I recently call on an ad for an '80 911SC with about 100K miles on it.  The PO said that
just after he placed it for sale the motor "Blew up" and started using alot of oil.

On the phone, we negotiated and he reduced the price accordingly,
and I went to look at the car expecting to put the motor in the nearest dumpster.

When I went to look at it the car was beautiful.  I asked him if it ran and he
said yes, but that  it was going through more oil than gas!

The minute I got home I got the following cold leakdowns:

6 2%
2 4%
4 3%
3 10%
5 5%
1 100%

Like absolutely no one home in #1.  So I pulled the motor.

The intake was full of oil and looked really horrible:

YUK!  What a nasty motor!
 

Took this group in case I needed help with the hose layout.  Notice the
oil pukeing from the oil-breather hose.
Again, just for my reference.
No carrera tensioners...Oh well!
Looks like we got some serious leaks....
She's a beauty all right!
OK, so I pulled the head and something explained the lack of compression in #1
Ring Ring Ring***..silence..No one's home!
.No rings on #1 at all!  That explains the semi-ciurcular
pieces of steel UNDER THE VALVE COVERS!
There is so much carbon on the piston and the bottom of the valve
that the stack of carbon on the valve!
Oddly enough, the engine ran well and didn't make any funny noises!
Even stranger yet - THE #1 CYLINDER LOOKS GREAT!  It's round,
and still has all the crosshatching form the factory.  Not a mark on it!
Weird.  Al the ring-lands are missing form about 9:00 to 11:00.
Luckily I had a 1980 3.0 on the shelf with carrera tensioners and a fresh top
end and about 90% done.
Nice and clean.  Could use som erockers though!
All the leakdowns within about 2-4%
Notice the nice shiney head-studs?  Can you say $12 * 24 = $288....
Dilivar.  All 24.  Wallet still hurts!
Install the rockers....
Adjust the valves....
Put on the valve covers....OK...time for a beer wnd then bed.  It's about midnight.
Next Day....
Put on the Alternator and hose to prevent oil cooler damage.
You'll also notice a de-rusted flywheel, though it really doesn't matter...
Note the nice polished fan ring...did that while drinking a beer in about 10 mionutes.
Secret technigue!
Oh what a tangles nasty mess,
When we practice C.I.S!
(Real poet, eh....and a greasy one at that)
Tangled, but clean....
New heater hoses were not in the budget...Unfortunatley ditching the A/C
wasn't either (grumble grumble)....There's that polished fan-ring again!
Now we have Carrera Tensioners
Considering all the externals are from the original engine, she
cleaned up kinda nice!  POwder-coating the external sheet-metal
wasn't in the budget either.
Lastly, just install the heat exchangers, pop on the exhaust and go...
WRONG!
Little did I know the PO had installed an early exhaust (I did sell that,
come to think of it...) which meant he had shortened the exhaust studs,
which meant I got to remove four of the exhaust studs and snap off the
remaining eight!  Then drill very carefully and tap them.  Talk about fun!
FOUR hours later the exhaust was on.
The next night (Thursday) I installed a new clutch and the transmission
I put the engine in the car the following Saturday morning, which took about 2 hours
as I was a) alone and b) extreemly careful.  After filling it with oil and cranking it
until the oil pressure came up, I connected the coil wire and it fired right up!
Not bad for an engine that had been sitting ont he shelf for six-months!
Entire project was completed Sunday to Saturday, 2 full days, 2 weeknights,
and three hours saturday morning.  Then off for a test drive.
The car can be seen HERE, after extensive de-dusting!
Dr. Steven Timmins
3:56 AM
Sunday, November 8, 1998