After all of the critical measurements needed on the crankshaft were done, it was time to put it back into its home with some fresh bearings to continue the engine build. Since there was no noticeable wear on the crankshaft, standard-size replacement bearings were used along with an appropriate amount of assembly lube. The torque specifications for all of the main crankcase bolts are torque-to-angle, which requires you to set the bolt up with a relatively low torque setting first, then finish with a final turned angle using an angle meter. Digital angle torque wrenches are great tools, but can be fairly expensive for the home mechanic. I’ve been using these manual angle gauges and although they take a little longer to set up on each bolt, I’m happy with the results and no batteries required. After using the proper torque sequence, the crank is in, spins nicely and we’re on to setting up the pistons and rods for installation as well as installing the balance shaft elimination kit 101k10333 and chain system 101K10151.
B207 Engine Build: Finishing the Balance Shaft Elimination Kit Install
The first step was the gather all the pieces required for the install, and have the diagram and torque spec sheet handy. First, I used our newly developed Balance Shaft Elimination Kit Tool (101E00042) , to precisely drive the inner balance shaft bearing further into the block, thus blocking the oil port. Here’s how it works:
Simply insert the tool into the balance shaft bore, it will seat inside the oil bearing towards the end of the balance shaft tube.
Hit with a soft mallet or dead-blow until the stop collar is up against the block (it will require a good amount of force, it’s a tight bearing).
The bearing is now sufficiently moved to block the bearing oil journals and maintain oil pressure in absence of the balance shaft. Repeat on the other side, done.
The other part of our Balance Shaft Elimination Kit, the balance shaft sprocket retainers, should be bolted to the housing to be installed as a complete assembly. Be careful when installing these as they are a very tight fit and must be installed absolutely straight. If they get off center in any way, straighten them by tapping the bolt head with a drift in the desired direction. Make sure to use assembly lube when inserting these into the block.
Also, a helpful trick is to install a longer 6mm bolt that will keep the mounting hole more or less lined up with the housing.
It might take a few tries. Be careful not to hammer directly on the housing ear or it can crack or be damaged, as the metal is fairly brittle. Next, assembling of the rest of the balance shaft system is pretty straight forward. All hardware should be replaced and treated with new dabs of Loctite. It is best to hand tighten everything and then give a final torque to bolts when you can lock the crankshaft to keep the sprockets from spinning. Just don’t forget about them!
Final Assembly of Pistons, Rings, and Connecting Rods
Without the cylinder head quite ready for installation, We can’t install the rest of the valve timing components, but we can move back to the rotating assembly to get the pistons and rods put together. The first step is check the specifications included with our Wiseco pistons for recommended ring gap. Since we’ve already checked that our rod bearing clearances are in spec and ready to go, we can size our rings, install them on the pistons, and get them in the short block. Depending on the type of driving you will be doing, there are different recommendations for ring gap. Proper ring gap is important because it allows the rings to expand when the engine is running at operating temperature, but limits the loss of compression and oil blow-by.
The recommendation for our purposes (we are going with Wiseco Piston‘s ‘circle track’ recommendations) is 0.0050 x bore diameter in inches (3.405512in, 86.5mm) for the top ring and 0.0060 x bore diameter in inches for the second ring. This equates to about 0.017 or (1st ring) and 0.020″ (2nd ring) on our set of feeler gauges. The bottom most groove holds the thin oil scraper rings and expander ring (to keep them separated), they do not need to be resized. To measure the current reading of the gap, the rings need to be inserted in the bore squarely. To aid this, I took the top ring of our old B207 piston and flipped it upside down until it bottomed out on the second ring, pushing down the ring to measure. This gives me a square and repeatable setup to take the gap measurement.
The top rings all seemed to start of at about 0.013″. I used our piston ring file wheel to open up the gap, re-checking the measurement in the cylinder bore often until sneaking up on the magic 0.017″. Be aware that there is a top and bottom direction for most rings, in our case there is an “N” which should face up. There is also some care to be taken in the direction when grinding the rings. The recommendation is to grind from the outside in, which means rotating the handle towards you with the ring facing up. This keeps any of the coating from chipping off the back of the ring. Only grinding one edge of the ring allows you to verify that it is square against the factory edge.
It is very important to not only grind the gap squarely, but to make sure any burrs are smoothed over and the edges slightly chamfered. I had a some 1000 grit emery paper that worked just fine, but you could use a small file or stone to break the grooves and burrs.
The process is repeated for each top ring and then repeated for the second ring. The second ring seemed to be in spec right out of the box, so that made life easier. Once the rings were ready to go onto the pistons, they were numbered and installed. Again, closely following the directions included in the piston/ring kit should make this a very easy task.
Giving everything a light oiling and installing the wrist pins and attaching the connecting rods was next on the list. I didn’t see any instruction on rod orientation, but I mimicked the factory setup of having the bearing tangs on the intake side. The pistons are directional, also marked with a dot, which should be pointed at cylinder number #1 (next to the timing chain). The pistons are then carefully installed into the block on to the crank. Rod bolts are once again torqued to spec using an two stage process. Once the rotating assembly is finished, we can install the oil pan, pickup tube and seals.
Now with the bottom end all together and waiting for the cylinder head to complete the B207 engine build, I’m going to switch gears back to the chassis in preparation of the cars return from the roll cage design. The entire 9-3 SS product line of Powerflex polyurethane bushings is here and I’ll be working through installing all of it!