Topic: Stripped cam tower/cradle threads

[Bailgang]

While disassembling my kids K3 750 engine I noticed some of the threads in the head for the cam tower bolts are getting ready to fail. The reason I can tell is that when a bolt feels sticky even after it's broke loose and has some remnants of the aluminum threads on the bolt once it's out, that's a pretty good indication those threads in the head won't be strong enough to handle being re-torqued when it comes time to reassemble the engine. I've done some searching to see what thread inserts are available and it turns out there are quite a few to choose from. My question is what inserts would any of you recommend? 

[ekpent]

Hopefully Mriek or Hondaman will chime in for you as I am sure they have done a ton and its probably advisable to do on a hypo engine anyways. Those screw do get punky real easy. Years ago before internet etc. I retapped those same screws to the next size up American thread,think 1/4" and went that way.

[City Boy]

Hi gang.A long while back I Heli-coiled every aluminum thread in my KO engine and am very satisfied with them.Others may suggest alternative methods of thread repair.    Rock On

[MRieck]

Hi gang.A long while back I Heli-coiled every aluminum thread in my KO engine and am very satisfied with them.Others may suggest alternative methods of thread repair.    Rock On

That is what I have done many, many times. I recommend it for the 4 long cam tower bolts when using heavier springs and larger cams.

[Bailgang]

Thanks for the replies. So far it seems helicoil is the way to go though the idea of going to the next size up with an american thread is clever. My kid wants to go with an F2 cam with new springs and knowing him the engine will be seeing some high rpm from time to time so a long term fix is in order. While searching I found different thread inserts such as one called a time sert and was wondering if anyone had tried them and if their was any advantage with them over a helicoil.       Scott

[Grabcon]

I just did a thread repair on all of my exhaust stud holes using  Time Sert inserts. I prefer these to heli-coils. I really like the time serts and they are easy to do.. See link below for photo on the exhaust stud holes.

http://forums.sohc4.net/index.php?topic=113482.0

[MRieck]

I just did a thread repair on all of my exhaust stud holes using  Time Sert inserts. I prefer these to heli-coils. I really like the time serts and they are easy to do.. See link below for photo on the exhaust stud holes.

http://forums.sohc4.net/index.php?topic=113482.0

Time serts work well. I'm a creature of habit and have installed a billion Helicoils. The Helicoils take up less room as they have no lip like Timeserts but that is generally not a problem unless you are working with countersunk threaded holes (which suck to repair). I generally use Big Timeserts if a hole has had a helicoil pulled out.

[lucky]

You can buy studs with larger threads on one end. Did you know that???

Go to:
http://www.google.com/imgres?q=Metric+stud+6mm+and+10mm+ends&hl=en&sa=X&tbo=d&biw=1009&bih=416&tbm=isch&tbnid=nxuRMgAZO_w0zM:&imgrefurl=https://www.belmetric.com/metric-studs-metric-step-studs-68910mm-c-9_73.html&docid=_Cg5OMfs9GX3mM&imgurl=https://www.belmetric.com/images/S6x8x31.jpg&w=300&h=300&ei=iO7MUNSULM3KiAKkwYHgAw&zoom=1

[bryanj]

Keenserts are another good brand but whatever you put in there make sure the outer is threadlocked in to prevent oil seepage

[MRieck]

You can buy studs with larger threads on one end. Did you know that

Go to:
http://www.google.com/imgres?q=Metric+stud+6mm+and+10mm+ends&hl=en&sa=X&tbo=d&biw=1009&bih=416&tbm=isch&tbnid=nxuRMgAZO_w0zM:&imgrefurl=https://www.belmetric.com/metric-studs-metric-step-studs-68910mm-c-9_73.html&docid=_Cg5OMfs9GX3mM&imgurl=https://www.belmetric.com/images/S6x8x31.jpg&w=300&h=300&ei=iO7MUNSULM3KiAKkwYHgAw&zoom=1

Yes....I do know that. The problem I have with those is the oversize OD is really large. On the other hand...did you know you can still fit a Big-Sert after using one of those studs (at least on the 750 exhaust studs).
 Also...that company you listed (Belmetric) are an excellent source of metric stainless fasteners etc. They are in Massachusetts and are great to deal with.