Jan 11, 2018 update to the Nissan 350Z project car

Project LSZ: Bottom End Assembly

Final assembly is the best part of engine building, but just like painting a car, it’s the shortest, easiest part of the process. Most of a good engine build happens during the prep work.

We were confident that we’d measured and machined our engine correctly, so now it was time to install the rotating assembly. First, though, we needed to really clean our engine block. We attacked every single nook and cranny with dish soap and an assortment of brushes and pipe cleaners, making sure to really scrub every single part and every single oil passage. At the same time, we cleaned the internals, too, with the same formula.

Then it was time to measure again. (Surprise!) We installed each main bearing, torqued the bearing caps, and measured the opening. Then we measured the corresponding journals on the crank to make sure everything was within spec.

Once we knew that yes, our crankshaft really would fit in our engine, it was finally time to install it. We set it in our block, making sure to spread lots of assembly lube as we worked. From there, the process was pretty self-explanatory: Put the caps on, then torque everything in order to ARP’s specs, meaning three incremental passes in a special pattern.

Our crank was officially installed! Time for pistons. We assembled each piston, rod, wrist pin, and piston ring combination (we’d gapped our rings earlier), then used the best tool we’ve ever touched: ARP’s tapered piston ring compressor. Rather than fighting with a universal ring compressor and cutting ourselves on its sharp edges, we just placed the ARP donut over the cylinder, inserted our piston, and lightly tapped it down into the bore. There is a downside, of course: Each ARP ring compressor is sized for a specific bore, so you won’t be able to use one for your entire fleet. Once the pistons were in, we torqued the connecting rod bolts to JE Pistons’ specs, and just like that we’d assembled our bottom end.

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