240sx SOHC spark plug won't line up.

[xKnownShadowX]

Today I bought four new NGK R spark plugs. The car had four Autolite spark plugs in it which I don't think are good?

Anyways I take out the first spark plug and it cracked as it was coming out. I then proceeded to putting the NGK in but for some reason it would go in 2-3 turns and get stiff. I looked at it and it wasn't lining up in the circle around it. I took it out and tried again but failed. I took spark plug 2, 3, & 4 out, which all went in with no hassle. I try again in the first one and this time I go slow. I also applied that grease thing (silver cream or something) which I forget what it's called. Then I turn it 2 turns and it gets really really hard. It was lining up so I proceeded to do until it was on like the others. Put everything back and cranked the car up for like 30 seconds. Took spark plug #2 out and it had a light carbon coat and there was white smoke coming out the tail pipe when I revved it which I think should be normal when replacing plugs. Took number one out and then the plastic part of the Spark plug cracked so I continued to remove and was really stiff. I dunno if the threads are all jacked up any idea?

This car has been a headache since the previous owner never told me he had a lifter problem and never told me he swapped the motor with an SR then a KA which I dunno if it's original.

Patience shall be my friend.

[rioredstang]

Go to the auto parts store and see if they have a thread chaser. Carefully line it up and clean the threads. Use some pentitrating oil while using it. This should do the trick.

[xKnownShadowX]

Thread chaser?Alright and would PB blaster be okay?

[rioredstang]

Yes, PB Blaster would do fine. Crank the engine over a few times after cleaning to blow any trash out of the cylinders.