Stripped threads on cam bearing

[JGRacing]

I was installing my exhaust cam and stripped out the threads on two of the bearing caps.  I looked up the torque settings, turned my torque wrench to what I thought was 8 lbs, and turns out that the wrench I have does not change when you dial it down under 20 lbs.  Wish I would have known that earlier.  One full steel thread instert came out and part of the other one (I think).  What do I do now?  Is this something I can fix with the motor in the car at home, or do I need to pull the head and take it to a bike shop?  I would prefer to not pull the head if possible (one more thing to go wrong when I re-install it).  Can't imagine that I am the only person who has run into this. 

John

[thunder938]

I dont know what size it would be, but heli coil it.  Thats what we use for pulled head studs.  Heli coils are stronger than the alum. thread in the head stock..

Dave

[JGRacing]

I think it had Heli coils in these two holes.  Steel threads were sticking up out of both of them.  Worried that I might have pulled out the threads that the inserts were threaded into.  I'm so ....... mad at my torque wrench right now. 

[tch38]

When I was Karting we had problems with pulling out an already heil coiled insert (head  bolt into alum. block) We were able to find two different  types of inserts one had notches to screw it in the other had pins you hammer in after screwing it in. How ever you must make the holes even bigger not sure if this works on a legend motor as I am new to legends.
 

     Todd

[tch38]

mdmetric.com/pdf/keysert.pdf
http://www.muller.net/mullermachine/howto/insert/index.html
http://www.timesert.com/
Here are a few web sites to try. I think we used Timesert.

[tch38]

got this from the other site
Re: Stripped Head Bolt Hole
Since I can't edit my other post ( sometimes I get carried on..
hehehe, and forget something ) I also do realize that heat and head
warping play a role in studs being pulled from a case. You can keep
the engine as cool as possable, but this area needs to be kept in
mind for being kept the coolest. The back 2 cylinders. Also let me
remind you all about a tip on retouqueing head bolts... Loosen them
first. I will remove the nuts and dab oil on the threads to make
sure of a good torque reading. Not only for that reason, but to
assure the stud does not spin farther into the case, if hte threads
of the head nut bind forcing it tighter in the case than specified
during stud installation into the case....
----- Gimp -----
--- In legendscars@yahoogroups.com, "gimpsterlegends"
<gimpsterlegends@...> wrote:
> The few decades I have been in the powersports industry have left
me
> asking the same question a few times, and it has been answered on
> occasion. I rely on an insert called Time Sert. They have pulled
my
> butt out of sloppy situations countless times in the past. The
insert
> kits from them have a a bit , thread cutter, top reamer for depth
> setting of the Sert, and an expander that installs the Sert and
> expands it so it will stay in place. Normally I will dab some
sleeve
> retainer on the threads of the insert before installing, but on
> occasion a little JB weld has been used to assure the Sert will
stay
> in place after repair. I have had head studs pull out of
crankcases on
> units that run a lot of heat and see a lot of hours. One unit in a
> fleet of railroad atvs, used to service brakes on coal train cars,
> pulled a stud from its crankcase multaple times. Pulled inserts
also.
> After the 3rd crankcase half I replaced, I drilled into the end of
the
> stud on the end of it that twists into the case making it hollow
the
> length of the threads. My thoughts on the hollowing was that
possably
> relieving some of the heat that the stud is retaining inside of
the
> crankcase half, and not letting it stay expanded so long grom
> retaining the heat possably cooling near as quickly sa the
aluminum
> case. Was holowing the stud the cure ? I don't know for sure, but
the
> unit had 21,000 miles on at the time of last stud repair, and last
> time it came in for routine service the odometer had clicked
48,000
> miles without further stud issues. This engine platform is simular
in
> design to our Legends engines in the fact that they are air/oil
> cooled. I do know that since that unit, I have dropped the head
> retorque back from specified 29ft lbs to 25. The 1200 I built this
> winter for my Legend has begun to pull the same stud as many of
yours
> have. Second cylinder from the firewall, stud on the exhaust side
next
> to the timing chain crossover on by the valvecover. On my digital
Snap-
> On torque wrench, I feel it gets soft at 16ft lbs so I have only
been
> torquing it to 14 hoping to make the season before Time Serting it.
> ----- Gimp -----
> --- In legendscars@yahoogroups.com, "bworell" <gramps@> wrote:
> > With the stud being torqued at 14 ftlbs into the block and then
> > repeatedly torqueing the head nuts to 25 ftlbs without any lube
to
> > speak of, after we abuse the hell out of the engine (heat and
rpms)
> I
> > am suprised that they don"t all pull out of the block. What
would be
> > the best type of thread insert to use to keep this from
happening or
> > will the insert also pull out of the block after some use?

[elimn8u_43]

The original thread size would be M6 x 1.00. If it already had a Heli-coil in it and you pulled out the threads. You might try to find 1/4 " bolts the same length and a Heli-coil  kit for them.

Geoff

[JGRacing]

Thanks everyone.  I'm going to give the Time Sert deal a try.  It looks like what I will need.  Any idea where I can get a torque wrench that reads 8.7 lbs.? 

[thunder938]

I have one that shows both metric and standard from sears. it does down to 5 newton meters.  THe cam cap bolt show be 12 newton meters / 8.7 ft pound.  If you are going to work on the these get a metric wrench.  I think mine, not dig. was about 150 bucks..

Dave

[tch38]

You can also get a small one that reads in inch lbs. I have a  small  1/4 drive  torque wrench

[JGRacing]

On the advice of Hank Scott, I drilled out the hole in the cap and head, and taped the hole up to 8mm to use an exhaust stud.  He thought that the timesert might be too big in that area.  I had to make a tap and drill guide out of a scap block of aluminum to make sure everything was square, but it worked great.