Spark Plug Blew Out of Hole

[HarryD]

First, I know, minimal P-Car content but you guys are SO helpful.

My 1970 VW (you know the car that traces it's ancestry to Dr Porsche) Bus (an early Cayenne) had the #1 plug blow out of it's hole.

There was no foreign material on the plug threads.

When I performed my road side fix, it went in about a turn or so and got very tight. I reinstalled the wires lead and started it up and drove home. I was able to get home without it blowing out again.

I know the "best" way to address this issue is to intall a Timecert.

I am thinking that since there was no head material on the plug, it may have worked it's way loose and the difficulty in threading it in may be due to carbon buildup instead of galled/damaged threads.

Does it make sense to try brushing the thread with a wire brush and using thread chaser to clean them up instead of immediately jumping to a timesert?

[James Brown]

sure does harry, try the least invasive fix first. i think there was a thread (no pun) on here about that same thing. it just unscrewed itself from the cylinder (going from positive to negative pressure).

[larrym]

just get the re-threadtool & insert kit - multiple sources on eBay etc

prices all over the maop - so shop carefully - they are all the same

I get mine at Bugformance

[skinnerd]

Harry...you had my imagination on redline with that one!

What hole? Etc, etc.
:-)

[Jcslocum]

As the plug probably unscrewed, it blew out when engaged with the first thread or two and caused some damage there. Chasing the thread is probably best and least invasive. You can coat the chaser with grease to keep any metal bits from dropping into the cylinder.

Good luck!

[HarryD]

Originally Posted by skinnerd

Harry...you had my imagination on redline with that one!

What hole? Etc, etc.
:-)

Poor bus engine, even at redline the fun factor is not what you think....

Just lost #1 plug.

Turns out, if you try to put the plug in a hot engine, the expansion of the aluminium head is such that the plug cannot go in very far.

This morning with a cold engine, it took out the plug (barely hanging in) and put some copper antiseize on the threads and threaded it in by hand. Went in with no drama, tightened it up and took a brief drive.

No drama not problem.

[HarryD]

And now .. the last thread gave up the ghost and the plug popped out.

Sigh ... time for a timesert.

[steve911T]

Good luck with the repair. My twin brother and I both had brand new 70 VW's. His blew a plug out at about 40k, no reason known or given ( fix was a timesert or whatever it was called back then) and my VW ran great until I sold it and got a 356. It was kind of a known problem back then. Good luck Steve

[azzarule]

Had the same problem with our 70 VW bug, had to put in an insert and a few thousand miles later, had another problem:



I think that the problem with the plug and misfire, had bent the exhaust valve stem and eventually it crapped out into the cylinder; fixed now, upgraded type three motor , and rhino gearbox, goes like the clappers now,