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Engine Overhaul:  Cylinder Head Overhaul

With the engine assembled as far as it can be and ready for the cylinder head, it's time to move onto overhauling the cylinder head (for specifics, visit the cylinder head overhaul page).  I moved the head into the basement and sat it on a sturdy table.  Here is the head, as removed; notice the amount of carbon and varnish:

Exhaust Side:

Notice the oil in the #3 exhaust port; this cylinder likely has a leaky valve seal:

Intake Side:

And Combustion Chambers:

To begin disassembly, the coolant temp sensor and plug were removed, followed by the camshafts and lifters.   A magnetic pickup tool works well to retrieve the lifters from their bore.  Here are the intake and exhaust cams, lifters and bearing caps, in as-removed, as-filthy condition:

With the cams and lifters removed, the valves can be accessed and removed:

To remove the valves, the springs must be compressed and the valve keeps must be removed.  A typical valve-spring compressor wont work on your SAAB due to the recessed springs.  I purchased a C-type compressor from Sears and made an adapter to reach the valves:

The adapter is made from a piece of 1" steel conduit.  I cut the conduit to ~3" length, beveled the inside edge and wrapped it with electrical tape (to protect the bores from scratching).  The spring compressor then grips the adapter, which presses on the valve spring.  A magnetic pickup tool was then used to retrieve the keepers and valve spring components.  Upon compression, the spring will "give" with a pop, as the keep is released.  Anticipate this when you compress each spring; additionally, only compress the spring as far as is necessary to remove the keeps. 


With the head bare, it's time to clean each of the components.  As with all other engine components, I used Castrol's Super Clean degreaser to remove the grim.  Here are the bearing caps & bolts, and camshafts, as cleaned:

The valves, springs, seats and keeps were then cleaned, again with degreaser.  To restore the exhaust valves, I began by degreasing them and then removed the glazing using a wire cup brush, mounted on my 4.5" angle grinder.  I removed all glaze until the valve was clean.  Finally, I polished the face and stem using 2000 grit wet-or-dry, being careful not to sand on the valve seating area.  Here are the before and after pictures of the #1 exhaust and intake valves:




The #3 exhaust valve was indeed leaking oil; the port is caked with burned oil and the valve had whiskers; this is the valve that had the leaky seal:

I followed the same procedure to clean and polish this valve; here is the result; notice the reflection in the face of the valve!:


All 16 valves were cleaned and polished in like fashion to the ones shown above.  With the cylinder head casting bare, I began the arduous task of cleaning the casting.  To do this, I began with a high-pressure bath using a pressure washer.  This removed most of the guck and grim.  I then scrubbed the ports and internal surfaces with a combination of gunbore and wire brushes, with Castrol Degreaser, until clean.  I also ran a 30 caliber gunbore brush through all of the valve guides to ensure they were positively clean.  Here is the casting after its initial cleaning:

The gasket surface showed evidence of pitting, so I took it to AMS and had the head gasket surface cleaned up.  They measured the cylinder head for warp and found it 0.004" out of spec.  0.006" of total material was removed to flatten and clean the gasket surface.  Additionally, although my valves sealed, I was not 100% comfortable with their condition, so I had the machine shop check them out while they were working on the gasket surface.  The valves did show some uneven wear, although they sealed properly, so I had them reground.  This set me back $80 for all 16 valves. 

To clean the remaining gasket surfaces, the exhaust manifold studs were removed using a double-nut method and the surfaces were polished using a fine-grit paper with a flat backing plate. 

Here's the head after it's final cleanup, ready for new valve seals and reassembly:

Gasket surface and combustion chambers:

Cylinder head interior:

Intake manifold gasket surface:

Exhaust manifold gasket surface:

Reground valve seats:

And reground valve surfaces:

With all cylinder head components clean and to spec, the cylinder head can be assembled.  I began by installing the new valve seals.  I used Loctite 454 to adhere the valve seals to the valve guides and lubricated them with Lubriplate 105. 

The valves were lubricated with camshaft assembly lube, slid into place and compressed.  I had to modify my adapter to allow for access to the keeps.  To fit the keeps, I applied a coat of Lubriplate 105 to each keeper and slid them into place with a pair of long forceps.  This is the cylinder head, with all valve hardware installed:

To recondition the lifters, I pumped all of the original oil out of them, washed them thoroughly, and then reoiled them.  If you flip the lifter over, you will see where it contacts the valve stem; this is actually a small pump.  Using the magnetic pickup tool, you can slide this pump up and down and all of the oil will be dispelled.  Once the oil is out, fill the lifter with degreaser and then rinse with water.  To ensure the lifter is flawlessly clean, repeat with mineral spirits and then pump full of new oil. 

Slide each lifter into it's bore and then install the camshaft.  Wash all cam lobes and bearing surfaces with lacquer thinner, coat with camshaft assembly lube and install the bearing caps.  NOTE:  the black bolt has an oil passage milled into it.  This black bolt must be installed on the inner side of the bearing cap.  Ensure that the timing marks are aligned and torque each cap, in stages, to 11 ft-lbs. 

That's it; you should now have a beautiful cylinder head, ready for installation!

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