Hi Guys,

Im in need of infomation that is beyond the typical install and torque side of longstud installation. Hopefully someone with experience machining the block reads this and can validate the information I am working with.

I have now had to install 4 helicoils in the bottom of the block, and thats only up to the torque plate honing process of the build!! It has seemed strange since the beginning of the exercise that on some studs, these 4 to be precise, only have 6-7 threads of engagement which equates to approx 12mm of engagement into the block material. Based on never hearing or being able to find anyone who has had issues installing the studs, I have proceeded.

When torquing the long studs to 55ft/lb into the bottom of the block that all goes fine, but once torqued to 95ft/lb with thread lube(as recommended) they let go after a few minutes. The repaired(helicoiled) studs now hold at 95ft/lb but I am seriously doubting the reliability of this set up.

Speaking to a friend with a qualification in mechanical engineering, he says that a 12x1.75mm thread should never be torqued to more than 80ft/lb in cast iron and that is only with at least 25mm of thread engagement.

Can anyone with long stud experience offer any idea's/comments? Is it normal for several of the studs to only engage by 6 or 7 threads? Are some 200 blocks different to others?

Has anyone else seen or had issues installing long studs? Are the torque specs that I have been given wrong?

Cheers,

Phil.