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Helicoil error, no compression

Posted: Sun Feb 04, 2018 12:51 pm
by cleverusername
I had to helicoil number one spark plug and I did it slightly off square. This means no compression cylinder one, because I can't torque the plug down. Too many turns and the socket gets stuck.

I am hoping that an extra long socket will let me torque it enough. Otherwise one dumb mistake may have trashed the head.

Happy days.

Mark....

Posted: Sun Feb 04, 2018 2:36 pm
by sprint95m
If you were to remove the rocker cover and the No. 1 cylinder spark plug tube
would that give sufficient space for the socket?



Ian.

Re: Helicoil error, no compression

Posted: Sun Feb 04, 2018 4:37 pm
by soe8m
Conical seat. Off square and it will never seat and seal. Maybe you can try another type plug what seals with a ring. Not ideal but a bit more forgiven.

Jeroen

Re: Helicoil error, no compression

Posted: Sun Feb 04, 2018 5:58 pm
by cleverusername
soe8m wrote: Sun Feb 04, 2018 4:37 pm Conical seat. Off square and it will never seat and seal. Maybe you can try another type plug what seals with a ring. Not ideal but a bit more forgiven.

Jeroen
Yep, I guessed that. Of course when I did it I thought the thread were the gas seal.

Re: Helicoil error, no compression

Posted: Mon Feb 05, 2018 7:30 am
by Magenta Auto Sprint
There are two types of heli-coil kit, one is a proper circular plug with a flared top and the other cheaper one looks like a coil of wire; which one did you use?

The first one uses a tap that picks up on the old thread and guides it till the larger new thread starts to cut and then leaves a small counter sink for the heli-coil to seat in, so it should all be reasonably square.

I would think that the head could still be saved.

Malcolm