Drilling head studs!

Jim Andritsakos · Post by **Jim Andritsakos** » Mon Dec 13, 2004 1:50 pm

Hello all!

I would like to ask what is the correct procedure to drill a wbx head stud ?
I like to know which is the biggest size of the drill bit that is required to be used ? If I am correct the head studs are 12x1.75 ?I want to clarify if you drill them with a slightly oversized drill bit and the helicoil them ?

Thank you all guys!

With rgds,

pocketrocket · Post by **pocketrocket** » Tue Dec 14, 2004 10:23 am

Hi Jim You are repairing the stud hole in a case with the water jackets on right. Is the stud broken off? If so I use a 3/8 carbide end mill in a long holder I made to core out the old stud then soak with kroil & use a easy out with heat to remove the cored stud. The boxer head stud at the case is a 12mm x1.50 thread. I use a very long .484 drill & I use a Timesert 14mm x 1.50 od with a length of .950 or 24mm. I made a long but thin tap holder to hold the tap in my milling machine to do the job. Hope this helps. Rocky

Guest · Post by **Guest** » Sat Dec 18, 2004 12:24 am

Hello Rocky!

Thank you for the detailed anwer.
Problem solved!

Rgds,

Jim Andritsakos · Post by **Jim Andritsakos** » Sat Dec 18, 2004 8:50 am

Ah! Forgot to log-on all the time!

Thanks very much for the help Rocky.
Now I want you opinion to properly repair the front engine mount in a engine case (LH side) as it was damaged and poorly repaired.The hole is off centre and enlongated also a small cap in the bottom (I think it seals the oil pressure valve ?) is come loose!
I want to make a faultless repair!

Thanks again!

pocketrocket · Post by **pocketrocket** » Sat Dec 18, 2004 1:11 pm

Jim, on the repair of the L-H side mount hole. How big is the hole now? If it is less than .468 15/32. I would bolt halfs together remove bottom 2 studs flywheel end set it flat on milling machine. Use the old mount as my template bolt the R-H 2 bolts loose and try to line up on the outside the L-H side boss from the case to the mount, Tighten the R-H bolts. Holes in the mount are about .425 or 27/64 bring drill to the center. Remove the drill & the mount plate, find a end mill to machine hole to get it centered then use 15/32 drill. Go down only about .900 or less DONT DRILL TO DEEP keep checking the bottom of the hole this is the outside of the pressure releif valve. Then I use a 14 x 2.0mm x 10mm steel insert. If the hole is very oversize I end mill & Drill to 37/64 .578 & I use a special insert that is 5/8 x 18 x 10mm . I have repaired a number of cases both ways worked great. Good luck Rocky