Build a mini caterham

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mr-mechanical

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So last year I bought drawings from @gbritnell for his straight 4 cylinder engine.

I intend to build the engine in the future but have decided that I'd like to have it drive a car.

In the past I have considered building a caterham / lotus 7 replica but never got round to doing due to fund or available space. But I did buy a book for building the chassis / car.

So I have decided to build the car at a scale that will work with the 4 cylinder engine.

In this project I will need to design and build a gearbox and dif etc. to make the car drive. A major project!

I have made a start and the car a few month ago and so far I have made the chassis, wishbones and front and rear uprights.

Here's are photos of progress to date:

MVIMG_20200411_112527.jpg
MVIMG_20200411_165153.jpg
MVIMG_20200507_141007.jpg
MVIMG_20200512_141547.jpg
 

goldstar31

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My son has just finished a rebuild of a 12" to the foot Lotus Elise SE having the wishbones etc powder coated.
To get room in his garage, I got his/ once mine Merc SLK230 back and had to leave my little Skoda outside.

He now wants a left hand drive Citroen Deux Chevaux to rebuild.
It never stops

Cheers
Norman
 

mr-mechanical

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My son has just finished a rebuild of a 12" to the foot Lotus Elise SE having the wishbones etc powder coated.
To get room in his garage, I got his/ once mine Merc SLK230 back and had to leave my little Skoda outside.

He now wants a left hand drive Citroen Deux Chevaux to rebuild.
It never stops

Cheers
Norman
Great, I wish I still had space for a full size car project. My last car project was the rebuild of a Mazda RX8 Wankel engine.
 

BaronJ

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Hi Guys,

A few years or so ago, I was maybe fifteen or sixteen at the time. I helped a friend build a Lotus 7. It had an Austin 1.5 Ltr engine in it. Bog standard no frills. It used Triumph Herold front suspension and a Ford Popular rear axle. Unfortunately I never drove it, however the first time I rode in it, with my friend George driving it frightened me terribly and I refused to go back in it.
 

gbritnell

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To simplify the drive parts why not look into using a centrifugal clutch from something lik a chain saw or weed eater?
Making a mechanical clutch and gear box would certainly be very cool but would certainly be more complicated
gbritnell
 

mr-mechanical

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To simplify the drive parts why not look into using a centrifugal clutch from something lik a chain saw or weed eater?
Making a mechanical clutch and gear box would certainly be very cool but would certainly be more complicated
gbritnell
Thanks George good idea.
I did have a question regarding the flywheel. Is there anything critical to the details of the flywheel? I.e. mass?
Or can I make any flywheel of my design to working with the crankshaft?
 

teeleevs

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So last year I bought drawings from @gbritnell for his straight 4 cylinder engine.

I intend to build the engine in the future but have decided that I'd like to have it drive a car.

In the past I have considered building a caterham / lotus 7 replica but never got round to doing due to fund or available space. But I did buy a book for building the chassis / car.

So I have decided to build the car at a scale that will work with the 4 cylinder engine.

In this project I will need to design and build a gearbox and dif etc. to make the car drive. A major project!

I have made a start and the car a few month ago and so far I have made the chassis, wishbones and front and rear uprights.

Here's are photos of progress to date:

View attachment 116424View attachment 116425View attachment 116426View attachment 116427
Great going, keep up the good work. Ted from down under.
 

wthomas

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Sir:
For your information Crosley built their Diff. (Rear end) with
bevel gears that can easily be machined without special machines.
 

goldstar31

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It may not be relevant but I cut the 4 lawns today with a Briggs and Stratton powered sit on lawn mower.
3 forward and one reverse speeds and a crash gear box-.I passed my car driving tests on a 1st gear crash gear box.

And then being in lockdown and 90/and disabled, I had a run around on my £200( 2nd hand) disabled scooter. A bit faster that my fit son can walk! In pre-virus days, my 4 grand kids all enjoyed 'my toys'

Cheers

Norman
 

craigdiver

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So last year I bought drawings from @gbritnell for his straight 4 cylinder engine.

I intend to build the engine in the future but have decided that I'd like to have it drive a car.

In the past I have considered building a caterham / lotus 7 replica but never got round to doing due to fund or available space. But I did buy a book for building the chassis / car.

So I have decided to build the car at a scale that will work with the 4 cylinder engine.

In this project I will need to design and build a gearbox and dif etc. to make the car drive. A major project!

I have made a start and the car a few month ago and so far I have made the chassis, wishbones and front and rear uprights.

Here's are photos of progress to date:

View attachment 116424View attachment 116425View attachment 116426View attachment 116427
Absolutely love it, of course I'm biased as have built a full size one.
IMG_20200513_095738.jpg
 

gbritnell

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There is nothing critical about the flywheel dimensions. The diameter is the most important. The smaller you make it the higher the idle RPM goes up. You need the flywheel's mass on the O.D.
gbritnell
 

Peter Twissell

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I didn't work directly for Caterham. I work for Multimatic and we were contracted to design and develop the CSR suspension.
Re. flywheels - a light flywheel can make the car very difficult to drive. I drove one of the prototypes from Norfolk back to Dartford. It had a light flywheel, about an inch of throttle pedal movement and a clutch which had a similar effect to just jamming it into gear. Manouvering around the car park at work was just a series of launches and equally abrupt stops.
 

mr-mechanical

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I didn't work directly for Caterham. I work for Multimatic and we were contracted to design and develop the CSR suspension.
Re. flywheels - a light flywheel can make the car very difficult to drive. I drove one of the prototypes from Norfolk back to Dartford. It had a light flywheel, about an inch of throttle pedal movement and a clutch which had a similar effect to just jamming it into gear. Manouvering around the car park at work was just a series of launches and equally abrupt stops.
Cool. I don't suppose you would have any contacts that could help me get hold of a cad model on the body work that I could scale to my chassis would you? I'm planning on 3d printing molds and making carbon fiber panels
 

Peter Twissell

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Tricky. I might have the CAD somewhere, but I'm not in a position to distribute it.
That said, Caterham bodywork is pretty simple. The only parts you need are the nose cone and mudguards - the rest is just skins on the chassis.
 
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