1968 Fiat 500 Breadvan, K1200RS, Spaceframe Race Car.

[metalshapes]

Lessons learned from my old blue racer ( I may have mentioned this car before...)

I bought a mostly parted out wreck of a Lola T492 Sports 2000.



Basically, what I got was the tub and the front suspension.

I wanted to build it as a parkinglot racer ( also known as slalom ), so I built it as short as possible. and as light as possible ( less than 350Kg ready to run )







The rear suspension on it was a DeDion as well, but because it had the engine in the back ( A Fiat Abarth 1000 mated to a Ford Fiesta gearbox ) I built it as its own separate spaceframe with aluminum panels bonded and riveted on for stiffness.





It had a single pivot at the front ( a big rose joint), height adjustable for anti squat.
The rear wheels were adjustable foe to in /out.
And it had a WOB link, also height adjustable to dial in rollcenter.






Here are some things I'd do differently today...

Since I started with stock Lola front suspension, the track was fixed.
With the ultra short wheelbase, it had unpredictable snap oversteer.
( as far as cornering, the DeDion could keep up with the Lola IFS.
But at the limit there was little warning when the rear would step out)

So I think the wheelbase was too short for the track.

Also, with the single front pivot ( like a Alfetta has ), any little play or give the Wob link had translated into rear steer ( and again the effect was greater because of the short wheelbase )

The adjustability of the rear wheels was nice, but after getting the right settings I never touched them again.
So that could have been a lot simpler...

In the end I got it to drive good enough ( it won me a championship ), but everybody that ever tried it spun it...
( I was always very proud of myself when I could catch it... )







Hopefully, some of the things I learned from that car will help me with the 500.

[peteh1969]

Even thought those suspension set up look so very complex it's a case of Keep It Simple Stupid and they are so practical with a transvers mid engine car as they balance everything out very well and kepping the CG low.

You could build the new set up for the 500 in a similar way but using the engine and g/box as part of the suspension frame mounting the front rose joints on the front of the engine and having the wheels/axle semi  fixed moving with the engine and box similar to F1.

You could go in several directions with it and it's all down to personal preference but alot to think about.

And worth folowing in your thread.

[metalshapes]

It was a fun car...

All out cornering force was really good.
And because of that, oil surge was a problem.
I didn't have the money or the know how to put a dry sump on that engine.
So I learned a lot about wet sump baffles, those couple of years.
( and I still have a box full of blue connecting rods and cranks with the scars of spun bearings as evidence of that learning curve...)

After I found one of my all time dream cars ( a Mallock U2 Mk6), I had to get rid of it.
So I took all the Fiat Abarth parts off it, and traded the tub against some vintage MAE parts to a buddy of mine.

He restored it back to original, and I think its being vintage raced right now...

[metalshapes]

Peteh, yeah.. Keep It Simple Stupid.

I really believe in that.

So the 500 is getting a Alfetta DeDion ( narrowed 7.5" ) with the front tiangle cut off.

With a 4 link ( tried and true system that is known to work )
The sideways location will be with a system I dreamed up which is based on the Mumford link.
( I couldnt use a Mumford because it usually sits where the gearbox is in my car )

So that one is still an unknown.

( I did name it the mac Gillavry link, incase it does work...
And if it doesn't, I'll live with the shame... )

[metalshapes]

[metalshapes]

I'm working on the chassis.

Mods to get the bike engine and the new rear suspension in are almost done.

A couple of years ago I got the sidepanels off a March single seater that was modified to run as a Can Am.

And I'm thinking about using those as a base for my new fenders and nose.

[stealthstylz]

That looks suitably mental. Love it.

[dikkehemaworst]

You make everything work , so i'm going to sit back and enjoy the ride 😀
What are the carparts on the shelving?
Looks fiat , but different

[metalshapes]

Thanks guys.

dikkehemaworst, 1932 Ford, Mallock U2, and Fiat ( fiberglass ) bodyparts.

[peteh1969]

Wow that looks good please keep the updates coming?

[metalshapes]

Thanks, I will.

This is just a mockup.

But I needed to do that to decide where I was going with the body work.

Now I can put in the radiators, clutch mechanism, shifter, driveshafts, etc.

More updates soon...

[dikkehemaworst]

Jul 10, 2020 1:09:08 GMT metalshapes said:

Thanks guys.

dikkehemaworst, 1932 Ford, Mallock U2, and Fiat ( fiberglass ) bodyparts.

Never ever heard of a mallock (mega Google session incoming ) but i thought i recognise the fibreglass bodyparts.
Is that the convertible one you make from a 126?

[metalshapes]

My Mallock U2 is a mid '60s clubmans racer. ( UK racing class for Lotus 7 like racecars)

They were also used for Formula 2, Formula Junior, etc .

[metalshapes]

So, because of the big gap in this thread, and because of all the Photobucket damage, a quick recap.

Phase 1 of this car.

Bone stock Fiat 500F.
By buddies daily driver.

Stock color - White.


1st rebuild, Phase 2.

Mild custom.
Slightly flared fenders.
Welded in sunvisor.
Functional X1/9 air intakes.
A lip on the bottom of the rockerpanel.
The same red Gianinni wide steel wheels that are on my '58 Nuova right now.

Color Black.


2nd rebuild, Phase 3.

Mild track car.
Smoothed off sunvisor and rocker panels.
Kept the X1/9 intakes.
Stripped interior, etc to add lighness.
Bigger flares for 10" fabricated wheels and Dunlop Racings , and later Avon's.
FIA legal rollcage.
Welded in steel roof insert.
Plexi windows, etc.

Color gray with black & white checkers.





3rd rebuild, Phase 4.

Added more lightness by removing everything except for the outside skin.
Built spaceframe off the FIA cage.
1 piece fiberglass nose, and fiberglass doors. ( big weight savings )
Modified suspension ( but still based on the original Fiat 500 design )
The car still had a aircooled twin, at this point. But heavily modified ( based off a Polish 650cc ), and a straight cut 4 speed dogbox.
Color, yellow with blue checkers.








So after about a 30 year gap, that's what I brought over.

4th rebuild, phase 5

After going through it, rebuilding the brakes etc I ran it once with the 2 cyl, so I'm going to lump the engine swap into this.
Changed the ratio on the steering ( was way too indirect )
Put discs on the front, bigger drums on the rear.
Changed the boltpattern to 4X98mm so I could use 6X13 Campagnolo's with 175 / 13 Yoko's.
Swapped in a 1000cc 4 cylinder Abarth engine & Fiat 600 gearbox.
Opened up the front for a Ford Fiesta radiator.
Started to experiment with Aero.






5th rebuild, Phase 6.

Another engine swap, this time a BMW K1200RS bike engine.
Mated to a Hewland Mk9.

In the early stages I was still undecided if I was going to keep the original engine layout.








Or if I was going to make it mid engined.






I went for mid engined.

Which meant a much bigger rebuild...

[metalshapes]

So my thought was to keep it fairly close to what it was ( as it turns out, so much for that... ).

One of the tracks I like to run my cars at is really tight ( its a gokart track )
And the narrow width of the car was a big advantage.

I could really tell the difference between this car and my Capri.
Its at least a foot narrower, which means I can run much cleaner racing lines ( through the esses this car was untouchable )
So eventhough I lost a lot on the straights and accelerating out of the corners, I won enough ground in the corners to get me very close to the V8 swapped cars.

What I needed was more power...

[metalshapes]

Stock this car had 18HP,
The modified 650cc had about 45 to 50HP.
The 4 cyl Abarth had about 65HP.

The K1200RS has 130HP stock, more with a remap.
And apparently good for some 225 to 250HP blown on a stock bottom end ( but a much modified K1200 bike ran at Bonneville with 320HP )

So lots op potential.

I'll keep it under 250 because of the Hewland Mk9, and not to go crazy with expensive engine parts.

And Ill run it unblown with just a remap to start out with.

At its lightest, this car was 930Lb ( spaceframe, fiberglass bodyparts, aircooled twin )
But hopefully I can keep it close to about 1100Lb with the bike engine ( about what the car weighed stock ).

[metalshapes]

Elsewhere in this thread there are probably pics of the bellhouse I made to mate the K1200 to the Hewland.
The Clutch I made out of Tilton, Quartermaster, Volkswagen, and Porsche parts.
New exhaust.
Mods to the oiling system.
Etc...

One of the big motivators for this rebuild was the rear suspension.

It was still based on stock Fiat 500/126 parts, and in racing conditions the rear stubaxles have a reputation for snapping.

I kept an eye on them by having them cracktested ( its nice to live in an airplane oriented town ), but if one would ever let go that could total the car.

[metalshapes]

I really like DeDion rear suspensions.

They are nice and simple, have perfect camber control, and give predictable handling at the limit.

Building one around a Hewland wasn't going to be easy, though...

I narrowed a DeDion out of a Alfa Romeo Alfetta by 7.5", to get the total width to where I wanted it with the 8" racing wheels.
And located it with a modified 4 link kit from Burton Power ( meant for a Mk1/Mk2 Escort ).

And I moved some tubes around to mount the engine gearbox combination.

[metalshapes]

The engine is angled down ( and the gear box up ) to give plenty of room under it for a big tunnel.

This should really help with aero.

[metalshapes]

I had a straight shot between the clutch throwout bearing lever ( the gearbox housing I used didnt have one, so I machined the case to accept VW Vanagon parts ), and the pedals ( modified Fiat 850 ).

So I could build a really simple system with 2 Heim joints ( AKA Rose joints ), and a 5.5Ft long pullrod.