Would you weld or use Lumiweld / Devcon putty to fix this ?

[Ironhorse2022]

Hi all,
pulled of my exhaust cover to understand why it was leaking. 3 of the 10 bolts were doing nothing except looking pretty. Considering the effort and expense of stripping down the block to be tig welded (alum block) / retapped AND the risk of distorting the piston bore directly behind these bosses …. vs the relative simplicity of using Alumiweld/Devcon putty with helicoils, and the quality/effectiveness of both repair methods, which approach would you take ? Budget is a concern for me but I don’t want to go the putty route, have it fail a year from now and then have an even more difficult welding job ahead cause there’s epoxy putty to deal with.

 

[eeshaw]

What I've done in situations like this before, is if a bolt hole gets stripped out I'll tap it with the next common size in a metric thread or vice versa. Remember that aluminum usually uses a fine thread so try to use them when required. Doing this will save you generating any heat from welding or having to go the epoxy route.
If a "boss" is broken like the one pictured I'd do a cold fix if at all possible before using the heat. Save that for your last resort.

 

[Ironhorse2022]

Thanks eeshaw- I’ll file that good advice away. In this case, however, the botched attempt to remove the broken bolts has obliterated some of the boss wall so it needs to be built up either using epoxy or weld.

 

[poorthang]

drill a little deeper, tap, insert stud. then fill between original hole walls and stud. or, if theres enough meat after drilling deeper, install tine-cert. then install stud.

 

[Ironhorse2022]

Good thought. I’ll look more closely to see how much meat is available.