ok one of the threaded holes on my intake manifold where the thermostat housing connects is totally effed.....the previous owner just jammed a screw down int othe soft aluminum and left it....it leaks.....and i heard i can tryin to just retap through everything and it could save me from having to do a heli coil.......what sort of tap set should i look for? i dono really much about them....just how to use it i guess....liek what sorta threads or whatever i guess....?


also, is a performer 289 intake going to be a good enough intake to get my 302 to around the 300hp mark? of course there are other factors but it wont be holding me back at all correct???

 

You might consider loctite thread former also...I have not used it, but it sound interesting.

 

If the original threads where all ready torn up, your best move is a heli coil. Especially as it's in aluminum. They are very easy to install. Once done that's the end of it. In fact if it were me, I'd do both holes. You're good for life then.
It will take you longer to read the directions than to do the job. If you are nervous of doing it yourself. I have a good friend who is one of the best technicians around (he's the only person I'd let work on anything I own). He lives in the city near the park on 16th.

Good luck with it.

Scott

 

I agree with Scott. The heli coil is the best way to go by far. The kit comes with the correct tap to do the job, it is a permanent fix, and actually better than the original threaded hole.

 

I disagree. If you drill and tap for the oversized bolt, you will have a stronger thread than the heli. Even in aluminum. Think about it, if the heli is so wonderful and stronger than the original theads in the aluminum, then why didn't the factory just put the heli in there in the first place?

 

Maybe so, however the beauty with using helic coils is that you dont need to go the the next sized bolt, which may not fit the application. (its head may interfere or the shaft size may be too large to fit through the hole on the therostat)
I have been involved with a few military vehicle component fabrication jobs, and when bolting into aluminuim, it is standard practice to use heli coils nowdays.

 

ok, so how do u know what size the hole is so i know what size heli coil to get? and where do they sell them? thanks

 

Take your bolt to the shop, and they have a chart to show you what size to go to. Unfortunately, the only places I know that sell them are in Australia, so I guess that doesn't help you too much

 

Hi Glen, you are not alone in that thought, but it's actually not correct.
The factory didn't do it due to cost. Heli coils are in fact stronger than the stock bolt in the aluminum thread for two reasons. First, the tapped hole for the insert in the aluminum is larger than the bolt you could install. That equates to a lot of additional surface area for better holding power. Second, when you tighten down the bolt into the steel heli coil insert, is actually wedges the threaded insert into the aluminum.
In high stress applications you will see heli coils installed for these reasons.

Scott

 

Your local Napa or Carquest should be able to help you out. Take the good bolt from the other side with you. It's a kit and will cost roughly $30-$40 (IIRC). You get a half dozen or so coil inserts and it is reusable.
I've used them in spark plug holes, Hydraulic cylinder heads, all kinds of good stuff.
BTW: Heli-Coil is a brand name like "Cresent Wrench" or "Freon". The name on the package may be different. And yeah, the last group of inserts I bought came from Australia when I mail ordered them from a Nut and bolt supply house. I had forgetten all about that.

Scott