Rust on valve springs
 

Ok, it seem intuitive to replace rusted valve springs... i have read that they might break, they might be week, as well as other negative badmouth remarks on the poor things. is there any quantitative or definitive information as to the effect of rust on the spring. if it meets specs. (after cleaning).... what right do we have for its condemnation (pretty or not) ? any thoughts?

If a spring breaks...you will lose a piston...maybe a rod...perhaps even a crankshaft...(for all above read BIG $$$).
Springs are cheap compared to a complete rebuild.
You can pressure the cylinders...one at a time...with air (to keep the valve closed) and replace the springs one cylinder at a time.
Another old trick is to stuff sash cord down the spark plug hole while the piston is down near the bottom of its stroke....then rotate (gently) until the sash cord jams the valves closed ( then replace the springs).
In either case...you do not need to drop the engine (might have to drop the oil though).
Bob

they WILL break

- only question is How Soon?

- rust creates tiny pits -

if ya want to confirm that - look at em with a magnifyer after you clean & polish them

If it's rust that was on there only a day or two from you having cleaned them up, then it's not an issue really. The problem is when they have been sitting for some time with rust just eating away. The harsher the environment (that's producing the rust) and the longer the period the rust sits on the spring, the more to worry.

related question. what tool does one need to be able to compress the valve springs while the cam towers are in place.

Tools like the two shown here for $60 each.

Porsche 911 & Carrera Tools - Page 6