Jump to content
Impact Bumpers
Rory

Various 81 SC Engine issues.

Recommended Posts

Hi guys, I've been directed to this forum as being a 911 fountain of knowledge.

Picked up a lovely 81 SC Guards Red Targa back in October that I've been slowly restoring.  I recently discovered 5 broken exhaust dilavar studs when doing a valve adjustment. Decided to drop the engine and tackle the studs myself/replace gaskets. Being the heavy handed idiot that I am I've created a few problems for myself.

Firstly, I've snapped the hard metal fuel line (the third one near the engine, not the ones not attached to the accumulator/filter) I thought I was spinning the nut and then snap! Great 😐 Is this a difficult & expensive fix? What is this fuel lines purpose and where would I source one, I 'm assuming its a return line perhaps? I'm in the UK.

The second issue I managed to create for myself during the engine drop was the snapping of the rear wiring harness black plastic 14 point connector housing, it was really brittle, the screw driver just went straight through it. I can't seem to find this part in any of the stores, any ideas if this part is even available to buy?2141244758_porscherearfuse.jpg.2bd8581d0292b35419a49de790275030.jpgPorsche-911-Wiring-Harness-Connector-for-Engine-14-Pin.jpg.00a831d17e83b3bb2aca2e5839e43428.jpg

Now, the engine tear down. It all went swimmingly, and I'm right down to the case thanks to Waynes engine rebuild book, and have even managed to remove the first dilivar stud, with heat and PB Blaster! This was until this afternoon, however when I've managed to damage piston #2 turning the crankshaft which then got stuck on the piston and broke off one of the small fins on the bottom of the piston. How essential is this 'fin'? Do I need a new piston? 😲Is it essential to remove the pistons to get at the studs? I had such a struggle removing and replacing the circlips holding them on that I abandoned it and began to get the studs out with them in place.

1636197586_911scpistons.jpg.4cf122be0bb368bbaf0d5078063b9605.jpg794439033_porsche911scpiston2.jpg.84b8ea5778c2a0c25244f5e148eb4eff.jpg

I should note that this is a budget fix with limited funds, all my dosh went on the purchase of the project, all i can offer the car is my time! I'm already shocked at the price of the steel studs. I'm hoping to replace them and the various gaskets, button it back up and get some mileage out of her (once I've rebuild the pedal cluster, addressed some bits of rot, fixed the door locks, renewed the targa top etc, etc, etc). I have made some progress in replacing the fuel pump/starter/fuses//new rotors and pads/getting rid of the whale tail. The seller assured me it had had a rebuild 5k miles ago, back in 2004 (It's sat for some years). 

Thanks for any help guys, love reading through the forums, full of great projects, advice and gorgeous 911s 😎

Rory

 

Share this post


Link to post
Share on other sites

Sorry to ask this, but are you sure the studs are Dilavar?  The Dilavar ones are threaded almost all the way along their entire length, with just a short non-threaded section in the middle; whereas the original Porsche studs have a long section, comprising most of the length of the stud, which is not threaded.  Dilavar studs supposedly have a coefficient of expansion that is similar to aluminium alloy, ie they're designed not to snap.  And they're £30-odd each (or currently on offer for 29 euros each from a German supplier that I saw mentioned on a thread here on IB).

Regarding sources of supply, I suggest starting with Type911, then Design 911, Porsche themselves, or Euro Car Parts.  For the connector, you could try 9Apart.  And the piston needs replacing, unfortunately.

Share this post


Link to post
Share on other sites
15 hours ago, Rory said:

The second issue I managed to create for myself during the engine drop was the snapping of the rear wiring harness black plastic 14 point connector housing, it was really brittle, the screw driver just went straight through it. I can't seem to find this part in any of the stores, any ideas if this part is even available to buy?

Last year I was hunting connectors for seat and Porsche GB had them, worth a try.

Share this post


Link to post
Share on other sites
36 minutes ago, GimmeShelter said:

Sorry to ask this, but are you sure the studs are Dilavar?  The Dilavar ones are threaded almost all the way along their entire length, with just a short non-threaded section in the middle; whereas the original Porsche studs have a long section, comprising most of the length of the stud, which is not threaded.  Dilavar studs supposedly have a coefficient of expansion that is similar to aluminium alloy, ie they're designed not to snap.  And they're £30-odd each (or currently on offer for 29 euros each from a German supplier that I saw mentioned on a thread here on IB).

Regarding sources of supply, I suggest starting with Type911, then Design 911, Porsche themselves, or Euro Car Parts.  For the connector, you could try 9Apart.  And the piston needs replacing, unfortunately.

On SCs the exhaust side engine studs are Dilivar.  Whilst they have good expansion characteristics, they suffer from chemical attack and then break under load.  The inlet side are all steel.  It is common for the Dilivar exhaust studs to be replaced with (inlet) steel ones (cheaper option), unless you are building a high-stress engine, when 993 or ARP bolts are used (spendy option).

Peter

Share this post


Link to post
Share on other sites

I'm not sure when Porsche introduced Dilavar studs on the exhaust side (I thought it was on 3.2s ..?) but on my '83 SC all the studs were conventional, non-Dilavar, until I replaced them recently.

Share this post


Link to post
Share on other sites
39 minutes ago, GimmeShelter said:

I'm not sure when Porsche introduced Dilavar studs on the exhaust side (I thought it was on 3.2s ..?) but on my '83 SC all the studs were conventional, non-Dilavar, until I replaced them recently.

I think there were different types of Dilavar studs in use from the 70's (think starting with Turbo), early ones didn't have proper corrosion protection, hence the failures. Last generation as used on 993RS, TT & GT2 variants have proper protection and some say better that AM variety.

Share this post


Link to post
Share on other sites

Dilavar studs were used back in 1974 on the bottom 12, 93010117000, many super-cessions take them to the 993 number 99310117054

Share this post


Link to post
Share on other sites
21 minutes ago, Type911 said:

Dilavar studs were used back in 1974 on the bottom 12, 93010117000, many super-cessions take them to the 993 number 99310117054

Not 993.101.170.53?

Share this post


Link to post
Share on other sites

Sounds like 993.101.170.53 has been superseded by 993.101.170.54 which would explain the discount by mittlemotor as per Ian's post - still a good deal though.

 

Share this post


Link to post
Share on other sites

Thanks for the advice guys.

The studs are most definitely the non-magnetic dilavar studs, I'm intending to replace them with steel. I've found the 14 point harness housing in America. Looks like I need to source some used pistons then. 

Does anyone know if I need to reattach the smog pump to pass a UK MOT emissions test. I 'd love to bolt the engine back in without.

Cheers!

Share this post


Link to post
Share on other sites
2 minutes ago, Rory said:

Does anyone know if I need to reattach the smog pump to pass a UK MOT emissions test. 

I’m going to say not, but I’ll leave it to more knowledgable people to confirm.

Share this post


Link to post
Share on other sites
38 minutes ago, Rory said:

Does anyone know if I need to reattach the smog pump to pass a UK MOT emissions test.

Do you mean the air-injection pump ? 

If so then no. You can just plug the holes in the heads. 

Make sure the plugs are in there properly. Ask me how I know 🤔

Edited by GaryH

Share this post


Link to post
Share on other sites

Sling the air pump and if the engine is out/exhaust off remove the pipe and get the correct kit to plug the 6 holes as the guys above have said. Its easy to do

Edited by Type911

Share this post


Link to post
Share on other sites

Rose Passion have the electrical connector in their catalogue. There are 2 shown. Rose Passion reference numbers P18213 and P129214.

Share this post


Link to post
Share on other sites

We list both male and female parts of the engine wiring loom connector

Share this post


Link to post
Share on other sites

Great thanks, I've added the connector to my ever growing shopping list over at your place Type911 along with the emissions plugs. Do you stock the metal return fuel lines? Can't seem to locate them. Also need to source some used 9.3 CR Mahle Nikasil pistons...

 

 

 

Share this post


Link to post
Share on other sites

Haha sorry Type911.

Thats the problem the photos in the shop look the same. 😁

So male is the 'main' one left in the car after ive removed the engine?

Edited by Rory

Share this post


Link to post
Share on other sites

Female pins have a hole in them (like females do) and the male pins have a round end to them (like males do)

Dusty is saying the one on the fuse/relay board is the male one, the one that comes out with the engine is the female one.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×