Modest upgrades to an R10

Your example makes sense but I don't think it applies. Twisting a bar is not a linear exercise (trigonometric functions will describe the angular twist dependence on force and they are not linear - duh!).

Deformation of a coil spring is linear (progressive springs notwithstanding - I don't think an OEM R10 spring is progressive) governed by a simple law, Hooke's F=-kx where the k is the deformation constant dependent on material and construction and x is the deformation produced under force F. If the spring wire is constant section and isotropic material, no matter how much you change its length, the constant k stays the same.

That said, there are other considerations when you take the spring from the lab and put it under a car in a suspension setup or another. That is why I added my last comment - I don't remember well enough my R10 days especially in regards to suspension. Like I said, angle for instance can change its behaviour simply because the force applied then varies (with a trigonometric law, by the way). In RC we "lay down" shocks to make the car "softer" or stand them up to make the car more responsive (our shocks are all coilovers so in effect we change the position of the spring).

Same applies here.

And if the angle is not constant throughout the suspension stroke (which it almost never is) then your spring mimics more or less a progressive behaviour.

By the way, introducing an angle between the spring axis and the force direction will always result in an apparent raise of the spring rate simply because less of the force applies along the spring the larger the angle. This does not take into account the leverage advantage of one setup or another. We would need to get under the car, take a few measurements and do some math then.
 
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Re : the weight in the front end. Back in the day when 8's and 10's were current and we used our stock road cars for overnight rallying, we used to melt down the lead out of old batteries, and make a slug of about 60 pounds (say 30 kg) shaped to fit into the inside of the spare wheel. In that position the weight was low down, completely stable, and enhanced the stability of the car substantially. we tried wider wheels, but found that we actually lost traction on gravel surfaces. We went back to the stock wheels. Ian
 
For a given angular "twist", measured at the very end of a torsion bar, the twist per unit length will be lower the longer the bar. I think that means that the force for a given angular movement of the whole bar must be lower for a longer bar than for a shorter bar. So I think taking one coil out must make the suspension firmer providing everything is within the elastic limit of said spring. I think so anyway. Superficially, it might be counter-intuitive I agree.
 
4cvgordini said:
I am not an engineer but this is what I take the story to be:

Imagine a torsion bar. Fix one end & apply a twisting force to the other. The bar accommodates this force by distorting along its length. Lots of molecules & their bonds are involved in this accommodation. As distortion increases the bonds resist it more (until rupture occurs).

With a shorter bar, & for a given twisting force, fewer bonds are accommodating the force & the bar is initially distorted more & the bonds involved thus enter the greater resistance zone earlier.

I no longer recall where I got this from & I would be delighted to have someone more technically competent in the area supply an antithetical analysis. No doubt there’s an “explainer” or three out there in the web. I haven’t yet looked.
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4cvgordini and JohnW are correct - the stiffness of a helical spring is inversely proportional to the length of the working material in the spring. (This obviously assumes that all other factors remain constant.)
 
Hi Schlitz :(
You are overthinking this simple thing. I have shortened lots of springs in the past and for Renaults too. Cutting a coil off does stiffen it. Cutting two off stiffens it more. :rolleyes: If you cut a spring to only one coil it would be almost solid.
The theory is simple as Peter said but put simply, it is like any spring, if you reduce the length of the springy bit it gets stiffer. If you lengthen the springy bit it gets softer. A coil spring is in first order a torsion bar. They usually have solid non flexing ends, and sometimes with coil spacings that close up to make it progressive or rising rate, as the working length able to flex is shortened. :cool:
There can be second order effects of angle and direction but these are less important.
Harrisonati replied while i was typing and is 100% correct.
jaahn
 
I would not describe adding 20 to 40 kg weight to a 1108 cc car as an upgrade, or putting skinnier tyres on it. More like a major downgrade.
In the late 60's and 70's there were a few R10's around NSW with upgrades similar to the Alconi modifications, that could stay with a Gordini.
The well established formula of suspension and engine tweaks to upgrade performance does not include adding weight.
My recollection of the most competitive Gordinis back in the day is that most had a fibreglass bonnet to reduce weight. The really fast ones that were on the race track had fibreglass everything on the front, even doors.. Definitely no added weight on the front end.
Rallying may be different however I still remember seeing fibreglass front panels on rally and rallycross cars that were winning championships, the light weight did not seem to be a disadvantage.

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R4gene said:
Waiting for a recently purchased R10 to be delivered and was wondering what upgrades are worth doing. As far as I can tell it is still stock standard. I intend to use the car as a daily driver, no city driving all country.
Any advice, tips or pitfalls greatly appreciated.
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Hi R4gene :)
Like most forum threads the discussion wanders ;) sometimes helpful, sometimes not !
I would like to say that possibly some enthusiasts here think that you must get the maximum power speed handling that is possible. Nothing wrong with that if that is what you want ! Several notable people on here are an example to anyone about what to do.
But I thought by your comment above, you might not be aiming that high just yet and possibly might want to enjoy your new car as a daily driver and over time do a few improvements to enhance your daily drive without braking the bank and more importantly the car. Perhaps learning a bit about cars as you go, like I did years ago, and many others here too !! :cool:
What should be remembered is these cars were designed as a budget small family car appropriate for their day and sold well as they had a bit of 'flair' also. But a sports car they are not. The simple things suggested might provide quick cheap improvements that overcome some design limitations and I think will enhance your drive. You can always do more if you plan it a bit.
But be aware that getting into a difficult situation going too fast and rolling it will ruin your day for sure !! I can still remember that !! Experience takes time to learn !
Jaahn
 
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I've seen a few racing R10s (and R8s) and I've never seen one with added weight in front, and most of them could out corner most sports cars of their period. My number one upgrade would be wider wheels/tyres and maybe shorter coil springs to make a very nice driveable car. I would also replace the rear axle limit straps with galv. chain inside clear plastic tubing (all from Bunnings), (easily adjustable). Good shocks are also necessary. The power upgrades can come later.

Henry
 
rubyalpine said:
I've seen a few racing R10s (and R8s) and I've never seen one with added weight in front, and most of them could out corner most sports cars of their period. My number one upgrade would be wider wheels/tyres and maybe shorter coil springs to make a very nice driveable car. I would also replace the rear axle limit straps with galv. chain inside clear plastic tubing (all from Bunnings), (easily adjustable). Good shocks are also necessary. The power upgrades can come later.

Henry
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I agree 100% with Henry and Bustamif. Adding weight is really backyard desperation.

I also agree with Jaahn to get the post back to normal but a good discussion never hurt anybody.

About 20 years ago, fresh from the plane, Harry and myself went to Taupo to watch the racing. One of the classes was the NZ V8s. They were a little less modified and not as extreme as the Aussie V8s at the time. At the start, the pole-sitter gained a car length and enough to take the ideal line through the first turn. He went on to win the race and second on the grid got a second in the end. On the second heat, the winner was penalised with a 20kg ballast. Still on the pole position as they finished the lights went out and there was a visible difference between the 2 front cars. They arrived neck-an-neck at the first turn. Now if 20kg makes a visible difference on a V8, then what does it do to a 1100? That is why I finish each race with less than a liter in my tank. I fill the tank with almost the exact amount of fuel required to finish.

Frans.
 
R4gene said:
Sounds good, will the R12 moter bolt straight up to the regular 10 gearbox. Wheels seem hard to find
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Depends what box you have. The late bellhousing (identifiable by a flat rectangular plate underneath the box held on by four bolts 10mm from memory) will bolt up. You may or may not need to change the input shaft - check with the driven clutch plate that matches the engine you want to use matches the input shaft splines note - the 1108, 1289 and 1397 engine all use a different sized clutch.

If you don’t have a late bellhousing as described, then you will definitely need the correct bellhousing and input shaft. You need the correct side engine plates but the rest should bolt up relatively easily.

The water pumps and housings are different - I used to use a 10 pump with a 12 housing from memory and blank off the bottom outlet. That puts the heater hoses exiting on the correct side, but means one of them has to run up over the alternator (which mounts off the head on that side on a 12 engine. I used to insulate the hose with a bit of clear plastic tubing from Clark rubber (tube in tube style).
 
harrisonati said:
4cvgordini and JohnW are correct - the stiffness of a helical spring is inversely proportional to the length of the working material in the spring. (This obviously assumes that all other factors remain constant.)
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Hi. I concur with comments from both JohnW and harrsonati. A coil spring is just a torsion bar that has been coiled, and they operates the same.
 
Okay , a lot to digest. Thanks everybody for their comments. I posted a moment ago before l had caught up , so my questions were answered.
The car in question that I have purchased and am waiting to be delivered is 1969 R10 square eye. I have only seen a few photos and had some questions answered. It is said to be completed rust free except for the top of one rear wing. Interior looks pretty good. It still rolls easily. Head is off and push rods are missing, so a mystery what condition the engine and gearbox are in.
I am prepared for a full overall of the mechanicals and electrics. I can tackle most myself and outsource any specialist jobs. I guess finding parts is what I will also need some pointers with as well as advice about how to tackle specific issues.
Much useful information has already been offered, please feel free to digress down rabbit holes, makes excellent reading!
Still unsure of long term goals, getting back on the road as a daily ( I have a year as my Fuego has just been recommissioned for that task) then ?
 
The upgrade modifications I am talking about are very cheap and affordable. I acquired the R12 motor for my Alconi from an Aussie frog member here. It was offered "free or a case of beer if you are feeling generous" It is still in the car, low mileage, included clutch and starter motor. I paid for it in beer. 12 motors do come up here occasionally.
The rear suspension and brakes can be sorted very easily for the cost of some caliper seals, pads and a couple of days work.
After buying and trying various spring combinations from Mecaparts I removed the expensive front springs from the Floride and just cut about 1/2 coil from a standard front spring and the resultant ride height and spring rate with new bushes in the front sway bar works fine for very crisp handling to match your average Gordini without any need for the addition of any weight in the front.
As far as wheels being expensive I could probably find a set of wide 13 inch wheels to offer at the right price.
 
Bustamif said:
The upgrade modifications I am talking about are very cheap and affordable. I acquired the R12 motor for my Alconi from an Aussie frog member here. It was offered "free or a case of beer if you are feeling generous" It is still in the car, low mileage, included clutch and starter motor. I paid for it in beer. 12 motors do come up here occasionally.
The rear suspension and brakes can be sorted very easily for the cost of some caliper seals, pads and a couple of days work.
After buying and trying various spring combinations from Mecaparts I removed the expensive front springs from the Floride and just cut about 1/2 coil from a standard front spring and the resultant ride height and spring rate with new bushes in the front sway bar works fine for very crisp handling to match your average Gordini without any need for the addition of any weight in the front.
As far as wheels being expensive I could probably find a set of wide 13 inch wheels to offer at the right price.
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Thanks Bustamif, I like the cut of your jib.
A well handling road car with a bit of performance without going to too much expense is what I am leaning towards .
Since the whole car needs attention , to do things once makes sense.
Back when I had my Caravelle the skinny zxz tyres were cheap and available, they now seem to be not so easy to get and expensive. What is the availability and choice for the 13’’ wheel like?
 
I believe that 14 and 15 inch would be the best option in terms of gearing and tyre selection. Suitable wheels come up here occasionally. You will find there will be no shortage of opinions on wheels and tyres. There are many factors, price, gearing, wear rate, ride, noise, wet weather grip, dry weather grip, feel, originality, brand loyalty, profile, tread pattern, gravel road grip, motorkhana grip, look, sex appeal, family history and the list goes on
 
On wheel size:

I would find out about tyre availability before choosing wheels.

The trouble with 13" is that your choice is either "track day" style tyres which do not operate well at low temperatures or in standing water or some mediocre 175/70-13 or 185/70 "eco" tyres.

The trouble with 15" tyres is finding anything good for a modest upgrade.

One modest path is to acquire a set of GS Citroen rims. supply them, plus your standard rims, to a wheelwright to have GS rims attached to R10 centres. Thus one has (R8G or R10S style) 4.5x15" wheels. Two mediocre tyres are available: Kumho's Ecowing KH27 & Nankang's AS-1.

More complicated in rim sourcing is to move to 5" or 5.5". This gives better tyres, including the above-mentioned Pirelli P6, in 175/65 (or 175/65 F & 185/60 R). But: the R10 centres are weak and tend to split around the stud holes under lateral leads. They can be reinforced in a simple way but things are becoming less modest. (I can advise on the reinforcement to the centres if asked.)

Or one could, for now, simply keep the standard 15" wheels & upgrade tyres. I note John W's experience with XZX & its benefits over ZX. Yes it is improved in structure & compared compared to its ancestor but it does cost quite a lot & is not the best performing tyre for a standard rim. Much more cheaply available is, again, Nankang's AS-1. Size is 145/65. Not a wonderful tyre but better in all ways than the XZX (the evidence is indirect but compelling - detail if asked) The only drawback is an almost 5% reduction in gearing (compared to 135/80). Don't fit tubes; tubeless is fine on R10 rims (detail available if asked).

I still favour "flipped" R16 14" rims as the easiest modest modification giving you good tyres. I would be surprised if you could not source some by trawling on AussieFrogs.

cheers! Peter

I, at least, am finding this to be one of the more interesting threads. It's a conversation & like, most conversations, diverts at times to where the participants choose to take it. Good!
 
Hi R4gene ;)
You have a rival in Newcastle for an R12 motor but he has been looking for a while :rolleyes:; Jaahn

Wanted: WANTED Renault 12 motor​

Negotiable. Carrington .NSW 2294

WANTED ; Renault 12 motor to fit 1964 Caravelle . Preferably worked or Super Charged ,Twin Carbies , a High Performance Engine with a bit of attitude . Phone Pete in Carrington 2294 , NSW
  • Date Listed:03/04/2021
 
wheelnut said:
Re : the weight in the front end. Back in the day when 8's and 10's were current and we used our stock road cars for overnight rallying, we used to melt down the lead out of old batteries, and make a slug of about 60 pounds (say 30 kg) shaped to fit into the inside of the spare wheel. In that position the weight was low down, completely stable, and enhanced the stability of the car substantially. we tried wider wheels, but found that we actually lost traction on gravel surfaces. We went back to the stock wheels. Ian
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Makes complete sense to me. And you trialled it thoroughly. More sophisticated than my bag of cement too!
 
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