Quickie 2.0 Rebuild Options

[McMark]

One of my winter tasks is to build a stock 2.0 with my MicroSquirt fuel injection that I can install in my car and get it dyno tuned. That's been the missing piece of my MicroSquirt setup for the last few years.

Since there isn't much demand for a stock 2.0, I just plan on doing the minimum to build a solid motor. I plan on having the valves reground, cylinder surfaces machined and reringing the pistons. Regrinding the cam and rebuilding the rods and all new bearings as well. This should give me a motor that will last through the testing, and be worth something when I'm done to pass on to a new owner at a nice price.

This thread does not represent my standard procedures for rebuilding engines. This is a special case and special circumstances.

For those of you on a budget, but looking to refresh their motor should appreciate this writeup.

Starting off with a core engine. The previous owner mentioned this engine had a 'knock', so I'll be on the lookout for what might have caused that. This is a 'GC' code engine with air injection ports in the heads.

[McMark]

FINALLY got caught up enough to jump back into this a bit. (IMG:style_emoticons/default/wacko.gif)

This is an alternate set of pistons I mentioned. Better shape, but still a few warts. These make a pretty good example of typical used pistons. I first hit these with my portable soda-blaster from Harbor Freight. Soda is soft enough to not damage the surface of the aluminum. No other media should be used on pistons. The soda was extremely effective at cleaning out the collected deposits in the ring grooves.

The small divots and the valve impact crescent aren't really a big deal for a budget build engine. The two big factors to watch out for when evaluating these pistons was making sure any divots near the edge of the piston weren't deforming outward and pressing against the cylinder wall. Small imperfections can be carefully and lightly filed and sanded smooth. The rings are what rides against the cylinder walls, so filing/sanding a tiny area is okay. It's also important to make sure there are no 'peaks' from the damage. Peaks sit higher than the piston and collect more heat. These hot-peaks can, in some cases, cause detonation/pinging by igniting the air/fuel mixture before the intended time. Knock down any peaks with sandpaper, small file, or a razor blade. No need to get it perfectly flat, and nothing pictured here is peaky.

Also, these pistons illustate why you ALWAYS knock wrist pins out with a brass drift. I had to carefully file and sand all four wrist pin bores. This takes a light touch and some skill to know when to stop filing. The idea is to remove only the high spots, and bring the wrist pin bore back to it's original size.

So here's the wrap up the piston evaluation: Remember the scope of this build is targeted at the home builder just looking to breathe a little life back into a tired motor. These pistons took a fair amount of labor to get right, but you save a few hundred dollars. These will work well for this engine, regardless of their imperfections.

[pichu]

Nice thread and idea! Not all of us are rich and I want to take out and 'refresh' my engine for education (and winter fun) (IMG:style_emoticons/default/smile.gif)