2fastfu

How bad is it if a spark plug is not screwed in all the way? The threads got stripped and the plug won't screw all the way in. It's about a 1/8 inch short visually from going all the way in compared to other plugs.

It idles and feels the same and no codes are coming up. Is it ok? Or should I rethread it or helicoil it?

Ferocious C6

Do it right.

2fastfu

what right?

njfl

If you can see the difference between it and the other plugs, it is too much. Over time, with heating/cooling cycles, it will develop a leak. Rethread it.

Ferocious C6

If you screwed it up, fix it. You screwed it up, so fix it.

sammyv

It will eventually blow out!

MachAll 2005

The plug depends on the correct fit (threads and tapered seat) and torque to transfer its heat to the cylinder head ... if it isn't installed correctly, you will likely experience detonation under heavy load...

Bottom Line ---- fix it.

AIR_RAM

One thing is for sure... If you dont fix it... you will NOT be able to back up your Screen name; "2fastfu" and will need to change it to "2SloFu" or "2Brokfu" ...

All kidding aside, yes you should repair the threads... hopefully it can be done with the heads still on the engine... worst case, pull the head and do it right. Im willing to bet you can chase the threads with a tap and be done with it.

Good luck

SPEED SAFE, AIR RAM

haljensen

Are you positive it's stripped? If it threaded in and then stopped the chances are just as good that the plug itself is assembled wrong (too long a threaded portion, porcelin insulation in the wrong position, too long of a core, etc).

Can you remove it without damaging anything further? Maybe pull that plug and compare it to a new stock plug?

2fastfu

I can easily remove it I did 3-4 times already its just hard gettting it to the 7/8ths a point where last little won't screw in. It just stops to where I know if I tighten harder something will break so I stop. I'm going to fix no matter what. What's tbs very best way? Helicoil, timesert, or just clean threads with a tool since it does go in all the way in n.out no problem?

AIR_RAM

Have you attempted to use a torque wrench? I would try that... i cant see how you could possible strip the END of the hole... Remove the plug and spray some WD40 or any liquid wrench type liquid... then run an old USED known good plug into the hole.... Using a torque wrench, tighten it till it torques.

If that dont work...

I would take a bolt (or used Plug) with the same thread pitch and then run a slot down it with a dremal... then run that into the plug hole a few times... the slot will remove and catch any crud thats blocking the threads... Kind of like a tap but not really... just a thread chaser...

AND YES it will make a difference. Plug placement is important for optimal performance... I would bet money that the gains lost would be however minimal but still measurable.

After using the WD or penatrating oil... be sure to run several squirts of motor oil into the cylinder through the plug hole... we dont want any dry cyiliders on start up...

SPEED SAFE, AIR RAM

Good Luck...

HOXXOH

If you cross threaded it from the beginning, it'll never seat correctly, since the plug is not aligned on the original axis. From your explanation that it takes more force the farther you attempt to insert it, cross threading is the usual explanation. It sounds like you've put this plug in and out several times already, so you've damaged threads for most of their length. Running a tap through won't be able to find the original threads anymore and will only cut the last couple of threads that are currently the reason the plug won't go in all the way. If you continue on that path, the plug won't fully seat to dissipate heat and you'll eventually melt the threads and blow out the plug. That will destroy the head and if you're lucky, nothing else.

The only real way to repair it, is to pull the head, bore the hole on the original axis, and rethread to install a helicoil. It's not a job you can do at home, so send it to a good shop like WCCH. They'll know exactly how to fix it to avoid any future problem.

When installing plugs, run them in at least 3 full turns with your fingers before you even pick up a wrench.

GOLD72

True for most anything threaded. If you can't give it several turns with your fingers, something is wrong and wrenching is going to make it worse.

torquetube

If it's sticking up 1/8" then it's not seated and there is no seal. You've got to fix it.

These engines will run with loose plugs and not throw codes, but they don't run well.

94ltz

Use a reverse tap, not a thread chaser. They go in the hole and you tighten the center to bring it out and back it out bringing all the shavings with you. I have used one in a LT1 head still in the car, believe summit sells them

VET4LES

Most auto parts stores sell a spark plug (tap, chaser, thread cleaner, or what ever your want to call it). I have one that I used on an old Mercedes with an aluminum head. It had a stripped plug and it worked fine. I drove it another 30,000 miles.

2fastfu

I am going to take the heads off this week and let the machine shop fix it. Koerner racing engines in tucson is doing it. Jeff said it will be a simple fix of $30-40 most out the door if he needs to rethread it. He is also going to check my ptv clearance check for free and clean up the other threads since I am going to have heads milled at the same time along with a back cut on the valves, and and performance valve job. I might as well get some more performnce of out of the heads while there off!

Ferocious C6

Why not just get the heads ported and polished while you're at it?

2fastfu

the heads I purchased are cncd ported from summit racing. Jeff is just going to do some touch up work on heads like blending things better,making everything the escat same lentgh,etc etc, simular to what TEA offers to get the absolute most out of the heads. My TF 225cnc heads only flowed 309cfm @600lift out of the box on a bench test. The paper they had said they flowed 332 @600 lift which was a bunch of BS! He said we should be able to get them to 330+cfm @600lift for around $300-400 total and guareentees it or I dont pay. SO i took him up on his offer. Apprently the guy has done some work for a few NHRA guys who had records set at las vegas and other stuff so I'm confident he will.

Ferocious C6

Set records at Las Vegas? I didn't think was possible, with how ****** the track prep usually is.