Problems Tapping/reaming new spark plug hole

[ltcsloan@hotmail.com]

Also, make sure the piston is down so that the tap does not touch the top of the piston and stop the downward movement of the tap.

 

[gamma_ray]

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.

Does the piston happen to be TDC? It's entirely possible it's keeping the end of the tap from going far enough to start threads.

In college I had a VW Beetle and had to install a couple of these. Before starting to cut, I would turn the crankshaft to the exhaust stroke of that cylinder (exhaust valves open) and piston down, so any aluminum slivers could be blown out with compressed air.

 

[purse]

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.

You Need a spark plug Helicoil repair kit . You also need the plug size when you purchase the helicoil kit. comes with the tap , insert and the tool to install . Never had any luck with a thread insert they usually pull out when you take out the plug.

 

[Joed756]

I would never do this with the head on the engine. Buy a new head gasket and do this job with the head clamped to a bench. You really don't want to have even one little chip of metal roaming around in there.

 

[MGT01]

At the risk of asking the obvious is the piston at the bottom of the stroke and out of the way of the tap? in my experience soft aluminum does not resist sharp hard steel without a good reason. I also second the recommendation of using grease on the tap to catch the cuttings. Hope that helps.

 

[jquack]

After I let the loctite cure for the full 24 hours, I cranked that sucker right up, and it ran like a champ! I'm going to change the oil, and get to work!

thanks for all your suggestions and help. I can't tell you how much I appreciate it!

 

[sparkplug55]

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.

Make sure piston is down so tool does not hit the top of piston and grease tool with wheel bearing grease to catch shavings. If available blow out hole with compressed air.