[notmytarga]

I dropped my #1 exhaust valve at Thunderhill.

I was not planning to rebuild my 1975 911S California motor for a few more years. It has 54,000 miles but had the thermal reactors removed at least 20-25,000 ago. It has been running well and I took it to Thunderhill for a Hooked on Driving HPD track day Dec 8th. I have done five track days at Thunderhill over the last year.

Braking into turn 14 I felt something change but I didn't pull into the hotpits. The flags were then out that the session was ended. The engine was rough but had OK power driving at 50% around the track to pull in. I didn't hear any horrible sounds when I pulled off but I had lots of blue exhaust. The engine died unless I kept the tach above 1500 RPM.

Looking back, I was having exhaust smoke while in pregrid and someone asked me if I had just added oil. I will presume that the valve guide was really leaking and heating the valve stem. Prior to that the only oil smoke was a puff at startup.

Diagnosis: A few days after the incident I turned the engine by hand to determine which cylinder had lost compression and thought it was #6. That plug was very oily so I thought I had bad rings. Pulling the rest of the plugs I found the #4,5&6 plugs to have about the same amount of oil with #2&3 dryer. The #1 plug came out with some effort like it was stripped. The side prong was gone and the center conductor was bent to one side. I was able to boroscope the cylinders and found a little oil to match the plug condition. #1 was all beat up - a hole in the piston but the circumference was intact and the cylinder looked OK. I could see the exhaust valve lying over its orifice. At first I thought it was mearly open but then I saw the stem facing the piston. I think it was stuck there because the sound didn't seem as bad as I would expect for the ...... 85 mile drive up I-5 home.

Ok - so stupid me. I was more concerned about getting home to my sick family to improve my chances for future track days. The whole drive I figured that the compression loss and oil burning symptoms meant a valve guide was leaking and I feared I could burn out a valve - it had already happened in a big way.

I have now read more of Waynes rebuilding book.

So a few questions for the sages:

1. If there is no ignition in the blown cylinder - what burns the oil?

2. Presuming that metal is everywhere in the engine, what parts are ruined?

3. Presuming oil filter perfection - what parts are ruined (other than the piston)?

4. If I had a rough 2.7 long block core of uncertain internal condition readily available, should I buy it and for how much?

5. No question here - I plan to rebuild myself. Heck, I did the whole restoration - and did a VW rebuild 20 years ago.

More about this car:
The whole Targa Story

Restoration Pics