Jomac
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| posted on 18/5/16 at 09:01 PM |
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Chassis mods
Ive finally decided after 15 years to look at starting a car build but using parts i have at hand.
I have a donor vehicle which is a little unusual, its a French car that has a plastic body shell and the engine and axles are built on subframes. The
engine being all of 505cc i think could be mounted at the back but using the original subframe and suspension.
Ive not looked too closely but i think the whole assembly could fit inside the confines of the rear chassis area.
Has anyone any experience or advice / comments on making a engined car?
a person who makes no mistakes, learns nothing
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emwmarine
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| posted on 19/5/16 at 06:10 AM |
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quote:
Originally posted by Jomac
Ive finally decided after 15 years to look at starting a car build but using parts i have at hand.
I have a donor vehicle which is a little unusual, its a French car that has a plastic body shell and the engine and axles are built on subframes. The
engine being all of 505cc i think could be mounted at the back but using the original subframe and suspension.
Ive not looked too closely but i think the whole assembly could fit inside the confines of the rear chassis area.
Has anyone any experience or advice / comments on making a engined car?
So you've no plans? No design?
Most people aim for a finished result, choose a kit, or set of plans, that meets their needs and then decide what donor, or donor parts, are needed to
complete the kit.
Having said that there are a few cars, like the MX5, that kits are based around. So sometimes people with an existing car have the luxury of just
being able to buy a kit based on that.
I would have thought that picking a French Micro-car and just trying to create something from it would end up just being another obscure unfinished
project in someone's front garden.
Building a Dax Rush.
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Neville Jones
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| posted on 19/5/16 at 07:37 AM |
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Well, I'll say something positive! 
Good on you for having a go at something novel. I'm building a rear engined car with a 900cc bike engine, based on the footprint of a classic
MIni. You might start at something similar, as people put bike engines in the back of silhouette Mini's all the time.
I'm familiar with those little french cars, and wouldn't say that they have startling power, but it should end up being a whole lot of
fun.
I've seen cars designed with chalk lines on the floor(once or twice on here!!!), and while I would recommend a more technical approach, it can
be done.
The boatbuilder should be familiar with the old time methods of drawing a boat full size from the drawings, on the lofting floor, if he's ever
built one from scratch. What you are suggesting is no different.
Go for it, but just be careful and methodical.
Cheers,
Nev.
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Jomac
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| posted on 19/5/16 at 08:29 AM |
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Im pretty fortunate in many respects, i'm a capable engineer with plenty of time and access to quite a lot of engineering equipment. Making the
frame isnt a problem. I originally earmarked the car for an electric conversion but that never advanced. The Microcars are pretty nippy in their
original form, how it would perform in a lighter frame would be interesting.
I also have access to some cheap material called 'composite', its used in signmaking. Composite is a strong plastic sheet with a thin
layer of aluminium each side, its very light and can be bent like aluminium panels.
Ive looked at the chassis drawings from here especially the dimensions, ive roughly measured up the front subframe with the engine in place and i
think, if im lucky, i could slot the subframe and engine into what was the rear boot area with very little work.
Using the front subframe like this, i think would save me a lot of work and money, everything is mounted on one frame.
My interest in these sports cars came after reading the book, build a sports car for £250, ive seen some smart versions in my time.
a person who makes no mistakes, learns nothing
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Neville Jones
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| posted on 19/5/16 at 09:07 AM |
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That sign makers 'composite' panel stuff would be ok for non structural panels, but you'd be heading for a world of problems using
it for a stressed chassis.
And bending it???? Just don't go there, you'd be opening up a minefield of problems that I'm not going to elaborate on. Just
don't even entertain the idea for something even remotely load bearing. Been 'discussed' on here too many times in the past.
Cheers,
Nev.
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nick205
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| posted on 19/5/16 at 10:40 AM |
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I thought through at length the idea of using a Pug 205 GTI engine and front sub-frame as the rear setup of a car. Whilst I love the engine and it
could be done it just didn't seem worth the effort and unknowns compared to established kits. I chose and built an MK Indy in the end and was
happy with the finished product. It seems to me quicker and easier to tread the tried and tested route.
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Jomac
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| posted on 19/5/16 at 11:28 AM |
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I'll follow up on the bending issue Neville, i'll take a piece down and see what a sharp bend looks like, ie the sort of bend you would
find on the edges of the bonnet for example.
I though about using the whole sub frame assembly Nick, purely because it has everything in one place, engine, drive shafts, suspension etc, the only
mod needed would be to lock down the track rods for the steering.
Ive seen a few plans, mainly of the £250 project. Looking at the rear end which would normally be the space for the boot, its dimensions and the cubic
size of the engine and sub frame, i think the sub frame chassis could easily be morphed into the main chassis. If i get time later, i will try and
take some pictures of the engine and sub frame with dimensions.
a person who makes no mistakes, learns nothing
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nick205
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| posted on 19/5/16 at 01:24 PM |
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The idea is certainly attractive to make use of the sub-frame a manufacturer has spent a lot of time developing and making - as you say it has what
you need on it already and can't be impossible to attach to another chassis.
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Jomac
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| posted on 19/5/16 at 02:45 PM |
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I went down to visit my friends engineering company and took a piece of composite with me, feeding the sheet through rollers the was no problems
bending the sheet with a 2" radius, it started to show signs of being unhappy at 1.5" with the aluminium showing signs of stretching on
the outer surface, i think this would work well for the bonnet and the rear panel.
I am the sort of engineer who would chalk the chassis on the floor and build from there, technical drawings in my day were scribbled on the back of a
fag packet 
I'm still a way off starting, just getting idea's and plans right in my mind but the whole thing is getting more appealing as i think
more.
I did realise another big plus point re-using the subframes, for those who don't know this sort of Microcar, its classed as a quadracycle,
simply put its a quad bike with a car body. As long as the overall weight is under 400Kgs any person without a car licence, but has passed their bike
test can drive one without a full car licence. The weight of this Microcar unladen is only 370 Kgs
a person who makes no mistakes, learns nothing
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