Spark plug stripped thread on head

[Dutch RR]

Hello again folks,

I had a issue with one of the plug threads on the head (somebody had over tightened and stripped the thread for one of the spark plugs,

After contacting several so called repair people, (all stated that the head would have to come off) for repair.

I finaly found one person with a full jig that could repair (rethread and place new insert) in situe.

Total cost was around 80€, against around 1000€ for the removal and refitting of the head.

Cheers Dutch RR

 

[Northern Irelander]

You wouldnt want any swarf going into the cylinder, would scratch it to pot.

All you need is a 3/8 socket to fit on the tap and long extension bar to reach into the head.

 

[ianda12]

If its stripped the thread, its no good trying to re-tap it as the metal isn't there anymore, you need to heli-coil it.

 

[david451]

If its stripped the thread, its no good trying to re-tap it as the metal isn't there anymore, you need to heli-coil it.

Yes you get kits to do this specifically for spark plugs, snap on tools do them, not so much a helicoil as an insert.

Have done a couple myself and if you coat the tap with grease it catches most of the crap, keep the cylinder just low enough to miss the tap then bring it back up to tdc and podger any other **** out with a greasy bit of rag on a welding rod.

 

[Dutch RR]

Hello Folks the point of posting this item was to inform people that it can be done.

The jig assembly used placed the cutting tool within 1/100 mm of the hole,

Swarf issues, alloy, starting the engine with plug out flung most of crap out,

The main point to watch was any open valves in the way of the cutter,

Over a week now and no reported issues with the new Insert

Regards Dutch RR

 

[david451]

Hello Folks the point of posting this item was to inform people that it can be done.

The jig assembly used placed the cutting tool within 1/100 mm of the hole,

Swarf issues, alloy, starting the engine with plug out flung most of crap out,

The main point to watch was any open valves in the way of the cutter,

Over a week now and no reported issues with the new Insert

Regards Dutch RR

Just need to watch now when you take the spark plug out, it's not un-common for the insert to come out as well, make that spark plug the one you coat with anti sieze grease "hi temp."

If you set your engine up on tdc then turn it back a bit you will always miss the valves, spinning your engine over is a bad idea as it can place metal between the valve and seat and cause it to drop a valve, or on a diesel bend it because they are so close to the pistons, always recomend you get all the big **** out first.

I dropped a washer once from a rocker cover down the carb and the bastid welded it's self to the seat, had to take the head off, main dealer as well and I got pelters. Had I known it went down the carb, well murphys law aint it miles away from the carb as well and it commited suicide down the fooking carb.