my spark plug holes are stripped, help

[wilderb]

so I bought a 79 620 and had not changed the plugs until today, when I want to change the plugs I instantly knew that something was wrong the num 1 plug had too much wiggle coming out, anyway it seems that the Num1,3,&4 plug threads are damaged, I was able to thread splugs in on the num 1 plug but was not able to tighten it plroperly, the third plug was able to go in but had too much wiggle up until the last few threads, the number 4 plug pulled some of the threads of when I took it out and had exesive wiggle also, so now I need to repair the spark plug holes on my L20 does anyone have any advice on how to do it? do I need to pull the head out or can I just fix the spark plug hole threads with the head on? also what is the best kit to use and does anyone here have one that I can use near los angeles?

 

I need to get my truck back on the road asap since it is my daly driver, please help

[Radim]

Helicoil or a thread chaser.

 

Don't install spark plugs when the engine is at operating temp, and don't thread the spark plugs in with the wrench, finger tight then 1/4th-1/2 of turn of the wrench usually does the job.

[wilderb]

Helicoil or a thread chaser.

 

Don't install spark plugs when the engine is at operating temp, and don't thread the spark plugs in with the wrench, finger tight then 1/4th-1/2 of turn of the wrench usually does the job.

 

 

I always thread the plugs in by hand and only tighten about 1/2 turns with whrench, I know from countles cars that I have worked on that I was not the one responsible one for the damage, but I will be responsible for fixing it so I want to do it right the first time.

 

so helicoil has a good kit?

[Radim]

Check this out, http://www.popularme.../repair/4212608

Would be best to just swap out the head, but don;t think it would be as cost/time effective.

[hobbes_the_cat]

I have used helicoils before and the work great, and hold real well, just follow the directions. I would be a little worried about doing it with the head on the block as small aluminum chunks might end up in the cylinders? maybe if your real careful it will be ok...

[leosnake]

If you are in Los Angeles...Call Jim 310-324-4446...He is the man! Helicoils are second rate compared to a Time sert!!

He is the person that Edelbrock, and so many others use for their repair on aluminum cylinder heads. He repaired a shoddy repair that was done (to my L20 U67 head) at a very high end motorsports rebuilder... to the point that you would never know it was damaged... :D

[Pacific coast Datsun]

I have the same issue on my #4 spark plug on my 620. I plan on drilling out, re tapping & inserting a Helicoil. I may do mine with the head on by bringing the #4 piston all the way up & vaccuming out the alluminum shavings. Another trick is to dip the drill bit in grease & drill slow. The shavings will stick to the grease for the most part. Auto zone has a "kit" that has everything you need except for the drill bit.

[Dguy210]

I have used helicoils before and the work great, and hold real well, just follow the directions. I would be a little worried about doing it with the head on the block as small aluminum chunks might end up in the cylinders? maybe if your real careful it will be ok...

 

Use a big glob of grease on the threads to catch the chips, go slow and clean and regrease often. A big zip tie with sticky tape can be used to probe/clean the cylinder of any chips you may have missed. Remember to clean off any grease when done.

 

Edit: Should have updated the thread before posting, I see P.C.D. already covered this.

Edited December 21, 2010 by Dguy210

[DanielC]

now, you can get anti-seize grease and put it on the spark plug threads. I used to as a matter of habit when putting the plugs back in a L-16, just pull the dipstick, wipe the oil on the end of the dipstick on the threads of the plug, and then put the plug back in, as mentioned, by hand.