Throttle Cable Upgrade - All The Way To The Pedal?

[zKars]

18 hours ago, Captain Obvious said:

Thanks for the additional info.

Jim, When you get a chance, I'd be interested in some pics of your soldered on ball at the pedal end.

So out of curiosity, has anyone done anything that did NOT start with a Lokar kit?

Here is a couple of pics of the ball socket I just soldered on to a Lokar cable.

 

I have two kinds of M8 ball sockets, one has a external spring, the other internal. Your choice. I might be tempted to use the external spring as it easier to get the ball on the pedal stud, then apply the spring.

Either way, cut the base length down to minimize ball length. I left .375-ish I think.

The apply solder to the bare clean wire end. I use standard electronic resin core solder. I've also used a silver bearing solder. The trick is two parts. First, used a solder flux paste. Second, use a soldering iron, not a flame. The flame creates too much oxidation and the solder will never "take".  Still this step seems tough to get to work all the time. Lots of paste, hot iron, apply solder fast and plentiful and pray to an appropriate deity I suppose.

Now put the ball socket in a vice and use a small flame torch to heat and fill the void with solder. Flame is fine here, the steel soaks this stuff up. 

Now get the tinned cable end, and flame melt the solder in the ball socket, stick the wire in to the bottom. Keep the heat on for a few seconds so the solder in the wire melts.

Remove the heat and hold the wire steady and in the middle until it solidifies. Done!

I have tested this with a vice grip on the ball socket and wire held in the vise and I cannot separate them except if I then pound on the vise grip with a alb hammer. The cable breaks before the cable is pulled out the solder. I have many many miles on mine and other Datsun's 'round here with this setup. About all that can go wrong is if the cable at either end rubs the centre inside lining and gets key seated. Make SURE the cable enters and exits in a straight line. Bend the top of the pedal to ensure alignment if necessary. Some silicon lube of your choice is like a good idea too. 

 

Edited September 7, 2017 by zKars

[Captain Obvious]

Nicely done! Thanks for the pics.

[zKars]

Bit more detail on the firewall solution I make.

I manufacture (actually wrangle up some aluminum round stock on my lathe) a very simple little stepped 1.25 OD ring that fits into either the 7/8" 240 or 1" 280z firewall hole. It is threaded to the 5/16"-24 thread that the Lokar cable fittings use. Then a fender washer and thin jamb nut for the inside to secure it. Put a little  ring of dum dum putty behind the aluminum ring to seal it to the fire wall. Toughest part is getting up with a wrench to tighten that jamb nut. Takes a partner on the outside holding it all in place and a backup 1/2 wrench on the outside nut.

Here is the cable sheath set in the back of Lokar fitting.  I'd cut some/all of that extra thread off to get the whole thing closer to the fire wall.

Seems like something folks might want. Cable with ball socket soldered on, fancy firewall Ring thing, couple of nuts and washers. Let me know if you want one. 

[Patcon]

I'm confused! If I understand correctly the threaded section goes through the firewall with an aluminum section on one side and a fender washer and lock nut on the other side of the firewall. How do you get it installed? I would think the ball socket end would interfere with assembly and disassembly

[zKars]

Ah yes the missing detail. You have to pull the cable out to install this fitting. The "other" end is bare, so you can thread it back through the fitting once you have it installed. 

Once threaded through, the bare end gets set screw-trapped into the Lokar fitting that has another ball socket end (theirs) that gets attached to whatever carb side arm arrangement you have.

Edited September 8, 2017 by zKars

[Patcon]

14 minutes ago, zKars said:

Ah yes the missing detail. You have to pull the cable out to install this fitting. The "other" end is bare, so you can thread it back through the fitting once you have it installed. 

Once threaded through, the bare end gets set screw-trapped into the Lokar fitting that has another ball socket end (theirs) that gets attached to whatever carb side arm arrangement you have.

OK, much better. I knew I had to be missing  something...

[Namerow]

Nice write-up, zKars.  A few additional questions for you:

• For an SU application, what is it that creates the end-of-travel (WOT) stop for the system?  Does the 'commercially-available arm' hit a stop?  Does the pedal hit its stop?  Or do the throttle plates hit their stops? 
• How does this affect the travel distance of the pedal, from rest position (idle) to the point where the system hits its stop?
• Where did you source the M8 ball-sockets and the 'commercially-available arm'?

[zKars]

End of travel = your pedal stop.  Must be set after any throttle adjustment. Must not bend thy throttle blades nor leave HP on the table.

Cable travel is determined by how far the tip of the pedal moves away from the firewall as you press the pedal. This is then converted to rotation at the carb trottle blades by some form of an arm that protrudes from the throttle rod. It is the distance from the center of that rod out along that attached arm that determines how the fixed cable travel is converted to the correct rotation angle. The shorter that arm, the more rotation you get for a given cable length pull. Takes a little trial and error. That is why most of these arms have multiple holes along its length.

And FINALLY someone asks for my secret source of those sweet metal metric ball ends. i hate to reveal my sources but....

https://www.midwestcontrol.com/part.php?id=3261

And while I'm spilling the beans, here...

http://www.speedwaymotors.com/Aluminum-Throttle-Linkage-Arms,1911.html?OriginalQuery=91018400

Edited September 10, 2017 by zKars

[madkaw]

Wow- nice write up. I am currently contemplating this for my TB. I have no return issue or binding for that matter - but it should would clean up the intake and make future intake plenums easier to install . 

[madkaw]

Question- have you attempted this without putting tin on the cable and just filling the ball socket?. I know the solder battery cable  ends are filled with solder and require no tin of the cable and it holds fine

[zKars]

I haven't tried it without tinning the cable end. When i think about it though, I think if you splayed the cable strands a bit or at least roughed them up so that the solder in the ball end can trap the cable well, it might be just fine. Maybe the natural irregularity of the stranded cable is enough too.

I shall conduct a few torture tests today doing nothing to the cable, and with a bit of cable end abuse. Maybe use the silver solder too, as I think it is harder then run of the mill electronics solder. Should be harder to pull out.

Edited September 10, 2017 by zKars

[ramsesosirus]

Good post.  Were any one you having trouble with the pedal returning to "idle" after accelerating?  I have an odd issue of the car continuing to hold a slight accel pedal after acceleration, almost like cruise control.  

It's not bad, but I had to manually lift the accel pedal with my foot before braking to return it to idle.  I cleaned the throttle plate last week but haven't driven it since.  

Does this upgrade give you "more throttle"?