Bottom End Assembly

After all of the original aluminium castings had been returned to like-new condition, and all of the other ancillary parts had been thoroughly cleaned and checked (cleaning old parts takes a looooong time), it was time to reassemble everything.

The build starts with a thoroughly cleaned bare block. Just as a precaution, high pressure air is run through all of the oil passageways to ensure that they are clean and free of any residue left over from the vapor blasting process.

Moving on to the thoroughly cleaned, inspected, and oiled crankshaft. No scoring, quite healthy. The Alfa 5-bearing crankshaft is probably the most robust part of the entire Nord motor design. They are bulletproof, and wonderfully made.

The bearing journals in the block were thoroughly cleaned with carb cleaner to remove the protective aluminum lubricant. The new crankshaft bearings were also cleaned in order to remove any oils left over from the manufacturing and packaging process. The bearings were then carefully placed in the block ensuring that all of the tabs lined up correctly.

Then same process for the thrust bearings--tough to find a new set these days, by the way. Another big thank-you to Jon at Alfa Parts in Berkeley, CA!

Then a liberal dose of Permatex Ultra Slick on all the new bearing surfaces before placing the crankshaft back in the block.

Once the crankshaft is in, time to put clean, new bearings in each of the cleaned crankshaft caps, again making sure that the tabs all align with proper notches. Then another dose of Ultra Slick. Each cap is numbered, to make installation simple.

The number five cap also acts as an oil seal for the block. I decided to forego the traditional "cigarette" rubber seals, which have a tendency to dry out and leak over time. Permatex Ultra Black is a more modern, leak-resistant solution.

Generous bead along one side...

...then the other side.

More Ultra Slick on bearing.

After seating cap, fill hole with more Ultra Black until full. Note the new lock tab washers too.

Same thing on the other side.

All that's left is to do is to tighten the cap nuts, starting with the center cap and working outwards towards each end. Lubricated with Loctite Red 271, each nut was tightened to 36 lb ft, per the factory specifications. Lock nuts were applied above each main nut, using more Loctite Red. No excessive end play and crank rotates like silk!

The block then gets rotated 180 degrees for installation of the new liners. In addition to ensuring that the new liner seals are seated properly using a 90deg hook tool, I also use silicone paste on the bottom end of the liners. This helps preserve the liner seal, while also acting as an additional layer of protection against internal oil leaks.

Next step is to assemble the pistons and connecting rods. I like to lay everything out neatly. Since Alfa connecting rods are asymmetrical, they were marked to make certain that they remain in the same cylinder locations and orientations. In the photos below, cylinder 1 is on the far left and cylinder 4 is on the far right.

Before assembly.

After assembly, including new bearings.

I use rubber tubing on con rod bolts to prevent marring the crankshaft journals during installation.

Now comes the fun part--fitting the pistons into the liners. I checked to make sure that all of the ring gaps were staggered and not facing the side of max friction.

Then more Ultra Slick on the upper bearing before installing in the liner. By the way, I highly recommend the custom- sized aluminum tapered sleeve ring compression tool from Spruell Motorsport. It worked like a charm and made installation much easier than with traditional compression sleeves. It wasn't cheap, but you know what they say about having the right tool...

After the piston is in the liner, time to secure the liners in the block, flip it 180 degrees again, and finish securing the con rod to the crankshaft. More Ultra Slick on the con rod bearing, and more Loctite 271 on the rod nuts before gradually tightening to 38 lb ft.

All four pistons installed in their respective liners.

Next up, installation of the timing pulleys, lower timing chain, front engine cover, and water pump.

New thrust washer on back of upper timing gears.

Well oiled and installed.

Ultra Black and Reinz gaskets installed

More Ultra Black on cover side...

...and new rubber oil seal.

Front cover installed, and M6 wave washers and hex nuts to tighten everything up.

Next comes the water pump. It's not new, but it's barely been used and is great shape. No real need to replace it.

This pump is the version for a SPICA-equipped motor. If you want to put Webers on instead, you'll need a different water pump. That's why I didn't use any Ultra Black on the Reinz gasket!

Now comes installation of the main pulley and crankshaft nut. Got a new tab washer too. Then tighten down the nut to factory-specified 72 lb ft.

Now comes installation of rear oil vent chamber cover and new gasket. Note new rear engine seal installed as well.

Next step is installation of the cleaned and inspected oil pump. Also a new rubber gasket seal between oil pump and block.

Finally getting to the end...of the bottom end. Need to put beautifully finned (and restored) lower oil sump cover onto the oil pan, which means (of course) more Ultra black in addition to a new Reinz gasket. But first, installation of a fresh, new oil pan expansion plug.