Noooooo! 1st a faint click developed into a loud claque

[The Radium King]

three culprits I can think of:

- over-temp - cyls go oblong and pistons score cyls

- bad aos - no vacuum to crankcase so piston rings don't function properly; pistons score cyls

- over-rev - all bets off

I don't think engine mods will have much effect unless they push you into a lean condition and start making thinks hot, or timing goes off. from what I've seen (check out insite's wideband o2 post) the ecu tends to keep even a heavily modified engine in the safe zone.

[Perfectlap]

Originally Posted by The Radium King

I don't think engine mods will have much effect unless they push you into a lean condition and start making thinks hot, or timing goes off. from what I've seen (check out insite's wideband o2 post) the ecu tends to keep even a heavily modified engine in the safe zone.

Yes but aren't m96 inherently hot-running even with OEM parts? If you're going to push the engine harder with aftermarket stuff, while using a 'conventional' oil, and no other augmented safeguards, aren't you inching the car closer towards unsafe temps on a fairly routine basis? In other words, If there is an 'event', the usual margin or buffer is no longer thus reaching a threshold breaking point more likely.

p.s.
i'm not an engine engineer I just play one TV.

[The Radium King]

well, a stock 996 3.4 engine is making 300 hp with the same cooling system, oiling system, bottom end and heads as a bolt-on modified 986 3.2 engine making 265 hp, so I don't think you are pushing any limits there. as long as the ecu can manage the mixture and timing which all evidence shows that it can.

people say these engines are built to rev, but perhaps a life spent at redline is a contributor - bits moving faster, more heat, etc. modifications tend to encourage harder driving?

[jaykay]

Originally Posted by The Radium King

well, a stock 996 3.4 engine is making 300 hp with the same cooling system, oiling system, bottom end and heads as a bolt-on modified 986 3.2 engine making 265 hp, so I don't think you are pushing any limits there. as long as the ecu can manage the mixture and timing which all evidence shows that it can.

people say these engines are built to rev, but perhaps a life spent at redline is a contributor - bits moving faster, more heat, etc. modifications tend to encourage harder driving?

Right on; more redline more stress; but higher M96 rpm apparently puts the ims bearing in a more stable symmetrically loaded condition and piston ring oil film strength is better. Perhaps this where the "made to rev came from". Maybe it should be have to rev?