Can't get #4 plug in.
 

I just changed plugs and all was well till I tried to get the new plug in #4. It goes in about 4 turns and then tightens up. It doesn't seem to be cross threaded, and when I take it back out the threads aren't buggered but seem to have carbon or something in them. I tried 3 different plugs and the same thing happens to each one. I'm able to clean the threads and they work perfectly well in #5 & 6. It seem to me that there is something in the cylinder threads. I tried to get a small toothbrush in to clean the cylinder threads but that didn't work.

It's getting late, a thunder storm is headed this way, and I can't push the car up the hill into the garage....damn. Why is there always one seemingly simple thing that gets screwed up? :mad: I'm going to have a beer and hopefully someone will have a good idea in the meantime.

Jim, try one of the old plugs. If that doesn't work try a known good new plug from jug 5 or 6. If that doesn't work, get a flashlight and a mirror and look down in the hole to make sure you haven't got something like a stray beru connector boot stuck in there or something. If that doesn't work, pull off the upper valve cover and REALLY take a look.

Whatever you do don't overtorque. Please tell me there arent some spiral looking grey metal chips on the plug. (threads!)

Good luck!

John,
No, it isn't galled and there are no metal shavings... it seems to be little black specks in the threads.?? Looks like carbon. I'm going to go back out and have another go, I'll try the flashlight and mirror.

Put the sparkplug in until it stops. Connect or not your choice.
Start it up and drive it in the garage.
Get a mirror and strong light after you take a break.
Was the previous plug in tight, maybe too tight?
Are we talking about your 356?
Do you install your own plugs?
Do you use oil, grease or anti-sieze on the plugs?
Use the Porsche tool tighten with one hand just snug. For you torque wrench types, not over 20 ft lbs.
Possible crossed threads or pulled threads.
Be very careful here. You don't want any further damage.
May need an engine drop or at least a partial drop to see what is happening.
Sorry to hear, but again be very careful.
Do not force anything.

Jim, rain is on the way, no hail I hope?. Did you coat the new plug with never seize? Any luck?

Oops,
You mentioned #5 and 6. not your 356. Must be "Sascha"

Ok, I give up for the night.

This is particularly frustrating as I just put in new Swepco, new brake fluid, adjusted the valves, new fuel filter, new cap and rotor, and saving one of the easier jobs for last....changing the plugs.....arrrrgh.

Ok, I got the car back in the garage. I couldn't see anything that looked weird with a mirror and light. I tried to put the plug that came out of that cylinder back in, and it does the same thing, about 4 revolutions and it tightens up. The plugs that I have tried in #4 aren't stripped, as they work fine in the other cylinders.

2.7RACER- no this is the 3.2, I didn't put any anti-seize or grease on initially, but put a dab of lithium grease on to try to chase the threads, it doesn't seem to be cross threaded, (seems like the cylinder threads have something in them, but where the hell it came from is a mystery). The previous plug wasn't installed by me, but it came out with no issues.

Any good way of clearing the threads?

Well, hopefully this will look better after a good nights sleep.

Get a spark plug tap and chase out the threads.

Yep, what ruf-porsche said. If the plug came out OK, without any AL on it, then likely the head threads have just got some carbon gunk on them. Get a tap and chase the threads with it and you should be good to go. Good luck,

ianc

I hope there's something like a spark plug thread chaser which is different than a tap. Put plenty of grease on the thread chaser to catch any alum bits as well as carbon. If a spec or two falls in the cylinder, I don't think that will harm anything. Don't tell Grady I said that ;)

thread chaser:

http://www.mytoolstore.com/kd/730.gif

When you finish with the thread chaser/tap, get the plug in start her. Let the engine run for about five minutes and then change the oil (just to make sure you get any metal bits out of the engine).

Jim,
Hopefully you are reading this Wednesday, after a good nights sleep.
Question. Is it possible #4 plug wasn't in all the way when you removed it?
Might explain carbon on the threads.

Doug,
I guess that it's possible, but it seems unlikely. Wouldn't the engine have a miss if the plug wasn't all the way in? And the junk on the threads seemed to be on the first four threads. I'm wondering if I got something on the plug threads as I was feeding the plug and socket down the black hole and now it's tranferred onto the cylinder head threads?

And is the spark plug tap something that I'm going to be able to get down in there without this getting a lot more invoved? I already feel pretty stupid, but if I have to drop the engine and open it up I will really feel like a dope.

Do exactly as Milt stated, with plenty of grease to hopefully catch anything that is dislodged or cleaned from the threads. Do NOT use a tap.

If you look at the thing, it fits into a deep socket. You can hold it there with some tape. Just make sure you're going in the hole correctly, which is at an angle. Do the one next to it to get the "feel."

If your a cheap sob like me take the old plug a copy the cut in the thread like the thread chaser thingy:)

Question. Why would you have to change the oil after chasing the spark plug threads?

If you get metal shavings in the oil from chasing a threaded hole in the combustion chamber you have a lot more problems then you want. Think about it!

Randy Jones
1971 911 "Iris"

Milt, that was the tool. It worked like a charm, thanks buddy I owe you.

And thanks to everyone for your suggestions and moral support. The lesson learned is stop when you're tired and don't try to rush the last few things on the list. :rolleyes:

So Jim, was it carbon? other? Did you catch anything in the grease on the chaser?

Good job! glad that worked out for you :)

-Chris

Chris, there were some very fine alum. particles in the grease the first time that I backed the thread cleaner out, after that nothing. I threaded it in and took it back out about 5 times, going deeper each time and cleaning the grease off and applying new grease each time that it came out.

I "think" what happened was that I got some of the crud that's around the outside of the spark plug hole on the threads of the new spark plug and when this stuff gummed up the threads and stopped the plug I used too much force to try to get the plug in, and in the course of removing and reinstalling the plug ( about 50 times ) I screwed up ( pun intended ) the threads. I surmise this because when I first took the plug back out, after it tightened up, there was all kinds of black junk on the threads of the plug.