Tuesday, May 19, 2009

Season Opener -Engine Failure

I entered the Spring Opener in Portland for the start of a good racing season. Jazzed that winter is gone, the car's winter projects completed. I decided to pay the extra bucks for the Test and Tune Friday sessions to get some serious seat tiem that last season's mechanical hiccups stole from me. Unfortunately, there was something lurking in the engine that I didn't know about.

Missed session one waiting for the expert help in adjusting the carbs. He wasn't available until the second session. I also had a non-functional tach suddenly, so I busied myself troubleshooting that. Wasn't about to over rev the engine or cause it to ping, so I passed on the first session. Ran the second, vowing to take it easy and just get seat time.
On this first run session, it started started losing power and some oil pressure dips. Not wanting to go through the head rebuild AGAIN, I wisely shut it off and coasted from the back stretch to the pits. Seems the valve cover gasket let go and washed the engine bay with a layer of Royal Purple protection. Took an hour to clean. The thought was that the double gasket set-up, left over from last season's head bolt spacing effort, was the root cause. Replaced the gasket and got ready for the next practice session.

Then, the next session ran fine until late in the period I smelled a bit of burning and then a temperature increase. Drove it back under low engine load. This time it appeared that the new alternator wasn't perfectly aligned when I modified the mounting casting. The 1/8' off at high RPMs caused the belt to jump the crank pully, get lodged, and the spinning motor burnt through the belt. Fixed that with more grinding of the casting and a new belt. Picked up a new tach from Baxters at the same time. Put that in, got it working, and the rest was showing well. Oil levels oddly still checked out as OK. Too much oil to start with???

Then, a very rude awakening 5 laps into the next run. Coming down the back stretch at full power (somewhere around 110+ MPH), I lightly touched the brakes to set the car for the high speed turn in to Turn 10. The car instantly swapped ends and I was spinning. On track, off track, on track, off track and still going. Don't flip, don't flip, don't flip I screamed in my head. Luckily, it didn't, I was fine and no collateral damage. But the tire wall was a damn sight closer. Fired her back up, got Black Flagged and went to the pits. The pit boss looked under the car and screamed "Get the hell off my grid" and pointed to the paddock. I got out, looked under and it looked like I'd taken the car through an oil car wash. It was dripping from everywhere!!!!

The valve cover had let go again and misted oil everywhere at 70psi and 100mph. SHAT!!!. Real nice on a white car.

A nice MGB Vintage racer happened by and graciously helped me figure out that the pressure is building too high in the valve cover and not venting out properly...hence the gasket pushing out. OK, drilled the center out of the catch tank and ran a new hose from the valve cover to the tank for the next day of "practice,/qualifying" and the Novice Race.

One practice session was flawless. Finally!!!
But then, the "race"....it lasted two laps for me. The oil pressure went to 20psi and I shut it off and pulled into the Turn 8 pull-out. Flat towed back after watching the other drivers f0r the remaining 25 minutes of their Novice experience. Popped teh hood. No oil anywhere it shouldn't be. Must be the gauge or pump. Hmph. Pack it up and go home busted, AGAIN.

Days later, I took off the oil pan and removed the oil pump. Oil pump pumped fine. Maybe a weak bypass spring (for over-pressure conditions, it opens a bypass valve)? But then, I saw it there, gleaming in the fine residue of oil in the pan. A big brass shaving of some sort. What's brass doing there. Then, further review and a trip under the car told the story. Billions of bits of what used to be the brass main bearings for the crankshaft. I can;t even find the right explitive for my feeling right then.
Now what? Besides a rebuild for the engine???

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