Striped Thread in engine block

[electrarc]

Helping a friend replace the head on his Perkins diesel but 1 of the threads in the block for the head bolts is striped. 20 years ago I used a product called "Heli - Coil" to repair threads, but never in the situation. Ideas please.

Cheers

 

[evan price]

Helicoil works fine for this as long as you do them right. Obviously motor will need head off to get good access to the block. Make sure hole is clean and dry before setting the helicoil insert.

 

[Baby Grand]

Because of the very high tensile loads seen in diesel head bolts it is important that the new thread you tap for the HeliCoil goes in perpendicular to the head gasket surface. I would recomend not "free hand" drilling & tapping, but using some sort of drill jig or magnetic drill to ensure that this gets done right. A little time invested up front could save you from big headaches down the road.

 

[electrarc]

Helicoil works fine for this as long as you do them right. Obviously motor will need head off to get good access to the block. Make sure hole is clean and dry before setting the helicoil insert.

Evan,

Thank you, I will ensure that I do as you have suggested.

Cheers Zac

 

[electrarc]

Because of the very high tensile loads seen in diesel head bolts it is important that the new thread you tap for the HeliCoil goes in perpendicular to the head gasket surface. I would recomend not "free hand" drilling & tapping, but using some sort of drill jig or magnetic drill to ensure that this gets done right. A little time invested up front could save you from big headaches down the road.

Baby Grand,

Thank you, I am doing this down next to his dam, so I think a jig may be the way to go. Is this an item I can purchase as I don't think I can hire a magnetic drill in our town.

Cheers Zac

 

[BlacknTan]

A piece of rectangular steel bar stock with a hole for the tap drill and a slot for an adjacent bolt will do the trick. I would try for steel about 1" thick. Drill a hole the size of the Heli-Coil tap drill and center the jig over the hole needing repair. I would insert a drill the size of the tap drill for the existing threads and center it off that. Now you can use the drill motor of your choice. Another hole in the steel that just takes the diameter of the Heli-Coil tap would keep your threads perpindicular.
Heli-Coil makes coils in different lengths, so be aware.
Drive the insert about 3/4 turn below flush, and don't forget to break the tang at the bottom...

Hope this all makes sense ..

 

[dodge man]

You can "stack" heli coils also. You just put more than one insert in threaded hole. I've had good luck with helicoils, buts its been years since I used one.

 

[psj12]

Most tool rental places will have a magnetic drill press.

 

[jonyyuma]

I used helicoils in flatheads and aluminum intake manifolds with good success..Do they still not use a sealant on installing?

 

[Skyco]

Might want to check out the TimeSerts, many say they are superior to Helicoils.
Don't know never used them myself.

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