Thread: Throttle cable dilemma

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I was going to cut and fit up my throttle cable yesterday - and might have a problem. The engine in my car has a significant set back for a couple of reasons - first of all, TCI installed the motor mounts an inch further back then they should have been. Great radiator clearance and almost makes me want to run a mechanical fan rather then the electric, but since it's already there........ The other problem is that Brookville supplied a 3" recessed fire wall instead of the ordered 5" . The lower half was modified to fit around the engine and bell housing, but I left the upper half at 3" to have room for my a/c and heater assembly.

The above brings me to my problem - there is only 5" between the Lokar throttle cable bracket and the firewall - which in my opinion is not enough room for some motor movement slack - Lokar recommends 2", and I could say that they recommend too much, that 1" would work in a normal situation. I wont have any slack with the firewall and bracket ferrules with only about 3" total flex cable shown. My fix would be a solid mechanical link, using rod ends and a piece of rod.

Any comment on this idea?? Should I consider 3/16" or just do the 1/4" and make sure I have enough "beef"??

I make my own with 1/4" stainless rod threaded 1/4-28.
A couple of female Heim joints and stainless nuts will do it.

You can get Heim joints at lots of places, but some of the best are at your Local Bearing House.

$7. each last time I bought some about 2 years back.

The stainless rod buffs up easily and so do the aluminum Heims although I don't usually polish them.
Some of my pals do and as long as you clean the bufing abrasive out of them, no probs.

Only other thing you'll need is a heat blocking device where the rod exits the firewall.
The 32.


Some pics of the 31s dual quad setup
Note that the throttle rod rises and falls vertically during operation.
You have to account for that when you cut the hole in the firewall.






4" firewall recess fwiw.

After I posted I started to look at the McMaster Carr on-line catalog and have just about come up with the same idea though was looking for some internally threaded tubing and male Heim instead, but will probably settle on what you did. Those Lokar cables are nice, but in my case as well as yours, wont work so it's back to the tried and proven.

What did you use for that insulation material? I think I have some .125 sheet Buna-N that might work.

After I posted I started to look at the McMaster Carr on-line catalog and have just about come up with the same idea though was looking for some internally threaded tubing and male Heim instead, but will probably settle on what you did. Those Lokar cables are nice, but in my case as well as yours, wont work so it's back to the tried and proven.

What did you use for that insulation material? I think I have some .125 sheet Buna-N that might work.

The one on my T is a Lokar and luckily I had enough room for a nice curve in it, but when we installed the Lokar one on my Son's T he has 2 fours, so the rear carb is pretty much right at the firewall. It created a steep bend in the cable. We couldn't figure out another way to do it, so we went with it bent that way, and it actually seems to work pretty well.

I don't know how it will accelerate the wear inside the cable being bent that much, but I just wanted to let you know they will work on weird angles. I don't have any pictures showing the one in Don's T, but here is one of my T. As you can see, mine is only about 7 inches long and now that I look at it, the bend is fairly severe.

Don

Don,
Thanks.
I only wish I had 7" of space - I just remeasured mine and have a hair under 4" allowing for the ferrules. I had no clue it was this close until yesterday when I took a break from wiring to set this throttle cable up. I've spent some time in the McMaster-Carr catalog and ordered some SS Heims and some SS rod. Guess I'll need to sell the cable now to pay for this new expenditure It should show up in the for sale threads in a few days

This is what I ended up with along with a chunk of 309 SS rod. The rod ends are not SS though but "A PTFE-lubricated, carbon-fiber-reinforced plastic race provides wear resistance and doesn't require lubrication. Rod ends are three-piece and have a zinc-plated steel housing and ball". These have almost twice the load capacity of the SS versions. I suspect that a bit of 0000 steel wool will polish them just fine then a coat of clear will keep 'em shiny. UPS will deliver today!!!!

Now that you've spent the money and are standing guard at the mailbox, there's another way out.

Which . . . still makes use of the Heims and rod.


Set up a bracket with bell crank or a simple swinging arm near the front of the engine (or at least in front of the carb throttle arm), run the throttle cable to it.

Run a short rod with Heims back to the carburetor.

That way, the firewall seal is easy and you have a smooth, long turn to the bellcrank/arm.

Originally Posted by C9x

Which . . . still makes use of the Heims and rod.


Set up a bracket with bell crank or a simple swinging arm near the front of the engine (or at least in front of the carb throttle arm), run the throttle cable to it.

That way, the firewall seal is easy and you have a smooth, long turn to the bellcrank/arm.

Too much complication ....and there really are no spare manifold bosses with tapped hole left ahead of the carb. What I will be doing is making up something like your "weather guard' using a couple of.25 thick X 2" dia. aluminum round stock, a piece of .125 neoprene outside and possibly another inside. The rise and fall will probably be minimal (need to 'calculate it' ) so vertical splits in the neoprene should do me

I failed to explain it earlier, but the throttle rod heat guard/pass through has a Teflon floater within that follows the vertical travels of the throttle rod.

The one on the 32 is about 10 years old and the original hole in the Teflon floater was drilled 1/4".
The 1/4" rod fit the 1/4" hole with a bit of friction, but not much.
A few months later it was very free and hasn't shown any further wear.

Well, made up a nice piece of throttle linkage - but used 3/16 (10-32 instead of the 1/4") as my Edelbrock carb is set up for that size. Now I have a spare pair of 1/4" Heims - but no big deal, they'll get used eventually somewhere.

I measured well and drilled a 3/8 - 7/16 hole. Every thing lines up nicely - that is except the fact that my throttle pedal has major bushing slop - like ~1/2 at the linkage bolt hole/tip. I don't recall what brand it is, but it isn't a cheapy. I could easily fix it if I had a lathe or a mill, but since I don't have either, I need some recommendations for another brand of pedal that is well made. Obviously the Lokar and Billet Specialties are the prime pieces - but at $100 or so bucks, makes me want to pursue other choices first. Any suggestions ????

My 32's Gennie Shifter throttle pedal has very little play.
Even now, 14 years and 48,000 miles later.

I guess I've narrowed it down - either the Gennie or the Speedway Mr Roadster version. I used a TCI on my last car, but it appears that they no longer offer them. That, too, was a nice solid pedal.

C9 - a "help me" question - what is the approximate firewall bracket bolt centerline dim and secondly, the arm centerline dims from the pivot to the linkage hole. Since I already have firewall holes, want to know if I need to make up some brackets as well.

As always, thanks

Irelands Child, before you buy a new pedal setup, check your PM's.. I think I can help you out easily.

The spacing between the two mounting bolts?

And the length of the upper arm and lower pedal arm end?