1982 Porsche 924 TrackBuild, Should it Stay or Should It Go?

Thanks for explaining, all makes perfect sense now.
James

In a distraction from the suspension stuff, which is a bit stalled until I finalise the designs and place an order for the laser cut bits, I made a brake pedal:



I've been trying to decide how to do the pedals for a while, as I want dual master cylinders and don't want the factory RHD system with the master cylinder on the passenger side.

Normally the easy answer is a floor mounted pedal-box but due to the shape of the foot-well I'd need to move the seat back a bit, which I don't want to do. After a bit of measuring, scribbling and drawing round stuff I've come up with a plan:



Essentially, I'll try and wedge a pair of cylinders on the bulkhead in the limited space above the wheel-tub. This does mean the cylinders will have to point up a bit so the push-rod aims low enough to keep the pedals pivot in the cabin. It also points the push-rods right through the mounting of the original pedal-box, so I'll be needing to make up a new one. I need to get some master cylinders on order but in the mean time I butchered a pedal from a partially finished pedal-box I made a while ago, extending it and moving the pivots. I still need to weld the pivot tube onto it. I'll use the matching clutch and accelerator pedals to make up a new box that'll sit where the factory one did.

Looking good! How do you find that lathe? Been looking at them for a while but always put off that they look like they might have loads of float or wear quickly? Cheers

Yesterday I popped out and finished off the brake pedal, knocked up a matching clutch pedal and made a start on butchering the pedalbox to suit the new brake set-up.

One pair of bushes and one pivot tube ready to be welded up:



The original clutch pedal would have worked just fine as I'm keeping the factory clutch set-up, but it wouldn't have matched the brake pedal, so clearly it had to go under the knife. In a rare case of sense, I did decide to use what the factory made for the top half as it'll work just fine.



Knowing what needed to be mounted into it, I could then made a start on butchering the pedal box to fit the new brake pedal, while retaining the clutch pedals pivot. I forgot to get any before pictures but it's a simple enough thing. Essentially just a plate bolted to the underside of the scuttle with 3 sides folded down and a couple of pins sticking out of the down turns for the pedals. The brake pivot was in about the right place, but only in single shear. It originally supported just one end of the long tube that transferred your jab at the pedal over to the passenger side where the servo and master cylinder lived. Without that long tube supporting things it's design wasn't nearly man enough, so, as usual, it's time to remake things.

A little chopping and welding later and I've got this:



That's the clutch pedal mounted and the first side of the brake pedal mount welded on. I'll need to add another mount for the other side of the brake pedal and make up some form of mountings to the shell, as some of them were in the way of the new cylinders push-rod's path so had to go.

That gives me something like this:



The pedals look like they're not inline but they're not in their at-rest positions, and as the pivots don't match (one's pushing, ones pulling and space is tight) they can only match at one point, like this:



The next decision is the throttle pedal. Obviously it has to match the other two pedals, so the factory one won't do. However I'm not sure whether to keep a factory style bottom pivoting pedal, or hang a top mounted one from the pedal box along side these two.

although, hinging the same way as your feet do, does make sense

Thanks for the feedback guys. I'm not really sure what conclusion to make from it though, so I've just gone with 'I like it when things match'.

I popped out to the unit the other day to be greeted with an unpleasant surprise:



Yep, my bare shell had leaked smelly oil all over the floor.

Ahh.. That's right, I fitted the gearbox, torque tube and an old block & sump to take some measurements for the front subframe design. Ohh, and gearboxes have oil in them, and they have breathers on top of them, and I left the car completely upside down. Well.... Cock.





For now I'm going to choose to ignore this and carry on with the pedalbox.

Adding some width:







To make sure I got the throttle pedal in line with the others I tacked an old off-cut to all 3 foot-pads (is that a real name? it sounds like one), then cut the pivot end off the old throttle pedal I started out with:



I measured a few cars around the unit to see what their pedal throw and throttle cable movement was then picked a pivot point that should give me enough adjustment to work with pretty much anything I fancy connecting it to:





You may notice I'd also added the other half of the brake pedal pivot before this point.

At this point I basically forgot I had a camera and just cracked on with the throttle pedal and its mount, so now I have this:





I need to turn up a bush for the throttle pedal and then I'll be onto mounting the master cylinders.

Also, in shiny new stuff news



Some very nice new suspension turned up from Gaz (a week and a half sooner than expected!). They look ideal, and are another great step towards the car rolling. Now I've measured them up properly they'll be getting boxed back up and put to one side for a while until I'm at that stage.

Thanks for the tip James. I may well give that a go.

Work's been crazy so no physical progress, but this did just happen



Spotting a well priced M62 on eBay finally got me to do the sums to confirm my suspicion that an M45 was a bit small, so all being well I'll have that M62 soon and can start thinking about the engines layout, bracketry and pipe-work.

Well, life went a bit crazy with moving house and a big project due at work, so the 924's been neglected a little.

I have managed to get a couple of evenings to finish swiss-cheese-ing the clutch pedal and begin getting the pedal box integrated into the shell.

One drilled pedal, the slightly uneven spacing of the holes bugs me a bit, but it started with some holes already so I couldn't space then out quite right:



Then I knocked this little lot up:





The outer piece will be welded into the bulkhead in front of the pedal box like so:



Then the inner piece will be welded to the pedal box its self with studs in it. This will keep the pedal box removable but also keep the master cylinder bolted directly to it, to keep the force-path clean and minimise flex.

This project hasn't quite died as the lack of posting might suggest, I've just had a pretty busy summer and I'm still trying to get to grips with the whole work/hobbies balance with the new(ish) job. It's amazing what an impact loosing a little over an hour from your evenings can have.

In the few occasions I've squeezed in some work, the master cylinder mounting plate's been fully welded into the bulkhead and I've been working on generally cleaning up and zinc priming any final grotty areas to get it closer to paint. I've removed the heater box and the last few bits of sound deadening from the bulkhead too. Before I actually throw any colour at it I need to make and weld in mounts for a hydraulic handbrake, gussets for the rear shocks upper mounts, brackets for a front strut brace and add back in a 4th pedal style footrest. I'm sure I'll come up with a few other items as well as countless new holes to drill and old holes to weld up, so I'm swaying towards doing a dry build getting everything in place and working before dismantling it all for paint. The risk comes if/when I decide I'm bored of not driving it and don't want to take it back apart!

Anyway, here's how the engine bay's looking half cleaned up, you can see the master-cylinder mounts in place too:



And a terrible shot of the interior:



I'm off to spend a fortnight driving down the US east coast in two weeks, which I'm hugely looking farward to but sadly means I'm not expecting much progress in the next month or so!