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The bottom end of my 75 TS needs a rebuild.

This car is used as a trackday car (Nurbrugring) and some public road, from home to the Nurburgring (151 km) and visa versa.

I want to build a rock solid bottom end, with some potential for future upgrades with a limited budget.
Last summer I rebuild the head and opened up the ports.

Bottom end ideas:
- Forged pistons, raised compression (10.5 or 11:1) , total seal rings and new or reworked standard liners.
(maybe 85 mm pistons, like Spruells )
- Drill extra oil passages for the main bearings 2 and 3 to feed them from the main gallery.
- New seals, bearings etc.
- Balancing Crank etc.

For now I will be running standard motronic and standard cams, fuel is 98 RON, and I'm using the 98 RON no cat map of the motronic.
Future: upgrade to other cams, reworked motronic software or other?

Questions:
- Can the standard motronic cope with the increased volume (85mm pistons).
- Are there other (better) alternatives to the JE pistons and liners.
- Other upgrades recommendatins?


So shoot, every idea/comment is welcome ....

Saluti,
Maurizio

no answers........

You will probably not see more power with the higher compression without getting new cams, not sure if you can even run that comp. ratio with the standard cams. Remapping the Motronic will help of course but for power you really need to switch the cams.

Make sure you ditch the AFM when you remap the ECU, should be doable. Aftermarket is better and will be a must in the future.

Thanks, Mats

power gain is at the moment not the goal. But I want to keep the road open for power gain in the future.
My foundation needs to be good enough

Ps mailed Spruell their 85 mm, 1:10.5 pistons will work with standard motronic and cams is their opinion.

check out this site!!he knows everything about 75

http://www.alfaromeo-performanceparts.com

I know ROn , he got me in to this mess

Maurizio,

I bought 10.5:1 pistons from Paul Spruell, but it's for my 3.0. Looked really good. Performed well too. My static ignition advance is down to 28 degrees (from 33 with 9.5:1) and I still have more midrange punch. I'm still using 91 Octane (R+M/2) fuel! At the track (hopefully next month), I hope to have 33 degrees advance and 95 Octane (R+M/2) fuel. SHould boost power quite a bit. I also have CB cams.

Isn't the TS cam already aggresive? It should match the 10.5:1 cams well I would think. And maybe Stephan Lenoir can burn you a custom chip!

Haha! Way to go Zamani! A lot of people thought I was nuts when I ran 23* static advance in my 3liter with 11:1 CR, Motronic cams and LJetronic from the BMW535.I used a modified recurved 2,5 distributor,without vac.advance. I then switched to everything Motronic and haven't had any pinging at all,even at the track in summer! This says a lot for the Bosch design safety margins!
At first,I used 98RON and then 100RON when it became available 2 years ago. With the std Motronic cams on the factory notches, I get ~210psi on the gauge after 80,000km+ and most important,the same reading on all cyls! (Yes Mats, the gauge works just fine!!heh!)
Regards,
Jim K.

OK this is the informatoin I was looking for.

Special squadra chip was something I was thinking about, maybe even in combination with different cams, on the next upgrade step.

Yes, TS cams are radical therefore the VVT is used to let the thing idle properly. VVT advances the inlet timing about 18 to 22 degrees above about 1600 rpm.

Hi ...sory for bad english ....
u can use old nord rods they are 1mm longer ...and get pistons 1mm 15 degrees miled on top perifery... also stock TS intake is very bad ... my intake colector has almost 1mm dismatch at head ports imagine flow disturb many people say that chipped stock motronic is shit due to AFM ... i think with new ECU (no afm based) slight port and polish ,higher CR like 10.5 11:1
new intake manifold and exhaust with long primaries 4-1 dezign
u can gain 10-15 fwhp and far better response ... thats i am doing now forgied stuff is too expensive for me ... with 400US $ month payment

Hi!
i'm Alex from Hungary, and i try to make the same things on my 2.0 TS, but my engine is in an Alfetta from '73
I'll put a new complete exhaust system, and 2 del'ortos on it. Last summer i tried the carburator TS variation and it's very good:)

After 8 weeks of waiting for a quote for 85 mm pistons and sleeves etc for a reasenable price. The machine shop and I decided to go a rather exotic route .

On the old forum Micke mentioned:
I have pics of both pistons. 155 TS pistons can be used in the old TS by some modification (valve clearance). The new design is higher giving a higher compression and it is considerably lighter with a short pin.

Some measurements:
Pin center to top 38 mm / 33.3 mm (new/old) Pin to top ring 26.6 mm / 26.1 mm Weight 483 g / 570 g (Forged Arias 416 g)


The pistons are on the way goal is 1:11.5 compression.
So 155 ts piston is 4.7 mm higher, for 1:11.5 we need a only 1.35 mm higher piston (this without the valve releave taken into account).

So the piston will have to be skimmed and a offset bore in the rods to compensate.
What kind of shape would be the best for the piston top?

Sound like you will need to take off an awful amount of material from the piston crown, are you sure it's possible without weakening the roof/crown too much?
Ring lands sounds like it shouldn't be a problem but maybe the design of the piston is different in that area too?

Sounds radical but interesting. keep us posted please...

Some quick math.....

Offset piston pin 1.75 mm
Skim piston crown 1.6 mm
And a 3mm 45 deg chamfer on the outside +
--------------------------------------------------------------
all together will added give 1:11.5

there is also some more material that can be lost, as there has to made some more valve relief (155 have the valves in a steaper angle) .

hmmm, interesting 1:11.5. I LIKE it!