Disc Brakes for Javelin/Jupiter?

[beachcomber]

Just read through the whole thread to bring myself up to date.

Moises Jr. there's a million Hot Rodders worldwide would disagree with you !!

And why should the chassis be causing problems down the line ? You are ASSUMING the stock chassis is used.

And looking at the stock Javelin front suspension set-up, it would be very difficult to obtain that amount of negative camber just by being lowered an inch or two.

I ran a similar amount [ 1.5 degrees ] of negative camber on my circuit racing R8 Gordini [ 2 degrees at the rear ] and that was completely deliberate - and for different reasons I suspect.

There will ALWAYS be the naysayers for modifying original machinery, but as I stated elsewhere - Hot Rodders were around a long time before restorers !

Hands up those who have OEM cars as they left the factory cars ? Not many I bet - the rest are "modified", it's just the degree of mofication which seems to raise the blood pressure.

Over on the Rover Forum my 200TDI engined P4 causes indignation everytime I post [ frequently, tee, hee, hee ], and yet they quite happily babble on about fitting radial tyres, power steering, alternators,........... to their otherwise "original" cars. Yes, these items are fitted to improve the car's OEM shortcomings - but rodded nonetheless.

ALL that said, I just got my "Jowett History" book, and that engine does seem exceptionally well designed for the period. Turbo, Eaton Blower ?????????

"Nelson" in early build



And "as is" - awaiting the next phase - lowering, alloy wheels, paint job [ Satin Black ? ]

[Moises Jr.]

Hi

I was not trying to give a lesson to anyone, just showing my disagreement with changes in a classic fully away from the original idea, not being a preparation for racing or rally circuit.

My current car has no modification, and is one of the most "tuned" Seat Leon FR TDi 150HP, may be the reason for my refusal to changes seeing the atrocities done with my car

[beachcomber]

Hi

I was not trying to give a lesson to anyone, just showing my disagreement with changes in a classic fully away from the original idea, not being a preparation for racing or rally circuit.

My current car has no modification, and is one of the most "tuned" Seat Leon FR TDi 150HP, may be the reason for my refusal to changes seeing the atrocities done with my car

Each to his own eh ? There's room for all from bog standard,fully restored and modified.

My contention is that once a vehicle has been modified away from the way it left the factory [ which includes factory tuning parts ] - it is no longer standard !! I think it's the degree of "non standard" which gets folk hot under the collar.

I will be the first to applaud a nicely restored, or even original car - I can appreciate that as well as a more radical approach.

No foul Moises - we'll just agree to differ !!!

[jowettgeoff]

This thread is an interesting subject indeed. Some find enjoyment in modernising old cars while others prefer originality. Neither is wrong - it's just 'different strokes'. In terms of historic competition there are strict rules regarding originality. Back in the '80s, those of us doing historic sporting events were hard pressed to convince organisers to allow even modest 'improvements'. Jupiter and motor sport expert Peter Dixon, I believe, pulled a few strings to allow us to use 32mm carbs (Weber/DelLorto) in place of the standard Zeniths. 15" wheels were another hard-won concession, though I had to obtain a laminated windscreen for the Javelin in order to satisfy the scrutineers. So at that time (and probably still), the fitting of disc brakes would be completely no-no. Which is as it should be, in my opinion. The Pirelli Classic Marathons of the late eighties/early nineties involved numerous headlong plunges down snaking Alpine passes, and as Keith says, providing that the right linings were chosen, (Ferodo VG95 or Mintex AM4 from memory), braking was quite adequate, even without a servo (banned!). So good luck to all the would-be modifiers out there - you're doing some fascinating research. For the old fuddy-duddies like me - I'm quite happy with the ex-factory cars. (Well - more or less!).

G McA

[beachcomber]

This thread is an interesting subject indeed. Some find enjoyment in modernising old cars while others prefer originality. Neither is wrong - it's just 'different strokes'. In terms of historic competition there are strict rules regarding originality. Back in the '80s, those of us doing historic sporting events were hard pressed to convince organisers to allow even modest 'improvements'. Jupiter and motor sport expert Peter Dixon, I believe, pulled a few strings to allow us to use 32mm carbs (Weber/DelLorto) in place of the standard Zeniths. 15" wheels were another hard-won concession, though I had to obtain a laminated windscreen for the Javelin in order to satisfy the scrutineers. So at that time (and probably still), the fitting of disc brakes would be completely no-no. Which is as it should be, in my opinion. The Pirelli Classic Marathons of the late eighties/early nineties involved numerous headlong plunges down snaking Alpine passes, and as Keith says, providing that the right linings were chosen, (Ferodo VG95 or Mintex AM4 from memory), braking was quite adequate, even without a servo (banned!). So good luck to all the would-be modifiers out there - you're doing some fascinating research. For the old fuddy-duddies like me - I'm quite happy with the ex-factory cars. (Well - more or less!).

G McA

Geoff - I'm not suggesting for one minute that disc brakes should be fitted [ assuming they can ! ] to an otherwise standard car.

It's when I read the phrase "adequate" - that self preservation rises to the fore.

In fact, it's looking more viable for a front clip swap to be used. I'm currently looking at Mazda MX5 - which not only gives the desired [ to me ] disc brakes, but also precise steering geometery and a decent steering rack.

Poweplant is also looking like being a PVR V6 - taken in this case from Volvo, which then gives me rear wheel drive transmission and the option of an automatic [ BW35 ].

The engine is very compact being virtually a 24" cube - and reasonably light.

I'm working a bit in the dark until the car finally arrives in sunny Redditch - when proper measurements can be taken.

[jowettgeoff]

Exciting stuff. Good luck with all that!

Geoff.

[Forumadmin]

Bear in mind that Roger Clarke ( in a Lotus Cortina if I remember correctly) was following Geoff in the Javelin down a pass in Northern Italy. In the evening he commented how well the Jav went. So 'adequate' as far as Geoff is concerned is that at rallying speeds they still stopped the car repeatedly unlike some others that had boiling brake fluid.

[beachcomber]

Bear in mind that Roger Clarke ( in a Lotus Cortina if I remember correctly) was following Geoff in the Javelin down a pass in Northern Italy. In the evening he commented how well the Jav went. So 'adequate' as far as Geoff is concerned is that at rallying speeds they still stopped the car repeatedly unlike some others that had boiling brake fluid.

As much as I like David and Goliath stories - are we really suggesting that one of the World's best rally drivers, in one of the fastest cars at the time was "following" a Javelin ?????

And "adequate" by dictionary definition is not as good as, well - good.

There's some excellent pix in the McAuley book "JJ and J the complete story" showing Javelins cornering on Rally events - they display the body lean of a 2CV ! It was a brave man indeed that pedalled a Javelin ahead of Roger Clarke down a fearsome Alpine pass.

However, enough of the tongue in cheek banter ........................


Disc brakes are a natural braking evolution, and MOST would say an improvement on drum brakes. When I went from a drum braked Dauphine to a disc braked Dauphine Gordini [ 1963 / 64 ? ],the difference in braking was immediate and dramatic.

So, I go back to my original statements - drums are fine for standard cars, but if an option of disc brakes is available and viable, and if the originality of the vehicle [ where desired ] is not an issue - I'm all for it.

The vehicle I am contemplating will in no sense of the word be "original" - although I do want to retain the silouette and styling.

That said, if an OEM de-Luxe model comes up that I can afford, it will have my name on it !

I am intrigued by the later engines, and I think they would be fun to work on.

[Jack]

TJ, I think the legendary Roger Clarke story is true, though whether in fact the brakes had faded to the point they had little choice about the speed they descended may be another matter

The Javelin does lean, but (like the Jupiter) it doesn't let go. Or at least, not easily. Like many well set up cars, the driver often sets the limits, not the car. I can confirm that it is entirely possible to slide right across a bench seat if you corner hard to the right without a passenger, without the tyres letting go of the road

I think that the disc conversion on a Javelin would be a big engineering modification, but it wouldn't be particularly visible - the solid wheels mean that nobody can see the drums or anything else that might be in there unless you choose to show them, and as a result modifying a few cars to have this wouldn't even be noticed by many, and the potential benefit seems obvious to me.

That said, the drums are not the weak point here in my opinion - with a servo the drums are more than capable of stopping a car, the limit to braking is the narrow tyre. If you can beef up the front tyres a bit, then discs start to pay off. Otherwise you will end up with a car that has huge stopping power, but not enough rubber to make a difference. In a racing environment obviously the brake fade factor comes in I guess.

Anyway, good luck with this, and keep us updated with how you are doing it. We are all interested in seeing it done, and a record kept for the future - as this thread has shown there are many who want to see how it could be done and the benefits.

Jack.

[jowettgeoff]

Maybe, in the interest of historical accuracy, I should clear up the Roger Clark story.

We (Frank Woolley and I), were actually following Roger and his navigator Tony Mason (in their Lotus Cortina), down the snaking 2236m Giau pass (in the Dolomites). Although the ascent had been a timed section, the descent wasn't. Roger was numerically just ahead of us in the starting order, so we saw quite a lot of him (usually disappearing into the distance!). However, we latched onto him on the aforementioned descent, and stayed with him all the way to the bottom. Of course he wasn't driving flat out (silly suggestion), but we were tanking on a bit - even to the point where normally laconic and uber-relaxed Frank muttered, "Steady on Geoff"!
When we reached the assembly area, Tony walked back for a chat and said how impressed Roger had been, remarking on the wild angles of BEG's front suspension.

At the final ceremony, Tony and Roger again alluded to being chased by the Javelin, "With his indicator flashing - trying to overtake us"! Roger was later heard to say, "Thank God they were only driving a Jowett", which I thought was rather unfortunate, since the episode had been significantly more down to the car's abilities than the driver's.

Incidentally, we finished the 7 day event less than 3 minutes behind Roger in the overall standings, (and but for a suspected timing error by the organisers, might have just beaten him). However, the Cortina crew did have mechanical problems (overheating, I think).

So, in summary, Is a Javelin quicker than a Lotus Cortina? Of course not. Are Geoff and Frank quicker than Roger and Tony? No way! Was it a good story? Yep! Did we suffer loss of brakes at any time? No. Obviously we weren't trying quite hard enough

[chapman]

The drums from the R1 which moises photographed look like the Alfin drums from a 1956 Mercedes Benz 220s ponton .
These are still available from Niemoller in Germany.
Tom chapman

[Moises Jr.]

I can not find the original photo in which drums are Jupiter R1: (

I can hardly believe that a Javelin can continue to away to a Lotus Cortina in the Passo Giau, let alone think I follow close to the Stelvio downhill!

[David Kemp]

Has anyone a friend with a Morgan, i ask as they have the same back axle as Jowett, & looking at their parts the disc brakes look like they are designed to fit the same hub as the drum brake.
This would make sense as a small manufacturer it would cost too much to make a new hub. The current model is I am guessing not much changed from the 1st 4 wheeler.
The original 1950's Morgan probably used the same brakes as jowl, or at least parts.
Can any one look into this.

[Srenner]

The Morgans of the Jupiter era typically had a 3HA rear axle. Only the center casting, ring & pinion and bearings are the same. The axle tubes, shafts and all the brake components are different. Around 1953-4, Morgan installed 7HA axles, which look somewhat similar but have no interchangeable parts.

The Morse taper on the end of a Morgan 3HA axle is not the same as Jowett, so there is not a bolt-on opportunity. I have not measured a Morgan 3HA for axle shaft length, but using their axle shafts would allow mounting those brake assemblies. One might be able re-taper the Jowett shaft, as it is slightly larger in OD.

Of course, this thread started with the idea of swapping to front discs (still not a bad idea if originality isn't an issue), as that is the end of the car that would need them first.

Having raced cars with both drums and discs, and having taken drums off to put discs on, IMHO the cars need to be driven differently to avoid brake fade. In Over 20 years of running E2SAL758 on race tracks, I have never had fade. I should point out that the backing plates are drilled for air circulation.

[David Morris]

Hi All,

Somewhere I heard that Jowett's manufactured their own back axle tubes and fitted them to the Salisbury diff? Certainly, there is a big difference in the mechanical and full hydraulic brakes axles.

Having been plagued with other cars with a handbrake on the rear disc brakes, fitting these to a Javelin/Jupiter would seem a retrograde step. Yes, by all means fit discs to the front wheels, but as the rear brakes only account for around 10% of the overall braking effort, I doubt the wisdom of touching the rear axle's brakes.

David