<VV> cylinder head studs

[craig nicol]

Tom wrote:

Tom Gould <tgould at hargray.com>

> wrote:

> 

>> While reinstalling the heads one of the .006 studs  backed out.  

>> Clarks

>> sells Heli-coil and Time-Sert inserts. I've used heli-coil type 

>> inserts on other bolt holes but this is the first time I've had to 

>> repair a head stud hole. It's on #2, next to oil cooler,  so I may be 

>> able to do it w/o

> pulling

>> the engine.  Any input (pros,cons, suggestions) will be greatly

*       appreciated.

 

I've used both and I find the time-sert kit a little simpler and there's no
tang to worry about losing as there is with a helicoil. Note that in either
case, you have to get a straight-thread stud or run a die over the original
(not oversize) stud.  Larry Claypool and I wrote it all up for a Communique
article. If you would like a copy just let me know.

 

BTW, you wrote "backed out" rather than "pulled out".  Are the threads still
intact in the block?  If the stud merely unscrews, you and always try
putting it back in. As long as the required torque is in the 10-30 ft-lb
range it should be fine. I always but some Loctite stud & bearing mount on
the threads to keep it in place, add a little strength, and provide some
seal. 

 

Also note, some of the studs "daylight" into the crankcase. It's critical
that these do not get screwed in beyond flush (inside) because some rods
will collide with the end of the stud. Also, these holes require removal of
the top cover during thread repair because the aluminum chips caused during
drilling and tapping go directly into the crankcase.

 

HTH, Craig Nicol