SC-L 3.1 parts and info

[Steve G]

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

[boyt911sc]

Steve,

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

Tony

[Steve G]

Originally Posted by boyt911sc

Steve,

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

Tony

[Steve G]

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

[Flat6pac]

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

[boyt911sc]

Originally Posted by Steve G

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

Steve,

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

Tony

[scottrx7tt]

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

[Steve G]

Originally Posted by boyt911sc

Steve,

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

Tony

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.





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

[Pesch]

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

[faapgar]

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

[djpateman]

Here are previous threads on the 911SC-L:
1980 911SC-L Prototype HELP
911 Sc 3,1
I now have 5 3.1 engines listed in my database, and would like to add more. VIN with engine # is very important.

[Steve G]

Originally Posted by faapgar

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

Pistons are Mahle, special for the factory 3.1




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



Still scratching my head!!

[Steve G]

Originally Posted by djpateman

Here are previous threads on the 911SC-L:
1980 911SC-L Prototype HELP
911 Sc 3,1
I now have 5 3.1 engines listed in my database, and would like to add more. VIN with engine # is very important.

Thanks for the link!

[faapgar]

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

[Pesch]

Steve, does your pistons have "counterweighted" pins?

I managed to retrieve some pictures of mine:



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

[Steve G]

Originally Posted by Pesch

Steve, does your pistons have "counterweighted" pins?

I managed to retrieve some pictures of mine:



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

Yes, they're exactly the same.

Did you use turbo rings?

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

[Pesch]

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

[scottrx7tt]

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

[Steve G]

Originally Posted by scottrx7tt

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....

[porschyard]

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