The IMS bearing failed on this engine. Using this and other forums, the cause of bearing failure appears to be related to loss of lubrication. The root cause of the lubrication loss appears to be due to differential pressure created by the IMS tube heating and cooling pumping engine oil through the IMS bearing. Venting the IMS tube eliminates this, and should allow the grease sealed in the IMS bearing to remain with the bearing. The "new" used IMS shaft is from Ebay, and the original bearing with buna-n seals was replaced with a Nachi 6204 2NSE sporting full contact Viton seals. The bolt is from the Pelican Parts kit. A vent hole can be seen drilled between the teeth of the camshaft drive sprocket. Another is drilled in the same place 180 degrees out from the first hole.
