914-6 throttle linkage setup/adjustment, Anybody written it up in detail w/ pics? Options

[campbellcj]

I just swapped-out my pedal cluster for a rebuilt one with a reinforced throttle bellcrank thingie, bronze bushings etc. The clutch and throttle cables are essentially brand new too.

The reason I swapped it is because the throttle-thingie was bent to hell on the old one AND the bushings were shot -- this led to me losing almost an entire day at the track due to inconsistent/sticking accelerator issues (i.e. idle was anywhere from 600rpm to 4K, LOL). It appears the PO decided to install a throttle-stop on the pedal board AFTER the throttle arm thingie on the cluster was already bent to shit. (Yes, I DO have a pedal board and throttle stop on the car.)

Anyways...the cluster swapout was no big deal, although DWD did set in a little bit (I found plenty of gook, spare change etc. under there, zinc-sprayed the area, rewired some of the tunnel and dash stuff, etc.)

Now it seems like the throttle is kind of maxed-out, i.e. I "loosened" several things to get more length/slack but it still barely hooks up without putting a preload on the carb linkage. The cable adjuster at the pedal end looked pretty normal; didn't fuss with that. I loosened the cable adjuster at the trans bellcrank essentially all the way to the "slack" direction. I also slightly lengthened the trans bellcrank to carb linkage rod-end.

So now I'm getting full throttle engagement with what seems like not a lot of pedal travel and the pedalboard stop is virtually all the way out. Is my throttle cable too short for some reason? Or do I just need to basically start over and "equalize" everything again...hence the request for any tips or pics of the procedure. There are so many little adjustable things in this linkage that you get a major chain-reaction when you change one of them.

Sorry for the ramble -- I've been working way too much lately and my brain is fried -- hopefully this makes sense somewhat.

[ArtechnikA]

... the request for any tips or pics of the procedure....

i can probably get you photographs if you know what you need - the linkage on my car is all original.

"is it plugged in"-type question - are you sure you have a 914.6 throttle cable ?

another option could be the highly adjustable Rennline throttle pedal - it has a couple of different slots (different lever arm possibilities) into which you can insert the pushrod. pricey but so cool i couldn't resist it ... due to the lack of throttle pedal bushing and the differences in geometry i'm currently dealing with too -much- pedal travel - about half the stroke is used takin up the various slacks... (new pedal bushes on the way ...)

[si2t3m]

Had the same issue after my first DE as that i noticed that i has getting 3/4 butterfly movement with the pedal to the floor (to the throttle stop).

Check the movement at the bellcrank on the tranny. I detached the rod that goes from the bellcrank on the tranny to the bellcrank on the carb manifolds. I asked my wife to get in the car and play with the pedal and i soon noticed that i was going out of travel on the tranny bellcrank. I ajusted my throttle cable from there, to get the proper travel and moved on up. Now if i attached the rod going from the bellcrank on the tranny to the bellcrank on the manifold i had preload on the carbs. I ajusted this rod to get it a little bit longer and ajusted the rod that links the bellcrank on the manifold to the crossbar so i didn't get any preload. Checked the travel again with my wife in the car and everything was fine.

I am getting immediate throttle as soon as i touch the pedal. Now for the last 2 weeks we are getting pretty cold mornings (around 6Celcius) and i noticed that my RPM stays around 1400 at idle while it's at 1000-1100 when I get back in the car afterwork (warmer around 20Celcius). Might be that all the metal parts are contracting at 6 celcius, or that the cold air is changing the mixture. I dunno, i have to get into it.

HTH

Marc-André

[Rusty]

Chris,

This spring I rebuilt my pedal cluster and then installed all new bushings along the entire linkage. All the original bushings were cracked and crumbled.

The PO kept adjusting the linkage tighter to compensate for bad bushings... I put it all together, and it was TIGHT! So, I loosened the throttle cable some, and loosed the rod between the tranny bell-crank and the carb bell crank.

-Rusty (IMG:style_emoticons/default/smoke.gif)

Hey Rich, about that Rennline pedal... is it spring loaded? What the price of admission, compared to a new pedal (which run ~80 bucks, IIRC).

[ArtechnikA]

Hey Rich, about that Rennline pedal... is it spring loaded?  What the price of admission, compared to a new pedal (which run ~80 bucks, IIRC).

RennLine Website

i've got the full pedal set, which means my "set" gas pedal overlay is available... and the aluminum floorboards 'cause the driver's side was in bad shape and the pax was gone ... they're nice products.

yes, the pedal is spring-loaded. - not a lot, but i'd guess it'd take up a bit of slack. $250. you get the "extended heel & toe" bottom part -and- a more conventional "non-winged" part. both the top and bottom are adjustable for extension and tilt. you can adjust the pivot point for the throttle rod along about a 2" range to tweak the speed/sensitivity ratio.

all stainless and high-quality aluminum, very well made. stainless hinge shaft, rides on bronze bushings. the fasteners are US so have a selection of US Allen keys and a 3/8" combination for assembly and adjustment...

is it "worth" an additional $170 - sheesh, i donno. i like it. i needed to do -something- 'cause the hinge connection on the stocker was starting to go... i do like the look and since it's on the inside of the car and not the outside, i don't feel too "ricey" - just "racey" :-) ...

one issue - i have some shoes i used to like for driving - with little rubber nubbies on the sole. they tend to catch in the texture of the pedal and make very fine throttle position adjustments difficult. they'd be great with my smooth-soled Simpson track shoes tho...

[campbellcj]

Thanks guys! I am figuring the main issue is what Rusty mentioned -- everything is basically brand-new and "tight" on the car. It literally has maybe 12 hours on it since the six conversion and only about 6 on the trans. The pedal cluster bushings were SHOT, in fact MISSING on the throttle bellcrank, plus it was bent so there was tons of slop/over-compensated adjustment.

To clarify - I confirmed full throttle range on the carbs. My main concern is that there does not seem to be a lot of pedal travel between closed (idle) and WOT, i.e. I hit WOT on the carbs with the pedalboard stop screwed WAY out, almost all the way.

I do have an aftermarket alum pedal (AJ-USA) AND a PO-fabbed pedalboard, which could certainly be related! It cracks me up that the PO seems to have spent hours and hours creating this pedalboard...which weighs a ton and is just black-painted metal so doesn't even look "sexy". He must've been really bored. (IMG:style_emoticons/default/confused24.gif)

I am "pretty sure" I do have the correct -6 cable; it was installed by the shop during the six conversion. I'm using the factory-style bellcrank and linkage setup, so everything is more-or-less a clone of a factory six.

I'll try to test-drive the car tonite after work...I am probably just overreacting to a non-problem (IMG:style_emoticons/default/rolleyes.gif)

[Rusty]

Chris,

You're not overreacting. I thnk you're right on with your diagnosis of the problem. Some tweaking here and there, and you'll get it.

I'm pretty sure that my linkage is a bit misadjusted - since I never quite reach WOT. On the other hand, I don't race the car, so I have no reason to ever be at WOT. (IMG:style_emoticons/default/rolleyes.gif)

Besides WOT on a 33 year old motor, that hasn't been rebuilt in at least the last 12 years, probably isn't wise.

-Rusty (IMG:style_emoticons/default/smoke.gif)

[seanery]

Chris,

I just got a set of pedals like yours. Any tips on installing them? Gas pedal a straightforward swap?

[campbellcj]

Argh. I think I might have crossed or twisted the throttle cable around the clutch up at the pedal end. It is hanging up a little bit; not really terrible but definitely can't stay like this. That would certainly explain the cable seeming "short". I'll check tomorrow.

There is also a bushing and circlip that fell off or broke on the carb linkage end, where the rod from the trans bellcrank connects at the carb. I should be able to fix that tomorrow too.

Sean -- AJ-USA gas pedal is plug n' play. I think as-shipped it is reversed for the later cars though. You have to "flip" the base around to the other side for our cars. Then it hooks up just like stock. The brake and clutch obviously involve drilling the pedals, which is MUCH easier to do with the cluster out of the car, but not impossible with it in. The pedal material is pretty hard so I used a good bit and a real corded drill instead of a cordless driver/drill.

[Brad Roberts]

Or.. leave it alone and I will do it for you on Saturday night (tech session before the beer begins).


B

[Downunderman]

I went through all this some time ago. I came to the conclusion that it was too much messing around to get all the bell cranks and levers adjusted properly, so I did away with them. I had a new throttle cable made which was about 600mm longer and it by-passes all the bell cranks etc down the back. It comes out of the tunnel, along the bottom of the engine and loops around the back of the axle and into the back of the engine next to the carb. I had to lengthen the lever on the throttle shaft up the front by 10mm to get full throttle. The thing works perfectly.

[ArtechnikA]

... I did away with them. I had a new throttle cable made which was about 600mm longer and it by-passes all the bell cranks etc down the back.... The thing works perfectly.

how did you get the hand throttle actuation to work ?

[Downunderman]

I left it out. I don't miss it or need it in our warm climate.

[si2t3m]

Howard,

If i understand, your cable is bypassing the bellcrank at the tranny end and the rod that goes from this bellcrank to the bellcrank on the manifolds (or even bypass this one and connect on the crossbar?.

I'm guessing that you made a bracket to hold the cable somewhere in the engine?

Any idea how much $$$ for the custom cable?

Got pics???

Marc-André

[Downunderman]

The cable cost about A$70 (abt US$40) and I made a bracket that comes off where the injection pump would mount. I will get some pics tomorrow (Sat) as I'm at the office now.

[si2t3m]

Thanks for the info. I get the picture now.

I'd say that it's a nice & effective way to bypass the 2 bellcranks and the 2 rods.

Actually if i was to do another conversion i'd do something like your setup and it would save 250$ or more for the tranny bellcrank setup.

Marc-André

[john rogers]

When we put the six in my race car we did the same thing. A short piece of 1 x 1 aluminum angle is bolted to the rear top of the engine and the cable goes through it. Works like a champ and the throttle pedal feels about the same as with the stroker four. The more connections there are, the more places can come loose on the track (and it will).

[campbellcj]

Howard, I'd like to check out your custom cable linkage. That sounds cool.

I got mine to a "mostly OK" point just now. The main issue I found was actually the pivot where the rod from the trans connects. The circlip had popped off and the bushing is pretty much shot (i.e. missing) too. The pivot was therefore flopping around all over the place on its shaft. I couldn't find an exact-fit bushing at the local hardware store but I got one that can possibly be modded to fit. I replaced the circlip & washers so the pivot can't move nearly as much on the wrong axis..

It seems like I still need a teeny-weeny bit more cable or rod slack somewhere because it does not snap back down to idle positively/consistently. Sometimes it kind of drifts down or stays at an elevated idle. (Maybe fresh throttle springs would help. Do they wear out over the years?) The linkage does not seem to bind up between the carb idle stops and WOT stops when operated by hand (from the carb end). It easily returns to the idle stops when you manipulate it by hand but only "sometimes" when actually driving. (IMG:style_emoticons/default/confused24.gif)

I got my oil press gauge hooked up finally too. I had hoped to tackle more this week, but work is extremely busy right now. After 13+ hours of work+commuting I am usually too hungry & tired to fart around with the car (IMG:style_emoticons/default/sad.gif)


Car seems checked-out to make it there and back on Saturday. (IMG:style_emoticons/default/boldblue.gif) The drive will be interesting with this ultra-short gearbox (basically full of 3rd gears).

[Brad Roberts]

I had my cable made at Pegasus. I use heim joint ends.. it ran me 100$ with the heim joints. I made a small bracket...



B

[914Timo]

This is my first throttle linkage. The 914-4 cable was too short and the throttle was too sticky. I didnt like it. Then I did 914-6 style linkage and I really like that.