Sunday, May 17, 2009

Rod Knock & New Rod Bearings

In our previous post, we determined that the troll hitting the inside of the motor with a hammer lived in cylinder #6. So we pulled the oil pan, got to the bearings, and boy did that troll do a number on the bearings:

For those of you who are not wise to the ways of rod bearings, the grey bearing on the left is an OK take off bearing. The 2 bearings to the right (cylinder #6) have worn through the grey metal to the tasty copper center. This is bad. Real bad. All the bits of metal that were worn away were found scattered in the oil pan or smeared across the other bearings.

New bearings are in. We threw some zinc rich oil into the motor, fired it up, and the troll from cylinder #6 is no longer angry. The BMW recommendations for rod bearing break in are something to the tune of "for 1000 miles do not go over 5500 rpm, do not exceed 100mph". Either we're going to put down lap times comparable to a Corvair, or we'll give the rod bearings a proper "racing break in".


  1. Did you pull the motor or were you able to drop the pan with it in the car?

    Team Porcubimmer

  2. We pulled the pan with the motor in the car. We used a $60 harbor freight engine support to hold it while we took off the entire front suspension. It took a day and a 12 pack.

    The good news is that while we had the suspension in pieces, it was easy to put in some homemade camber plates. I should post them up, the pictures are truly ghettotastic.