Problems Tapping/reaming new spark plug hole

[jquack]

For all of you who replied, I would like to say thanks. I really appreciate the time and effort you all took.

Combining what you all suggested I do, with what I COULD do, I abandoned the ratchet in favor of a drill on the very slow setting. I put the mower in a position where I could put some shoulder into it, lubed the crap out of the tap, went in straight very slowly, backing out frequently to lube and clean the tap and hole, and reamed new threads in less time than I thought it would take. All in all, following your advice, it turned out much easier than I expected. I cleaned everything thoroughly, and the insert went in without a burp. Now I'm just waiting for the loctite to dry, and I expect I'll be good to go.

Or have ruined my lawnmower for good. The jury's still out. I'll let you know tomorrow.

J

 

[pickateer]

I've used those kits many times to repair VW engines with 100% success Most people buy Champion plugs but the problem with these plugs finds the thread in not rolled into an Apex shape, but simply has a very sharp peak at the end. This along with not clearing out the carbon in the plug tread on the engine results in blowing plugs out at a later time. Now here's the challenge, put a vacuum hose on the exhaust pipe and as someone suggested use a T drive and put pressure on the tool to bite into the plug opening. Once the new tread is cut then blow out the cylinder with compressed air. Then carefully and SLOWLY turn the engine over to ensure all the cutting chips have been removed. If the engine stops while slowing turning, then back it up, spray in carb cleaner and repeat the process until the engine turns freely. The install an NGK plug and TORQUE it in at 15 to 20 foot pounds, and use a torque wrench every time

 

[pickateer]

One more thing do not put anti-seize or anything else on the plug thread since this will result in the plug being over torqued and stress the threads in the plug bore

 

[905sharpie]

I had a spark plug blow out of the engine, damaging the threads. I've got a combination tap/reamer that's supposed to remove the old threads, and cut new ones, so I can screw/loctite an insert into the new threads to hold the spark plug. I watched a few videos that make it seem pretty straightforward and simple; the tap engages the existing threads, and the torque applied to the ratchet removes them and cuts new ones.

The problem I'm having is that the tap doesn't seem to be engaging the threads. It's cut most of them out, but that seems due to inward pressure I applied to the ratchet in an attempt to engage the threads as opposed to the threads themselves engaging, and the reamer doesn't seem to be getting any purchase to cut new threads. Now all I'm really doing is just spinning the tap without any real result.

I don't know if I've got the wrong tap/reamer, used it incorrectly, didn't realize how much pressure the guys in the videos were applying, or what.

Any help or advice would be very much appreciated.

Worst case is you go to a local dealer that has scrap lawnmowers and get a used head and a new head gasket I'd possible. Tecumseh has been out of business for many years now and parts are getting hard to find. I might even have a old head leftover my from my repair days.

 

[Caregiver5354]

this is pretty much what it looks like. it's an OEM TOOLS 14mm Spark Plug Rethreader Kit.

 

[mystic240]

Is the head removed? Unless the spark plug is over the piston
I don’t think there is room for the tap.

 

[Caregiver5354]

One more thing do not put anti-seize or anything else on the plug thread since this will result in the plug being over torqued and stress the threads in the plug bore

Looking at your picture of the tool you have there your missing the drill bit that should of come with that tap and the replacement threads. It is a kit usually. You need the drill bit that is the correct size for that tap. You should first drill the spark plug hole with the bit which will leave the hole a perfect size for the tap.

 

[pickateer]

What I saw in the photo was a standard KD kit 2126 14 MM Spark Plug repair kit

 

[Caregiver5354]

What I saw in the photo was a standard KD kit 2126 14 MM Spark Plug repair kit

View attachment 56723

On every kit that I have used came with a drill bit. The drill bit sizes the hole for the tap.

 

[pickateer]

That kit has a combination reamer and tap and does not need a drill bit - 50 years in the business and never bought one with a drill bit, does not mean to say the KD kits never included a drillbit