Water and Oil Lines

Modern turbochargers are water cooled and lubricated with engine oil.  That means making new connections to source and drain these vital fluids between the engine and turbo.

First we need a place for the oil to drain back into the engine once it's gone through the turbo.  That means drilling a hole and tapping threads for a brass fitting in the side of the oil pan.  I probably used about 4 different sized drill bits during the process.  This picture was taken just after I started.

 

One trick I picked up is that while you're drilling holes into the side of your engine, you can use regulated air pressure (~5-10psi) fed into the valve cover and it introduces some positive pressure into the engine, so as you drill, shards of aluminum actually blow out of the engine instead of falling inside.  Most of them anyway.  This picture shows the air compressor hose with a regulator.

 After the hole was done and threads tapped, I JB Welded this fitting into the engine.  It has a 5/8" hose barb fitting on the outboard side for the drain line to slide on.

 

Here is the finished product.  I could have gone with a hard line, or one made of braided stainless steel, but instead I chose a special high-temp silicone hose because basically, it was the cheaper and easier alternative.  It will need to be replaced every 2-3 years, but I don't really track that often so it should hold up fine.

While it might looks like the engine is chugging a cheap beer very fast, this is just the stage where I pour mineral spirits, chased with some engine oil, into the hole I just drilled to flush any remaining aluminum shavings out the oil drain hole.

All of the above was for the oil drain line.  The oil supply line is completely different.  This time I did go with a stainless steel braided line because this line is under pressure.  It is visible on the right side of the turbo in this photo.  The oil is actually sourced from an unused port available on miata engines from 90-95.  This was a relic from when these engines were turbocharged from the factory in the 323GTX.

Onto the water lines.  I had to reroute the lower radiator hose to make room for the intercooler piping but still keep space available for A/C and power steering components.  I ended up buying a 1 piece hose that was designed for a second generation miata, and trimming about 5.5" off the top to make it fit in the new arrangement without bunching up and kinking.  The ratchet extension is pointing toward the subject hose.

The two lines laying over the power steering bracket are the water feed and return lines for the turbo.  I'm not crazy about how they sit right now and will slip a larger hose over them to protect them from abrasion damage from that bracket.