Guzzi motor on Fiat 500?

Author
Discussion

Dizel

Original Poster:

13 posts

48 months

Saturday 26th September 2020
quotequote all
This possibility has amused and intrigued me for some time.
I saw that some folk put a Guzzi engine in a Fiat 600 for the 24 Hours of Lemons a few years back.... But with mixed results.
It can be argued that the 90⁰ Guzzi v-twin motor was essentially designed for the tail of a Nuova 500 in 1961, prior to its use elsewhere and ultimately in the V7.

I love the Fiat 500 and also have fond memories of blatting around on various Guzzi motorcycles (V50, V65TT, T3, T3 Cali, 1000 Spada). That was many years ago, but the feeling stays in the bones.

The notion, therefore, of a Guzzi motor in the tail of a Nuova 500 just brings a smile to my face.

The standard car is around 500Kg and depending on the engine one might expect anything from 45 to 90bhp.

That sort of power-to-weight ratio can bring enormous fun.

Has anyone on these pages seen such a thing?

I am aware that the sensible money says stick a 126 motor and gearbox in and tune it....

But I cannot get out of my head the idea of a Guzzi motor behind the back seat slowly winding itself up and pushing a tiny 500 along the highway.

Apart from the immediate purchase of a straight jacket, does anyone have any advice that might encourage or deter me?





Edited by Dizel on Sunday 27th September 07:05

Pericoloso

44,044 posts

168 months

Saturday 26th September 2020
quotequote all
One of the fundamental problems of bike engines in cars is a lack of reverse gear in a bike gearbox .

Equus

16,980 posts

106 months

Saturday 26th September 2020
quotequote all
Pericoloso said:
One of the fundamental problems of bike engines in cars is a lack of reverse gear in a bike gearbox .
But unlike most bike engines, the Guzzi V-twin isn't wedded to an integral gearbox. It's therefore possible to graft the engine to a Fiat 500 or similar gearbox (complete with reverse gear).

For example, the Blackjack Avion trike couples it to a Volkswagen Beetle transaxle:
.


kev b

2,724 posts

171 months

Saturday 26th September 2020
quotequote all
Not certain but doesn’t the Guzzi engine spin the wrong way to mate with the Fiat transmission?

Dizel

Original Poster:

13 posts

48 months

Sunday 27th September 2020
quotequote all
kev b said:
Not certain but doesn’t the Guzzi engine spin the wrong way to mate with the Fiat transmission?
I hadn't even thought of crank direction.
It would be mounted "back to front", with exhausts to the rear and carbs forward.
I do not relish the thought of one forward and four reverse gears.
The Guzzi set-up was always a bit more "car" than bike. Dry single-plate clutch between separate engine and gearbox. The frame tubes come apart to remove the whole thing. But I hadn't thought of crank direction.... I like the image (above) of the motor mated to a Beetle 'box, although that is a much bigger, heavier piece of metal that may cost the rear seat even if possible... But it shows there may be solutions.

Turbobanana

6,634 posts

206 months

Sunday 27th September 2020
quotequote all
Years ago I recall watching a race for bike engined kit cars at Snetterton.

A guy had built what looked like a Caterfield 7 and, rather than follow the herd with the likes of Hyabusas or Blackbirds, had fitted a Guzzi v-twin.

It wasn't very fast, relative to the rest of the field, but I do remember it sounding like a NASCAR.

kev b

2,724 posts

171 months

Sunday 27th September 2020
quotequote all
Once again I am not sure of my facts but there is at least one transmission that you can fit the crown-wheel either side of the pinion to swap the direction of driveshaft rotation, or was it you could fit the transmission upside down for the same result.

Renault/Lotus and VW/Porsche spring to mind, these makers using similar style transmissions in FWD, RWD and mid engined positions ie Beetle 911 914 and R4 Dauphine Europa.

Not sure if Fiat ever did the same.

Equus

16,980 posts

106 months

Sunday 27th September 2020
quotequote all
Turbobanana said:
Years ago I recall watching a race for bike engined kit cars at Snetterton.

A guy had built what looked like a Caterfield 7 and, rather than follow the herd with the likes of Hyabusas or Blackbirds, had fitted a Guzzi v-twin.

It wasn't very fast, relative to the rest of the field, but I do remember it sounding like a NASCAR.
Are you sure it was a Guzzi V-twin?

There have been a few Locaterfields fitted with V-twins (usually Suzuki TL1000 or Aprilia RSV1000), but I've never seen one fitted with a Guzzi (certainly not racing in the 750 Club series), and I'd have thought that the air cooling would be a very major issue within a Locaterfield bodyshell at race speeds.

The Suzuki and Aprilia engines (both circa 130bhp) simply aren't powerful enough to be competitive, but a Guzzi (at least 40bhp less) would be woefully underpowered compared to the competition in the 750 Club Bikesports class. Actually, the Bikesports class has now become so specialised (with wings-and-slicks 'mini-le Mans'/Radical style cars) that BEC Locaterfields are no longer competitive, anyway - which is one of the reasons why the market for road-going BECs has been decimated - but that's another discussion.

The Guzzi engine has been a popular choice with three-wheelers like the Triking, Blackjack Avion and JZR, though.

Turbobanana

6,634 posts

206 months

Sunday 27th September 2020
quotequote all
Equus said:
Are you sure it was a Guzzi V-twin?

There have been a few Locaterfields fitted with V-twins (usually Suzuki TL1000 or Aprilia RSV1000), but I've never seen one fitted with a Guzzi (certainly not racing in the 750 Club series), and I'd have thought that the air cooling would be a very major issue within a Locaterfield bodyshell at race speeds.

The Suzuki and Aprilia engines (both circa 130bhp) simply aren't powerful enough to be competitive, but a Guzzi (at least 40bhp less) would be woefully underpowered compared to the competition in the 750 Club Bikesports class. Actually, the Bikesports class has now become so specialised (with wings-and-slicks 'mini-le Mans'/Radical style cars) that BEC Locaterfields are no longer competitive, anyway - which is one of the reasons why the market for road-going BECs has been decimated - but that's another discussion.

The Guzzi engine has been a popular choice with three-wheelers like the Triking, Blackjack Avion and JZR, though.
Yup, certain it was a Guzzi. Like I said, it wasn't as quick as it should have been and I do remember most of the engine being on display, presumably to facilitate air cooling.

Equus

16,980 posts

106 months

Sunday 27th September 2020
quotequote all
Turbobanana said:
Yup, certain it was a Guzzi. Like I said, it wasn't as quick as it should have been and I do remember most of the engine being on display, presumably to facilitate air cooling.
Well, I'm a long term follower of the 750 Championship, and I find that odd on two counts: firstly that I've not come across it, and secondly that it was capable of serving any function beyond that of a mobile chicane... 'not as quick as it should have been' would be a dramatic understatement, I think - the Guzzi motor isn't capable of producing enough power to even prevent it being a nuisance to other competitors!

Keep it stiff

1,781 posts

178 months

Sunday 27th September 2020
quotequote all
https://www.pistonheads.com/gassing/topic.asp?t=17...

The engineering on this little beauty is quite stunning.

Dizel

Original Poster:

13 posts

48 months

Sunday 27th September 2020
quotequote all
That Aprilia is certainly something.
A very thorough and professional job.
I am of an age and generation who saw 130bhp as rather a lot, even on something the size and weight of a 205 1.9, going through the front wheels. The thought of a 130-horse Nuova 500 terrifies me.
This Aprilia beast looks quite track focussed, although I can well imagine it sees some road use.
I am thinking really of a road car with the Guzzi/Fiat mix. Although in my childhood the very first Le Mans model saw some success in national race series, that was a bit of a one-off. Despite the efforts of Dr John and others, a Guzzi is more a 2-wheeled lorry than a racer. The smaller (500cc) Guzzis were very fast on the road, but struggled on a track.

However.... The joy of rumbling up alongside a car on a Spada at 80-ish on a dual carriageway at seemingly low revs, before changing up into top and disappearing is a wonderful experience. I would be very happy to be able to do the same (depending on gearing) in a Fiat 500.

I am thinking more of a Fiat 500 that can squirt its way easily out of corners at road-legal speeds and lope along English A Roads with plenty in hand.

I left track days behind (motorcycle, IMOC and similar) in the early nineties. Huge fun, but within a particular age range.

I think those of us who are drawn to the sound, feel and power delivery of a Guzzi are really in denial about being lovers of diesels...

Nonetheless. This thread has given me much food for thought. Particularly the Guzzi motor on a. Beetle transaxle.

kev b

2,724 posts

171 months

Sunday 27th September 2020
quotequote all
I think a Guzzi would be better suited to a road car than an Aprilia RSV due to its lower rev range and lazy torque spread.

I have an Aprilia Mille and the engine doesn't really feel comfortable below 5K rpm, it is certainly not a lugger by any means, of course between 6 and 10K rpm its an absolute beast but probably a bit highly strung for a bike engined road car.

Konrod

882 posts

233 months

Monday 28th September 2020
quotequote all
I would have thought cooling would be a major concern. The Fiat 500 twin is designed to cool itself with jacketing and an engine driven fan/dynamo (alternator) combo driving air across the engine bay. You would need to recreate that to provide airflow front to back with no crank driven pulley system. Not impossible, but probably a lot harder than mating engine to gearbox.

Keep it stiff

1,781 posts

178 months

Monday 28th September 2020
quotequote all
However.... The joy of rumbling up alongside a car on a Spada at 80-ish on a dual carriageway at seemingly low revs, before changing up into top and disappearing is a wonderful experience. I would be very happy to be able to do the same (depending on gearing) in a Fiat 500. I am thinking more of a Fiat 500 that can squirt its way easily out of corners at road-legal speeds and lope along English A Roads with plenty in hand.



Mindful of course that the 500 chassis in terms of steering, road holding and general stability is not exactly precise. Granted it can be improved but the wheelbase and track is such that combined with English A Roads it would most likely have you heading in directions of its own choosing!

Dizel

Original Poster:

13 posts

48 months

Monday 28th September 2020
quotequote all
As a firm believer in mechanical democracy, I support the right of every vehicle to travel in a direction of its own choosing.

But I do take your point.

I am old enough to have driven and ridden things that do not always demonstrate an entirely clinical response to (and understanding of) instructions given through pedals and steering.

I do slightly lament the "over-tyred" nature of modern cars. We recently sold an old Corsa in which the children learned to drive. A shopping car with less than 80bhp, it sat on 195 X 16 tyres with a soppily low aspect ratio....for shopping and driving lessons.

So going back to a tyre size you can fit on a shopping basked and drum brakes with friction surfaces made of cake will be a tactile pleasure.

We already run older cars (60s) on sunny days and there is something quite special about not knowing whether you will drive past the next hedgerow of stop for a chat in the middle of it, backwards.

But... I do take your point.

Madison Hardware

1 posts

9 months

Saturday 23rd December 2023
quotequote all
Hey guys. I am new to the PistonHeads forum. You guys really seem to know your stuff.

I have owned a '48 Fiat Topolino 500 B for five years. The engine is in front with the radiator facies the firewall. I bought it on BaT. Its horrendously under powered at 15 h.p. and the gear box is so sloppy, its a slight miracle to find 2nd or 3rd and not lose revs. Once the revs are lost, I have to pull over and start over in 1st. Miserable. I have maybe put 15 miles on the car and its been sitting for years.

I looked into an engine swap to a 36 h.p. Abrath, but that would take a major cut and chop job to the frame rails, et al and still does not solve the really sloppy gear box which is actually a bigger problem than the h.p. My goal is simply to upgrade the h.p. and not change the character of the car.

I looked into electric conversion. That would cost double what I paid for the car, the range would only be 60 miles (figure 40) and there is a three year wait. I am to the point of re-selling the car absent any other good ideas.

I tried attaching a photo, but I am prohibited from doing so as a new member. If you google: BAT, 1948 Fiat 500 Topolino and click on the powder blue car, it still has all the photos of the car and the engine bay. If any of you really smart guys have a solution for me including the Guzzi motor, it would be good to hear from you. In this thread, I could not figure out if the forward and reverse rotation of the Guzzi transplant would work for this car. Being this is a front engine car and since the Guzzi has a gear box connected to it, maybe that is the way to go. I also don't car if the car ends up being automatic or shift.

Here is the thing, I am a motorhead for sure, but my detailed knowledge at this level is not deep. Lastly, if you know of any shops on the West Coast, or even as far as the Mid-West that would be a good fit for doing this work, those suggestions would also be welcome as well.

Thanks in advance guys!

Merry Christmas!

Paul

Mr Tidy

23,767 posts

132 months

Saturday 23rd December 2023
quotequote all
Hi Paul.

The Guzzi motor idea was for the Nuova 500 as they were built with an air-cooled twin (flat not V though). I remember reading about one years ago that had been fitted with a BMW flat-twin motorbike engine for a bit more performance.

But I don't think it would straight-forward to put an air-cooled V-twin in a Topolino in place of a water cooled 4 cylinder motor.

I don't know but I would be surprised if nobody had found a way to tune a Topolino back in the day.

CQ8

789 posts

232 months

Sunday 24th December 2023
quotequote all
Hi Paul,

I searched for your Fiat on BaT and found it, what a lovely looking car!

I also saw a listing for one that had been turbo charged by a shop in Salinas. That seems a good and much simpler solution to the problem, and you get 40bhp.

https://bringatrailer.com/listing/1951-fiat-500-to...

I wonder if your gearbox needs attention? I know it won't be the last word in precision shifting but that doesn't sound right.

Edited by CQ8 on Sunday 24th December 16:36

Skyedriver

18,498 posts

287 months

Sunday 24th December 2023
quotequote all
Apologies for taking this "off-piste" a little but there is a trend to fit the BMW in line 4 bike engine to an Imp gearbox, giving up to 120bhp in the back of an Imp.