911sc
 

I just finish rebuilding (replaced 2 broken studs) my 1980 911SC engine and it started and ran great. The 3rd time I started it (several days later) there was a loud clanking noise on the driver's side of the engine. Fearing I jumped timing I dropped the engine but the carrera tensioners and timing was intact and when I manually turned the engine over it was fine (no signs the pistons were hitting the valves). Got the engine back in and it started and ran fine again but days later it that the clanking sound on the Left side of the engine was there again. I changed my starter but no difference. I ended up allowing the car to run and that clanking sound went away. Could it be no oil getting to a rockers? Help.

I would be more inclined to be looking at the tensioner. Chain rattle at about 2000.
If a rocker fell out, it would stay clanking
Bruce

We've discussed tensioners recently and even talked about failure modes and possible causes. They can apparently be bad right out of the box or as maybe you're experiencing, a gradual or episodic failure. I'm betting if you look inside your left chain box, you'll find a collapsed or mushy tensioner. I'd also poke around for a loose chain ramp too for giggles.