500 (Classic) Newbie with a 500L engine swap project

[Cam500]

Hi everyone. I have had it for a while, but I purchased a 72' Fiat 500 Lusso in Atlanta Georgia US.

It was complete when the previous owner blew the engine (likely pushed the small engine just a bit too hard). At that point he thought "we'll if I'm going to rebuild the engine I should do the entire car!"

Unfortunately he only got half way before choosing to trade the project for a BMW 2002 project.

The mechanic who traded it did not want to fund it but was nice enough to help me build it up and we are keeping the 500 engine for the future but swapping in a fiat 850 spider engine (a more common car in the US but often rusts before the engine gives out). Although I can't find an example I'm under the impression SOMEONE has done this before. I'm hoping to keep the appearance original in most respects and a standard 850 should triple the HP while leaving the option of boring to 1 liter if I go crazy. Although I think front disk brakes might be in order before that. But I digress.

I'll post pictures up shortly of its state when I purchased it and follow up when it comes back from paint, post Christmas I expect. I look forward to any suggestions or input!

Cam

 

[Cam500]

A look at what it looked liked before any metal work and unpainted.

Edit: sorry if the links are not showing images, you can visit this site and scroll down to fiat 500 Lusso in the projects section: http://heritagemotorsports.us/projects/

 

[babbo_umbro]

It may have been done but there's no sensible way to put an 850 engine - four-cylinder, water-cooled - in the space normal occupied by a 500 engine - two-cylinder, air-cooled. Apart from the need to put a radiator somewhere, when there's nowhere, along with all the plumbing, (from memory) the 850 engine is about six inches longer than the 500. The rear cross member of the 500 body would have to be completely rebuilt and the chances of having a standard-looking car are nil. Look for a 500 engine, or an engine from a Fiat 126 before it went to a flat twin engine late in its production life.

 

[the hobbler]

Hi Cam;
Welcome to the Fiat Forum---look at the u-tube films regarding Fiat 126. In Poland (where they were made) it is quite common to fit the small Fiat 4 pot water-cooled engines into the back of the 126's, often without any big external bumps and lumps. If you have even simple engineering facilities, i see no reason why the 850 engine and gearbox can't be made to fit. If you do proceed with this change, you MUST uprate the brakes and suspension--again you might be able to use these bits from the donor 850--there is a very good site--Fiat 500 Lusso to Abarth 695 (I think that's the title) which I think will be of great help---go for it!!

 

[babbo_umbro]

Hi Cam;
Welcome to the Fiat Forum---look at the u-tube films regarding Fiat 126. In Poland (where they were made) it is quite common to fit the small Fiat 4 pot water-cooled engines into the back of the 126's, often without any big external bumps and lumps. If you have even simple engineering facilities, i see no reason why the 850 engine and gearbox can't be made to fit. If you do proceed with this change, you MUST uprate the brakes and suspension--again you might be able to use these bits from the donor 850--there is a very good site--Fiat 500 Lusso to Abarth 695 (I think that's the title) which I think will be of great help---go for it!!

I'm sorry, but I know quite a bit about rear-engined Fiats, having owned and modified several 500s, 600s and 850s, and - unless you know a lot more than I do - I think this is a wild goose chase.

There is much more space under the square rear bonnet/hood of a 126 than under the sloping one of the 500, but I still doubt that the 850 engine would go in without major surgery. I'd call a front-mounted water radiator where there was none beforehand a big external bump and lump; mounting the radiator in the back, like the 600 and 850, would be crazy from the handling viewpoint. 126 production moved to Poland in 1979 I think. The 126 Bis had a water-cooled flat - but not opposed - twin and I'd imagine that this is the base for any 4-cylinder, water-cooled, modifications.

The 500 has been fitted with a variety of engines (Panhard Dyna 850 flat twin, BMW 700 flat twin - I did that myself many years ago and the result was sensational - and, of course the Steyr 650 flat twin). Going from the vertical twin to a flat, opposed, twin has a major beneficial effect on the handling as the centre of gravity at the rear is lowered significantly. The air-cooled flat four Citroen engine - the GS if I remember correctly - was another extreme possibility. Even if it would go in, the weight and centre of gravity of the 850 engine - higher and further back - would destroy any hope of a good-handling car, you'd have to put an anvil or a bag of cement in the front just to keep the wheels on the ground.

The suspension parts from an 850 will simply not fit on to a 500, with the possible exception of the front uprights and brakes. The 500 was a lot smaller in all respects than the 600, and even more so than the 850, which was a stretched 600. As you note, in the unlikely event that an 850 engine could be squeezed into a 500 body shell, you'd also have to instal the 850 gearbox as the engine spins the other way from a 500 - 500 crank goes clockwise looking from the timing chain end while the 850 is anti-clockwise. There were 124 engines fitted to 850s, with standard and non-standard bodies, generally involving a gear-driven camshaft - rather than chain - to enable the crankshaft to spin the other way.

500L to Abarth 695 is one thing but 500L to 850 mongrel is quite another.

I'd like to be proved wrong - believe it or not - but I think you'll find this an expensive waste of time compared with going for an air-cooled twin, probably based on the 126 engine, as you start off at 650 cc, which was also used in the Mark 1 Panda in some European markets.

 

[the hobbler]

Morning all;
Beware if you do decide to try and fit a Mk1 panda engine into a 500--I am advised that it turns the opposite way to the aircooled 126 '650' and I don't know whether it can be made to turn the opposite way (as the 850 engine could when fitted into a 600). I realise that Cam would need to fit the 850 gearbox if he tried to fit an 850 engine (and he can always leave the boot lid propped open), but when I was at Radbourne Racing you would be surprised what we saw inserted into the rear end of 500s--including vw engines! I do realise the engineering problems Cam would encounter, but where there is a will there will always be a way!

 

[Cam500]

Thank you all for both your critical observations and supportive comments. It's late here in the US but I thought I'd throw a few more bits out.

I will be using the gearbox as well as the motor from the 850. And my mechanic has much the same attitude about "where there's a will...". He is often seen doing M20 engine swaps into the aforementioned 02's but for something more in the vein of this forum he's also working on a beautiful Fiat 850 with a 124 motor conversion.

I expect that even with my best efforts the rear will need to be propped and I know that the transmission won't fit without both alteration and a modification of the rear trailing arm mounts. But both seem surmountable problems. But I'm aware that those are only a few of them

A minor point but we'll also be changing to a dual master cylinder for improved safety.

I'm excited to move forward and I'll keep you all informed of any changes Merry Christmas and a Happy New Year!

 

[jjacob]

Have to agree with babbo umbro on this one. If you are hiring someone to do this work then it will be EXPENSIVE. Results are iffy. This is not an easy conversion. It would be way cheaper to build a 700cc engine from a 126 650 engine. It would have similar performance without the fitment headaches.
John

 

[PointFiveO]

Hi Cam I'm just wondering if you are going to all of that trouble to re-engineer the car, changing the gearbox etc and I imagine you'll need to have parts made up etc, why go for an 850 engine that would be little more powerful than a bored out large capacity 650 engine anyway? I have seen threads on some of the 126 UK sites about turbocharging the 650 engine with very good results or altenatively if you still want to fit a different larger engine check out this thread on the UK 500 owners site about fitting a 1.8 Subaru flat four engine, one the second post there is a link to a YouTube video of a conversion that was done by a company called z cars. It is also the much older ohv flat four from the seventies and eighties which is quite common in the USA, certainly easier to source than the fiat 850 engine. I think the expense of fitting a larger four cylinder engine to a 500 would be high but if going down that route the Subaru engine would be my preference, at least you would have a significant enough increase in power and torque over a tuned twin to maybe justify the expense.

Colm.

 

[dragonwagon]

Considering the light weight of the 500 installing a huge great lump of iron in the back will ruin the car's balance and handling to such an extent as to render it all but undriveable except in a straight line. A 650 / 700cc twin will produce 35 - 40 bhp, much the same as a standard 850 unit without the fitment and cooling headaches and perhaps more importantly retain the balance of the car. A further bonus of this route is the ability to leave the car looking standard adding to the fun.

 

[PointFiveO]

Typical! I forgot to attach the link to the thread on the UK forum about the Subaru flat 4 transplant, here it is http://www.fiat500club.org.uk/clubchat/viewtopic.php?f=1&t=7952
On the second post there is a YouTube link showing the car with the Subaru engine and while I agree with the previous poster about fitting a tuned 650 engine being preferable my point was that if you still insist in going to all that trouble to reengineer the car to take a water cooled 4 cylinder engine and the required bits then it might at least be an engine that would show a tuned 650 a clean pair of heels! In fairness if you check out the video it seems to be a tidy conversion that fits in the engine bay without the need for modification thereby keeping the car standard looking, also seems to handle pretty neatly as well. Big bucks though I'd say as certain parts need to be made up specifically.

Colm.

 

[Cam500]

The worry i have from writing on forums is that In my experience replying to each objection gets out of hand because your justifying your thought process to a group.

that said I will say that the 700cc project requires its own levels of technical knowledge and work and push the engine close to the boundaries of what can be taken out of it. From my research the original head can only be bored out close to 650. And even then your threatening to make the walls of the chamber too thin... The solution being a Panda head. Which is not sold, used, or offered in the US making it a bit cost prohibitive. Not to mention that while it will slide right on I'm under the impression modification would then need to be done.

Forgot to mention that the Panda head would most likely fit on a 126 engine. Again, Rarely seen here. One popped up on eBay about 8 months ago and was quickly sold for much more than double what a used 126 is worth in the UK.

I do hear all of your arguments and take each one seriously though. Mostly because I've gone through them myself on more than one occasion.

The weight increase has been a worry in the past but I always have questions that can't be answered by google, for example. A stock 850 weighs 1500 lbs, where as a 500 is 1100 lbs. but what is the actual wight difference between the power plants? I haven't seen fit to carry my respective motors to an industrial scale, so I'm curious! If anyone has this knowledge at their fingertips it would be a great help.

On a related note, as someone who has culled the Internet for information on 500 engine swaps I think it would be helpful if this forum tried to combine as much as they know into one source, saving a bit of trouble for 500 fans in the future. For example I swear it took three different sources to find out which direction the respective engines turned! And even then peouple still aren't quite clear about it sometimes... But all of this is just my 2 cents. Hope everyone is having a great Boxing Day

Cameron

 

[babbo_umbro]

Typical! I forgot to attach the link to the thread on the UK forum about the Subaru flat 4 transplant, here it is http://www.fiat500club.org.uk/clubchat/viewtopic.php?f=1&t=7952
On the second post there is a YouTube link showing the car with the Subaru engine and while I agree with the previous poster about fitting a tuned 650 engine being preferable my point was that if you still insist in going to all that trouble to reengineer the car to take a water cooled 4 cylinder engine and the required bits then it might at least be an engine that would show a tuned 650 a clean pair of heels! In fairness if you check out the video it seems to be a tidy conversion that fits in the engine bay without the need for modification thereby keeping the car standard looking, also seems to handle pretty neatly as well. Big bucks though I'd say as certain parts need to be made up specifically.

Colm.

So where's the radiator?

 

[babbo_umbro]

The worry i have from writing on forums is that In my experience replying to each objection gets out of hand because your justifying your thought process to a group.

that said I will say that the 700cc project requires its own levels of technical knowledge and work and push the engine close to the boundaries of what can be taken out of it. From my research the original head can only be bored out close to 650. And even then your threatening to make the walls of the chamber too thin... The solution being a Panda head. Which is not sold, used, or offered in the US making it a bit cost prohibitive. Not to mention that while it will slide right on I'm under the impression modification would then need to be done.

Forgot to mention that the Panda head would most likely fit on a 126 engine. Again, Rarely seen here. One popped up on eBay about 8 months ago and was quickly sold for much more than double what a used 126 is worth in the UK.

I do hear all of your arguments and take each one seriously though. Mostly because I've gone through them myself on more than one occasion.

The weight increase has been a worry in the past but I always have questions that can't be answered by google, for example. A stock 850 weighs 1500 lbs, where as a 500 is 1100 lbs. but what is the actual wight difference between the power plants? I haven't seen fit to carry my respective motors to an industrial scale, so I'm curious! If anyone has this knowledge at their fingertips it would be a great help.

On a related note, as someone who has culled the Internet for information on 500 engine swaps I think it would be helpful if this forum tried to combine as much as they know into one source, saving a bit of trouble for 500 fans in the future. For example I swear it took three different sources to find out which direction the respective engines turned! And even then peouple still aren't quite clear about it sometimes... But all of this is just my 2 cents. Hope everyone is having a great Boxing Day

Cameron

Remember that with the 500/126 engine the weight of the engine tells the whole story, with any water-cooled engine you need to add the weight of the water, radiator and water pipes - though I admit a radiator at the front would help to keep the front wheels on the ground.

It's decades since I handled a 500 or 850 engine but I can tell you that I could shift a 500 engine around easily on my own but not an 850 engine - my guess would be that the difference is about 40 lbs. And the 850 gearbox has an iron casing unlike the 500 (and 600) which is aluminium, so that probably adds another 15 lbs or so.

Don't understand your point about the head being bored out to 650 cc.

My honest opinion is that putting an 850 engine in a 500 would ruin it from every aspect. If you really need more oomph than a well-tweaked 700cc Fiat engine could offer and you're going to all that expense and engineering input, I'd have thought the modern solution is either a flat (opposed) twin BMW motor bike engine or a Moto Guzzi V-twin. Both would need help with cooling - though they have no problems in a 'bike - both would fit, both would make the Cinquecento a real bomb and both would leave the character otherwise unaltered and returnable to standard spec without too much difficulty..

 

[Cam500]

Don't understand your point about the head being bored out to 650 cc.

Sorry if I was unclear, my knowledge is limited and I'm doing some learning on the project as you would expect. My point is that anyone attempting a 695 clone would likely first acquire a 126 motor and transmission to add strength and avoid double clutching. Not to mention the head (as far as various sources say) of a standard 500 is likely to fail if bored out too far. The implication is that regardless of the modification I will be forced to throw out (figuratively speaking) both the engine (which needs rebuilding before modification) and the transmission (which should also be rebuilt if I'm going that route).

That is; if I want to increase the power of a standard motor I find myself on a slippery slope that will likely cost me my wife if not kept in check. And no girl wants to ride in a motorcycle powered, chain driven car. So that keeps me firmly away from that level of modification.

The problem is that I'm walking a thin line between purists (same company and generation motor as the 500) and modified car enthusiasts. a position guaranteed to get me put to death by either side, but likely will interest both when its successful.

Hope that sheds a bit more light.

Cameron

 

[babbo_umbro]

Sorry if I was unclear, my knowledge is limited and I'm doing some learning on the project as you would expect. My point is that anyone attempting a 695 clone would likely first acquire a 126 motor and transmission to add strength and avoid double clutching. Not to mention the head (as far as various sources say) of a standard 500 is likely to fail if bored out too far. The implication is that regardless of the modification I will be forced to throw out (figuratively speaking) both the engine (which needs rebuilding before modification) and the transmission (which should also be rebuilt if I'm going that route).

That is; if I want to increase the power of a standard motor I find myself on a slippery slope that will likely cost me my wife if not kept in check. And no girl wants to ride in a motorcycle powered, chain driven car. So that keeps me firmly away from that level of modification.

The problem is that I'm walking a thin line between purists (same company and generation motor as the 500) and modified car enthusiasts. a position guaranteed to get me put to death by either side, but likely will interest both when its successful.

Hope that sheds a bit more light.

Cameron

I still don't understand what/why you're writing about boring out cylinder heads - why would a cylinder head need boring out? I'd have thought using a 500 head, preferably with oversized valves - specially inlets - would be the answer as it would give you an automatic lift in compression ratio. You might reshape the combustion chambers to improve combustion and possibly to prevent the compression ration from going too high, but you bore out something cylindrical - like a cylinder, in fact.

Also - why would you want to avoid double declutching? That's half the fun of having a 500.

I never mentioned a chain-driven car. (Along with several others, I'm trying to be helpful, so help yourself by reading what's written.) You could put a modern air-cooled twin where the 500 engine is without any need to change the body (or add all the paraphernalia of water cooling), but using a 500/126 (or maybe 600) gearbox. Modern bike engines come with useful features like starter motors and friendly clutches, and bags of poke. If it spins the wrong way, perhaps you could go for your 850 gearbox. Google "moto guzzi morgan replica" to see what the motor looks like and imagine that mated to a Fiat 500/126/600 gearbox.

The BMW 700 engine that I put in a 500 many years ago was very similar to the current BMW 'bike engine with the addition of a fan on the end of the crankshaft and some rudimentary cowlings for cooling, plus a combined dynamo and starter motor inside the fan, but a modern engine would have those already. It was an opposed twin, so silky smooth - unlike a 500 or 126 - with masses of lovely ball and roller bearings, efficient hemispherical cylinder heads, feather-light pushrods and an insatiable appetite for revs - which the 500/126 engine will never have. I fitted it with twin Amal Monobloc carbs to increase the power significantly and it offered something like 45 horsepower at 7000 pm, making it a real Mini Cooper eater. I could whip the engine out and slot the original 500 engine back in in less than half an hour, including connecting the heater trunking (to keep the girlfriend happy).

 

[Bambino]

Have to agree with babbo umbro on this one. If you are hiring someone to do this work then it will be EXPENSIVE. Results are iffy. This is not an easy conversion. It would be way cheaper to build a 700cc engine from a 126 650 engine. It would have similar performance without the fitment headaches.
John

I have to agree also.

You'll get a lot more fun and much less heartache (and wallet ache) by starting with a standard 77.0mm bore (652cc) and going up to any of the following: 79.5mm for 695cc, 80.0mm for 704cc, 82.0mm for 740cc and 85.0cc for 794cc all with a 70.0mm stroke. All these kits are available.

Then add bigger valves, ported and matched inlet tracts, sports exhaust, fast camshaft, balanced components, higher compression ratio, better carburettor etc. etc. and you'll get remarkable improvements in both torque and power over the standard car.

Then there is the transmission, suspension, brakes etc.

And as John and others have said, the bonus is that it all fits without major surgery

I've done the 695cc conversion recently to a 500F and written about it on this bulletin board. I've owned a few exotics over the years and my little red car is about as much fun as you can get for the money spent.

Chris

 

[Cam500]

I reiterate that arguing my vision is difficult when not in person, but I'll try cost next to point out a problem.

To start my mechanic is doing this for little to no cost.

More importantly, on eBay UK as we speak is a complete engine+gearbox for roughly $2500 which can be picked up in a matter of hours. To purchase the same in the US, without shipping (I don't live near the seller who is the only key provider) is roughly double. $5000 before I can even see it, and comes with no warranty.

No dilussions of converting the un-believing or simply more reasonable people above. Just painting a picture

 

[babbo_umbro]

How much would it cost to ship a Fiat 126 engine and gearbox from Italy? Serious question. The cost of buying a standard engine in Italy would be very small and I'd be prepared to look into doing so and then arrange shipping if it stops you from going down the cul-de-sac that you describe.

Just by Googling "Fiat 126 motore" I came up with this

http://annunci.ebay.it/annunci/rica...na/fiat-500-126-motore-elaborato-650/39114533

on the first page a completely tweaked 126 engine for 2000 euros - 2500 dollars I reckon.

Or for 250 euros

http://annunci.ebay.it/annunci/rica...ie-montabile-anche-su-fiat-500-l-f-r/37508718

if you want to do it yourself.

I'm going to be really brutal here, as I hate to think of a perfectly feasible project going wrong.

I predict that going the 850 engine and gearbox route your project will become mired in almost insoluble engineering difficulties, which will extend the timescale - and cost - beyond anything bearable; in the massively unlikely event that it's ever finished the result will be an abortion that's undriveable on the road; it's much more likely to become a heap of hacked-about Fiat 500 and Fiat 850 bits that never see the light of day.

Sorry - the best that I can hope for is that this persuades you to take all the advice that you've been given; next best is that my opinion makes you so determined that you do actually prove us wrong by completing a decent project.

 

[Bambino]

No dilussions of converting the un-believing or simply more reasonable people above. Just painting a picture

I guess we are just trying to convince you not to build a FrankenFiat that may turn out to be an undriveable dog that no money will fix.

I've witnessed the destruction of at least one nice car by shoehorning a larger engine into an engine bay that had to be severely modified. It never ran well, was badly under-braked, overheated terribly and wouldn't handle because the chassis wasn't designed for the power or weight transfer. It ended up being scrapped after a nasty accident that nearly killed an occupant.

Whatever you do, research it well and keep us informed - there is knowledge, experience and wisdom on this list.

Kind regards,
Chris