NewbVetteGuy

Help again!

I installed my spark plugs into my heads yesterday to be able to mark off the sharp thread that extend into the chamber further than the plugs, but I've got one spark plug that just isn't screwing in correctly; it's getting fairly scarily tight with a good 4 turns to go so I don't want to keep tightening it in and screwup the aluminum threads.

I think what I need is a thread chaser but I'm not clearly on exactly what size or what details I need to get the right thread chaser...


Here's my exact heads: http://www.jegs.com/i/JEGS-Performan...14032/10002/-1


Jegs says to use spark plugs that are: 14mm x 3/4" Reach - Gasket Seat - 5/8" Hex

They're the Profiler heads so I followed Profiler's recommendation of using NGK R5671A-7.




Thanks,


Adam

NewbVetteGuy

Ok jegs says to just use a 14mm thread chaser with some oil on it and then be sure to install the spark plugs with anti-seize- sound right?


Adam

Metalhead140

Sounds fair to me - its what I would do.

REELAV8R

Yes, sounds right. I would investigate as to why it's not screwing in though. Is the plug cross threaded? Are the threads not cut all the way in the hole? etc.

It would also make me question other items that may not be correct on the head as threading a spark plug hole is pretty straight forward.

If it's an assembled head. Take it apart and check stuff out. Valve seats, valve guide clearances, etc. It's a whole lot easier now than a problem will be later.

Kevova

They make specific thread chasers for spark plugs as opposed to a tap. A little bit of grease instead of light oil can catch metal chips that may break loose. Tighten and loosen thread chaser 1/4-1/2 turn at a time.

Big2Bird

Is it in the car, or on the bench, or???

NeverTooOld

Lisle Tools sell the double-ended 14 mm/18 mm thread chasers for about $10. I just bought one about 2 months ago.

Grumpy 427

Shitty to find that out after you install them.

sunflower 1972

I made sure I chased EVERY threaded hole, including the spark plugs, before I installed my aluminum heads.

Metalhead140

I thought it safe to assume from his post that they aren't installed yet - he's talking about touching up the chambers.

sunflower 1972

Yea, just reread his post. My reading comprehension is none to good!

calwldlife

I missed the brand of head!
sucks that one hole needs work.
Good luck with the fix

derekderek

the Jegs ad does not mention the brand.

theandies

I always use anti-seize on my plugs because of the dissimilar metals (I have AL heads). It's just an old aircraft mechanic thing. Keep in mind if you use copper based anti-seize don't get any on the electrode or it could short out the plug keeping it from firing. Don't ask me how I know......

slofut

If that's a new unused aluminum head I'd be sending it back I think. If it's used, chase it carefully a few times and silver never seize always.

Jeff_Keryk

When changing plugs I spray a little WD-40 into the plug hole to clean the threads. It also lubricates. It has made a big difference in many cases. I always use a little anti-seize on the plugs. Any fastener that cannot be threaded in by hand has an issue that must be accounted for.

NewbVetteGuy

I tried to go to Harbor Freight and pick up a thread chaser yesterday but they didn't have one- I'd have to buy a whole tap and die set, which I didn't want.

Found the Lisle 20200 thread chaser on Amazon for $7.09 and free shipping.


The heads are Profiler Heads that are rebranded and assembled by Jegs with hardware of their choosing. I bought them LAST Christmas and have just been accumulating all the other stuff for my build so I just bought the spark plugs last week or so and tried to install them now.

They are not on the motor.


I'm hoping that the thread chaser does the job.

Anyone have any recommendations for someone who's never used a thread chaser before? I just use a socket wrench, put some oil on the thread chaser and threads, and then screw it in 2/3ds of a rotation, then unscrew it, then screw it in 4/3rds, then unscrew it, then 2 full rotations, and just continue until I've chased all the threads, right?

-Then just make sure I clean it out real good to remove any fillings and try the spark plugs again (being sure to use anti-seize when I install them for real).



Adam

redvetracr

as far as anti-seize on the spark plug threads less is better, you don`t have to coat the threads.

NeverTooOld

If it is just one spark plug that won't screw in it could be a nicked thread on THAT spark plug. It makes more sense the spark plug threads got damaged than the threads in the cylinder head.

76strokervette

Make sure you start the thread chaser by hand and when it starts to get tight back out a turn and add oil. Thread chasers should not generate chips so if thread is not all the way thru you may need a tap.
Just as an fyi the end holes on Pro-filer heads are threaded with a form tap which is what you will want to use if you want them deeper.
Aluminum tap magic is a good tapping fluid if need to use a tap and will work well with the thread chaser.
Dave