MTFCA Forum

Anyone know where I can find a Heli coil kit "7/16-24"?

in almost every garage that holds a model T...

is this a trick question??

John

this is about as cheap as it gets...you supply the 29/64 drill: https://www.summitracing.com/parts/hll- ... iWxIoJe1wI

this one might be a better deal and it has a much better install tool: https://www.autotoolworld.com/SW-Anders ... 6b9sZjuUGI

be sure to measure the depth of the threaded hole to make sure the entire insert is going to be able to go in, or grind off a couple coils to shorten the coil to fit. Flex the last coil off of the stack and go at a grinding wheel on its corner and you can put a "vee" in the wire and it will break off and look just like a factory finished coil.

I have a 2nd tap ground to a bottoming tap to get one more coil installed than a normal tap would allow...used for 1 more "twist" after the normal tap has run its course

good luck

Scott_Conger wrote: ↑

Sun May 21, 2023 7:36 pm

in almost every garage that holds a model T...

is this a trick question??

Yes, it is a trick question.
7/16-24 would not be a tread currently found in nature.
7/16-14 coarse.(model T size) & 7/16-20 NF.

If OP really wants a 7/16-24, I would be looking for a possible close interchange with a metric size.

and here I thought that was just a typo...

if it is not a typo, well, 7/16-24 is ADMF British Admiralty Thread and absolutely no one is going to have a STI for it

so, it begs the question: what on earth has or had this thread?

if this is for a flare nut or flare fitting like I suspect, then replacement of the part is probably the only easy choice

Helicoils are nothing more than a wound spring . They will not hold a real torque. The only thing that is permanent, is "Thread/Time Cert" this is a hardened insert that is approved for aircraft, Rolls Royce, Ferrari and Porche. You need a kit which includes all the parts to do the job an oversize tap, and the installation tools. You then screw the hardened insert in using lock tight, when doing the installation you cut a chamfer into the top of the insert hole, chamfer tool included in kit. The insert has hardened grips on the underside of the insert which locks into the part that you are working on. It will not loosen or pull out. It rather straight forward and if done correctly you cannot pull it out like a Helicoil will.

WE have used these on cast iron and aluminum Engines manifolds and exotic housings that would have cost thousands to replace. The Thread/Time Certs are the correct answer.

We have used Thread Certs for over 20 years and never never had one fail. Spend the money do it right the 1st and only time. They have all US and metric threads in several different lengths. We recently saved an $8000.00 V-12 Volkswagen block using 3 thread/time certs. Might mention there was a 6 -8 month wait for a new block. We did the work and had the block back to the shop in 2 days.

Just sayin'
frontyboy.

My father had a saying, "there's never time to do it right BUT always time to do it over!!"

frontyboy wrote: ↑

Mon May 22, 2023 12:03 am

Helicoils are nothing more than a wound spring . They will not hold a real torque.

Years ago, every thread in every Pratt & Whitney turbo prop engine housing we made for them, had HeliCoils installed, from new.

Allison turbine helicopter engines used helicoils in magnesium cases.

The thread is available in time cert.
https://www.amazon.com/TIME-SERT-Inch-1 ... B0057OLYMC

John

Having worked in the Aerospace industry myself, building things like the Hand Controls for the Space shuttle (which contain helicoils), Minuteman Guidance Systems (which contain helicoils where the parts are not beryllium) and Howitzer-mounted navigation systems (which contain helicoils), I am always amused when some arm-chair engineer (cloaked in anonymity, no less) feels sufficiently informed as to make a statement along the lines of Helicoils "are just a wound spring and will not hold a torque". It is one thing to offer an honest opinion no matter how ill-informed, but quite another to offer that opinion in an attempt to try to sway someone away from using an excellent product. None of the above mentioned items live in a benign environment and all are subjected to G forces, Random Vibration and in general, stresses that boarder on the unimaginable or survivable. The genius simplicity and effectiveness of that "wound spring" is lost on folks who don't know what they don't know. Fortunately, one does not need to know how something works in order to successfully use it, so long as they are minimally able to follow directions.

I can’t think of where a 7/16-24 thread is used on a Model T but as far as Heli-Coils go I worked in the nuclear industry for over 30 years and can tell you that Helicoils will hold more then the original thread due to the design of the coil. We used them because torque specs could be increased giving a stronger hold where increased pressure was a problem.

I did heli coils for head bolts in the block after the threads were stripped and it’s working fantastic and took the proper torque just fine.

I have not used many heli coils but the 1's I did use, they sure did save some other wise ruined stuff.
I would think the space shuttle parts were made very precise with quality machines and taps and bits. Unlike a back yard guy with a 1/4 inch drill and a few cuss words. That may be a smart part of the failures people speak of.

Scott_Conger wrote: ↑

Sun May 21, 2023 8:57 pm

and here I thought that was just a typo...

if it is not a typo, well, 7/16-24 is ADMF British Admiralty Thread and absolutely no one is going to have a STI for it

so, it begs the question: what on earth has or had this thread?

if this is for a flare nut or flare fitting like I suspect, then replacement of the part is probably the only easy choice

I purchased the following from Langs: https://www.modeltford.com/item/3009CS.aspx

Every bolt there is a 24 thread

Scott_Conger wrote: ↑

Mon May 22, 2023 9:23 am

Having worked in the Aerospace industry myself, building things like the Hand Controls for the Space shuttle (which contain helicoils), Minuteman Guidance Systems (which contain helicoils where the parts are not beryllium) and Howitzer-mounted navigation systems (which contain helicoils), I am always amused when some arm-chair engineer (cloaked in anonymity, no less) feels sufficiently informed as to make a statement along the lines of Helicoils "are just a wound spring and will not hold a torque". It is one thing to offer an honest opinion no matter how ill-informed, but quite another to offer that opinion in an attempt to try to sway someone away from using an excellent product. None of the above mentioned items live in a benign environment and all are subjected to G forces, Random Vibration and in general, stresses that boarder on the unimaginable or survivable. The genius simplicity and effectiveness of that "wound spring" is lost on folks who don't know what they don't know. Fortunately, one does not need to know how something works in order to successfully use it, so long as they are minimally able to follow directions.

I've used them numerous times with great success. Even learned how to install a "time cert" (SP) when a previous owner totally screwed up a heli-coil installation on a corner head bolt for a Model T. I still run the heck out of my little 1915 T with the head cert installed. Have for MANY years.

John_Aldrich wrote: ↑

Mon May 22, 2023 5:55 pm

Scott_Conger wrote: ↑

Sun May 21, 2023 8:57 pm

and here I thought that was just a typo...

if it is not a typo, well, 7/16-24 is ADMF British Admiralty Thread and absolutely no one is going to have a STI for it

so, it begs the question: what on earth has or had this thread?

if this is for a flare nut or flare fitting like I suspect, then replacement of the part is probably the only easy choice

I purchased the following from Langs: https://www.modeltford.com/item/3009CS.aspx

Every bolt there is a 24 thread

ALL those bolts are 3/8" not 7/16" 3/8-24 is a common NF bolt.

John_Aldrich wrote: ↑

Mon May 22, 2023 5:55 pm

Scott_Conger wrote: ↑

Sun May 21, 2023 8:57 pm

and here I thought that was just a typo...

if it is not a typo, well, 7/16-24 is ADMF British Admiralty Thread and absolutely no one is going to have a STI for it

so, it begs the question: what on earth has or had this thread?

if this is for a flare nut or flare fitting like I suspect, then replacement of the part is probably the only easy choice

I purchased the following from Langs: https://www.modeltford.com/item/3009CS.aspx

Every bolt there is a 24 thread

These bolts are for the timing gear cover on my Canadian built 1927 Touring.

speedytinc wrote: ↑

Mon May 22, 2023 6:00 pm

John_Aldrich wrote: ↑

Mon May 22, 2023 5:55 pm

Scott_Conger wrote: ↑

Sun May 21, 2023 8:57 pm

and here I thought that was just a typo...

if it is not a typo, well, 7/16-24 is ADMF British Admiralty Thread and absolutely no one is going to have a STI for it

so, it begs the question: what on earth has or had this thread?

if this is for a flare nut or flare fitting like I suspect, then replacement of the part is probably the only easy choice

I purchased the following from Langs: https://www.modeltford.com/item/3009CS.aspx

Every bolt there is a 24 thread

ALL those bolts are 3/8" not 7/16" 3/8-24 is a common NF bolt.

You are right. My "Bad". Somewhere in the history of this car one hole was over-sized to 7/16.

Over the years I have repaired quite a few 1/2” npt spark plug holes with that specific Heli- Coil. Very successful!

John, you have the opportunity to bring that odd thread back to size. Thread serts are solid tubes. They come in varying wall thicknesses. They are fitted with standard sized drill bits.
I had a nice 1913 block where every head bolt hole was drilled out to take 1/2" studs. I drilled the holes and tapped them for the threads either, again with standard type taps.

The supplier should be able to advise you which threadsert to use and what drill bit and tap is used to install it.

Hope this helps.
Allan from down under.

Question is where on the "timing" cover the problem hole is.
Is there room for an insert? There isnt much meat available.