CLASS RACER FORUM - View Single Post

RonP · 06-22-2017, 01:04 PM

OEM head gaskets require a "smoother" surface finish to seal coolant and oil passages. The "rubbery paint" is there to provide a micro-seal against leaks. OEM head gaskets are beaded to provide an effective sealing load around these passages and the chamber.

A torque wrench measures torque, not friction as someone stated earlier.

Torque = friction coefficient x tension x thread diameter (for elastic region bolts).
Friction coefficient is generally 0.1 ~ 0.3.

Adding oil or other lubricant will increase the bolt tension over a dry or unlubricated condition. Something a friend and I did at work years ago with a strain gauged bolt to see for ourselves.

06-22-2017, 01:04 PM	#3
RonP Junior Member Join Date: Mar 2003 Location: Detroit,MI Posts: 81 Likes: 28 Liked 29 Times in 14 Posts	Re: cometic head gaskets OEM head gaskets require a "smoother" surface finish to seal coolant and oil passages. The "rubbery paint" is there to provide a micro-seal against leaks. OEM head gaskets are beaded to provide an effective sealing load around these passages and the chamber. A torque wrench measures torque, not friction as someone stated earlier. Torque = friction coefficient x tension x thread diameter (for elastic region bolts). Friction coefficient is generally 0.1 ~ 0.3. Adding oil or other lubricant will increase the bolt tension over a dry or unlubricated condition. Something a friend and I did at work years ago with a strain gauged bolt to see for ourselves. Last edited by RonP; 06-26-2017 at 11:08 AM.