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BRM P578

6509 Views 40 Replies 12 Participants Last post by  Groomi
Hi All,
Inspired by this thread about improving the old Scaley Formula Juniors (and in particular, ThaiRacer's outstanding work), I've decided that my first foray into slot car modelling after many years of thinking about doing something will be to upgrade the Scaley C72 BRM. This will be a slow moving, long-winded thread however, because I'm going to document my thoughts and approach to the model and would very much like to see what others think of it, what suggestions they make and in particular some guidance with techniques. I'm an ideas type of person, a real deep thinker rather than a leap into action kind of guy. My Airfix days were back in the 80's where I focussed on cars rather than planes, I ran an informal Scalextric club in the early 90's with some school mates before progressing onto RC cars (including home-built experiments) and then onto 1:1 bicycle racing and then women - at which point all things technical stopped, followed by marriage then kids and ultimately the loss of any free time. This project is an attempt to get involved in something intricate enough to force me away from my office desk at all hours and onto the dining room table to actually make something I can feel a sense of achievement with. So here we go then:

The Concept
I've chosen the BRM P578 as I had a wreck of a C72 kicking around in my cars box along with various spares and bits and bobs. I have fond memories of racing such a pair of my Dad's cars around when I was a kid - the thrill being that they were difficult to drive quick, moved around a lot (more realistic than the larger GT cars) and ofcourse had steering. They had the feeling of being more delicate, more intricate and more of something special to handle. This is a quirk I've always been enticed by - the idea that something can be unnecessarily complex, perhaps perform less well than something simpler, but be more of a joy to own, handle and use as a result of it's intricacy.

So my grand scheme for my future slot car fleet is to gradually build a collection of realistic performing (relative to each other), realistic looking, intricate working models, each reflecting the important aspects of the specific, or generic type of, real car.

The Subject
After spending a bit of time researching what the Scaley C72 was actually modelled on, I was eventually satisfied it's a BRM P578 (P57 with a V8 engine) from part of the '63 season. The exhausts and the bodywork around the engine cover changed a few times over the '62 and '63 seasons but I found proof that this configuration raced at Monaco where Graham Hill won and also at Silverstone, where Hill was pictured racing with part of the rear bodywork missing.

I've chosen to base it on the Monaco winning car as pictured below:

The Project
I'm starting with a real wreck:

And will be taking the running gear out of the yellow Porsche as it is complete, works and the wheels are almost a perfect match for the BRM:

I found a scale drawing on the internet of the exact model of P578 I was working to, but the scale bar shown was completely wrong, so I imported it into AutoCAD scaled it working to a theoretically known (verified by two websites) wheelbase and then applied my own scale bar. In the absence of any better dimensional information I'll now be working to this. Although the pictures below don't show it well, when overlaying the existing model over the drawings it is surprisingly pretty accurate. The most obvious point of inaccuracy is the angle of the rollover hoop and screen - both of which will be remade. The body is about 2mm too narrow, but so close it's not really worth trying to improve it. I think achieving a good finish and removing the panel joint is the most important job with the sides. Surprisingly, even the wheel sizes and track width was correct!

One of the elements which I always loved about the old Scaley FJ's was the rear 'suspension' with a travel of 3 or 4mm. It always seemed though that the weight of the car was enough to compress the travel anyway so it didn't really do anything. However, this is something I want to play with - especially as the relatively softly sprung stance is a key feature of 60's racers for me. For a realistic appearance I will need to model some kind of rear suspension - so therefore I may as well make it work. This is where the intricacy is going to come in! After fiddling around I realised that there is burr from the moulding which is preventing the motor assembly from moving and preventing any travel, so this will need removing. You can just see it between the circular cut-out and the square recess for clearing the crown gear.

Having now stripped the car down, the next job will be to clean the body up and start marking out where things need to be cut, modified, joined etc. But before I actually make any cuts I need to work out how the suspension is going to work and how I'll mount it into the body - space is very tight around the motor. I have a few ideas so watch this space or suggest some ideas of your own.

This is what I need to recreate, so if anyone has some better pictures please share them!
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QUOTE (loosesalute @ 11 Jan 2012, 20:40) <{POST_SNAPBACK}>That`ll be worth seeing Groomi!
Have you got any ideas how you might make a new steering system?
Steering is actually quite forgiving on them .
I like how the existing steering works (apart from the excessive play), so I'm thinking along the lines of essentially remaking it out of brass with tighter tolerances. It would be good to make it look a bit more like wishbones too and ofcourse to squeeze in shock absorbers (possibly working).

I'd also like to use a blade rather than a pin, but if it's a straight replacement then it affects the way the steering works - ie the wheels turn with the slot, rather than the car running slighty wide before the pin is pulled to one side and wheels turn. I'm sure that's why the cars wonder around on an uneven straight and also why a simple S-bend can be a bit tricky - I like this feature!
Very clever indeed!
The only problem I find with FJ steering is that the car has to drive slowly through my Goodwood Chicane, or else it can de-slot.
I`ve got a few of the later c81 & c82 Cooper & Lotus cars with the elastic bands still intact on the steering. This doesn`t half tighten things up nicely!
QUOTE (loosesalute @ 11 Jan 2012, 21:30) <{POST_SNAPBACK}>I`ve got a few of the later c81 & c82 Cooper & Lotus cars with the elastic bands still intact on the steering. This doesn`t half tighten things up nicely!
Any chance of a photo of how the elastic band sits? I've never seen a car with one!
Give us five minutes mate. I`m on it now.
Here you are Groomi.
This is a French made c81 Cooper from 1966/67.
Luckily it is in mint condition so the band has survived.
It doesn`t half eliminate that roll you get on the front axles!

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Great stuff - thanks!

So does the band loop back under where the undertray clips into the body?

I'm thinking if this was replaced by a spring with an adjustable mounting point, then it can become a tuning tool. Not for outright performance, because presumably the tighter the better, but more for equalising performance against other cars.

As an aside, I wonder how a simple friction damper (just a sliding rod within a tube with a bit of resistance) would affect the steering...
It does Groomi, & I think using a spring is a great idea.

I also collect 1/40 scale Jouef slot cars.
The cars made between 1963 -1969 use adjustable spring pick-up shoes. This also gives a car a lot more stability.
Wow Kev,
Have often wondered how the band fitted. Never before ave I seen a picture of such a thing. This is an important moment in Slot Forum and probably in general Scalextric history. Hope you don't mind me grabbing the image (and no doubt others will do too).

Respect, Leo
PS -I have glued the steering units in but still have not glued...
I`ve got THREE with laccie bands on Leo!

You grab what you like mate...

Joking aside mate, I haven`t got a clue how they tied that knot!
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QUOTE (Groomi @ 11 Jan 2012, 13:52) <{POST_SNAPBACK}>I like how the existing steering works (apart from the excessive play), so I'm thinking along the lines of essentially remaking it out of brass with tighter tolerances. It would be good to make it look a bit more like wishbones too and of course to squeeze in shock absorbers (possibly working).

Dave Jones made this wonderful brass steering system for a BRM P578 of his own design that was entered in a proxy race series this past year. I hope that Dave won't mind that I've posted the pictures of the steering system as well as his finished car.. the 1962 stack exhaust model. All I can say, is my hat is off to anyone who can build at this level.. I have more than enough of a challenge soldering static suspension systems.

Good luck with your project.

An avid BRM Fan (no surprise there I suppose).
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Wow - that looks stunning. I'm under no illusions of being able to produce that level of workmanship. My thinking for this model is just to reproduce the original steering system, which is essentially a flat upper and lower plate sandwiching the moving parts and the suspension being of the swing-axle type. If I can improve the look and the accuracy of it's function then I'll be happy.

Dave's work can serve as inspiration for the next one - perhaps one of those Porsche's...
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Kev you're spot on as usual, the later "rubber band" guide is much better so I intent to use a modified version of it with my "upgrades".
I'f I'm going to start slapping paint onto them and sooping up the motors , does it matter if they don't have the correct guide!
Now where did those rubber bands go that came off the spring onions.........
A little update. Still no physical progress yet as I'm working on getting the detail right before I start cutting things up. I've been particularly looking at the rear suspension and mounting points of the original car and comparing them with the packaging restrictions of the Scalextric car. Packaging is oh so tight!

Comparing the drawings with photos and with the car I have in front of me, I'm pretty sure that the Scaley body is too shallow - the belly of the car should be deeper. I'm thinking about possibly making a brass horizontal spacer plate, shaped to the effectively provide a filling between the two existing body parts - this could then be used to solder tubes to for the suspension mounting points. I much prefer this than trying to mount directly to plastic.

One worry I have though, is that I will need to apply a skim of filler to hide the brass plate on the outside (it'll gain the couple of mm of girth that the Scaley car lacks to the original), but I'm concerned that it may crack over time due to the different properties of metal and plastic. Anybody have any experience of dealing with this?
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QUOTE (Bigskybanker @ 15 Jan 2012, 04:31) <{POST_SNAPBACK}>what's the depth of the body in mm?
Difficult to measure accurately without a vernier guage, but I'd say no more than 20mm from base of windshield to the underside. Visually, I think it needs about 1-2mm more - the same as if you place the two parts together without clipping them in. Ridiculous as it sounds - that sort of difference might make the difference between (relatively) realistic working suspension and not.

Managed to order a few bits and bobs today to help with the project including some assorted sizes of brass rods, tubes and sections.

Another question for anyone who may be in the know - I'm intending to cut down a Biro spring for the shock absorbers, but would love to have red springs. I'm assuming any kind of conventional paint will just crack and break off when the spring compresses, so is there some sort of flexible paint that anyone could recommend for such applications?

Really getting into the thinking behind this now - can't wait to start building something though!
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13.6mm through the cockpit, so, pretty shallow for sure. That's 16-3/4" depth.

Biro springs won't compress in a 1/32 scale suspension, so, no problem of the paint chipping off. You will need something much lighter.
Break open a small lock and the tumbler springs may be the right size.
No it isn't ridiculous, with these cars every mm counts!

Here's a picture of the Supershells BRM next to the Dave Jones BRM with comparative measurements:

Supershells Dave Jones
Length 117.0 114.3
Width 26.8 27.0
Depth Cockpit 14.0 14.7
Depth rear cowling 19.3 19.8

As for springs, you might try the spring in a disposable Bic lighter... it makes a nice set of four.

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I work at a hardware store and we rekey locks, I think the tumbler springs would be perfect for this.
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