Torqueing a helicoil

CNKS · Nov 30, 2014

I need to put a helicoil in a stripped block hole for my tractor engine head. Torque for the Farmall Super M head is 113 ft lbs. Is there going to be a problem here such as the helicoil turning while torqueing? I'm guessing that for only one stud I could get by with 80 lbs?

kub6040 · Nov 30, 2014

My opinion if it want hold the pressure before you crank it it will give problems later, others my dare to ride the edge but a head bolt has caused me grief before.

glennster · Nov 30, 2014

I'd locktite the stud into the helicoil, let it set a day before torquing the head.

rhtx55 · Nov 30, 2014

They bottom out when turning clockwise, once installed with green Loctite retaining compound, as stated above, let sit for 24 hours & install head stud & torque as always.

Janicholson · Nov 30, 2014

If in doubt, the coil can be locktited into the block. I would just torque it to spec. I do it all the time Jim

CharlieNJ · Nov 30, 2014

Four years ago we were putting a basket case Farmall A back together when we noticed a head stud coming up as we torqued it. Those studs are 1/2". So, we put a Heli-Coil in. Well, using a hand drill the hole did not go down straight. The top of that long stud was out of line enough that we could not get the gasket on. So, we heated the bottom of the stud till red, and tapped it back in line. Torqued the head to 80 lbs. no problem. There are a lot of hours on that old A since then with no problem. Heli-Coils are plenty strong. Had an old pressure that vibrated three bolts threads out of the pumps head. Heli-Coiled those too, so far so good. So, drill straight!

CNKS · Nov 30, 2014

Thanks to everyone, I thought it would be ok, but 113 ft lbs is the highest of the letter series row crops. Sometimes I don't think much about what I'm doing and mess something up. This all started when I forgot that the studs above the water jacket go into water, and I twisted it off--of course below the top of the block, and I messed up the hole and threads. A machinest "fixed" it but did not use a helicoil or enlarge the hole. He rethreaded it with a 1/2 inch tap and said it was ok. It wasn't, the threads didn't hold.

Phil Tibbetts · Dec 1, 2014

Worked as a machinist for 40+ years and installed lot of heli-coils. There is no need to use locktite. The design of the coil is such that the harder you pull on the thread the tighter it grips the walls. That is why they have the little tab on the bottom to install them. It slightly collapses the heli-coil.

Torqueing a helicoil

CNKS

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kub6040

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glennster

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rhtx55

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Janicholson

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CharlieNJ

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CNKS

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Phil Tibbetts

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