4 in my 68 c10 years ago before the ls change. I went to the junkyard and found an 1981 qjet 700r4 combo and robbed the throttle shaft out of it and put that into my 70's vintage qjet. I remember the final frustration was the cable attachment bracket. Cable was perfectly horizontal and trans didn't shift right. It worked correctly when i robbed a tbi truck bracket, as the cable was slopped uphill. Easier to find 90's parts in the rusty north than trying to find 70's parts. Good luck Brian F.

Question: When you robbed the throttle shaft out of the newer quadrajet, did you take the cable bracket off the same engine as well?

Is that the one that did not work out for you?

Did the 700R4 that you used come out of a car with a Quadrajet or a 2bbl?

If it was a 2bbl or a TBI transmission, did you change the spring on the throttle valve to the proper one for a Quadrajet?

All the 700 swaps I have done were from T350's. They all had Quadrajets, and we simply put the 700 TV cables on the 350 cable brackets. The transmissions we used were off either TBI or TPI, so we put the GM recommended springs in the throttle valve in the trans to match the Quadrajets. One was a TBI trans into a TPI car, we did not change the spring in that one. They all worked like a charm.

I just don't know if you can get that spring for a 200.

[68c10airstream]

Originally Posted by mechanicalman

Question: When you robbed the throttle shaft out of the newer quadrajet, did you take the cable bracket off the same engine as well?

Is that the one that did not work out for you?

Did the 700R4 that you used come out of a car with a Quadrajet or a 2bbl?

If it was a 2bbl or a TBI transmission, did you change the spring on the throttle valve to the proper one for a Quadrajet?

All the 700 swaps I have done were from T350's. They all had Quadrajets, and we simply put the 700 TV cables on the 350 cable brackets. The transmissions we used were off either TBI or TPI, so we put the GM recommended springs in the throttle valve in the trans to match the Quadrajets. One was a TBI trans into a TPI car, we did not change the spring in that one. They all worked like a charm.

I just don't know if you can get that spring for a 200.

the bracket was gone from the 1981 donor. My truck was a 283 powerglide originaly, so it didn't have any bracket. I mocked something up and tried but just wasn't right. My 700r4 came from i think 89 van v6. I worked next to a trans repairman so he told me to find a newer one with the auxiliary valve body on the side ( a bulge outwards) He went through it and put a shift kit in it. We parted ways shortly after and once i installed it i did the corvette servo, different springs in the governor but it wasn't right till i went on the prowl for a tv cable bracket. Thats about the time when i found the article and then i sourced the cable bracket from a tbi truck. I knew that the tv cable set up was touchy so my approach was duplicate what the factory did. Bowtie overdrives i believe has the right approach with their install kits. I worked at a gmc dealer and i attended a gm electronics class (set#2= specialized electronics training level 2) and we got into the nitty gritty about oversize tall tires burning up 700r4's because of the late lazy slide by shifts. I got into a pissing match with a local tire dealer that put on extreamly oversize tall tires on a shortbox std. cab v6 (4.3 1989). We put a replacement trans in under warranty and the wife came in complaining that the truck was a dog, before and after the trans was replaced. Between the door jamb sticker (tire placard info) and the original spare tire underneath it i took a tape measure around the spare and i think it was 97" and the tire dealer put on a tire that was 110". I got involved and debated with the tire dealer, something to the effect of going from a 245/65 to a 265/75 was a major change, he said it was only 2 sizes change. I informed the woman that until the tires were changed you will burn up trans's and be soggy on take off. About 6 months went by, i was paged to the service counter to meet a customer. She said come outside with me, i have something i want to go over with you. (first thought i was in trouble) Anyway she stood next to her pickup and said "do you remember me"?? I paused for a second and then it hit me. I looked at the truck and she went so far as to exactly match the spare, right down to the brand. I asked "how does the truck work"?? She said as you probably know we are the original owner of this truck. I threatened the tire dealer with a law suit, he sourced the EXACT tires, and i want to thank you for giving me the info i needed. The truck works as new the day we bought it. You remember the really good days and the really bad days and the rest of it sort of becomes a blur. If i ever get alzhiemers i'm screwed.

[68c10airstream]

Mechanicalman, your tv spring question i now remember was addressed in the rebuild as i think it was a spring inside a plunger mod maybe? I remember getting my wife to slowly step on the gas pedal as i went over the tv plunger travel inside the trans. Mad that i couldn't get it right i found the info, installed the bracket and travel was correct.

[mechanicalman]

Originally Posted by 68c10airstream

Mechanicalman, your tv spring question i now remember was addressed in the rebuild as i think it was a spring inside a plunger mod maybe? I remember getting my wife to slowly step on the gas pedal as i went over the tv plunger travel inside the trans. Mad that i couldn't get it right i found the info, installed the bracket and travel was correct.

Regardless of how you got from A to B, that was a good piece of engineering/geometry to get that right. Kudos.

[WIDESIDE72]

Originally Posted by mechanicalman

Also, the 2004R never came behind a 4bbl spread-bore carb, that I know of.

I have seen more cars with 200 4 r trans and 4 barrel carbs that 2 barrel. Monte Carlo (SS and non SS with 305 engine) olds cutlass with 307 ( i dont think ive ever seen a 307 2 barrel) my mom had an 83 olds 88 with a 307 4 barrel and 200 4r, neighbors mom had and 84 olds 98 with same engine and trans.

[mechanicalman]

Originally Posted by WIDESIDE72

I have seen more cars with 200 4 r trans and 4 barrel carbs that 2 barrel. Monte Carlo (SS and non SS with 305 engine) olds cutlass with 307 ( i dont think ive ever seen a 307 2 barrel) my mom had an 83 olds 88 with a 307 4 barrel and 200 4r, neighbors mom had and 84 olds 98 with same engine and trans.

Well that would be a good source for a bracket and reference for the proper throttle valve spring for the quad.

Really, that would have been a good lead in for you to help with people needing assistance with this like the OP.

Thanks for the info, now I've used it for my lead in.

BTW, all the throttle body fuel injected 2004Rs were 2 bbl. I worked at Cadillac from 83-89 so I was not tuned into the carb ones.

We both learned something here it's a win-win.