Filthy intake manifold - Making new air filter assembly

When I removed the intake manifold from the existing engine...I saw that it was FILTHY inside. First, there was a lot of oil, obviously blowby that was sucked into the manifold by the breather tubes. Second, it was covered with dirt, some mixed with the oil to form grit. It's obvious that the shop vac air filter held on by a shoestring put on by someone else obviously did a very poor job of filtering. This makes me really glad I'm changing the motor....and that it got me all the way back home.

I seriously considered using the [very clean] intake manifold from the replacement engine, but being a JDM [Japanese Domestic Market] engine, it didn't have one of the sensors, so I needed to use the original engine's intake manifold. To scrub it clean, I used a bottle brush with a water-based degreaser, then brought the manifold to the local car wash and used the high pressure rinse to blast it clean.

Considering I needed to design a better air filter setup. When I discovered that the outside diameter of the airflow meter tube was 3", I realized that this would be an inexpensive solution. All I would need to do is cut off the square flange on the output side of the tube, and mount a 3" K&N filter to it.



At the self-service wrecking yard, the airflow meter tube [without the sensor] cost $5. the K&N filter cost $30. Total cost: $35 for setup which will work 1000 times better than the one on it.