280z Throttle Linkage

[ckurtz2]

Hey guys,

      Decided to work on some of the smaller projects to make my car drive better. My gas pedal has 1/2 to 3/4 inch of slop in it before it actually starts opening the throttle butterfly valve. I have narrowed it down to two things. First is this circular joint nearest the firewall. It seems like whatever bushing used to be there has completely seperated and now the rod can just freefloat inside with tons of slop. In the photo I am referring to the big circular joint that the main rod rides in. Is there a replacement, and if so how do you do it?

 

Second is where the rod attaches to a secondary rod (don't know their names) with a spring, washer, and cotter pin. Does this look right? I kinda feel like this looks like a hack job. This is the primary reason for the slop. The rod with the "hook" seems to freely move inside of the hole it sits in without putting pressure on the rod it is attached to. Any advice for fixes? I was thinking washers to space it out, a bushing of some sort, or a much stronger spring. 

 

Finally I guess that rubber boot for the throttle rod at the firewall is important. Mine doesn't have one so I will replace that.

Let me know your advice, as always thank you!

[Captain Obvious]

There is a plastic bushing in the linkage piece mounted to the firewall that started sloppy from the factory and has only gotten worse over the years. It is not replacable as there is a metal joint swaged into place that prevents disassembly. Many moons ago, I rebuilt one, spending a completely unprofitable amount of time milling the swaged metal off so I could take it apart, making a new bushing, and threading the previously swaged joint for reassembly. Turned out great, but I would loathe doing it again.

As for the spring and washer joint at the end of the hook... It looks stock to me. Maybe a missing washer between the spring and the linkage? But no... That system was not dreamed up by your PO. Nissan did that.  

[ckurtz2]

27 minutes ago, Captain Obvious said:

 Many moons ago, I rebuilt one, spending a completely unprofitable amount of time milling the swaged metal off so I could take it apart, making a new bushing, and threading the previously swaged joint for reassembly. Turned out great, but I would loathe doing it again.

What's your price to do it again, I would be genuinely curious🙃

Anyways, Nissan sucks for making it "unservicable" but so goes it. Sounds like I will be loading up that linkage rod with washers to make it a snugger fit. I am trying to learn how to heel toe, and the slop in the pedal makes it impossible to even start learning:(

[ckurtz2]

Here is a video of the slop. 

 

[Captain Obvious]

10 hours ago, ckurtz2 said:

Here is a video of the slop. 

I've seen much worse. Doesn't make your heel/toe learning any easier, but that looks pretty much normal.  

[crayZlair]

I agree with the Captain. Also, the linkage has to be somewhat flexible to allow for the movement (think rubber motor mounts) between the engine and the rest of the body.

[ckurtz2]

Well last push to see if you guys have any other tips to fix the slop. I was able to tighten the connection at the two rods with washers. However, I noticed that there is play at the two ball sockets where the actual throttle vane connects to the throttle rail. Is there anyway to remove play here. Of course I provided a video to make things easy. 🙂

 

 

[Zed Head]

On 3/14/2023 at 6:42 PM, ckurtz2 said:

My gas pedal has 1/2 to 3/4 inch of slop in it before it actually starts opening the throttle butterfly valve

My memory is that you could take up the slop with your foot on the pedal in the cabin, without moving the throttle blade.  It's not clear what you're actually moving in the 1/2 to 3/4.  Or why the pedal would come back up that 1/2 to 3/4.  Are you taking your foot completely off of the pedal?

Can you describe the actual driving effects?  What you feel your foot doing and why you think that there is slop?  My linkage was adjusted in a way that put the bellcrank over-center at rest.  So it was hard to control at low throttle opening.  But as far as all of the parts along the way to the actual throttle body, all slop could be removed with slight pressure on the pedal.  Riding the throttle pedal is not the same as riding the brake pedal.

[Captain Obvious]

11 hours ago, ckurtz2 said:

Well last push to see if you guys have any other tips to fix the slop.

Looking at the video, it appears that the plastic ball socket up at your throttle body is cracked and a chunk is missing. That may account for some amount of play beyond what is considered "normal", but honestly I think it's just the nature of the beast.

There are something like seven mechanical joints in the system and each one of them is a contributor to the total play. Add to that years of use and wear, and you have the pedal uncertainty principle. If you want to get rid of all of the play, the only real option is completely bailing on the original linkage and changing over to a custom cable system. That's what I did.

[Yarb]

Datsun Spirit has a kit with the cable and adapter plate sold separately. I bought the kit to put on my triple OER carbs from Japan. Might want to reach out to them and see if the kit will work for you’re application.

[crayZlair]

My autocross car has triple TWM/Borla throttle bodies. Tried to make the OEM style linkage work, but gave up and went with a silicone jacketed cable that I got from Pegasus Racing.

[ckurtz2]

Whoops, forgot to post my solution. The mechanical linkages all have a threaded portion at the ball socket in order to legthen or shorten the rods. Thus, I tightened these and no more slop at the pedal:) One day I will probs switch to a cable, but this fix postpones that for at least a few years!