Stripped spark plug hole...I think

navy_chopper · Post by **navy_chopper** » 19 Sep 2007, 20:15

Just bought a 96 850 turbo wagon shows 127k but odo stopped-typical. Long time volvo guy, 1800's etc/ Tuning the 850 up for first step in trying to get rid of #2 cyl misfire code. As I was trying to get the #2 plug out, it got tighter as it unscrewed. I assume stripped hole so I stopped so as to not break it. tightened it back down so I can drive it in the morning.

I need to get the tune up done, but whats the best way to fix that stripped hole if it is stripped> Heli-coil? I didnt want to force it and crack the plug. Any other ideas or tips?

Site is great by the way, I wish I had this when I was in college driving my 144E and 69 p1800s.

Post by **MadeInJapan** » 19 Sep 2007, 20:39

Have heard good things about the Heli-coil...others have used it in these cars with success. Strange that this has happened. Take it to a good mechanic who has the equipment and the heli-coil kit to re-do the plug hole if it's necessary.

navy_chopper · Post by **navy_chopper** » 19 Sep 2007, 20:45

The fact that the plug that came out of #1 was an "autolite" tells me about the person who may have stripped this. You wouldnt force it out would you?

Post by **MadeInJapan** » 19 Sep 2007, 21:16

Like I said, I would have a good mechanic deal with it...yeah, I would avoid Autolite's in our cars. I personally use Volvo plugs but even plain copper Bosch plugs gapped correctly (even for turbo) are much better.

Post by **Ozark Lee** » 19 Sep 2007, 21:49

I'm reading this and saying - in my best Scoobie Doo voice -"Ruh Row". Helicoils work great but it is nearly impossible to tap out the old thread for the new helicoil without dropping the shavings into the cylinder.

In a variation of the popular vernacular, "That is a bad thing."

I'd be inclined to see if I could line the plug back up and drive the crossthread back out to normal. You have about a 1 in 10 chance of it working but if it doesn't work don't sweat it - the head was coming off anyway.

...Lee

chuckcintron · Post by **chuckcintron** » 20 Sep 2007, 06:05

Lee, that's why we have Compressed Air

I'm a bit more of a risk taker, but I would just chuck up my spark plug socket into the old air wrench and hold the trigger down until either the plug came out or I had a nice "ported and polished" spark plug hole.

Tap...shop vac and/or compressed air...helicoil...new plug...everyone walks away safe.

Just MHO...

-Chuck

dripcandles · Post by **dripcandles** » 20 Sep 2007, 20:32

I was once told that if you have to retap a spark plug hole that you fill the cylinder with foamy shaving cream, retap it, then vacuum out the shavings. I never did it, but it sounds logical.

navy_chopper · Post by **navy_chopper** » 22 Sep 2007, 05:12

Went to a cylinder head shop. The guy said to spray some liquid wrench down there at night, let it sit until the morning to ensure the engine is cold, not just cool. I backed the plug out until the resistance I felt before and then a little more. Sprayed a little more LW, tightend it back, let it sit for a while then back it all the way out. Autolites, garbage wires, rotor and distrubutor gone; OEM stuff in--car running 4.0. Hopefully I will be able to clear codes. Thanks everyone.

Post by **MadeInJapan** » 22 Sep 2007, 08:18

Glad you got the resistant plug out and new stuff back in...I'll keep my fingers crossed for you!

Volgrrr · Post by **Volgrrr** » 26 Sep 2007, 00:17

With respect to Helicoils - I had to insert some into a Humber Super Snipe I had many years ago.

I was advised to use heavy grease to trap the aluminium swarf - and it worked just fine.