71 Fiat 850 sedan the redux

I wasn't here for the first time around, but will be following from here out. That thing is just cool!

Ever run down a drag strip to get an idea of speed relative to other stuff?

flatlander937 wrote: Ever run down a drag strip to get an idea of speed relative to other stuff?

I have not. The car is gearing limited to about 90mph. As it is I am turning around 4800rpm at 65.

Can you swap to a VW transaxle?

What kind of final drive and top gear does it run to be that bad?

4.68 ring and pinion with a less than 1:1 fourth. With 22" tires I am pulling 7000+rpm at 90

Better gearing is one of the big jobs during this rebuild. And I kinda need to decide what transmission I will end up using soon as it will determine whether the motor I am building turns CC or CCW.

It might be an awkward fitment, but the Subaru stuff can go either way. There are reversing setups that the VW guys use and I assume the 818 does too.

Then you get your pretty easily available choices of 3.90, 4.11, 4.44 off the shelf, with double-overdrive split-case 5-speeds growing on trees and tight-ratio solid-case 6-speeds (for heinous money). There might be some kits or some 80s-era stuff that could do even lower ratios.

Some of the newer cars (2012+ Impreza, 2010+ Legacy) have cable-shift 6-speed transmissions that might make that part of the job easier.

The biggest part of the problem would be getting the bellhousing to match up and working the whole clutch mess in there. Maybe axles, if you can't centre-mount and have to end up doing an unequal length half-shaft and carrier bearing on one side.

I know the VW transaxles are easily reversed, to a point you need to be careful when rebuilding one or you'll have a bug with 4 reverse speeds. Good amount of aftermarket for those too.

Yeah, using a VW trans makes a lot of sense if you can find them and the associated parts easily. I assume a final drive ratio change is pretty easy; if it can be done, an ACVW person has probably already done it.

Plus, then you get the nice aftermarket on axles.

Lets just do the transaxle post and get that discussion really started.

Not many options out there for rear engine stuff.

1. VW Freeway flier box. rotation CW

2. Renault R5/LeCar 5 speed . Yeah good luck finding that one rotation CW

3. Porsche CW rotation

4. Delorean? It's probably similar to the R5 unit and freakishly expensive CW

5. ??????

6. Audi FWD stock CCW rotation

7. Subarugears equipped scooby box ($1900 for the special bits $? for a known good trans) CW

8. Fiat box with Bernimotori sourced 4:11 R&P ($1500 for the gears before customs and another $400 for synchros and whatever else) stock CCW

I have discussed the Audi option here before but here is the cliffs notes.

It occurred to me a while back that a FWD Audi 4000s transaxle is pretty much the same case as a bug unit but stuffed with gearing very similar to an 80's GTI. If I flipped it around and hung it in the back of the car I would have 5 reverse gears, but the 850 mill turns counter clockwise so that would actually be 5 forward gears. The reasoning seemed legit and I mentioned this on an international forum at one point. Any way I was always nervous about spinning the input shaft on a trans the wrong way. Thrust loads and whatnot, so I put it in the back of my mind. Not before I went out and bought one though.

Fast forward to a year later and I received an email from a dude in Croatia asking me how it was working with the 5 speed. His 4 speed Audi swap was awesome and he was wanting to upgrade. The dude had cooked up the thing with a mixture of parts and some awesome former soviet ingenuity based on a google translated version of my throwing the idea out there. He reported a year of trouble free service with the complaint that his shift pattern was backwards.

Well holy crap. If Gabi could do it with what looks like an angle grinder, 6011 rod and scrap metal I should be able to pull it off, right?

I asked a transmission and gearing engineer what would happen and he looked at me funny. Dude was an engineer at Hewland and later became the transmission and differential guy for a famous nascar team who's driver died and was known for "intimidating" competitors. He said yes the gears would thrust to the other side of the case, synchros would still work and the final drive would be louder, but stronger than turning the correct direction. The idea seemed unsettling to him but he couldn't say why since every component should be fine.

So that is one option.

Also Burrito mentioned he still had the original 914 box he decided not to use.

Converting this motor to clockwise rotation isn't that big of a deal.

Discuss

Yikes! $1900 is ridiculous, I agree. I've gotten Subaru 3.90 linkage-shift 5-speeds for anywhere from $50-300, but it depends on the box, the ratios, synchronizer types, the age, the seller... all kinds of variables.

I think the Audi 5000 had a similar gearbox to the Audi 4000 as well, since it was also a sawed-off Quattro setup in FWD. Might help availability. I think the 5000 became the 100 and the 4000 the 80 later in life, but one of the many 80s Audi guys here would probably be a better idea.

How does the starter work in the Soviet setup? Is it easy to turn backwards? Did he just fabricate a sketchy bellhousing and put the starter in pointing the other way? I forget what it looks like on the original car.

Gabi managed to use the Fiat flywheel and pressure plate with a VW polo 1.1 clutch disc. He used the factory 850 starter mounted on his adapter in the stock location.

I was thinking of using a Honda flywheel and pressure plate (only one I can think of that uses a pressure plate made to turn CCW) with the Audi disc so I would have to get really crafty to mount a starter.

I'd go with the VW or the Audi, probably the Audi. As I said, making a bug trans run CCW is so easy people do it on accident. There is no problem spinning any manual trans backwards (unless equipped with an oil pump), it's designed to handle thrust loads on both sides so you can engine brake without breaking it. Tons of old 4x4 trucks ran the front diff "backwards" too, it's no huge deal. Just like the trans, all you've done is flipped the drive/coast sides.

Is making a custom flywheel to incorporate both a Honda pressure plate and stock starter ring gear possible? Not a very complicated machining project if you have access to the equipment.

I'd use a VW Beetle box and put the differential in from which ever side gives you the rotation you want.

OR, just flip the Beetle box over . It'll run fine upside down.

Subscribed.

I have nothing for you on flipping gearboxen about but I love this little car and can't wait to see it come together. Judging by other work you have posted - I'm expecting to feel pretty lousy about my own skills.

Now that I think about it... what about a bike motor with a shaft? You can find a final drive in either direction and almost any bike over 750cc will make more power than you had before. A liter gets you 130hp easy for 1k with trans, cpu, and cluster according to the interwebz.

You can rig a starter motor for reverse.

Never knew about these until this one. Now it's a favorite. Can't wait to see some magic with it like all your other work

Drug the Audi transaxle out of the garage. It is surprisingly close in a lot of dimensions. The nose of it is a good deal longer which will likely require a bit of trimming on the body. The clutch release arm is on the opposite side. From the mounting face to axle flanges to rear mounts they are almost spot on!

Taking it to work to clean it off and slap together a mock up block so I can make an attempt at an adapter and see how far the flywheel needs to be spaced out.

I'm obviously no VW expert, but is the '88 VW Fox transmission the same as an early non-Quattro Audi box? The Fox had a longitudinal four and was front drive only. Most were four speeds, but the top of the line Fox got a five speed. Based upon nothing but speculation, it's the transmission that I was thinking about a few years back when I had a bare Formula Ford chassis and didn't want to shell out for a Hewland.

I know the Fox folks swap in this Audi transmission as an upgrade for the 4 speed boxes. The Fox 5 speed is pretty much the dodo bird, often referenced in historical documents but no one has seen one in recent years.

I understand the b5 passat box is similar to the earlier audi stuff but a bit smaller. There were none in the PNW when I was looking.

In reply to Jumper K. Balls:

Like this?

Yep!

Tempting but I do already have the Audi 2P in my possession. I have been looking into gear ratios and it seems favorable.

Audi 4000 2P 3.46 1st 1.94 2nd 1.29 3rd 0.97 4th 0.80 5th 4.11 FD

4th is about 300rpm lower than the current 4th and that 0.80 really seems fantastic. I expect to have to downshift a lot to bring the boost up for passing and whatnot but that is part of the charm.

I was just scrounging through older posts in build threads, instead of wrenching on my own project, and was compelled to reaffirm one thing. AWESOME!

Things get busy and set aside. Work has been ridiculously busy. So busy that we have had to start our own paint and body shop. The fiat has languished in storage. Our paint guy was over having lunch and said "We really should get going on your Fiat, Lets bring it over tomorrow and start in" I wasn't going to turn that kind of offer down. So he, another coworker and I transported it to the other location and DAMN did we all just tear in.

Jason started stipping the panels we removed right away

And Eric and I removed most everything else from the car

There are so many things I need to fix and improve. The havoc I wreaked on the trunk when I relocated the radiator is heinous.

The package tray and engine cover shut panel are mainly oxides

Jason had all the pieces down to bare metal quickly

Tomorrow he wants to start in on the roof damage and order a half pint of the paint to do sprayouts so I can verify I still like the color as much as I did when following a new Chrylser 200 a few months back

Ceramic blue. In person it looks exactly like the color of steel when you cut in too hard on the lathe and the chip comes off so hot it is blue and then cools to a blue grey.

Oh and here is why we had to start our own paint and body shop.

You have your choice of fast, low quality and expensive or slow, high quality and expensive. This GT6 came back from paint in an unacceptable state and needed to go down to bare metal to save it. This is what we found

There should have been a small flare here

Hack work at premium rates. The body industry is so focused on insurance/collision work that finding a proper restoration body guy who can do the job in our time frames is nigh on impossible. So you try a new person who has good references and get this in return

how thick is that bondo? 1/2"?