Well that was exciting!
Took the car out to do some early morning runs on the freeway when traffic’s light. Did 12 runs without a problem and headed home, happy that the rev-limiter problem seems to be solved. On the way home I figured, what’s one more run, lucky #13… and at a rather high speed, had a rather spectacular “poof”…
Midlana suddenly filled with smoke and oil mist. At first, I thought that I’d blown the engine, because in the mirror I could see that I must look like an F1 car that just blew the engine. However, there weren’t any terrible noises and the engine was idling smoothly as I pulled off the freeway. There was oil everywhere: in the engine compartment, in the passenger compartment, on the inside of the windscreen, all over the rear view mirror, it’s going to take a while to clean up.
I get out and looked back down the freeway, happy to not see any familiar looking engine parts or big oil hemorrhage, just a thin line. Okay… start looking around the engine compartment… no holes in the block, all the oil lines looked intact, so where’d it come from? Since the dry sump has an 8-qt tank, so there was sufficient oil so the engine could be started to see where the leak was… and there it was. See the big brass-looking bolt on top of the remote oil filter block (fifth picture from left)? See how it’s backed off about 1/8”? That’s not good because there’s an O-ring under the head of the bolt. As purchased, the bolt is held in solely by friction; there’s nothing preventing it from slowly backing out, and indeed it had. I instantly remembered someone pointing at that block about 6 months ago, saying that it had failed this same way for him. I’d put it on the mental list of things to do but never got around to it. Well I am now! The bolt was drilled so that safety wire can positively retain it.
The last picture shows the $0.25 part that failed, the O-ring… well it was allowed to fail. As the bolt backed off, oil pressure stretching it until it popped out of the seat. On the side of the road I tried tightening the bolt, but the damage was done; the O-ring had been stretched so much that it wouldn’t go back into its groove, and all tightening the bolt did was kink the O-ring and not fix the leak. New O-rings (a replacement and a spare) are on the way. This failure could have been so much worse in about a hundred ways. However, listening to some of the 10th-anniversary stories of what Hurricane Katrina survivors went through, I have nothing to complain about.
With this issue diagnosed, and the rev-limiter puzzle sort-of solved (there are a few aspects of the “fix” that don’t seem to quite fit, but I’m tired of dealing with it), I’m going to switch back to the weaker (8 psi) wastegate spring and see if the problem reoccurs. I don’t expect it to since switching to the 15 psi spring didn’t solve the problem the first time. After that, it’s on to setting up the knock sensor and other wonderful features.