1971 fiat 850t 3 years in and still welding

[homersimpson]

As much as I like a crazy plan I would be inclined to stick with the original engine type and find a way to get a bit more power out of it, do they make any tuning parts that would fit this engine?

What are the original engines like, are they a good solid engine like the a-series or a bit more fragile?

[grumpybadger]

I could try and have the fiat flywheel mounted to the honda crank in one way or another but that kind of work becomes expensive very quickly, and
I don't have the machines to handle something of that diameter so it would need to be out sourced.

The honda flywheel could be turned down, but the contact patch for the clutch would be a pitiful 20mm

I think that honda designed the d series at the top of the cc range and then downsized for the smaller engines so the 1.7 vtec has the same size block and flywheel as the 1.3.

I massively underestimated how small the fiat motor actually is.

The main reason for swapping engines was reliability and the ease of getting parts in the event of a breakdown.

[commycouper]

I've been doing a bit of catching up as I've missed quite a few Retro Rides thread updates recently.
Well....that panel you formed using
the 'clamp/former/buck/trip hazard' is fantastic!....it looks amazing. I did a similar thing when I was welding the truck up. It took a bit of time to make the buck/former....but it definitely paid off in the end.....just as it clearly has for yourself.
I like how you're thinking where the engine is concerned. I was toying with the idea of put an M57 BMW engine in the truck for the same reasons you have explained. The thing's I took into consideration were, it would be a lot more powerful than the original engine and parts would be easier and cheaper to source. But then there was the extra time and effort to fit it into the bay, fabrication of adapter plates for the gearbox etc, cooling is an issue according to folk that have previously done the conversion amongst a whole host of other stuff. Plus, the whole telling the D.V.L.A and insurance thing put me off. So....I opted to stay with the original....or should I say, the same 'variant' as the original engine. Which....I think I'm now starting to regret as the cost of the 'no going back' rebuild on it has spiraled out of control. I'm £1800 in....and all I have is a block and pistons!
Anyway....enough about my problems, keep up the great work, it's really starting to take shape now 👍🏻

[grumpybadger]

May 3, 2024 21:15:04 GMT homersimpson said:

As much as I like a crazy plan I would be inclined to stick with the original engine type and find a way to get a bit more power out of it, do they make any tuning parts that would fit this engine?

What are the original engines like, are they a good solid engine like the a-series or a bit more fragile?

100 series engines have been race tuned at upto 100hp with road going variants commonly around 80hp.

There is the coupe/spider engine with 52hp and much better gear ratios.

The problem with any of these is that they're rare and expensive.
There are even parts to reverse the direction of a twin cam and mount it to the 850 gearbox, but again, it'll be expensive.

As far as i'm aware the 903cc engine is seen as a solid unit by most despite being a three bearing crank but it's not the easiest to tune

The small block limits bore size and the head configuration limits valve size.
The head also contains the intake manifold making gains there a little awkward.

That said performance exhausts and a better carburetor are readily available and can give some gains.


I figure converting to an alternator with electric fan as well as water and fuel pumps should help with cooling and reliability.

[grumpybadger]

May 4, 2024 6:59:23 GMT commycouper said:

I've been doing a bit of catching up as I've missed quite a few Retro Rides thread updates recently.
Well....that panel you formed using
the 'clamp/former/buck/trip hazard' is fantastic!....it looks amazing. I did a similar thing when I was welding the truck up. It took a bit of time to make the buck/former....but it definitely paid off in the end.....just as it clearly has for yourself.
I like how you're thinking where the engine is concerned. I was toying with the idea of put an M57 BMW engine in the truck for the same reasons you have explained. The thing's I took into consideration were, it would be a lot more powerful than the original engine and parts would be easier and cheaper to source. But then there was the extra time and effort to fit it into the bay, fabrication of adapter plates for the gearbox etc, cooling is an issue according to folk that have previously done the conversion amongst a whole host of other stuff. Plus, the whole telling the D.V.L.A and insurance thing put me off. So....I opted to stay with the original....or should I say, the same 'variant' as the original engine. Which....I think I'm now starting to regret as the cost of the 'no going back' rebuild on it has spiraled out of control. I'm £1800 in....and all I have is a block and pistons!
Anyway....enough about my problems, keep up the great work, it's really starting to take shape now 👍🏻

Thanks

Yep the admin side can be a pain for sure though i've already upgraded the brakes all round so thats wxrabbit hole I'm already in.

I've got a way to go before it becomes urgent but then I have been looking out for a coupe motor and box for three years now to no avail.

Time will tell

[glenanderson]

What about a C1/107/Aygo engine.

Could you fit the whole engine and gearbox from a front wheel drive donor and ditch the Fiat transaxle?

[grumpybadger]

May 4, 2024 10:40:40 GMT glenanderson said:

What about a C1/107/Aygo engine.

Could you fit the whole engine and gearbox from a front wheel drive donor and ditch the Fiat transaxle?

Not without a massive amount of work either flipping the gearbox and moving the bulkhead forward a little or moving the bulkhead a lot and re building the rear suspension at the same time.

Both a step too far for me.

[Jonny69]

May 4, 2024 9:01:06 GMT grumpybadger said:

I figure converting to an alternator with electric fan as well as water and fuel pumps should help with cooling and reliability.

Absolutely 100% go for an alternator and electric fuel pump. Alternator will stop you killing the battery-dynamo-starter-battery-dynamo-starter in an endless loop. Electric fuel pump self-primes everything and the engine just starts with no excessive cranking to get fuel up, no matter how long you’ve left it. Those two things transformed the usability of my car 👍

[grumpybadger]

Having put the engine to one side quite literally it was time to start chopping into the rear wheel well.
Everything on this side has been worse that the other. I think it might have been parked up against a wall, or possibly half in a lake at some point.

I started to fabricate repair sections




Before deciding to do the whole thing.
Lets see how deep the rabbit hole goes





It didn't put up too much of a fight in the end, the spot welds are really prominent, partially due to a heavy handed operator but mainly due to fiat using the welder as a clamp to make up for poor alignment.


I've made sure I don't run out of discs anytime soon



I got a look at the spring seat and decided to take it off just to be sure







Sure enough



Nothing else for it





At this point I realise that having started from the outer arch lip i'm now 180mm from the centre of the van and still cutting.
At this point i'm wishing i'd taken the blue pill. (Not that one)



I knew the suspension mount was also suspect but hadn't been in a position to get a really good look at until I turned the van around.
I'd left it in situ to help with aligning the rear cross member and only tacked it in place.

I decided to chop it out for a good look









As suspected





This is 2mm steel so not as easy to work with but so much nicer to weld




Clamped in for a trial fit of the rear arm


Then made permanent



I decided to do that now as access is so much easier with the arch and well out of the way.

Next up, rebuilding the well.

[jonsey]

You are a hero.

[vitesseefi]

May 10, 2024 20:23:57 GMT jonsey said:

You are a hero.

I’m impressed on a number of levels. I’ve been accused of stubbornness and unreasonable in fixing stuff that was beyond fixing…. But I’m pretty sure I’d have run away from this……

Your wheelarch panel maker device is just brilliant and the resulting panel looks excellent.

As for the mechanicals…. Reluctantly (I do like an engine /gearbox swap), I’d probably have agree with sticking with the Fiat basics and improving them as far as possible. The scale, layout and reverse rotation is a highly problematic combination!

Keep up the good work!

[teaboy]

May 10, 2024 20:23:57 GMT jonsey said:

You are a hero.

He is either a hero or a lunatic, possibly a combination of the two.

This thread is inspirational, whenever I start to feel overwhelmed with my own project I just think about this.

If he can fix this up then I can do mine.

The work going into this is incredible.

So on reflection, I’m going to go with hero.

[grumpybadger]

May 10, 2024 20:23:57 GMT jonsey said:

You are a hero.

Wow, utterly humbled.

[homersimpson]

May 11, 2024 16:40:09 GMT teaboy said:

May 10, 2024 20:23:57 GMT jonsey said:

You are a hero.

He is either a hero or a lunatic, possibly a combination of the two.

This thread is inspirational, whenever I start to feel overwhelmed with my own project I just think about this.

If he can fix this up then I can do mine.

The work going into this is incredible.

So on reflection, I’m going to go with hero.

To restore some vehicles you definately need a combination of the two, when it is so bad that the vehicle isn't really worth doing thats when the insanity and the determination to fix it come what may kicks in.  Once finished though you have something to be proud of and the best part for me is if people looking at it don't know you have had to do major work on it :-)

[ditchdigger]

I really like the idea of the Honda motor on the Fiat transaxle.

One thing of note. These transaxles have ridiculously short gears. The "tall" ring and pinion from an 850 Special is 4.65:1, the spiders and coupes used a 4.87:1 the Abarths used the incredibly rare 3.97:1.

I believe the vans had a 5:57:1 R&P, so with the factory tire size it will be spinning 4500RPM at 50mph. It would have a gearing limited top speed of around 75mph, that would be at a redline of 6500rpm.

I just want to bring this to your attention before you invest too much time in the swap and then realize you won't be satisfied until you swap the ring and pinion to the 3.88:1 gearset (over 1000 from Berni Motori or Middle Barton) and realize you have to rebuild the entire transmission just to get to it. The pinion gear is the first thing that gets installed in the box.

Also being an 850 transmission your 2nd gear synchro is perished, they all are. They use an expanding ring synchro like a Porsche 901 or Alfa 105/115 and aren't inexpensive pieces to buy.

This is why I am putting a Porsche 5 speed into my 850 Berlina. It was actually more affordable for me than building the Fiat box the way I wanted.

[metalshapes]

I think I'd look into Renault ( 5 ) or rear engine Skoda's before I'd go for a Porsche ( 901?) box.

Or, if it doesnt have to be a 5 speed, the 4 speed out of a Simca Rally 2 ( google has the final drive of that one at 3.89).

With the Fiat 850 and the Simca 1000 being as closely related as they are, it may even fit between the rear swingaxles without having to move or modify them.

[danknight]

i would try and fit a vw transaxle there is loads of parts available and specialist , then fit a modern short 3 cylinder engine

[grumpybadger]

May 14, 2024 15:39:09 GMT ditchdigger said:

I really like the idea of the Honda motor on the Fiat transaxle.

One thing of note. These transaxles have ridiculously short gears. The "tall" ring and pinion from an 850 Special is 4.65:1, the spiders and coupes used a 4.87:1 the Abarths used the incredibly rare 3.97:1.

I believe the vans had a 5:57:1 R&P, so with the factory tire size it will be spinning 4500RPM at 50mph. It would have a gearing limited top speed of around 75mph, that would be at a redline of 6500rpm.

I just want to bring this to your attention before you invest too much time in the swap and then realize you won't be satisfied until you swap the ring and pinion to the 3.88:1 gearset (over 1000 from Berni Motori or Middle Barton) and realize you have to rebuild the entire transmission just to get to it. The pinion gear is the first thing that gets installed in the box.

Also being an 850 transmission your 2nd gear synchro is perished, they all are. They use an expanding ring synchro like a Porsche 901 or Alfa 105/115 and aren't inexpensive pieces to buy.

This is why I am putting a Porsche 5 speed into my 850 Berlina. It was actually more affordable for me than building the Fiat box the way I wanted.

Thanks for your reply, I appreciate you sharing your knowledge on the subject.

Despite the hours of research I've put in I've decided against the honda engine.
It appeared to be an easy solution to several problems in one go especially if it could be mated the the fiat box however whilst doable it actually turned out to be pretty complicated.
I was never in this for the technical exercise so it started to make less and less sense.

That and the fact that the van engine bay is so small the honda gradually gets further and further out of the back as you add adaptor plates and mounts etc.
It could still be a good option for a spider or coupe though.

One thing that cropped up in the research is that the track width of the vans is narrower than the spider or coupe, as they share rear arms the difference must be the pick uo points either side so I'm not sure which transaxles will even fit, the fiat unit is pretty snug.

I'd heard about the low gearing but I'm not sure how much further north of 55mph i'd want to go in a 50 year old brick.

I hoped to pick up a skoda 5 speed but in three years looking I've never even seen one for sale in the uk but I have heard of vw owners paying over 2k for one.

I'm hoping for reliability over all so this kind of rarity makes me nervous should you need simple spares.
I did look at modern 3 cylinder units but they're not that much smaller that a 4 pot and a change of cylinders can cause other issues with the classic status.

My mind still wanders on this subject though, other ridiculousness that's crossed my mind have been,

Bmw k100 brick and imp transaxle
There is already several of these in imps

Alfa boxer and vw transaxle
Again nothing new in that, i believe there are a few 850 coupes already done.

Fiat twin cam and vw transaxle
This was just a technical exercise, largely because it sounds cool

And possibly the weirdest, maybe even the easiest
A late model seicento 899 with the ignition and fuel injection mounted to a 126 transaxle.
Apparently a reliable 45hp with all fiat running gear
A lot of work for 10hp though.

For now though I really have to focus on the never ending welding.
I do have a plan to attempt to combat the dodgy fiat electrics and poor cooling with the original engine which if nothing better comes along is what I'll do.

With that said I am open to suggestions.

[horrido]

I was thinking if some transverse motor and 'box would fit, but you really want something where the motor tips backwards and the driveshafts are forwards, but I'm drawing a blank.

I know some of the VW camper guys run the Audi O1E(?) gearbox upside down, but I can only imagine it's going to be too big and heavy for what you need. You can get reverse cut gears to run a Subaru gearbox backwards, for VW use, but it's money and might well also being an overpowered nightmare in the van.

The VW IRS 'box is going to be about perfect I would think. Small and light. How about fitting a newish BMW watercooled Boxer motor behind it? Not sure how low the sumps are on those, but it's only one cylinder long at least. The aircooled version will pull a 2CV around.

[redratbike]

that or a k series bmw motorbike engine?