Looking at the heads and the SAI passages

From pcarworkshop

Lets start to get to the heads...first step is to take the cam covers off. Note the way the oil connection to the cover...

Off comes more parts getting ready to remove the cam towers..

The cams pull out of the back of the engine. There are two access panels to support the factory timing tools and the cams just slide out. My cams appear to be in fine shape with no real pitting, grooves or marks...

I don't know if you remember this but the 993 uses a friction fit sprocket on the cam chains rather than the old method of a keyway and an indexed sprocket. I want to backdate the sprockets so I don't need the factory tools to time the car (and I can set the timing to what I want). I was worried about getting a keyway cut since the later 993 cams did not have one...but guess what mine still have the keyways!! I think they had the keyways in the cams well into 1996 production since Porsche was using up its "old" stock of cams. As the new cams were introduced the keywas were phased out.

So off comes the cam carrier that spans the heads. Lots of bots with lots of locktite...good **snap* noise when you undo them!

Here is a suprise....whatever person was on the Porsche line when my engine was build almost fully stripped out the insides of this bolt that holds the cam carrier in. You can see the inside being rounded out. I had to gently hammer in an allen key into the bolthead which just gripped enough to get the bolt out...that caused some swearing! (and sweat...not a good place to have a bad bolt). Turns out that on the OTHER side there was another one...which I just managed to get out. Put down a note in my book to order new bolts......

Here is part of the world famous SAI ports. Mine were clear in that they blew air fine...but you can see all the carbon that has blown up into the head. This location is at the top of the head just above the little port that comes out just behind the exhaust valve.

A close up of the tiny hole that is the SAI passage. Its tiny and mine are covered in black caked on carbon/soot. This is not going to be easy to clean and all the passages have to be cleaned...

Here are all three heads still bolted onto the engine. You can see the SAI port "smuges" on each of the heads....

Here is the engine once the heads are off....it getting smaller and smaller...

And finally all the heads are off the engine and we are left with the case and P/Cs.

The 964 sprockets (gear wheels) have the indexing holes in them. A picture might help....here it is. It requires a key and a keyway. Part 4 on a 993 is a different design and does not have the index holes for the lockpin but relies on the friction from a very tight cam nut.

Links to Rebuild Tour

1. Getting started, dropping the engine and superficial stripdown
2. Checking the default timing and Cams
3. Looking at the heads and the SAI passages
4. Valve guides, valves and carbon
5. Further Dissassembly
6. Exploring the SAI passages
7. Cleaning and getting ready to put it all together again
8. Rods and last minute checks before putting the case together
9. Sealing the case (or tomb)
10. Putting the pistons/cylinders back
11. Camshaft timing Part I
12. Camshaft timing Part II
13. Messing up a clean looking engine
14. Not quite there
15. Cranking it up