Loud clacking sound while engine idles

[rfeierbach]

My 1990 Porsche 911 Carrera 2 engine stopped while at an intersection this morning. Restarted engine, ran fine for 1 minute, then a loud clacking sound began in the engine compartment. Pulled-over, clacking became VERY loud, then engine froze with one last loud clack. I thought I had a broken cylinder rod. Had car towed to my home, reluctantly started engine again to trouble-shoot and, to my surprise, the engine idled, but still made a loud clacking sound from somewhere in the header area.

Any ideas on what the problem may be? Could this be a defective valve and/or valve spring? I want to avoid having to rebuilt entire engine! Help, please.

Robert

[s5uewf]

I had the lock nut on the tappet adjuster back off and the clearance went way up - start banging like crazy...check your valve tapper adjusters.

[BURN-BROS]

2 other things.

Chain tensioners

rod knock due to low oil pressure when at operating temp.

Verify oil pressure and a failed tensioner.

[rfeierbach]

Thanks for the pointers, guys. I will only be able to get to my car in a couple of weeks to work on it some more.

Another detail: The car is leaking oil from the right header area in a big way on my garage floor now...if this helps.

Thanks,

Robert
1999 911 Carrera
1990 911 Carrera
1992 BMW 730i
1989 BMW 520i
1984 Saab 900s
1982 Saab Turbo 900
1976 Fiat 124 Sport Spider
1972 Opel GT

[BURN-BROS]

Rocker arm shaft working its way out of the cam tower. This would expose a nice hole for oil to come out. Pull the valve cover, get that cylinder on TDC and repair offending rocker shaft. Hope this is your problem and not something more substantial.