[QUOTE=porschyard;10288008]hey steve, i dug up these old tech info pages on the 3.1 factory conversion. there is some new info i did not see in any of the the other post including cam timing, ignition timing and it shows that the 930 rings are the correct ones, hope this helps as they are original porsche tech. documents
richard


Hi Richard,

Thats absolutely brilliant, all the information is coming out of the woodwork now.

Thanks a million.

Steve

Great information! How about the oil pressure fed tensioners?

No oil fed tensioners on mine '79

In the excellence magazine article it states that the 3.1 was the first engine with the pressure fed tensioners. My motor was made in 1980 and has them. Maybe that was true of the engines made after 1979? Or maybe mine were retrofitted at some time in its life.

steve, is the car a 79 or 80 the engine serial # and model designation # says its a 1980 ROW engine, also notice on the second page system and control press specs do not change with the bore increase only the fuel distr. volume. on the cam timing the 0.9 -1.1 MM is the setting overlap @ TDC

Confirmation from Porsche !
 

Dear Stephen,

I asked our importer about your 911 SC.
We can confirm that the VIN-number and the engine number are matching. The car was first registered in 11/1979. It’s a model year 1980.
It was new delivered in Germany and produced in factory with an 2994cc engine of 188 HP.
As you know, Porsche Motorsport developed at the time an engine kit to meet the demand of customers discontented with too low engine power.
This kit could be ordered at the same time as the car, but it was not installed when assembling the vehicle on the assembly line.
The engine was reopened later to mount the kit including 97 mm pistons/cylinders, a recalibrated injection head and a larger oil cooler to reach 210 HP
It seems that very few models have been equipped with this kit, mainly in Germany, but there are no production statistics for this engine or VIN databases.

Best Regards.


Coordinator Porsche Classic
Grote baan 395 Grand Route
1620 Drogenbos
Tel : + 32 2 37.17.962
Fax : + 32 2 37.17.960
www.porschecentrebrussels.be

Piston and cylinder condition
 

Ok so i measured up the P's and C's as below

They are a group 1 set

1
C 97.040mm
P 96.957mm
2
C 97.032mm
P 96.965mm
3
C 97.036mm
P 96.961mm
4
C 97.020mm
P 96.988mm
5
C 97.035mm
P 96.941mm
6
C 97.030mm
P 96.946mm

Delta's
1 0.083mm
2 0.067mm
3 0.075mm
4 0.032mm
5 0.093mm
6 0.084mm

Does someone please have some specs for 3.3 turbo 97mm barrels and pistons?
My Bentley book only covers the normally aspirated engines.

If i look at the limits for Mahle 95mm them they are within spec.
All the barrels measured 97.025mm at the base. The wear limit of the 95mm is 0.08mm. If i use this limit all my barrels are in spec as none exceed 97.105
Also the max delta between P's and C's allowable is 0.12mm - 0.15mm depending on year, so looks goos there too!

Has anyone got the specs for the 97mm cylinders?
It would be greatly appreciated!!

here you go stevehttp://forums.pelicanparts.com/uploa...1545386289.jpg

Thanks Richard, you're a gentleman!!

Ok so has anybody much experience in this one?

So the Bentley gives up to 0.12/0.15 mm but Richards book gives 0.030mm - 0.047mm

So not really sure which way to go to stay as authentic as possible. It looks like the original pistons are made from pure unobtanium even if i can get new barrels from Mahle.
I've contacted Mahle but i haven't had any response. And the Porsche fella in Stuttgart isn't back until the new year.

Option 1
Re-ring my existing P's and C's with 0.093 (max) clearance, face .25mm off the top of the barrels to clean them up and fit the .5mm base gasket.

or

Option 2
Have my existing barrels machined, re-plated and search for a custom solution ( JE maybe )

I'd love to her you suggestions.

Head scratching.........

I have a set of P&C I may never use, wanted to keep them but I reach a point where I have to let go some of my odd items...
Got to measure them 1st, if in spec I can propose them for the price I payed...

Hi there, thats super gracious of you!

Please let me know how they measure out.

Happy Christmas!