My 131 abarth (never ending) story - 2017 season updates

[ace124]

Thanks for that. Its interesting that Ruota Market hyped it up, but never produced any.
Ill email John anyway.
BTW, did you end up selling your other wheels?
I know we are off topic now.
You can PM me.

Thanks

[miro-1980]

New development :

Bought a beautiful two sets of original Cromodora CD 68 7x15 wheels (plus one spare).

Abarth 010.jpg (53.13 KiB) Viewed 25715 times

.

This gave a reason to do engine RPM vs. speed calculations.

Using my two diffs (one 7/43 = 6.14 and the other 10/39 = 3,90) and projected set of tires 195/50/; 15/205/50/15 and 215/65/15 one can make significant difference in performance ( especially top speed and acceleration).

To my surprise it appears that by using possible combination of tire/diff the the top speed at 8000 RPM on 5th gear will very between 160.9 km/h and 293,2 km/h !!!!.

The potential speed gain on tires alone is ca 15% , while the gain on diff is ca 57%. Total gain on both is 82 %.

This is really surprising that using proper tire and diff combination can speed you up so much ....

No wonder professional race rally teams have so many tires and so many diffs for each event.


Miro

See attached tables

131 abarth engine vs wheels speed diff and tires .xls

(88.5 KiB) Downloaded 1068 times

[miro-1980]

The rear diff and suspension assembly will be mounted Monday.

With the long weekend I took some time to play with my other toy -124 spider

R0016912.JPG (118.48 KiB) Viewed 25660 times

Though it looks impressive on CD66's , I will put it on CD 134 - as better matching original setup.

Also Classic Rally requirements say that the wheels should be original size.

Actually , the CD 134 was the original factory setup.

I do not have a spider's pictures on these wheels yet , but will soon.

So, just the picture of cd 134

cd 134 .jpg (22.86 KiB) Viewed 25660 times

Miro

[miro-1980]

In fact the spider ended up in a garage anyway.

In Poland the vintage cars do not require MOT - they get a lifetime MOT at first registration as a "vintage vehicle". But all of us are trying to keep these cars in tip-top shape , so before hitting the road this weekend I had the key elements checked ( all suspension and brake elements , steering system.

All systems were OK. The car would pass an MOT with flying colors.

We just tightened the steering box.

Similar checks are done before every event.

The 131 is being installed with proper straightened bolts and nuts. Few of he me needed adjusting as to length and this is why it rook ore than expected . Hopefully we will be able to put the car on rear wheels and see how high /low it stands.

Once this is done, we will start puting the engine in ....

In the mean time all of my "Fiat fleet" was in garage service for some time ...

[miro-1980]

Well, finally effort it brought expected results.

The car is standing on its rear wheels. ( as you see very much temporary...

CURRENT WHEEL 1 .JPG (78.68 KiB) Viewed 25567 times

The rear is real stiff ( as stiff as the front ) . Few minor adjustments are required. The rear stands a bit to low. and need s to be brought a p just a bit , ca. 1 inch. It is totally without any load (no tank , no seats , no spare wheel and no battery). When all this is mounted , it will likely be too low. Currently rear stand about 2 cm lower than the front.

The small movement on the bearing itself was dealt with by a rubber busting between the not and the not on the strut top.

It actually looks quote impressive. We will still check the full shock travel to make sure that the wheel will fit under the arches and the shock is positioned in a way that allows its maximum working travel range.

The top shock mount looks like this ( still w/o the rubber bushing .)

tenssion bar .jpg (59.99 KiB) Viewed 25567 times

I also plan to put a rear tension bar to make sure that the turrets work in concert and the rear does not have a tendency to tear the car apart and make the rear stiffer as far as the side forces are concerned.

The bar will be like the one on the front , but straight from one turret top to the other . How is it possible ? Simple, the original tank will be removed and replaced by a safe tanks that fits in spare wheel bay.

Tession rod ..JPG (102.01 KiB) Viewed 25567 times

Engine will be installed next week....

Finally some visible porgress...

Miro

[TR-Spider]

Nice to see the progress!

The rear strut bar seems a good idea to reduce the body flexing, now that you will put load on.
Have you already checked that camber left/right is equal?

Thomas

[miro-1980]

Thomas ,

Thanks !

Re rear geometry: We were extremely careful to weld the suspension supports as well as the diff in vert0y center position. with a naked eye it looks OK but we have not measured it yet. Both look positive about 3-4 degrees, but since we are still lifting the car on one side or the other often it is difficult to really ascertain.

Maybe once we have the right wheels , even without the brakes we will put the car on a trailer and drive it to alignment shop nearby to see what we have. It is easier to do it at this stage than when the rear is really finished.

Appreciate the tip.

Miro


From GC: what is vert0y?

[miro-1980]

CG

This is is misspelled "very" , sorry ....

I have corrected the mistake...

Miro

[miro-1980]

Ok,

1/ The car stands on its own with rear suspension assembled.

2/ The old engine is out and next week we will be mounting the new GC engine (finally).
I will need CG assistance with putting together the oil installation ( External oil filter, oil cooler and Accusump).
At this stage I am not sure I understand the sequence of connections , placement of sensors and valves ....
Tomorrow I will try to lay it out on the floor and see if this makes any sense to me . Will take pictures and post them here for GC comments and tips.

3/ the wheels are on their way , so we can thinking about the brakes ...

I think we are over the hill with this project (hopefully).

More pictures are comming ...

Miro

[miro-1980]

In preparation for engine installation I have made the first attempt to understand the connections between all of the oil gear.

It took a long phone conversation with Guy to construct this simple sequence ...

Guy , is this ok?

[Guy Croft]

That is correct, yes,

G

[miro-1980]

Preparations are making progress .

The old engine is out :

ex header (7).JPG (149.01 KiB) Viewed 25361 times

ex header (6).JPG (87.02 KiB) Viewed 25361 times

Maybe we will start putting the new engine in this week.

In view of this I discussed the ex header with Guy.

I was surprised how strict his instructions were ;

Well here is the data I collected off my two headers 4-1 and 4-2-1 :


4-1

Primaries diameter : internal ca. 35 mm

Effective length :
cyl # 1 - 67,3 cm
cyl # 2 - 59,7 cm
cyl # 3 - 58,7 cm
cyl # 4 - 67,3 cm

Secondary diameter - all the way through - (internal) 52 mm
Final pipe diameter : (internal) 52 mm

4-2-1

Primaries connection 1 and 4 , 2 and 3.
Primaries diameter : internal 35 mm
Primaries effective length:

cyl # 1 - 54 cm
cyl # 2 - 51 cm
cyl # 3 - 51 cm
cyl # 4 - 54 cm

Secondaries : internal 41 mm
diameter
1/4 - 63 cm
2/3 - 58 cm

Final pipe diameter : (internal) 52 mm

The task of measuring the exhaust header proved to be far more challenging than ever imagined. The concept of "effective length" is theoretically very simple, but applying it in practice is quite a task which requires knowledge , experience and also some technical means.
appears to be (far ?) too big. In 4-1 the variance length between primaries is as much as 76 mm and in the case of 4-2-1 it 30 mm between primaries and 50 mm between secondaries.

Guy,

Are these headers usable or do I need to make a new header?

Some pictures of the headers below :

4-1

4-1.jpg (34.42 KiB) Viewed 25361 times

ex header (11).JPG (46.37 KiB) Viewed 25361 times

This is a connector for exhaust gas temperature sensor. Very useful to quickly assess the fuel mixture : too hot indicates too lean mixture , too cold too rich ...

ex header (8).JPG (38.63 KiB) Viewed 25361 times

Flexible connection was installed after several problems with exhaust braking off during a stage , causing loss of power and terrible noise.

ex header (1).JPG (60.74 KiB) Viewed 25361 times

Picture showing the flexible connection from inside the exhaust pipe.

4-2-1

ex header 4-2-1.JPG (43.28 KiB) Viewed 25361 times

ex header (3).JPG (72.48 KiB) Viewed 25361 times

ex header (4).JPG (73.95 KiB) Viewed 25361 times

ex header (5).JPG (73.97 KiB) Viewed 25361 times

Miro

[Honza]

From my experience with coupe headers, I would preffer 4-2-1 header with enlarged secondary pipes to ~45mm ID

[engineerted]

OK, back to the oil circuit for a minute. Would it not be better to run the oil first to the filter, then the thermostat, oil cooler, etc? What you have is just find, but as a preventive in the case of a spun bearing or worse, the filter will keep contaminates from going thru the cooler and thermostat. I personally have my acusump piped directly into the passenger’s side main oil gallery.

Ted

[Guy Croft]

House Rule, Engineerted!

You should always run the oil thru the filter last before engine.That means before the acc too because that is feeding direct to the engine main gallery.

G