Anyone know anything about these hardened head bolts for a 12 valve? At $130 they are much cheaper than studs.

http://www.mightydiesel.com/store/pr...oducts_id=1011

 

I used some regular bolts from a place like fastenal, they lasted through two years of 50psi before the head gasket blew an that was probably just because i never retorqued them lol. They were just a 12.9 grade

 

Yes, and there's a reason they are so cheap.

First question: why are the Socket head instead of Hex Head?

Second: what material are they made of? Simply being class 12.9 only tells you how hard they are-- it gives you NO information about their strength unless they are class 12.9 per a given industry standard (DIN/ISO, etc) and correlated to a standard capscrew geometry.

You can easily make a cheap 1010 steel screw hard and brittle. It will have terrible fatigue performance (no ductility) and will fail pretty early.

Harder is not always better.

Many grades of steel are prone to hydrogen embrittlement when hardened fully, and operated in a hot environment like the engine.


Save your money. These screws are a ticking time bomb for your engine.