Greetings,
I purchased a 74 911 Targa, 2.7 Cis last december with 84,000 miles.
The previous owner had done a tensioner update at about 79,000 miles. He drove the car about 6,000 miles in 14 years. Always used Valvoline 20-50 racing oil and basicly let the car sit 9-10 months out of the year.
When I bought the car. There would be a loud banging for the first 30 seconds when the car was started cold. I first thought that it was motor mounts (3/8" play in the mounts and 3/8" clearance between the muffler and valance panel) and I replaced them. The noise continued but now not as pronounced and only when the car was cold.
Oil pressure? I noticed that when the engine would start, the oil pressure would be in the 80-100 range and when the noise stopped the pressure would be 140psi.
At the recommendation of a long time porsche mechanic, I tried CD-2 and rislone. The noise at startup became occasional. Once every 10-12 cold starts.
Well, I changed my oil, 20-50 non-synthetic. Ran a couple of DE events at Waterford Hills, where my oil temperature hit 240-250. Still has the loop cooler in it and no missed shifts or over-revs.
Now when it starts, I get the banging for a few seconds and then a new noise from the engine.
I've never heard a chain dragging from a collapsed tensioner, but that is what I think I am hearing.
Wayne, Love your 101 Projects book! How about adding some sound files to your website to aid in diagnosis.... Pulled head stud, Flashed cylinder, timing chain... Plus some of the good sounds 917, 935 wastegates
Well, I'm planning on dropping the oil, pulling the sump to inspect the screen, check adjustment on the valves.
Do you think I should pull the cam covers to inspect?