Losing Compression: Another option besides a Helix Coil?

It seems as though I am missing most of my threads in my #2 spark plug hole on my inline six powerhead. I feel some air coming from that hole when the engine is on.<br /><br />I have heard that the best option is to put a helix coil in the hole. I am worried about doing this because there is still a little thread in the hole and I do not want pieces of metal falling into the cylinders when I am pounding in a coil. Is there another option that is safer than the coil?<br /><br />I have also heard about a teflon tape alternative. Is this a good idea? Any help is greatly appreciated.

Re: Losing Compression: Another option besides a Helix Coil?

Installing a Heli-coil involves drilling and tapping larger threads so as to screw the heli-coil in. Removal of the cylinder block cover is most likely required.

Re: Losing Compression: Another option besides a Helix Coil?

You can use a Helicoil Sav-A-Thread. They actually assume you have a couple threads left so that is can get a good grab to start. Use grease on the tap to catch the cuttings, and back it out often to clean them off. Make sure you have it aiming perfectly square, and take your time. You only get one chance.<br /><br />No drilling required. Just tap it larger, install the appropriate length insert with locktite and use the tool supplied to swage it outwards.<br /><br />The Merc inlines don't have a cylinder head to remove. To do it any other way means taking the complete powerhead apart. Teflon tape will not survive the combustion temperatures. <br /><br />My 2 cents. <br /><br />

Re: Losing Compression: Another option besides a Helix Coil?

I've done hunderds of the over the years just as AMD says never have had a problem. We do all of our racing engines with them because they are stonger than original

Re: Losing Compression: Another option besides a Helix Coil?

Cool. I've never seen those before!

Re: Losing Compression: Another option besides a Helix Coil?

Thank you very much for the advice. It is much appreciated!

Re: Losing Compression: Another option besides a Helix Coil?

Dood - what HP inline you got on that G3?<br /><br />-W (had a Merc 800 on a G3 once)

Re: Losing Compression: Another option besides a Helix Coil?

Time sert <br />Time sert also makes a pretty good spark plug insert setup. <br />I used these on my wife's expedition when it suddenly threw a spark plug out of the head last year and then again when it threw another this year. <br />Fix Or Repair Daily