At this point with all the machining, polishing and tweaking done, the engine was finally ready for a good wash... I was getting tired of all that burnt oil-varnish ruining my photos. I took the block to a different machine shop here that specializes in rebuilding cylinder heads, which I knew from experience could wash the block in a high-pressure hot water and detergent machine that wouldn’t ruin my polished exterior. The results were great and the block came out looking better than brand new. Over the course of the next few photos you’ll see the difference.

One thing I decided I wasn’t going to do was polish anything that wouldn’t be seen, like the intake valley (or the lifter valley if it were a pushrod engine). After the wash, the valley was super clean but still quite pitted so I wanted to protect it from future corrosion as much as possible. The dreaded white powder starts in the little pits and grows outward so the idea is to seal off the pits with paint to keep water and other contaminants out. Here's the bare valley:



I masked off the cylinders and bought some Duplicolor Chrome paint… this stuff is amazing… looks great and dries fast. I think you’ll agree. It does smudge if oil contacts it once it's dry though, so if anyone reading this plans on spraying their entire engine with it, it will need to be clearcoated to keep the sheen.



With that little loose end tidied up, I could turn the engine over on the stand and start working on building up the lower end. The first thing was to measure the main bearing clearances so in-went the bearings. This is #3. You’ll notice it’s the thrust bearing with the side wings. I wear gloves when I handle bearings because finger grease is acidic enough to etch the finish on them if you’re not careful.



Here’s a pic of all the bearings in place (notice the clean innards?). Like any other engine, they go in the block dry. I lubed up the surfaces that contact the crank with a thin layer of motor oil before laying in the crank, but nothing thick like assembly lube at this point since I didn't want to throw off measuring the clearances.



Next up was laying the OEM neoprene case-half seals and a piece of green Plastigauge on each of the main crank journals. The whole thing had to come apart again to read the Plastigauge, so no sealant was used on the case-half seals at this point. In retrospect I could have left the seals out at this point, but I figured they couldn’t do any harm. Later, I would discard these seals altogether and replace them with a new engine sealant that GM recommends instead.



The lower bearing halves were installed in the lower case half, and the lower case half was then installed carefully onto the upper case half. There are four tight fitting guide pins that make installing the lower case half difficult without a rubber mallet.



Because the main bearing cap bolts pass through the windage tray and the oil manifold, these parts must be assembled onto the lower case half as well before finally installing the bolts. Here’s the oil manifold sitting there awaiting the windage tray installation.



And here’s the windage tray in position and the main bolts (all 20 of them) being set in place. Unlike the connecting rod cap bolts, these are not TTY (Torque To Yield) and can be reused.

[This message has been edited by Bloozberry (edited 05-12-2010).]

quote Originally posted by Bloozberry: And here’s the windage tray in position and the main bolts (all 20 of them) being set in place. Unlike the connecting rod cap bolts, these are not TTY (Torque To Yield) and can be reused.

The bottom end of the Northstar is extremely robust. I believe that Alan Johnson of CHRF uses stock main bolts in all of his engines at any power level (including 2000 HP Methanol burners).

BTW, I'd torque the main bolts first, THEN tighten the smaller bolts that help seal the oil manifold.

[This message has been edited by Will (edited 05-13-2010).]