Holley heli coils float bowl screws, what size tap
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- jmarkaudio
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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.
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Adam
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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.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.
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
Automotive Machining, cylinder head rebuilding, engine building. Can't seem to quit
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
Good luck
Last edited by banjo on Sat Jan 12, 2008 10:32 am, edited 1 time in total.
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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.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.
"Oh," says the guy "can I just borrow your tap?"
"No"
BTW, Heli-Coil stuff is now made in China.
tom
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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 $$$
Taping to 1/4 would be the cheapest way to go but yes, then everything else needs the be drilled to size.
Either way it sure beats spending $90 or even $59 at Amazon--I am spending waaay tooo much on gasoline so I need to watch my $$$
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Call your local parts store. In our Napa store, that # sells for 35.49 over-the-counter.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.
tom
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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.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 $$$
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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.
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.
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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.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
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
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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.Masher Manufacturing wrote: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.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
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
Mark Whitener
www.racingfuelsystems.com
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Good work isn't cheap and cheap work can't be good.
www.racingfuelsystems.com
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Good work isn't cheap and cheap work can't be good.