Don Terrill’s Speed-Talk

Those kits have the proper tap to return the threads to 12-24. It will be bigger than original to allow the insert to go in.

Dodge Freak wrote:Aren't those the thread repair size. Thats way too big, 1/4 inch is even, at .25.

I was asking the tap size to thread the heli coils in to repair it right to the holley screws size.

I am sure they do have 10-32 kits, then all I need is the drill bit and new 10-32 screws the right length.

You could could go 10-32 with the original size. Heli coil's are bigger so the original screw fits. 12-32 is going to be bigger.

Dodge Freak wrote:Aren't those the thread repair size. Thats way too big, 1/4 inch is even, at .25.

I was asking the tap size to thread the heli coils in to repair it right to the holley screws size.

I am sure they do have 10-32 kits, then all I need is the drill bit and new 10-32 screws the right length.

You aren't getting it. The Heli-Coil tap is a SPECIAL SIZE. It is a larger diameter with the same threads per inch. So you get the 12/24 kit from heli-coil , holley or brand X. You drill oversize and use the SPECIAL SIZE tap, then install the coil back to standard.

Some people have no luck with coils and prefer inserts. These are solid (not a wound spring) and require a larger hole and tap. this is why when using a solid insert, you use a smaller 10/32 size

The inserts that I speced, You will have to drill and tap the hole to a 5/16-24 thread, which is very close to the size of the helicoil, Just a tic bigger. You then just screw in the insert. It will be a lot better fix than the helicoils. I have rehelicoiled my carb several times and the helicoils would always eventually start pulling. You will need a 2.5 inch 10-32 bolt. I order everything I needed from mcmaster. I didn't go with the 1/4 inch bolt because I would had to drill the metering block and float bowls holes bigger. The insert is going to be a lot better way to go if you are constantly tunning on the carb.

Good luck

Keith Morganstein wrote:
You aren't getting it. The Heli-Coil tap is a SPECIAL SIZE. It is a larger diameter with the same threads per inch. So you get the 12/24 kit from heli-coil , holley or brand X. You drill oversize and use the SPECIAL SIZE tap, then install the coil back to standard.

I get that quite a bit in the shop. Some guy will call or come in and say "I need a tap for a 7/16 coarse (or whatever) Heli-coil". I tell them they need the Heli-Coil tap for that application. They say "Don't you just use the next bigger size tap?". "No," I tell them, "you need THE Heli-Coil tap for that particular insert size. I can sell you the kit or the Heli-Coil tap for that kit.

"Oh," says the guy "can I just borrow your tap?"


"No"

BTW, Heli-Coil stuff is now made in China.

tom

Now its starting to sink in, the inserts seems to sound better, both might work for me since I have the quick change fuel blows.

Taping to 1/4 would be the cheapest way to go but yes, then everything else needs the be drilled to size.

Either way it sure beats spending $90 or even $59 at Amazon--I am spending waaay tooo much on gasoline so I need to watch my $$$

If it helps Napa's part # for the heli-coil set is 770-3043 and list is 44.10$. Might be cheaper especially if you get a discount and save shipping and time.

Cogburn wrote:If it helps Napa's part # for the heli-coil set is 770-3043 and list is 44.10$. Might be cheaper especially if you get a discount and save shipping and time.

Call your local parts store. In our Napa store, that # sells for 35.49 over-the-counter.

tom

Either way it sure beats spending $90 or even $59 at Amazon--I am spending waaay tooo much on gasoline so I need to watch my $$$

I already supplied the info to buy the whole perma coil thread repair kit for only $19.95, which is approx 23% of the $90 you quoted from Jegs' Ebay listing and 33% of Amazon's $59. I can't imagine 20 bucks being cost prohibitve. An insert kit would cost more than $20.

I've bought and used the kit Greg is recommending on Ebay. I ended up tapping all eight holes because after two stripped I figured the others would catch me at a bad time.

For the smaller heli coil sizes I use a tire valve tool, works great, just be sure to start the coil in the first thread of the hole.

For the larger sizes I use a bolt that has it's end reworked to engage the tab. Just look at a factory tool and you get the idea.

Heli Coils patent went away about 5 or more years ago. You can get taps / coils from places like MSC , KBC tool, Enco .

Taps are special for the inserts.

Keith Morganstein wrote:
Some people have no luck with coils and prefer inserts. These are solid (not a wound spring) and require a larger hole and tap. this is why when using a solid insert, you use a smaller 10/32 size

The trick is to chamfer the start of the hole to prevent the parent metal from pulling the start of the thread and then set the coil a thread below the surface. If the coil is flush with the surface, the coil will pull out starting with the open end.

Also be sure to fully tap the hole to the botton, if the last few threads are tapered like the end of the tap , the coil will be tapered causing the bolt to bind then pull the coil during dissassembly

Masher Manufacturing wrote:

Keith Morganstein wrote:
Some people have no luck with coils and prefer inserts. These are solid (not a wound spring) and require a larger hole and tap. this is why when using a solid insert, you use a smaller 10/32 size

The trick is to chamfer the start of the hole to prevent the parent metal from pulling the start of the thread and then set the coil a thread below the surface. If the coil is flush with the surface, the coil will pull out starting with the open end.

Also be sure to fully tap the hole to the botton, if the last few threads are tapered like the end of the tap , the coil will be tapered causing the bolt to bind then pull the coil during dissassembly

This requires grinding the end of the tap some to allow it to bottom, just not too much that the tap won't start the threads.