SC-L 3.1 parts and info
 

Hi there,

I've recently discovered my old targa is a little bit different!
Just before i was going to junk half the engine and turn it into a 3.2ss i discovered 3.1 stamped on the block!
I checked the paperwork and it seems to be a factory delivered 3.1 SC-L, nice!

Can anyone tell me where i could get parts for it, in particular piston rings and cylinder head gaskets?
So as it was never a factory official option i cannot find anything. The bores look to be in good condition so want just to clean it, re-ring it and put it back together to original spec.
The big/small ends and mains will be stock 3.0 i suppose.
Also is there any set up info specific to this engine?
I will want to get the fuel distributer tested as well and thats not standard so i'm thinking this could be interesting!
Any help gladly received!
thanks
Steve

CIS components..........
 

Steve,

Could you post the Bosch ID #’s of the FD and WUR? Thanks.

Tony

http://forums.pelicanparts.com/uploa...1544736832.jpg

Hi Tony,
Thanks for your reply.
I'm away from home at the moment and i don't have any details for the WUR.
Do you think it will also be different to standard?
Kr
Steve

The head gaskets would be 3.0
The rings may match turbo 3.3. If not contact EBS in Reno for some custom sizes
Bruce

What model year?
 

Steve,

What model year is car/engine? Do you have a picture of the motor? Thanks.

Tony

I have a 3.1 also, but it’s a bit bastardized. Mine has 3.2 heads and EFI via a Carrera intake and megasquirt. The 3.1 is going to have similar performance to a 3.2 SS

Hi Tony,

So the car is a November 1979 targa in dark grey.
I don't know much apart from the guy i bought it from purchased it in Belgium about 15yrs ago.
The Belgian paperwork describes the model as a 3.0 but quotes the power as 154k @ 5800 which is correct for the 3.1 , it also has the CC wrong.
I don't have the handbook or the delivery papers so i don't know if it's originally German or Belgian.



http://forums.pelicanparts.com/uploa...1544873646.jpg

It also has 97mm barrels borrowed from the 3.3 turbo, Mahle pistons and flat head gasket rings.


http://forums.pelicanparts.com/uploa...1544874025.jpg

Hello Steve, I have some very similar P&C set, could you post a picture of the underside of the pistons?
Mine have new rings so I think the ones for the 3.3 can be used.
Thanks

3.1
 

Interesting motor.Pistons look like 97mm Max Moritz.The cylinder head gasket is from a 3.2.It should be 0.5 mm thick.It is a repair gasket for when the cylinder head is machined to make the height correct.I would be surprised if this was original given the year of the engine.Fred

Here are previous threads on the 911SC-L:
http://forums.pelicanparts.com/porsche-911-technical-forum/766802-1980-911sc-l-prototype-help.html
http://forums.pelicanparts.com/porsche-911-technical-forum/281573-911-sc-3-1-a.html
I now have 5 3.1 engines listed in my database, and would like to add more. VIN with engine # is very important.

Pistons are Mahle, special for the factory 3.1

http://forums.pelicanparts.com/uploa...1545051318.jpg
http://forums.pelicanparts.com/uploa...1545051318.jpg

I'm trying to find out if the rings are the same as the 3.3 turbo as they are both Mahle 97mm...

Head gasket is 97mm, 3.2 would be 95mm

http://forums.pelicanparts.com/uploa...1545051703.jpg

Still scratching my head!!

Thanks for the link!

3.1
 

Very cool to see.I saw one of these motors years ago and just thought it was a rebuilt on a stock motor from the factory.It was in for a few broken headstuds.What a rare beast with new parts that would not be in production for a few years.Fred

Steve, does your pistons have "counterweighted" pins?

I managed to retrieve some pictures of mine:

http://forums.pelicanparts.com/uploa...1545061334.JPG

We can see below the extended pin that goes past the retainer to balance the heavy weight of the piston crown on one side:

http://forums.pelicanparts.com/uploa...1545061334.JPG

Yes, they're exactly the same.

Did you use turbo rings?

Maybe someone on here has some in their workshop they can measure?

I bought them with new rings, I can measure them next week when I’m at home.
The guy that sold me those thought they were MM ones for turbo... the crown looked quite high for 8:1 CR but I was curious about them and just bought the set.
I’ll try to check with him if he has the matching CIS

Make sure you report your findings. I will be doing a rebuild soon. I was thinking about putting lower compression pistons in mine to run more boost. I would be open to selling my block or trading if someone were interested. That way I could quit bastardizing a super rare engine

Will do !

I've got some more info regarding the original spec from an old porsche technician.

Quote

we spook to an old master craftsmann who is retired now.

He told us that the following modifications were done on these engines:

-12 upper studs for cylinders changed against Dilavar-studs
- cylinders and pistons changed from 95mm to 97mm (serial from 3,3 Turbo 930 103 973 00)
- baffle plates from Turbo
- compression ratio 9,8:1 with cylinder gasket 0,25
9,6:1 with cylinder gasket 0,5
- camshaft adjustment 0,9-1,1
- spark plugs changed from platin 260 to 265
- distributor with vacuum controlled advance (Bosch 0237306001)
- fuel distributor changed to 10% higher ratio
- clutch plate from 2,7l
- van housing with impeller,pulley from 3,3l Turbo

Im also waiting for responses from Mahle, Porsche Belgium and Porsche Stuttgart !!

I'm going to measure the cylinders and pistons tomorrow. I'm not holding my breath!!
The cylinders are easy to replace but the pistons will be a bit more tricky!!

Has anybody any idea what "camshaft adjustment 0,9-1,1" means? i guess its set-up but....

3.1 tech info
 

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 SmileWavy
http://forums.pelicanparts.com/uploa...1545155206.jpghttp://forums.pelicanparts.com/uploa...1545155521.jpg

[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!