Topic: Best 600 upgrades with other model Fiat parts ?

[DaveA]

Hi

What are the best upgrades using  normal Fiat parts from other models ?

I would think  :

A112 motor with 600 flywheel and 850 clutch

600D gearbox

850 front disc brakes , will 124 brakes fit ? YES
124 rear brakes with homemade adapter for calipers YES

13 inch rims from ? ALL REARWHEEL DRIVE FIAT/SIMCA 1000

late brake master  cylinder with 2 circuits

are there any better Fiat Rear axles ? 

any better steering  ?

any larger radiator that will fit ?

Would love to hear of your  ideas

Thanks  Dave.....the junkyard hunter

[DaveA]

what rims will fit the disc brakes  and have the right off-set to fit under a 600 body ?

will 850 rims fit ? or yugo rims ?

it looks like the 124 rims will be too wide

thanks for the info

DaveA ....the junkyard dog

[guy moerenhout]

a yugo is a frontwheeldrive car so take a wheel from a rearwheeldrivecar.All depends of the wings that you have made.850 wheels are small.124 is ok.

[ChrisD]

I used a late Zastava 750 steering system. The steering wheel axle has a lock and the axle end (from the steering wheel side) is the same with Fiat 126, 128, A112. This allowed me to use Fiat 128 steering wheel switches witch are better than the standard Fiat 600 ones. For a long time a had an A112 abarth wheel. I also have Fiat 850 front wheel spindles with Fiat 124 disk brakes, and Fiat 124 rear disk brakes with custom made adapter. The handbrake wire can be tricky though, so you can install Fiat Uno turbo rear disk brakes instead. I use Fiat 124 rims and evrything is ok. Fiat 850 13" rims fit to, but as Guy say it is to small, I just use them for snowtyres during winter.

[Abarthreplika]

Hei Chris

Can i use the uno brakes at the rear???,- what about adaptorplate??

I have 850 calipers in front, with 48 mm pots

Do you know the diameter of the uno brakes at rear, i have been told, that it should be around 30 mm, to prevent overbraking at the rear.......I use standard master cylinder

Kind Regards
Max

[ChrisD]

With the standard master cylinider it is not recomended. I tried that in the past and the brake pump just didn't had the power for 4 disk brakes. I switched to Double circuit brake pump instantly;-)

[guy moerenhout]

you can use also from Multipla(old type)

[Paul vander Heyden]

Hello all

Ugrades for Fiat 600 chassis

Things you MUST do.

1.  dual circuit master cylinder.  Purely for your own safety.
2.  Replace crush sleeve between the rear hub bearings with good steel sleeve.  Nasty things happen when axles break.
3.  Limit straps in rear swing-arms.  If you are going to go fast this is a MUST DO.
4.  Front disc brakes from Fiat 850.  Rears if you like, but for a street car the drums are OK.

Next things to do in no particular order.

A112 or 903 motor.  - Easy swap, good oiling systems.

600D gear box - stronger.  Poss. with 9/39 diff gears for better top speed.  Also close ratio gear sets available for nicer spacing.

Better cooling - Bigger engine means more heat - thus better cooling

13 inch rims will be a requirement if using 850 discs.

Rear axles. - Other than modification #2 above, when you get over 75 HP there are a number of options for replacing axles, particularly if you lower the car.


This is a good start.

Paul Vanderheijden
www.scuderiatopolino.com
USA

[DaveA]

Thank you Paul for the information ,

were all the 600D gearboxes the same ?
same gear ratios too ?

Will the duel master cylinder from an 850 work with the 850 disc brake conversion ?
What else do I need to take off the 850 for my 600 ?

Thanks

Dave

[ChrisD]

Dave,

the 850 brake pump has diferent mounging than the 600. It will never fit in the 600.
From the 850 you need the front spindles and disk brakes (but I recomend using Fiat 124 brake calipers), the 13" wheels (unless you go for a diferent style, like aloys), and if you pan to use a bigger engine the flywheel and cluch

ChrisD

[Paul vander Heyden]

Dave A

Chris is correct.  You need a Zastava master cylinder (available from several sources including us).

Physically the Fiat 600D gearboxes were all the same with the exception of the final drive ratio.  Most sedans came with a 8/39. (4.88:1)  Multiplas would have come with either 6.24:1 (early) or 5.38:1 (late).  As I understand it the "T" type delivery van also used the Multipla ratios.  The 600D gearbox is perfectly reliable for up to 125 HP.  Abarth made ratios of 9/39 (4.33:1) and 9/41 (4.55:1) and others have made variations on these over the years.  We carry the 9/39 as this seems to be the most advantageous, particularly with a close ratio gearset.  See below.

The design of the Fiat 600 type gearbox pretty much dictates that 1st gear cannot be synchronized.  The gear ratios in a standard 600D gearbox are 1st - 3.38, 2nd - 2.10, 3rd - 1.33 and 4th 0.89.  As you can see there is reasonable gap between all gears (for street use) except between 3rd and 4th.  This gap is quite large and with limited horsepower will cause many situations where the RPMs are too high in 3rd  and too low in 4th.  Several aftermarket companies, Scuderia Topolino included, have produced alternate gear sets (1st - 3.38, 2nd - 1.75, 3rd - 1.20 and 4th - 1.04) in order to remedy this situation.

Good luck,
Paul
www.scuderiatopolino.com
USA

[DaveA]

Hi

So all the stock 600D sedan gearboxes are the same ,
thanks for the info , ,

".  You need a Zastava master cylinder (available from several sources including us)."

But I thouht you would need a "disc brake" master cylinder ,
the Zastava master cylinder  would be for stock drum brakes ,  will it work OK ?

Dave

[Paul vander Heyden]

Dave,

The Zastava cylinder was used with front disc brakes and rear drums.  If you are going to out discs in the rear as well (such as Fiat 124), then you will likely have to put a 'proportioning valve' in the rear circuit.

A good way to set up the brakes is as follows after everything is plumbed and bled.

1.  Put can on jack stands
2. Have someone sit in the driver's seat and press on the brakes "just hard enough so that you cannot rotate the front wheel".  Now, without the person pushing on the brake pedal changing anything, go the the rear wheel and you should just be able to turn the rear wheel.  Adjust the proportioning valve so that you achieve this result.  This will mean that the front brakes will activate and lock up before the rears.  The othe way around is VERY SCARY !!.

Good luck.

Paul
www.scuderiatopolino.com
USA

[DaveA]

"The Zastava cylinder was used with front disc brakes and rear drums."

is that a  Zastava  600 master cylinder ?
I did not think they had disc brakes

Dave

[zippyfiat]

Paul, what do you recommend for a proportioning valve?

Thanks,
Gil

[ChrisD]

I have Zastva brake aster cilinder in my car (zastava 750). I have installed disk brakes in both front and rear and I have no problems. The braking is excelent and the pump has the power required for braking. I have not used a proportioning valve so far but I will in the future, although I have not experienced or noticed the rear wheels locking before the front ones. Maybe it is because the drums had all the same size and the calipers I use also have same size front and rear and that way I use the pumps stock adjustment. Maybe when I change to Fiat Uno turbo front disk brakes I will need a proportioning valve.

Chris

[Paul vander Heyden]

Gil,

I use one of the "screw type" proportioning valves.  Once adjusted, they generally do not need to be touched.  The only time I touch mine in the race car is if I am racing in the rain.  I then add more front bias (along with softer shocks).  Makes the suspension more compliant and the tire/road interface easier to manage.

Chris D. 

Under normal driving the Zastava master cylinder installation works great.  In regards to rear wheel lock up, you have not tried hard enough I guess.  Remember that in hard braking vehicle weight is shifted towards the front axle.  The standard, static weight distribution is 60/40 (rear/front).  Under braking you will transfer at least 10% more to the front axle, so at BEST it would be 50/50.  Only a few problems with this argument.  1)  Yes the distribution is 50/50, but because of "chassis dive" the rear wheels have greatly reduced tire/road contact patch (that swing axle problem again). 2) If the braking is in preparation for a corner, the there will be chassis roll and only one rear wheel will have decent contact.  The light wheel will lock up easily and the wheel still on the ground now has to deal with both deceleration and cornering forces.  It is my view that you must start out with less than 50/50 brake bias if you are to manage the dynamics of braking and cornering well.

Re: the Subaru starter.  1980 Subaru sedan or station wagon, 1800cc motor, manual transmission, 2 wheel drive.  Also some models of the Subaru BRAT.  There were two models of starter used and they are the same except for one item.  One has a "nose housing" and the other does not.  You want the one WITHOUT the nose housing.  The adapter I have in stock here.

Regards to all

Paul