I am giving the GL a tune up on this fine raint day and I wentto autozone I wanted NKG but they only had Densos.

 

Ok so I purchased Denso U groves and on the passenger side I am having trouble telling if the barrel of the plug is to big or if there is some problem with the threading either on my new plugs or exsisting in the engine. Its very difficult to see if the barrel is getting in the way or the threads. I noticed that removing the old NKGs had more turns to take it out and when compared to the other side, the drivers side (new) plugs are in much further.

 

So I hope someone has installed these or attempted to.

 

I

I don't know about your specific spark plugs, but I've had messed up spark plug threads before. Try putting the old plug back to see if you have the same problem, and if you do, you will need to fix the threads. You can get a thread chaser for spark plug holes (very common in old aluminum heads) that is just basically a tap you use with a spark plug wrench. If that doesn't work, you might need to take more drastic measures (a helicoil), but if nothing serious happened to the threads, that will probably fix it.

Its very easy to cross thread the spark plugs. Make sure you're putting them in at the proper angle, they don't go in straight (one side kinda points forward, the other kinda backward).

Don't know if it helps any but I've always used anti-sieze on spark plugs in aluminum heads.

i've had 2 subes with a crossed thread plug. My XT6 had one and when i got it it was in half way and pointed straight while the others were all slanted slightly. My GL wagon had one like that also. Took a long time to clear the carbon off the threads on the holes which prevents the plug from threading in all the way. 2 different thread chasers didn't help much either.

 

Penetrating oil eventually loosened the carbon enough for the plug to go in all the way and seat the plug against the head. Took about a month of periodic retries. The trick for me was getting the plug to match the angle of the others that weren't xthreaded. That's the only way to find the factory threading which were coated with baked on layer of carbon.

 

Wayne

Thanks guys.

 

I tried the old plugs and they wentin further however I did notice two slivers of aluminum when I attempted installing the new plugs which concerned me.

 

If I retap them what about the alum. shavings? Will it cause harm if any fall in? I figure if I am only retapping there will be a minimal amount.

 

Thanks,

John

Coat the tap with grease and the shavings will stick to it instead of falling in.

make sure to get a good spark plug thread chaser too, and dont use a normal tap.. i dont know if the taper from a normal tap would be wise or not, but the spark plug gapper tool is easier to line up like the spark plugs anyhow..