Piston and crankshaft installation on a Saab B204/B234 engine. This engine is found in all four-cylinder Saab 900 and 9000 from 1994 to 1998, as well as 1999 9-3. Newer cars have lighter pistons and a slightly different block but the procedure is still the same.

Tools and supplies:

  • Torx E16 socket: main crankshaft cap bolts;
  • 12-point 14 mm socket: connecting rod cap nuts;
  • 6-point 14 mm socket: oil jets;
  • torque wrench;
  • piston ring compressor;
  • piston ring expander;
  • fresh engine oil.

Before installing new piston rings, clean the pistons and scrape all the ring grooves with an old ring to remove all dirt and reposits.

Aftermarket rings often come as a complete set, bagged and labelled for an easy installation. Saab OEM rings would come as a "per piston" set.

Oil the cylinder bores slightly and push the rings in with a piston top one by one. Check the fit and measure the gap between the ring ends. The factory specifies a 0.30-0.50 mm gap for the first compression ring and a 0.16-0.65 mm for the second. If the rings were ordered correctly for your application (e.g. standard size), you should not have to adjust them.
Rings ready

The first compression ring is a solid metal ring. The second is a scraper type and might come with an expander ring (Saab OEM kits don't have expander rings). The third ring is a multi-piece oil scraper, which has two thin rails with a spacer between them, as well as an optional expander. Have some oil ready to lubricate the rings before installation.
Ring tool

Although it's possible to install compression rings with your bare hands, it's much easier with a ring expander. Use some old rings to practice. The #2s seem to be more fragile, I broke a couple checking how far they would stretch ;)
Expander A

The key point in installing piston rings is to fit them so the gaps of the neighbor rings are as far from each other as possible. Start with the oil scraper ring. Turn the piston so you're looking at the connecting rod pin, and fit the expander ring (if you have it).
Rail B

Turn the piston 90° and fit the lower scraper rail.
Spacer C

Turn the piston another 90° and fit the spacer so its gap is on the opposite side from the expander ring.
Rail D

Finally, turn the piston yet another 90° and fit the upper scraper rail.
Ring 2 Expander

Go back to the wrist pin and fit the expander ring for the compression ring #2 (if you have it).
Compression Ring 2

Turn the piston 180° and fit the lower compression ring. The ridge on the ring should look down (the ring will likely have "top/bottom" markings on it).
Compression Ring 1

Fit the remaining top compression ring so the gap on it is on the opposite side from the compression ring #2.
Crankshaft bearings

Crankshaft bearings come as thin semi-round metal shells with special coating on them. Be sure to verify the label on the box before opening as no supplier will take them back if you remove the protective film.
Engine block

Secure the engine block on the stand and throroughly clean the mating surfaces.
Oil jets

Attach the piston cooling oil jets (14 mm socket), ensuring their correct orientation.
Main bearings

Carefully place five main bearing shells in their sockets, matching the notch on one side. Avoid touching their surface with anything, including your bare hands, as it would introduce dirt.
Thrust washers

Install the thrust washers on both sides of the #3 bearing. The side where the part number is embossed should face the bearing.

Lubricate the bearings and place the crankshaft in position. Mind the thrust washers as they like to drop on the floor at the first touch of the crankshaft.
Main caps

Clean and prepare the main bearing caps. They are numbered 1 to 5, starting from the timing cover.
Main bearing tops

Place the remaining main bearings into their caps, lubricate them and install the caps (they only fit one way).

Tighten the bolts to 81 ft-lbs (Torx E16 socket).
Connecting rod

On to the piston installation. Wrap the studs on the connecting rods to avoid scratching the crankshaft while the piston is being inserted.
Piston ring compressor

Put the piston half-way into the cylinder and compress the rings with a special tool.
Piston in

Tap the piston gently with a rubber hammer handle until it fully enters the cylinder.
Rod cap

Place the bearing shell into the rod, oil it and tap the piston further until the rod is in full contact with the crankshaft. Place the other shell into the cap and put the cap on.

Install the remaining three pistons. The rods and rod caps are numbered 1 to 4 from the timing cover. The nuts need a 12-point 14 mm socket, tighten to 35 ft-lbs.

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