Topic: 289 Carb Linkage

[PraireBronze]

Something seems to be wrong with my carb linkage, and I can't figure out where the problem is.

This is not mine, but it is an accurate representation of what mine looks like, except for the return spring.


Notice the long distance between the throttle return spring bracket and the bend in the throttle rod, and the length of the return spring.

Here is another picture I've been staring at:


Notice how much shorter the distance is between the return spring bracket and the bend in the throttle rod.  It looks to be about an inch shorter.  Also notice how much shorter the return spring is compared to the picture above.  This is the spring that I have and the one that is supposed to be correct.  Now image this short spring in the second picture being stretched to cover the long span in the first picture.  I have the spring installed, but it seems way overstretched.  The catalogs only show one throttle rod for all 289s.

[rockhouse66]

I found that the original on my car is about 1" longer to the first bend than either the repro part or the NOS service part.  The original gives the right throttle "feel" whereas use of the repro/service part gives a soft feel that I don't like.  I am in the process of having my original replated for installation.

[PraireBronze]

A throttle rod that was an inch shorter, which the one in the second picture looks to be, would work fine on a manual transmission car, but I don't see how it would engage the kick down properly on an automatic.  I have no doubt that my throttle rod is original, as I've owned the car since 1979.  So now I'm wondering if auto transmission cars used a different throttle rod than manual transmission cars?  If this is the case, then there is probably a different return spring too.  All speculation on my part. 

I took a picture of what I have.  The throttle rod is original.  The spring and bracket are reproductions.  The spring looks way overstretched to me.

[jwc66k]

The rod length from the arm's bend to the carb to the first bend to the rear is 5 1/2 inches, 12 9/16 inches overall. I measured a couple I have. The spring is Ford service part number C5ZZ-9737-B and is 1 13/16 inches long overall un-sprung, with the coil part 13/16 inches. The bracket looks correct.
Jim

[PraireBronze]

Thanks Jim

My throttle rod is 6 1/2 inches, so it looks like I've had the wrong one all these years.  Overall length is the same.

Having said that, I find it a bit disconcerting that this directly contradicts what rockhouse66 said about his original rod.

I wonder if this is a 65 vs 66 issue?  66 used a different kick down, didn't it?  And thus maybe a different throttle rod?  Just speculating again.

[CharlesTurner]

66 used a different kick down, didn't it?  And thus maybe a different throttle rod?  Just speculating again.

Yes, '66 used a different auto trans kick-down.  Instead of being an add-on piece bolted to the intake, the accelerator linkage at the firewall was modified and a cable setup used.

The '65 and '66 MPC shows C5ZZ-9A702-A on the line for 260/289 2/B carb , 11.67" long from center of ball to rod end
The '65 and '66 MPC shows C5ZZ-9A702-C on the line for 289 4/B carb, but does not give a description or length

The '75 MPC shows C5ZZ-9A702-D for 65-67 260/289, all and 11.56" long

If you notice, there is a '68 small block version that is an inch longer, but carries a C8ZZ part number.

I've attached a snippet from the '75 MPC with all the versions and sizes.

[rockhouse66]

The overall length is the same for the 3 that I have.  The NOS one and the repro are both about 5-1/2" to the first bend.  The one that was on my car is 6-1/2" to the first bend and I believe it to be correct, as it provides more spring tension and a better throttle feel IMO.  If you don't want your 6-1/2" one, I'll take it!  This is the repro one currently on my car while my "original" is out being plated.

[Chris]

Here's the 4v set up from Mannel's book: