Supercharger bolt holes stripped

kenshi

Registered User
I don't want to go into how it happened, but the bolt holes on my supercharger where the top goes are stripped, and it's causing a vacuum/boost leak. I have a new one ordered, but I don't think it's going to get here before a local TCCoA meet next weekend which I really want to attend. So I need a fix, at least a temporary one, for the blower I have now. Do you guys think I should put in some helicoils (if there's enough room for them) or drill it to the next size larger bolts (I can't go larger than the holes in the blower top) or what? I believe these bolts are 8 mm, so 5/16" would be slightly larger. In fact, according to my calculator it's only 0.00246" larger, so I might would only need to retap it. What do you guys think?
 
I made a mistake. The 5/16" bolts would be slightly smaller, not larger. I'd have to go to 3/8", which is 0.0600" larger.
 
There's lots of room on the sc for them. Just be sure to use a permanent loc-tite on the heli-coil's and to let it set over night before you put everything together.
 
I put them on today. They work well, except that I had to drill all the way through the blower housing in order to tap the holes deep enough. That caused metal shavings to get in the blower. I managed to blow most of them out with an air compressor, but it can't be good for the bearings. I'm not too worried about it because, like I said earlier, I have another blower on the way and I'm mostly running without the belt on this one. Anyone with this same problem may want to take note though and opt for a threaded insert that doesn't require a tapped hole instead of helicoils.
 
You should not have to drill all the way through, if you did there was probably flashing left behind. I hope that you disassembled your blower and took it off from around the holes.

And I wouldn't worry too much about the shavings wrecking the bearings, as I don't think they'd make it to them. However, if you did run the blower on the car already then I'd be worried about the shavings wrecking the motor by scoring the walls of the pistons.
 
how do those heli coils work, ive heard alot about them but ive never had to use them but im needing a fix, i also have 2 stripped out bolt holes in my blower where the top bolts on. And also what is the correct procedure in putting them in and how long do they last, thanks for the help.
 
i just had to use them on my heads they work well. i didnt drill it and tap it far enough so i have more bolt showing than before but i loaded it wiht sealent and it holds torque. but the heli coils i put in are holding 75 lbs of touque so there a pretty good thing. there really easy to use it tell u whut size to drill. the only thing is that there really expensive. i bought one kit for 45 dollars and then i bought a 60 psc. tap and die kit later that day for 30 dollars. thats crazy.
 
heli-coils. Stainless spring steel that will be stronger than the aluminum it replaces. It shouldn't ever need to be redone once done right the first time with a heli-coil.
 
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