Why doesn't broken head stud destroy the engine within a few seconds ?

[sugarwood]

I think people who rub their car with a diaper, drive it 200 miles a year, and mothball it 6 months a year since they only drive in 72F or warmer are more likely to suffer broken head studs. Sad !

[juanbenae]

^^^^ that shows just how informed you really are.

[proporsche]

Originally Posted by juanbenae

^^^^ that shows just how informed you really are.

[Rawknees'Turbo]

The lower/exhaust sides break because the dilivar alloy used was garbage (until the 993TT version) - plenty of instances reported where brand new ones broke upon assembly, which rules out corrosion being the only negative factor.

[911pcars]

The cylinders slide into spigots in the crankcase. 4 studs/cylinder, anchored in the case, snake through each cylinder and each cylinder head. The one-piece cam housing then clamps onto the three cylinder/cylinder head assemblies as one structural assembly. So no.

One or several head studs, even if simultaneously breaking, will not allow a cylinder to fall out or shift to any appreciable distance to implode the engine. This is not to say the engine cannot self-grenade. That requires other major component failure to occur. I’ll leave that scenario to your follow up question.

Sherwood

[Bob Kontak]

Originally Posted by sugarwood

I think people who rub their car with a diaper, drive it 200 miles a year, and mothball it 6 months a year since they only drive in 72F or warmer are more likely to suffer broken head studs. Sad !

Maybe you could get a copy of Bruce Anderson's 911 Performance Handbook and read through it. It would be an investment in your credibility.

Seriously. It's old school. Pretty cool stuff and Anderson is a good writer.

[Bob Kontak]

Originally Posted by Rawknees'Turbo

The lower/exhaust sides break because the dilivar alloy used was garbage (until the 993TT version) - plenty of instances reported where brand new ones broke upon assembly, which rules out corrosion being the only negative factor.

Lion's share is pitting and axial shear post heat cycling.

Tell your Mom I said Hi.

[Rawknees'Turbo]

Originally Posted by Bob Kontak

Lion's share is pitting and axial shear post heat cycling.

Tell your Mom I said Hi.

Agreed with that - amazing how weak and non-resilient those studs are (must be millennial "studs" ).

You sister just gave my mom your message, bro!