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Trent PowerDork
3/19/20 3:02 p.m.

As I was wading, seemingly hip deep in aluminum chips for the last dozen weekends it occurred to me I might have made enough progress to start a new build thread.

I have been putting off a new build thread for a while. Progress is slow. Photobucket killed my other threads with their ransom tactics.

But I am excited about building the car again. I also find having a build log that people can interact with keeps me motivated.

So follow along (or don't) as I bring this beastie back from the brink.


Cliffs notes on the 850 Berlina if you are unfamiliar. It WAS a turbocharged and fuel injected 843cc car that made 120hp at the wheels and weighed in at 1375lbs. Mercilessly quick, but gearing limited to 89 or 90mph. 


The car was built when it was my daily driver, meaning it was never off the road for more than a weekend. This is why nothing on it was ever done well or never fully finished. If I couldn't start a task between 6pm and have it road ready by 10pm for the 5:30AM trip to work it didn't get done. The car was ROUGH.

Anyhow, now is my chance to make it what I want.


Some years ago my shops painter (at the time) convinced me that blowing the car apart and having him do a quick repair and repaint would be a fast fun project. I tore down the car and he promptly disappeared leaving my shop and my Fiat kinda boned. It has languished in various storage spaces since. I have been building up trade equity with one of our talented, responsible and trustworthy body men to get things moving again and finally had the time and energy myself to focus on it.

So it moved back into the shop


More later

Trent PowerDork
3/19/20 3:51 p.m.

The look I have in mind no longer includes the Panasports. I'm going for a bit more retro look than the +3 fitment alloys with rubber bands wrapped onto them. 

This car is my current inspiration for wheel, tire and flare fitment

Tires need to be under 22 inches tall, preferably with a shorter front option. 14" tires were pretty much a bust. That brought me to 13" tires where the 185/60 and 175/60 exist in the Yoko A539 range. So 13's it is! But which 13's?

As if on cue, not an hour after the 13 inch tire decision was made this spider was pulled up to the shop as a panel donor and the rest was heading directly to scrap metal

You can guess where this is going

13X6.5" and 7" wheels

Because I do love deep steelies with hubcaps




Trent PowerDork
3/19/20 4:14 p.m.

I pretty much have to build this car from the tires in. Wheels and tires bolted to suspension, car set at ride height, flares shaped ....




The suspension will be based on the Fiat 600 chassis package that Ransom and I designed and built.


It is a total revamp of the original. Gone are the transverse leaf, king pins and steering box. In their place is double wishbones, coilovers and a rack and pinion. It does marvelous things to roll centers, bump steer, brake dive and camber curves.

The trailing arm geometry was also modified to tame the camber and toe curves. The arms were lightened and the biggest disc brake package I could fit inside 13" wheels was fitted.


But that is the Fiat 600 version. It will require a different front subframe for an 850. The trailing arms are also slightly different. More software modeling is in order.

I also decided I did not want to drop over a grand in brakes. Different calipers means different caliper carriers so the ones I have on the shelf are no longer viable.


Mr_Asa GRM+ Memberand HalfDork
3/19/20 4:16 p.m.
Trent said:

Cliffs notes on the 850 Berlina if you are unfamiliar. It WAS a turbocharged and fuel injected 843cc car that made 120hp at the wheels and weighed in at 1375lbs. Mercilessly quick, but gearing limited to 89 or 90mph. 


RossD MegaDork
3/19/20 4:25 p.m.


Trent PowerDork
3/19/20 4:38 p.m.

Let me know if the photos are not showing up or acting otherwise odd. I am experimenting with hotlinking directly from google photos and it is pretty easy and awesome.

Dusterbd13-michael MegaDork
3/19/20 4:53 p.m.

I need a napkin. I love your work and sense of style. 

californiamilleghia Dork
3/19/20 6:22 p.m.

What are you using for a gearbox ?

there is not much room under there ,

and the 850 box rotates backwards as an 850 motor runs backwards.....

Yes I know the builder knows this......

TurnerX19 Dork
3/19/20 7:08 p.m.

The 850 Berlina was Fiat factory styling at its finest. The flairs then make it awesome.

Azryael Reader
3/19/20 7:40 p.m.

I have always wanted one of these.

Trent PowerDork
3/19/20 8:13 p.m.

In reply to Dusterbd13-michael :

You flatter me sir

Trent PowerDork
3/19/20 8:25 p.m.
californiamilleghia said:

What are you using for a gearbox ?

We will get there. wink patience 


Pushrod Reader
3/19/20 8:36 p.m.

In reply to Trent :

Hi, Trent - PM sent.... :)

RichardNZ GRM+ Memberand New Reader
3/19/20 8:55 p.m.

Keep up the good work sir smiley 

850 sedans were like rocking horse manure in New Zealand but the coupe's were very popular. A friend had a couple and they were an absolute riot to drive if you were brave enough to NEVER lift off.

Unfortunately delivery was, the joke went, as deck cargo on submarines and you could hear them rusting in the driveway.

stay safe and healthy


EvanB GRM+ Memberand MegaDork
3/19/20 8:57 p.m.

I loved this thing back when I was reading about it as your daily driver. I'm excited to see where it goes now. 

GoLucky Reader
3/19/20 9:41 p.m.

Wow! Kind of lost for words. 

AngryCorvair GRM+ Memberand MegaDork
3/19/20 10:18 p.m.


brad131a4 Reader
3/19/20 10:19 p.m.

Yeehaa, Having visited Trent ,on me and my wife's driving vacation last October. I can say these parts look even better in person. I think the front brake bracket would work great on a 124 spider as well. Even though this car was mothballed at the time I was there. There were some truly amazing cars at his shop.

Trent and his wife are by far some of the nicest people I've had the pleaser to meet. He opened up his shop and showed us around and I got to see his little, cough cough, corner of the world that the magic happens in. It's a good thing I live 200 plus miles north or I'd be a permanent fixture at his shop after work. 

Great to see the little one getting some love. Been hoping to try and get down south this summer for a little more of a visit. Just not to sure with how things are playing out when that will be.yes

Trent PowerDork
3/20/20 12:37 p.m.



One of my favorite modifications I made to the car was the brakes. I went from 4 wheel drums to the 850 spider front disc setup and then to Suzuki GSXR-1100 calipers on the Fiat rotors

It dropped almost 7lbs of unsprung weight from each wheel and the performance was excellent. I'd swear that thing could have done a stoppie.

I also collected a lot of the things. At the time you could buy a pair off of ebay for under $10 any day of the week.  So I had a pile of super light, high quality forged alloy 4 pots collecting cobwebs in the garage. I considered the caliper decision made.

New problem. They don't fit in 13" wheels

The areas with too much material are just there for style. I can cut that off and remedy the fouling. The bleeder screw is going to be another issue

So I machined off the excess and welded up the bleed screw port


And then using the sketchiest setup I could, drill and tap the new bleed screw location


So, all four calipers were reshaped, and the bleed port was filled and relocated.


For the front caliper carriers I was just going to duplicate the parts I had already made for the 600 with the different bolt pattern and height, but something about them bothered me. If you scroll up you can se that the fixed 9 degree caster angle makes it look like the caliper is drooping. 

So onto the chips

I'm embarrassed to admit how much this angle, and the fact they had to be mirrored messed with my head. 

The finished caliper carriers. Any resemblance to my home state of Oregon is entirely coincidental


Oh. Also the front spindles, hubs and rotors are 65-85 Fiat 124 pieces. The decision to use a non-vented rotor was deliberate. I am working hard to keep the weight gain minimal and considering the intended use for the car is street car occasional auto-X and zero track time I think it will be more than OK.


Here it is all bolted together


With the new alloy caliper carriers I have probably shaved another half pound off the setup. They fit into the wheels with 3/16" clearance as well!





Adrian_Thompson MegaDork
3/20/20 2:01 p.m.

OMG, I am so happy this is back.  Isn't this your second re-boot of the thread, so third thread on here?  I also read your old thread on Retro Rides.  I've always loved this build, really glad your getting the band back together.  I think part of the reason I love it is it reminds me of Hillman IMPs and their variants, of which I had about 20 in my younger years.  Wish I had an Imp plus the time and skill to do something similar.

Subscribed, I hope progress is rapid for my own purely selfish reasons.

wheelsmithy GRM+ Memberand UltraDork
3/20/20 6:44 p.m.


Trent PowerDork
3/20/20 7:19 p.m.

Brakes part 2:


Ok so I have 4 radial mount four piston calipers. What do I do for a parking/emergency brake?

The two wilwood mechanical caliper options are their spot caliper which is garbage and the MC4 which is amazing. How these two items can be so similarly priced when one is a complicated jewel and the other is a steaming turd is baffling. Sadly the MC4 is made for thick vented rotors and modifying it for what I am using seems counter productive. 

I guess I should mention now that all the raw materials I am using for everything are scraps and offcuts and in a few examples shorts the steel yard made me a crazy deal on. When I order materials for obs at work I always give myself an extra 6-10 inches of stock in case I make a mistake or need the extra material for fixturing and in the case of round bar a 12" piece is only another dollar more than the 2" I need for the job.


These blocks were the waste from a job last year. I squared them up

and set about duplicating and enlarging an industrial mechanical caliper design 

First few cuts

The backside after some shaping

In that 25mm bore I ball milled two pockets that hold ball bearings

The cam in the center has corresponding divots with a ramp to one side


So when you twist the shaft the button cams outward with a significant mechanical advantage

Assembled for the first time to assess functionality. A little pressure from the lever and I could not pull the caliper from the rotor. 

Detail work to make them look a little less 8 bit

And then to secure the pads. The threaded one is from one of the Tokicos as a possible idea, The spring roll pin totally would have worked and been super easy but then I found the pins from some Ate calipers I had rebuilt for a 76 911 earlier and thought they did the job very cleanly. I just had to shorten them a bit.


Much like the primary calipers these will need a fair bit of work with hand files and sanding to prep them for finishing. I am waiting until all the aluminum fabrication is done so that can be one batch.


Currently cannot decide between gold anodize or electroless nickel plating for the calipers and carriers. Both are inexpensive and durable. 


Trent PowerDork
3/20/20 7:26 p.m.

A sample of the gold anodize on the upper contol arm relocation mount for the Fiat suspension

Sure is pretty.


I do not have a sample of electroless nickel plated aluminum, I know Brembo offers it as an expensive option, which is kinda hilarious since both processes cost the same amount. $65 a batch at our local plating shop.

TurnerX19 Dork
3/20/20 9:50 p.m.

In reply to Trent :

Oh you lucky! My local is $200 per batch for electroless nickel. Different shop for anodize is in line at $70. 

Trent PowerDork
3/22/20 1:31 p.m.



This caused no end of hand wringing. I actually quite liked the 843 motor. It really needed a bigger turbo to bring intake temps down, but it took 21psi like an absolute champ and when off boost driving around in town netted almost 50mpg. The gear box was the issue. Even after stepping from the 5.12 gears to the comparatively tall 4.68 gear set it was still turning over 5k at 60mph.  For the low low price of $1600 US I could have imported some 4.37 gears and enough synchros and bearings to rebuild the transaxle and still not have been happy. So I'm at this point transaxle shopping.

I really wanted to keep the motor Italian and shopped around for an early Fiat twin cam in the 1400cc range, but at the same time I already had this

Suzuki G13b.  Purchased for my mini, decided not to do that swap because it too would have also meant a transmission rebuild to make its gearing work with the 10" wheels on that car.

The motor has had a hard life as I imagine most of these did when swift GTIs were essentially valueless transportation driven by folks who bought them because only because they were so cheap. Head gasket blown due to a broken thermostat housing, then sat for years. My buddy has had experience with them and donated a set of forged D16 Honda pistons that are a common swap for these motors. 

I still need to find a clean set of camshafts for this motor. They are the last item to check off the list before the rebuild starts. 

Positive manifold pressure will be supplied by a Garrett GT1446 from a Fiat 500 Abarth that was wrecked with less than 500 miles on the odo

As for the transaxle, I am lucky enough that one of my best friends is our own burrito lovin' GRMer and extra lucky that he cut me a sweet deal on the Porsche 901 5spd and adapter bits he made when doing this exact swap in his 850 coupe.

Now to duplicate the work he did to his tub to make it all fit

After an initial mockup I felt that I had two options. To modify the oil pan and pickup or to tilt the motor 15 degrees so they sat flat, gaining me 2 inches of ground clearance.  I immediately twisted the adapter plate and was happy but can see it won't be possible as an adapter.

I am back to either modding the pan or making the adapter in aluminum and welding it to the bellhousing. Either way the bell on the Porsche trans needs a big cut in it for starter clearance


We figure a stoutly built G13b running 14-15psi from this turbo should be putting out a pretty solid 200hp without much stress. The 901 gear box ratios and final drive end up with 4th gear being a tad taller than my old top gear with the benefit of a whole 5th gear on top of that.


Any thoughts on mounting the engine at the factory angle versus modding the oil pan and pickup? They both look to be the same amount of work. It sure looked great in Burrito's coupe with the cam gears sitting level but I can't imagine it wouldn't look equally cool at an angle. I obviously lose one of the 4 bellhousing bolts on the 901 in this position so I would have to weld the adapter plate on.

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